Federal Register, Volume 74 Issue 128 (Tuesday, July 7, 2009)

[Federal Register Volume 74, Number 128 (Tuesday, July 7, 2009)]
[Proposed Rules]
[Pages 32352-32387]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-15828]

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Part V

Department of the Interior

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Fish and Wildlife Service

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50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 12-Month Finding on a
Petition To List a Distinct Population Segment of the Roundtail Chub
(Gila robusta) in the Lower Colorado River Basin; Proposed Rule

Federal Register / Vol. 74, No. 128 / Tuesday, July 7, 2009 /
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R2-ES-2009-0004; MO 92210530083-B2]

Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List a Distinct Population Segment of the Roundtail
Chub (Gila robusta) in the Lower Colorado River Basin

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
12-month finding on a petition to list a distinct population segment
(DPS) of the roundtail chub (Gila robusta) in the lower Colorado River
basin as endangered or threatened under the Endangered Species Act of
1973, as amended (Act). The petition also asked the Service to
designate critical habitat. After review of all available scientific
and commercial information, we find that the petitioned listing action
is warranted, but precluded by higher priority actions to amend the
Lists of Endangered and Threatened Wildlife and Plants. Upon
publication of this 12-month petition finding, this species will be
added to our candidate species list. We will develop a proposed rule to
list this population segment of the roundtail chub pursuant to our
Listing Priority System. Any determinations on critical habitat will be
made at that time.

DATES: The finding announced in this document was made on July 7, 2009.

ADDRESSES: This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R2-ES-2009-0004. Supporting
documentation we used in preparing this finding is available for public
inspection, by appointment, during normal business hours at the U.S.
Fish and Wildlife Service, Arizona Ecological Services Office, 2321
West Royal Palm Road, Suite 103, Phoenix, AZ 85021-4951. Please submit
any new information, materials, comments, or questions concerning this
finding to the above address.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor,
Arizona Ecological Services Office (see ADDRESSES), telephone 602-242-
0210. If you use a telecommunications device for the deaf (TDD), please
call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.) requires
that, for any petition to revise the Lists of Endangered and Threatened
Wildlife and Plants that contains substantial scientific or commercial
information that the action may be warranted, we make a finding within
12 months of the date of the receipt of the petition on whether the
petitioned action is: (a) Not warranted, (b) warranted, or (c)
warranted but the immediate proposal of a regulation implementing the
petitioned action is precluded by other pending proposals to determine
whether species are threatened or endangered, and expeditious progress
is being made to add or remove qualified species from the Lists of
Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of
the Act requires that we treat a petition for which the requested
action is found to be warranted but precluded as though resubmitted on
the date of such finding, that is, requiring a subsequent finding to be
made within 12 months. We must publish these 12-month findings in the
Federal Register.

Previous Federal Actions

In 1985, the roundtail chub (Gila robusta) was placed on the list
of candidate species as a category 2 species (50 FR 37958). Category 2
species were those for which existing information indicated that
listing was possibly appropriate, but for which substantial supporting
biological data were lacking. Due to lack of funding to gather existing
information on the roundtail chub, the species remained in category 2
through the 1989 (54 FR 554), 1991 (56 FR 58804) and 1994 (59 FR 58982)
candidate notices of review. In the 1996 candidate notice of review (61
FR 7596), category 2 was eliminated, and roundtail chub no longer had
formal status under the candidate identification system.
On April 14, 2003, we received a petition from the Center for
Biological Diversity requesting that we list a DPS of the roundtail
chub (Gila robusta) in the lower Colorado River basin (defined as all
waters tributary to the Colorado River in Arizona and the portion of
New Mexico in the Gila River and Zuni River basins) as endangered or
threatened, that we list the headwater chub (Gila nigra) as endangered
or threatened, and that we designate critical habitat concurrently with
the listing for both species.
Following receipt of the 2003 petition, and pursuant to a
stipulated settlement agreement, on July 12, 2005, we published our 90-
day finding that the petition presented substantial scientific
information indicating that listing the headwater chub and a DPS of the
roundtail chub in the lower Colorado River basin may be warranted, and
we initiated 12-month status reviews for these species (70 FR 39981).
On May 3, 2006, we published our 12-month finding that listing was
warranted for the headwater chub, but precluded by higher priority
listing actions, and that listing of a population segment of the
roundtail chub in the lower Colorado River basin was not warranted
because it did not meet our definition of a DPS (71 FR 26007).
On September 7, 2006, we received a complaint from the Center for
Biological Diversity for declaratory and injunctive relief, challenging
our decision not to list the lower Colorado River basin population of
the roundtail chub as an endangered species under the Act. On November
5, 2007, in a stipulated settlement agreement, we agreed to commence a
new status review of the lower Colorado River basin population segment
of the roundtail chub and to submit a 12-month finding to the Federal
Register by June 30, 2009. On March 3, 2009, we published a notice in
the Federal Register that we were initiating a status review and
soliciting new information for reevaluating the 2003 petition to list a
lower Colorado River basin DPS of the roundtail chub (74 FR 9205).

Defining a Species Under the Act

Section 3(16) of the Act defines ``species'' to include ``any
subspecies of fish or wildlife or plants, and any distinct population
segment of any species of vertebrate fish or wildlife which interbreeds
when mature'' (16 U.S.C. 1532(16)). Our implementing regulations at 50
CFR 424.02 provide further guidance for determining whether a
particular taxon or population is a species or subspecies for the
purposes of the Act: ``[T]he Secretary shall rely on standard taxonomic
distinctions and the biological expertise of the Department and the
scientific community concerning the relevant taxonomic group'' (50 CFR
424.11(a)). As previously discussed, the population segment of
roundtail chub in the lower Colorado River basin is classified as Gila
robusta, the same as other roundtail chub populations, and as such we
do not consider the population segment of roundtail chub in the lower
Colorado River basin to constitute a distinct species or subspecies.
Since the population segment of roundtail chub in the lower Colorado
River basin is not a

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distinct species or subspecies, we then evaluated whether it is a
distinct population segment to determine whether it would constitute a
listable entity under the Act.
To interpret and implement the DPS provisions of the Act and
Congressional guidance, the Service and the National Marine Fisheries
Service (now the National Oceanic and Atmospheric Administration--
Fisheries), published the Policy Regarding the Recognition of Distinct
Vertebrate Population Segments Under the Endangered Species Act (DPS
Policy) in the Federal Register on February 7, 1996 (61 FR 4722). Under
the DPS Policy, three elements are considered in the decision regarding
the establishment and classification of a population of a vertebrate
species as a possible DPS. These are applied similarly for additions to
and removals from the Lists of Endangered and Threatened Species. These
elements are (1) the discreteness of a population in relation to the
remainder of the species to which it belongs, (2) the significance of
the population segment to the species to which it belongs, and (3) the
population segment's conservation status in relation to the Act's
standards for listing, delisting, or reclassification (i.e., is the
population segment endangered or threatened?).

Distinct Vertebrate Population Segment Analysis

In the 2003 petition, we were asked to consider listing a DPS for
the roundtail chub in the lower Colorado River basin (the Colorado
River and its tributaries downstream of Glen Canyon Dam including the
Gila and Zuni River basins in New Mexico). Per our November 5, 2007,
stipulated settlement agreement, we are reevaluating our May 3, 2006,
determination (71 FR 26007) that listing the roundtail chub population
segment in the lower Colorado River basin was not warranted because it
did not meet our definition of a DPS.
In accordance with our DPS Policy, this section details our
analysis of the first two elements we consider in a decision regarding
the status of a possible DPS as endangered or threatened under the Act.
These elements are (1) the population segment's discreteness from the
remainder of the species to which it belongs and (2) the significance
of the population segment to the species to which it belongs.

Discreteness

The DPS policy's standard for discreteness requires an entity to be
adequately defined and described in some way that distinguishes it from
other representatives of its species. A population segment of a
vertebrate species may be considered discrete if it satisfies either
one of the following two conditions: (1) It is markedly separated from
other populations of the same taxon as a consequence of physical,
physiological, ecological, or behavioral factors (quantitative measures
of genetic or morphological discontinuity may provide evidence of this
separation); or (2) it is delimited by international governmental
boundaries within which significant differences in control of
exploitation, management of habitat, conservation status, or regulatory
mechanisms exist.
The historical range of roundtail chub included both the upper and
lower Colorado River basins in the States of Wyoming, Utah, Colorado,
New Mexico, Arizona, and Nevada (Propst 1999, p. 23; Bezzerides and
Bestgen 2002, p. 25; Voeltz 2002, pp. 19-23), but the roundtail chub
was likely only a transient in Nevada. Currently roundtail chubs occur
in both the upper and lower Colorado River basins in Wyoming, Utah,
Colorado, New Mexico, and Arizona. Bezzerides and Bestgen (2002, p. 24)
concluded that historically there were two discrete population centers,
one in each of the lower and upper basins, and that these two
population centers remain today. Numerous authors have noted that
roundtail chub was very rare with few documented records in the
mainstem Colorado River between the two basins (Minckley 1973, p. 102;
Minckley 1979, p. 51; Valdez and Ryel 1994, pp. 5-10-5-11; Minckley
1996, p. 75; Bezzerides and Bestgen 2002, pp. 24-25; Voeltz 2002, pp.
19, 112), so we do not consider the mainstem to have been occupied
historically, and have not considered the Colorado River in our
estimates of historical range. Early surveyors also variably used the
term ``bonytail'' to describe roundtail chub (Valdez and Ryel 1994, pp.
5-7), further clouding information on historical distribution, as some
accounts of roundtail chub in the mainstem may have been bonytail (Gila
elegans), which is a mainstem species in the Colorado River. Records
from the mainstem Colorado River also may have been transients from
nearby populations, such as some records from Grand Canyon, which may
have been from the Little Colorado River (Voeltz 2002, p. 112). One
record from between the two basins, a record of two roundtail chubs
captured near Imperial Dam in 1973, illustrates this. Upon examining
these specimens, Minckley (1979, p. 51) concluded that they were strays
washed downstream from the Bill Williams River based on their heavily
blotched coloration. This is a logical conclusion considering that
roundtail chub from the Bill Williams River typically exhibit this
blotched coloration (Rinne 1969, pp. 20-21; Rinne 1976, p. 78).
Minckley (1979, p. 51), Minckley (1996, p. 75), and Mueller and Marsh
(2002, p. 40) also considered roundtail chub rare or essentially absent
in the Colorado River mainstem based on the paucity of records from
numerous surveys of the Colorado River mainstem.
We conclude that historically, roundtail chub occurred in the
Colorado River basin in two population centers, one each in the upper
(largely in Utah and Colorado, and to a lesser extent, in Wyoming and
New Mexico) and lower basins (Arizona and New Mexico), with apparently
little, if any, mixing of the two populations. If there was one
population, we would expect to find a large number of records in the
mainstem Colorado River between the San Juan and Bill Williams Rivers,
but very few records of roundtail chub exist from this reach of stream.
Also, there is a substantial distance between these areas of roundtail
chub occurrence in the two basins. The mouth of the Escalante River,
which contains the southernmost population of roundtail chub in the
upper basin, is approximately 275 river miles (mi) (443 kilometers
(km)) upstream from Grand Falls on the Little Colorado River, the
historical downstream limit of the most northern population of the
lower Colorado River basin. The lower Colorado River basin roundtail
chub population segment meets the element of discreteness because it
was separate historically, and continues to be markedly separate today.
In more recent times, the upper and lower basin populations of the
roundtail chub have been physically separated by Glen Canyon Dam, but
that artificial separation is not the sole basis for our finding that
the lower basin population is discrete from the upper basin. The
historical information on collections suggests that there was limited
contact even before the dam was built. Available molecular information
for the species, although sparse, seems to support this; mitochondrial
DNA markers (mtDNA; a type of genetic material) of roundtail chub in
the Gila River basin are entirely absent from upper basin populations
(Gerber et al. 2001, p. 2028; see Significance discussion below).

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Significance

If we have determined that a vertebrate population segment is
discrete under our DPS policy, we consider its biological and
ecological significance to the taxon to which it belongs in light of
Congressional guidance (see Senate Report 151, 96th Congress, 1st
Session) that the authority to list DPSs be used ``sparingly'' while
encouraging the conservation of genetic diversity. To evaluate whether
a discrete vertebrate population may be significant to the taxon to
which it belongs, we consider available scientific evidence of the
discrete population segment's importance to the taxon to which it
belongs. Since precise circumstances are likely to vary considerably
from case to case, the DPS policy does not describe all the classes of
information that might be used in determining the biological and
ecological importance of a discrete population. However, the DPS policy
describes four possible classes of information that provide evidence of
a population segment's biological and ecological importance to the
taxon to which it belongs. This consideration may include, but is not
limited to: (1) Persistence of the discrete population segment in an
ecological setting that is unusual or unique for the taxon; (2)
evidence that loss of the discrete population segment would result in a
significant gap in the range of the taxon; (3) evidence that the
discrete population segment represents the only surviving natural
occurrence of a taxon that may be more abundant elsewhere as an
introduced population outside its historical range; or (4) evidence
that the discrete population segment differs markedly from other
populations of the species in its genetic characteristics.
Ecological Setting. Based on our review of the available
information, we found that there are some differences in various
ecoregion variables between the upper and lower Colorado River basins.
For example, McNabb and Avers (1994) and Bailey (1995) delineated
ecoregions and sections of the United States based on a combination of
climate, vegetation, geology, and other factors. Populations of
roundtail chub in the lower basin are primarily found in the Tonto
Transition and Painted Desert Sections of the Colorado Plateau Semi-
Desert Province in the Dry Domain, and the White Mountain-San Francisco
Peaks-Mogollon Rim Section of the Arizona-New Mexico Mountains Semi-
Desert-Open Woodland-Coniferous Forest Province Dry Domain. Populations
of roundtail chub in the upper basin are primarily found in the
Northern Canyonlands and Uinta Basin Sections of the Intermountain
Semi-Desert and Desert Province in the Dry Domain, and the Tavaputs
Plateau and Utah High Plateaus and Mountains Sections of the Nevada-
Utah Mountains Semi-Desert-Coniferous Forest Province in the Dry Domain
(McNabb and Avers 1994; Bailey 1995). These ecoregions display
differences in hydrograph, sediment, substrate, nutrient flow, cover,
water chemistry, and other habitat variables of roundtail chub. Also,
there are differences in type, timing, and amount of precipitation
between the two basins, with the upper basin (3-65 inches (in) per year
(8-165 centimeters (cm) per year)) (Jeppson 1968, p. 1) somewhat less
arid than the lower basin (5-25 in per year (13-64 cm per year)) (Green
and Sellers 1964, pp. 8-11).
The type (snow or rain) and timing of precipitation are major
factors determining the pattern of annual streamflow. A hydrograph
depicts the amount of runoff or discharge over time (Leopold 1997, pp.
49-50). The hydrograph of a stream is a major factor in determining
habitat characteristics and their variability over space and time.
Habitats of roundtail chub in the lower basin have a monsoon hydrograph
or a mixed monsoon-snowmelt hydrograph. A monsoon hydrograph results
from distinctly bimodal annual precipitation, which creates large,
abrupt, and highly variable flow events in late summer and large,
longer, and less variable flow events in the winter (Burkham 1970, pp.
B3-B7; Green and Sellers 1964, pp. 8-11; Minckley and Rinne 1991,
p.12). Monsoon hydrographs are characterized by high variability,
including rapid rise and fall of flow levels with flood peaks of one or
more orders of magnitude greater than base, or ``normal low'' flow
(Burkham 1970, pp. B3-B7; Ray et al. 2007, p. 1617).
In the upper basin, roundtail chub habitats have strong snowmelt
hydrographs, with some summer, fall, and winter precipitation, but with
the majority of major flow events in spring and early summer (Bailey
1995, p. 341; Carlson and Muth 1989, p. 222; Woodhouse et al. 2003, p.
1551). Snowmelt hydrographs are characterized by low variability; long,
slow rises and falls in flow; and peak flow events that are less than
an order of magnitude greater than the base flow.
The lower basin has lower stream flows and warmer temperatures in
late spring and early summer; in contrast, this is typically the
wettest period in the upper basin (Carlson and Muth 1989, p. 222).
Regarding the differences between the two basins, Carlson and Muth
(1989), for example, conclude, ``The upper basin produced most of the
river's discharge, and peak flows occurred after snowmelt in spring and
early summer. Maximum runoff in the lower basin often followed winter
rainstorms.'' Sediment loads vary substantially between streams in both
basins, but are generally lesser in the upper basin than the lower, and
patterning of sediment movement differs substantially because of the
different hydrographs. In general, roundtail chub habitat in the lower
Colorado River basin is of lower gradient, smaller average substrate
size, higher water temperatures, higher salinity, smaller base flows,
higher flood peaks, lesser channel stability and higher erosion, and
substantially different hydrographs than the habitat in the upper
Colorado River basin. Measurable hydrographic differences between the
two basins are evident, as are differences in landscape-level roundtail
chub habitats between the upper and lower basins.
Gap in the Range. Roundtail chub in the lower Colorado River basin
can be considered significant under our DPS analysis because loss of
the lower Colorado River populations of roundtail chub would result in
a significant gap in the range of the taxon; this area constitutes over
one third of the species' historical range (2 out of 6 States),
including the species' entire current range in two States (Arizona and
New Mexico) and all of several major river systems, including the
Little Colorado, Bill Williams, and Gila River basins. Additionally
there are 74 populations of roundtail chub remaining in the upper basin
and 31 in the lower basin; thus, the lower basin populations also
constitute approximately one third (30 percent) of the remaining
populations of the species (Bezzerides and Bestgen 2002, pp. 28-29,
Appendix C; Voeltz 2002, pp. 82-83). The populations in the lower basin
also account for approximately 107,300 square mi (270,906 square km; 49
percent) of the 219,310 square mi (568,010 square km) of the Colorado
River Basin (U.S. Geological Survey 2006, pp. 94-102). In addition, the
roundtail chub historically occupied up to 2,796 mi (4,500 km) of
stream in the lower basin and currently occupies between 497 mi (800
km) and 901 mi (1450 km) of stream habitat in the lower basin. These
populations are not newly established, ephemeral, or migratory; the
species has been well established in the lower Colorado River basin,
and has represented a large portion of the species' range for a long
period of time (Bezzerides and Bestgen 2002, pp. 20-29; Voeltz 2002,
pp. 82-83).

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Whether the Population Represents the Only Surviving Natural
Occurrence of the Taxon. As part of a determination of significance,
our DPS policy suggests that we consider whether there is evidence that
the population represents the only surviving natural occurrence of a
taxon that may be more abundant elsewhere as an introduced population
outside its historical range. The roundtail chub in the lower Colorado
River basin is not the only surviving natural occurrence of the
species. Consequently, this factor is not applicable to our
determination regarding significance.
Marked Differences in Genetic Characteristics. Long-standing
difficulties in morphological discrimination and taxonomic distinction
among members from the lower Colorado G. robusta complex, and the genus
Gila as a whole, due in part to the role hybridization has played in
its evolution, have plagued conservation efforts. But it is important
to consider variation throughout the entire Colorado River basin to
place variation and divergence in the lower basin Gila robusta complex
in appropriate context. Two isolated species of hybrid origin
(involving G. robusta with G. elegans and G. cypha) can be found in the
Virgin and White River drainages (G. seminuda--DeMarais et al. 1992, p.
2747; G. jordani--Gerber et al. 2001, p. 2033, respectively). Gila
robusta is relatively abundant in the mainstem Colorado River and
tributaries above the Glen Canyon Dam in the upper basin. All
individuals from the headwaters of the Little Colorado River and the
mainstem Colorado River and tributaries above Glen Canyon Dam in the
upper basin possess G. cypha or G. elegans mtDNA (Dowling and DeMarais
1993, pp. 444-446; Gerber et al. 2001, p. 2028). However, populations
of the G. robusta complex of the lower basin in the Bill Williams and
Gila River basins (including G. robusta, G. intermedia, and G. nigra)
possess a unique, divergent mtDNA lineage that has never been found
outside the lower basin (Dowling and DeMarais 1993, pp. 444-446; Gerber
et al. 2001, p. 2028). But as Gerber et al. (2001, p. 2037) noted,
genetic information in Gila poorly accounts for species morphology,
stating ``the decoupling of morphological and mtDNA variation in
Colorado River Gila illustrates how hybridization and local adaptation
can play important roles in evolution.'' Although individuals in the
Little Colorado River illustrate some minor genetic uniqueness, the
evidence, though limited (samples size in Gerber et al. 2001 was
limited to 7 individuals) indicates these populations align more
closely with the upper Colorado River basin populations. But
discriminating between populations of Gila based on these data is
difficult, and more data and analysis may help to place these
populations in better perspective.

DPS Conclusion

We have reevaluated the lower Colorado River populations of the
roundtail chub to determine whether they meet the definition of a DPS,
addressing discreteness and significance as required by our policy. We
have considered the extent of the range of the roundtail chub in the
lower Colorado River basin relative to the rest of the species' range,
the ecological setting of roundtail chub in the lower Colorado River
basin, and available information on the genetics of the species. We
conclude that the lower Colorado River populations are discrete from
the upper Colorado River basin populations on the basis of their
present and historical geographic separation of 275 river mi (444 km)
and because few historical records have been detected in the mainstem
Colorado River between the two population centers that would confirm
significant connectivity historically. We also conclude that the lower
Colorado River basin roundtail chub is significant because of its
unique ecological setting compared to the upper basin, and because the
loss of the species from the lower basin would result in a significant
gap in the range of the species. Genetic information for this species
has long been difficult to interpret, and additional data and analysis
may help to clarify this.
In our 2006 finding, we made the determination that the roundtail
chub in the lower Colorado River basin did not meet our definition of a
DPS. We have reevaluated that determination and now find the best
available information has demonstrated that these populations are
discrete, persist in an ecological setting that is unique for the
taxon, and, if lost, would result in a significant gap in the range of
the taxon. Because this population segment meets both the discreteness
and significance elements of our DPS policy, the lower Colorado River
population segment of the roundtail chub qualifies as a DPS in
accordance with our DPS policy, and as such, is a listable entity under
the Act. Below we provide a summary of the biology, status, and
distribution of the DPS, and an analysis of threats to the DPS, based
on the five listing factors established by the Act.

Biology

The roundtail chub is a cyprinid fish (member of Cyprinidae, the
minnow family) with a streamlined body shape. Color in roundtail chub
is usually olive-gray to silvery, with the belly lighter, and sometimes
with dark blotches on the sides. Roundtail chubs are generally 9 to 14
in. (25 to 35 cm) in length, but can reach 20 in. (50 cm) (Minckley
1973, pp. 101-103; Sublette et al. 1990, pp. 126-129; Propst 1999, pp.
23-25; Minckley and Demaris 2000, pp. 251-256; Voeltz 2002, pp. 8-11).
Baird and Girard first described roundtail chub from specimens
collected from the Zuni River in northeastern Arizona and northwestern
New Mexico (Baird and Girard 1853, pp. 368-369). Roundtail chub has
been recognized as a distinct species since the 1800s (Miller 1945, p.
104; Holden 1968, pp. 27-28; Rinne 1969, pp. 27-42; Holden and
Stalnaker 1970, p. 409; Rinne 1976, pp. 87-91; Smith et al. 1979, p.
623; DeMarais 1986, p. iii; Douglas et al. 1989, p. 653; Rosenfeld and
Wilkinson 1989, p. 232; DeMarais 1992, pp. 63-64; Dowling and DeMarais
1993, p. 444; Douglas et al. 1998, p. 169; Minckley and DeMarais 2000,
p. 255; Gerber et al. 2001, p. 2028), and is currently recognized as a
species by the American Fisheries Society (Nelson et al. 2004, p. 71).
The chubs of the genus Gila in the lower Colorado River basin are all
closely related and are often regarded as a species complex (Minckley
1973, p. 101; DeMarais 1992, p. 150; Dowling and DeMarais 1993, p. 444;
Minckley and DeMarais 2000, p. 251; Gerber et al. 2001, p. 2028).
Roundtail chubs in the lower Colorado River basin are found in cool
to warm waters of rivers and streams, and often occupy the deepest
pools and eddies of large streams (Minckley 1973, p. 101; Brouder et
al. 2000, pp. 6-8; Minckley and DeMarais 2000, p. 255; Bezzerides and
Bestgen 2002, pp. 17-19). Although roundtail chubs are often associated
with various cover features, such as boulders, vegetation, and undercut
banks, they are less apt to use cover than other related species such
as the headwater chub and Gila chub (Gila intermedia) (Minckley and
DeMarais 2000, p. 2145). Water temperatures of habitats occupied by
roundtail chub vary between 0 degrees and greater than 32 degrees
Celsius ([deg]C) (32 to 90 degrees Fahrenheit ([deg]F)) (Bestgen 1985,
p. 14). Carveth et al. (2006, p. 1435) reported the upper thermal
tolerance of roundtail chub to be 36.6 [deg]C (97.9 [deg]F); spawning
has been documented from 14 to 24 [deg]C (57 to 75 [deg]F) (Bestgen
1985, p. 14; Kaeding et al. 1990, p. 139; Brouder et

[[Page 32356]]

al. 2000, p. 13). Spawning occurs from February through June in pool,
run, and riffle habitats, with slow to moderate water velocities (Neve
1976, p. 32; Bestgen 1985, pp. 56-67; Propst 1999, p. 24; Brouder et
al. 2000, p. 12; Voeltz 2002, p. 16). Roundtail chubs live for 5 to 7
years and spawn from age 2 on (Bestgen 1985, p. 62; Brouder et al.
2000, p. 12). Roundtail chubs are omnivores, consuming foods
proportional to their availability, including aquatic and terrestrial
invertebrates, aquatic plants, detritus, and fish and other
vertebrates; algae and aquatic insects can be major portions of the
diet (Bestgen 1985, pp. 46-53; Schreiber and Minckley 1981, pp. 409,
415; Propst 1999, p. 24).

Status and Distribution of the Lower Colorado River DPS

The historical distribution of roundtail chub in the lower Colorado
River basin is poorly documented because there were few early
collections, and perhaps more importantly, because many populations of
native fish, including roundtail chub, were likely lost prior to early
comprehensive fish surveys because habitat-altering actions (e.g.,
dewatering, livestock grazing, mining) were widespread, and had already
severely altered aquatic habitats (Girmendonk and Young 1997, p. 50;
Minckley 1999, p. 179; Voeltz, 2002, p. 19). Roundtail chub was
historically considered common throughout its range (Minckley 1973, p.
101; Holden and Stalnaker 1975, p. 222; Propst 1999, p. 23). Voeltz
(2002), estimating historical distribution based on museum collection
records, agency database searches, literature searches, and discussion
with biologists, found that roundtail chub in the lower Colorado River
basin was historically found in the Gila and Zuni Rivers in New Mexico;
the Black, Colorado (though likely only as a transient), Little
Colorado, Bill Williams, Gila, San Francisco, San Carlos, San Pedro,
Salt, Verde, White, and Zuni Rivers in Arizona: and numerous
tributaries within those basins. Voeltz (2002, p. 83) estimated the
lower Colorado River basin roundtail chub historically occupied
approximately 2,796 mi (4,500 km) of rivers and streams in Arizona and
New Mexico. Although roundtail chubs were never collected from the
Colorado River or San Pedro River basin in Mexico, they may have
occurred in these areas based on records near the international border
in the lower Colorado River and upper San Pedro River and the
occurrence of suitable habitat in these streams in Mexico (Voeltz 2002,
p. 20).
Miller (1961) first comprehensively documented the decline of
fishes of the southwestern United States in 1961, but interestingly,
F.M. Chamberlain made similar observations in Arizona in 1904;
roundtail chub was included in these assessments and in subsequent
evaluations of imperiled fish species of the region (Miller 1961, pp.
373-379; Miller 1972, p. 242; Deacon et al. 1979, p. 34; Minckley 1999,
pp. 215-218). The decline of the species has been documented both in
the scientific peer-reviewed literature (Bestgen and Propst 1989, p.
402) and in State agency reports (Girmendonk and Young 1997, p. 49;
Propst 1999, p. 23; Brouder et al. 2000, p. 1; Bezzerides and Bestgen
2002, pp. iii-iv; Voeltz 2002, p. 83). Roundtail chub is considered
vulnerable by the American Fisheries Society (Jenks et al. 2008, p.
390).
Roundtail chub in the lower Colorado River basin in Arizona
currently occurs in two tributaries of the Little Colorado River
(Chevelon and East Clear Creeks); several tributaries of the Bill
Williams River basin (Boulder, Burro, Conger, Francis, Kirkland,
Sycamore, Trout, and Wilder Creeks); the Salt River and four of its
tributaries (Ash Creek, Black River, Cherry Creek and Salome Creek);
the Verde River and five of its tributaries (Fossil, Oak, Roundtree
Canyon, West Clear, and Wet Beaver Creeks); Aravaipa Creek (a tributary
of the San Pedro River); Eagle Creek (a tributary of the Gila River);
and in New Mexico, in the upper Gila River (Voeltz 2002, pp. 82-83; the
upper Gila River is used in this document to denote that portion of the
Gila River basin in New Mexico). The Salt River and Verde River are
occupied in several reaches that are fragmented and separated by two
large dams and reservoirs on the Verde River, and four large dams and
reservoirs on the Salt River. Roundtail chubs also occur in canals in
Phoenix that are fed by the lower Salt and Verde Rivers. Roundtail
chubs inhabit several streams in the Salt River drainage, although
survey information on the San Carlos Apache Reservation and White
Mountain Apache Reservation is proprietary and confidential, and their
status is not currently known; these streams include Canyon, Carrizo,
Cedar, Cibecue, and Corduroy Creeks, and the White River (Voeltz 2002,
pp. 82-83).
The Arizona Game and Fish Department (AGFD) conducted a
comprehensive status review of roundtail and headwater chub (Voeltz
2002) in the lower Colorado River basin that included a review of all
available current and historical survey records and estimated
historical and current range of roundtail chub using information from
museum collections, agency databases, records found in literature, and
consultation with experts. The report found that roundtail chub
populations and distribution had declined significantly from historical
levels. Based on Voeltz (2002), roundtail chub is known to occupy only
18 percent of its former range in the lower Colorado River basin;
status in an additional 14 percent of its range is unknown. Based on
the best available scientific information in Voeltz (2002), the
roundtail chub in the lower Colorado River basin appears to occupy
about 18 to 32 percent of its former range (approximately 497 mi (800
km) out of the 2,796 mi (4,500 km)) considered to be formerly occupied)
in Arizona and New Mexico. We now consider the Colorado River in the
lower Colorado River basin to be outside the historical range of the
species (Voeltz considered it to have been occupied); given this,
roundtail chub has been extirpated from 672 mi (965 km) of 2,197 mi
(3,535 km; approximately 60 percent) of its formerly occupied range. Of
the populations for which status and threat information is available,
all but one of the remaining natural populations are considered
threatened by both the presence of nonnative species and habitat-
altering land uses.
In the report, Voeltz (2002) used a classification system to report
status and threat information. Populations were defined as an
occurrence at a stream-specific locality. A population was considered
``stable-secure,'' ``stable-threatened,'' or ``unstable-threatened,''
based on abundance, population trend, and threat information for the
locality (see Table 1, Voeltz 2002, p. 5). Voeltz (2002, p. 5)
considered a population ``extirpated'' if the species was no longer
believed to occupy the site, and ``unknown'' if there are too few data
to determine status. Note that the term ``threatened'' as used by
Voeltz (2002, p. 5) is not the definition of ``threatened'' used in the
Act in which a species is likely to become endangered in the
foreseeable future, but rather is an estimate of the likelihood that a
population is likely to become extirpated. Of 40 populations of
roundtail chub in the lower Colorado River basin identified in the
report, Voeltz (2002, pp. 82-87) found that none were ``stable-
secure,'' 6 were ``stable-threatened,'' 13 were ``unstable-
threatened,'' 10 were ``extirpated,'' and 11 were of ``unknown''
status. Populations with an ``unknown'' status in Voeltz (2002)
included nine populations wholly or partly on Tribal lands. Tribes are
sovereign nations and

[[Page 32357]]

survey data is proprietary and confidential, but existing survey
information for these streams was provided and indicated occupancy. The
remaining two populations with ``unknown'' status lacked sufficient
information to assign a category.

Table 1--Definitions of Status Description Categories Used to Describe
Roundtail Chub Populations
[From Voeltz 2002]
------------------------------------------------------------------------
Status Definition
------------------------------------------------------------------------
Stable-Secure (SS)........................... Chubs are abundant or
common, data over the
past 5-10 years shows a
stable, reproducing
population with
successful recruitment
(survival of young to
Age 2, reproductive
age); no impacts from
nonnative aquatic
species exist; and no
current or future
habitat altering land or
water uses were
identified.
Stable-Threatened (ST)....................... Chubs are abundant or
common, data over the
past 5-10 years shows a
reproducing population,
although recruitment may
be limited; predatory or
competitive threats from
nonnative aquatic
species exist; and/or
some current or future
habitat altering land or
water uses were
identified.
Unstable-Threatened (UT)..................... Chubs are uncommon or
rare with a limited
distribution; data over
the past 5-10 years
shows a declining
population with limited
recruitment; predatory
or competitive threats
from nonnative aquatic
species exist; and/or
serious current or
future habitat altering
land or water uses were
identified.
Extirpated (E)............................... Chubs are no longer
believed to occur in the
system.
Unknown (UN)................................. Lack of data precludes
determination of status.
------------------------------------------------------------------------

We have updated this assessment with new data from various sources,
particularly Cantrell (2009) as provided in Table 2 below. It is
important to recognize that these status categories are qualitative,
and based on very limited data in most instances. We have very little
information on the population size, length of the stream reach,
survivorship, recruitment (survival of young to Age 2, reproductive
age), or age structure of these populations. These categories are also
often based on only a few surveys conducted over decadal time scales.
We now consider 1 population ``stable-secure,'' 8 populations ``stable-
threatened,'' 13 populations ``unstable-threatened,'' and 9 populations
``unknown.'' Ten populations remain extirpated although we now consider
what was called a population in the Colorado River to have been
occupied only by transient individuals. In the nine populations with
``unknown'' status, two (Ash Creek and Roundtree Creek) are newly
established via translocation and have not been extant long enough to
determine successful establishment. Information on the Black River and
Conger Creek provided since the 2002 report resulted in
recategorization of both of those sites from ``unknown'' to ``stable-
threatened'' and for recategorization of Eagle Creek from ``unknown''
to ``unstable-threatened.'' Improved status at Fossil Creek that allows
that population to reach ``stable-secure'' is due to removal of the
power plant and associated structures, construction of a new fish
barrier, and chemical renovation to remove nonnative fish species.
Recent surveys have confirmed some of the information in Voeltz's 2002
status review; in the upper Black River, Chevelon Creek, and East Clear
Creek, the species persists in the presence of abundant nonnative
predators, and apparently reproduces successfully, but distribution
appears limited, abundance is unknown, and other signs, such as
abundance of other native fish species, indicate these native fisheries
are deteriorating (AGFD 2005a, p. 4; 2005b, pp. 4-5; Clarkson and Marsh
2005a, pp. 6-8; 2005b, pp. 6-7). Other roundtail chub populations in
waters with abundant nonnative predators are less able to reproduce
successfully and the particular circumstances at these three sites are
worth further investigation. Roundtail chub in the lower Colorado River
basin in New Mexico may now be extirpated. The species has long been
considered extirpated in many Gila River tributaries in New Mexico, and
has become very rare in the mainstem Gila River (Carman 2006, pp. 9,
18).

Table 2--Summary of Roundtail Chub Status and Threats by Stream Reach
[Voeltz 2002, Cantrell 2009, service files]
------------------------------------------------------------------------
Regional historical or
Location Current status current threats
------------------------------------------------------------------------
Management Area A--Gila River Basin
------------------------------------------------------------------------
Aravaipa Creek................. ST Factor A: Water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing,
road use.
.............. Factor C: Nonnative
species.
Blue River..................... E Factor A: Water
diversions,
groundwater pumping,
logging and fuel wood
cutting, recreation,
livestock grazing,
road use.
.............. Factor C: Nonnative
species.
Eagle Creek.................... UT Factor A: Dams, water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing.
.............. Factor C: Nonnative
species.
San Francisco River............ E Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
Upper Gila River............... UT Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
Lower Gila River............... E Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
San Pedro River................ E Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.

[[Page 32358]]

.............. Factor C: Nonnative
species.
------------------------------------------------------------------------
Management Area A--Salt River Basin
------------------------------------------------------------------------
Ash Creek...................... UN Factor A: Recreation,
logging and fuel wood
cutting, livestock
grazing.
Black River.................... ST Factor A: Water
diversions,
groundwater pumping,
recreation, livestock
grazing, mining,
logging and fuel wood
cutting, urban and
agricultural
development.
.............. Factor C: Nonnative
species.
Canyon Creek................... UN Factor A: Livestock
grazing, recreation,
limited fuelwood
harvest, limited
agriculture, fisheries
and wildlife
management, and
localized municipal,
urban and rural
development and
associated water use.
.............. Factor C: Nonnative
species.
Carrizo Creek.................. UN Factor A: Livestock
grazing, recreation,
limited fuelwood
harvest, limited
agriculture, fisheries
and wildlife
management, and
localized municipal,
urban and rural
development and
associated water use.
.............. Factor C: Nonnative
species.
Cedar Creek.................... UN Factor A: Livestock
grazing, recreation,
limited fuelwood
harvest, limited
agriculture, fisheries
and wildlife
management, and
localized municipal,
urban and rural
development and
associated water use.
.............. Factor C: Nonnative
species.
Cherry Creek................... ST Factor A: Water
diversions,
groundwater pumping,
mining, recreation,
livestock grazing,
logging and fuel wood
cutting, urban and
agricultural
development.
.............. Factor C: Nonnative
species.
Cibecue Creek.................. UN Factor A: Livestock
grazing, recreation,
limited fuelwood
harvest, limited
agriculture, fisheries
and wildlife
management, and
localized municipal,
urban and rural
development and
associated water use.
.............. Factor C: Nonnative
species.
Corduroy Creek................. UN Factor A: Livestock
grazing, recreation,
limited fuelwood
harvest, limited
agriculture, fisheries
and wildlife
management, and
localized municipal,
urban and rural
development and
associated water use.
.............. Factor C: Nonnative
species.
Salome Creek................... UT Factor A: Recreation,
logging and fuel wood
cutting, livestock
grazing.
.............. Factor C: Nonnative
species.
Salt River..................... UT Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
White River.................... UN Factor A: Water
diversions,
groundwater pumping,
recreation, livestock
grazing, mining,
logging and fuel wood
cutting, urban and
agricultural
development.
.............. Factor C: Nonnative
species.
------------------------------------------------------------------------
Management Area A--Verde River Basin
------------------------------------------------------------------------
Dry Beaver Creek............... E Factor A: Water
diversions,
dewatering, livestock
grazing, logging and
fuel wood cutting,
recreation.
.............. Factor C: Nonnative
species.
Fossil Creek................... SS Factor A: Water
diversions,
groundwater pumping,
dewatering, mining,
contaminants, urban
and agricultural
development, livestock
grazing.
Oak Creek...................... UT Factor A: Water
diversions,
groundwater pumping,
dewatering, mining,
contaminants, urban
and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
Roundtree Canyon............... UN Factor A: Recreation,
logging and fuel wood
cutting, livestock
grazing.
Verde River.................... ST Factor A: Water
diversions,
groundwater pumping,
dewatering, mining,
contaminants, urban
and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
West Clear Creek............... ST Factor A: Water
diversions,
dewatering, livestock
grazing, logging and
fuel wood cutting,
recreation.
.............. Factor C: Nonnative
species.
Wet Beaver Creek............... UT Factor A: Water
diversions,
dewatering, livestock
grazing, logging and
fuel wood cutting,
recreation.
.............. Factor C: Nonnative
species.
------------------------------------------------------------------------
Management Area B--Bill Williams River Basin
------------------------------------------------------------------------
Big Sandy River................ E Factor A: Water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing,
residential
development.
.............. Factor C: Nonnative
species.
Bill Williams River............ E Factor A: Water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing.
.............. Factor C: Nonnative
species.
Boulder Creek.................. ST Factor A: Groundwater
pumping, recreation,
livestock grazing.
.............. Factor C: Nonnative
species.
Burro Creek.................... UT Factor A: Water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing,
residential
development,
contaminants.
.............. Factor C: Nonnative
species.
Conger Creek................... ST Factor A: Groundwater
pumping, mining,
livestock grazing,
recreation.
.............. Factor C: Nonnative
species.
Francis Creek.................. UT Factor A: Groundwater
pumping, mining,
livestock grazing,
recreation.
.............. Factor C: Nonnative
species.

[[Page 32359]]

Kirkland Creek................. UT Factor A: Groundwater
pumping, recreation,
mining, livestock
grazing, residential
development,
contaminants.
.............. Factor C: Nonnative
species.
Santa Maria River.............. UT Factor A: Groundwater
pumping, recreation,
mining, livestock
grazing, residential
development,
contaminants.
.............. Factor C: Nonnative
species.
Sycamore Creek................. UT Factor A: Water
diversions,
groundwater pumping,
recreation, mining,
livestock grazing,
residential
development,
contaminants.
.............. Factor C: Nonnative
species.
Trout Creek.................... ST Factor A: Water
diversions,
groundwater pumping,
recreation,
residential
development.
.............. Factor C: Nonnative
species.
Wilder Creek................... UN Factor A: Groundwater
pumping, mining,
livestock grazing,
recreation.
.............. Factor C: Nonnative
species.
------------------------------------------------------------------------
Management Area C--Little Colorado River Basin
------------------------------------------------------------------------
Chevelon Creek................. UT Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing, contaminants.
.............. Factor C: Nonnative
species.
East Clear Creek............... UT Factor A: Logging and
fuel wood cutting,
recreation, mining,
livestock grazing,
contaminants.
.............. Factor C: Nonnative
species.
Little Colorado River.......... E Factor A: Dams, water
diversions,
groundwater pumping,
dewatering, logging
and fuel wood cutting,
recreation, mining,
urban and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
Zuni River..................... E Factor A: Water
diversions,
groundwater pumping,
dewatering, mining,
contaminants, urban
and agricultural
development, livestock
grazing.
.............. Factor C: Nonnative
species.
------------------------------------------------------------------------
SS--Stable-Secure; ST--Stable-Threatened; UT--Unstable-Threatened; E--
Extirpated; UN--Unknown.

Populations of roundtail chub are found in five separate drainages
that are isolated from one another (the Little Colorado River, Bill
Williams River, Gila River, Salt River, and Verde River), and
populations within the drainages have varying amounts of connectivity
between them. Using large-scale watersheds, AGFD created ``management
areas'' and ``significant conservation units'' based on currently
occupied roundtail habitats. AGFD has utilized new genetic studies
(Dowling et al. 2008; Schwemm 2006; See Table 2) to refine these
management areas. Based on genetic similarity, the Verde, Salt, and
Gila Rivers and their tributaries constitute Management Area A, the
Bill Williams and its tributaries are Management Area B, and the Little
Colorado River and its tributaries are Management Area C. Cantrell
(2009, p. 9) also refined significant conservation units for management
purposes based on genetic information (Dowling et al. 2008; Schwemm
2006); however the mechanism for selecting these units and
determination of stability versus instability of a management area or
significant conservation units was not clearly described.

Summary of Factors Affecting the Species

Section 4 of the Act (16 U.S.C. 1533), and implementing regulations
at 50 CFR 424, set forth procedures for adding species to the Federal
Lists of Endangered and Threatened Wildlife and Plants. A species may
be determined to be an endangered or threatened species due to one or
more of the five factors described in section 4(a)(1) of the Act: (A)
The present or threatened destruction, modification, or curtailment of
its habitat or range; (B) overutilization for commercial, recreational,
scientific, or educational purposes; (C) disease or predation; (D) the
inadequacy of existing regulatory mechanisms; and (E) other natural or
manmade factors affecting its continued existence. In making this
finding, information regarding the status and threats to the Lower
Colorado River Basin DPS of roundtail chub in relation to the five
factors provided in section 4(a)(1) of the Act is summarized below.

Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range

Roundtail chub has been eliminated from much of its historical
range because many formerly occupied areas are now unsuitable due to
dewatering, impoundment, channelization, and channel changes caused by
alteration of riparian vegetation and watershed degradation (Miller
1961, pp. 367-371; Miller 1972, pp. 240, 242; Deacon et al. 1979, pp.
32, 34; Bestgen and Propst 1989, p. 409; Girmendonk and Young 1997, p.
16-44; Bezzerides and Bestgen 2002, pp. 6-9, 24-33; Voeltz 2002, pp.
87-89). In addition, areas where roundtail chub still occurs have been
significantly altered or are currently being altered by the same and
additional factors, including mining, improper livestock grazing, wood
cutting, recreation, urban and suburban development, groundwater
pumping, dewatering, dams and dam operation, contaminants, and other
human actions (Minckley 1973, p. 101; Minckley 1985, pp. 12-15, 65-67;
Bestgen and Propst 1989, p. 409; Bezzerides and Bestgen 2002, pp. 24-
33; Tellman et al. 1997, pp. 159-170; Voeltz 2002, pp. 87-89; McKinnon
2006a, 2006b, 2006c, 2006d, 2006e). These activities and their effects
on the roundtail chub are discussed in further detail below. It is
important to recognize that in most areas where roundtail chub
historically occurred or currently occur, two or more threats may be
acting in combination in their influence on the roundtail chub or on
suitability of habitat to support the species (Voeltz 2002, pp. 23-81;
Cantrell 2009, p. 15).

[[Page 32360]]

The modification and destruction of aquatic and riparian
communities in the post-settlement arid southwestern United States from
anthropogenic (human-caused) land uses is well documented (Miller 1961,
pp. 367-371; Sullivan and Richardson 1993, pp. 35-42; Girmendonk and
Young 1997, pp. 45-52; Tellman et al. 1997; Webb and Leake 2005, pp.
305-310; Ouren et al. 2007, pp. 16-22). Significant loss of habitat and
species range has also been well documented (Miller 1961, p. 365;
Minckley 1985, pp. 4-15; Minckley and Deacon 1991, pp. 7-18), and has
been reported specifically for the roundtail chub in the lower Colorado
River basin (Voeltz 2002). An estimated one-third of Arizona's pre-
settlement wetlands have dried or have been rendered ecologically
dysfunctional (Yuhas 1996). Although many of these habitat changes, and
the greatest loss and degradation of riparian and aquatic communities
in Arizona, occurred during the period from 1850 to 1940, (Miller 1961,
pp. 365-371; Minckley 1985, pp. 4-15; Webb and Leake 2005, pp. 305-
310), many of these land activities continue today and are discussed in
detail below.
Dams, Diversions, and Groundwater Withdrawal
Major dams have been constructed throughout the historical and
current range of the roundtail chub in the lower Colorado River basin,
including four dams on the Gila River, four on the Salt River, and two
on the Verde River, and have been a substantial cause in the decline of
the species (Minckley 1985, pp. 12-14; Tellman et al. 1997, pp. 159-
170; Voeltz 2002, pp. 19-22, 44-45). Although roundtail chubs survive,
reproduce, and can even be cultured in small ponds, they do not appear
to be able to persist in reservoirs. Much of the lower Salt River and
portions of the lower Verde River are now reservoirs where roundtail
chub formerly occurred (Voeltz 2002, pp. 20, 84-85). In addition to the
loss of flowing river habitats through inundation, dams also modify
sediment dynamics, timing and magnitude of downstream flow, and
temperature characteristics of habitats (Gloss et al. 2005, pp. 17-32,
69-85). Such changes can negatively affect the distribution and
survival of warm-water adapted native fishes like roundtail chub.
Tailwaters of large dams are often too cold for successful reproduction
by native warmwater fishes. Cooler water temperatures can also reduce
the growth rates and survival of embryos and juvenile warm-water fish.
Larvae grow more slowly, which increases their risk of predation and
decreases accumulation of energetic reserves needed for overwinter
survival. Cold water temperatures may slow growth and reduce
reproductive success (Marsh 1985, p. 129; Valdez and Ryel 1994, pp. 4-
16; Muth et al. 2000, pp. 5-1-5-39). Reservoirs also capture sediment
and discharge sediment-poor water downstream that alters channel
characteristics (Collier et al. 1996, pp. 63-85; Gloss et al. 2005, pp.
17-32; Wright et al. 2008, p. 4). Alteration of the magnitude and
timing of flow and capture of sediment in reservoirs can increase water
clarity and channel scour downstream from the dam (Collier et al. 1996,
pp. 63-85). Changes in discharge timing and magnitude may shift
environmental cues needed by fish for proper timing of migration and
spawning, thereby preventing successful reproduction (Muth et al. 2000,
pp. 5-1-5-39). Dams also prevent upstream, and to a lesser degree
downstream, movement of all age classes to historical spawning,
rearing, and overwintering habitat (Martinez et al. 1994, pp. 227-239;
Schuman 1995, pp. 249-261).
Within the range of roundtail chub in the lower Colorado River
basin, water for human uses is supplied by reservoirs created by dams,
surface water diversions, and groundwater pumping. The hydrologic
connection between groundwater and surface flow of intermittent and
perennial streams is becoming better understood. Groundwater pumping
creates a cone of depression within the affected aquifer that slowly
radiates outward from the well site. When the cone of depression
intersects the hyporheic zone of a stream (the active transition zone
between surface water and groundwater that contributes water to the
stream itself), the surface water flow may decrease. Continued
groundwater pumping can draw down the aquifer sufficiently to create a
water-level gradient away from the stream and floodplain (Webb and
Leake 2005, p. 309). Finally, complete disconnection of the aquifer and
the stream results in dewatering of the stream (Webb and Leake 2005, p.
309).
Roundtail chub has been eliminated from much of its historical
range because many formerly occupied areas are now unsuitable due to
dewatering (Miller 1961, pp. 367-371; Miller 1972, pp. 240, 242; Deacon
et al. 1979, pp. 32, 34; Bestgen and Propst 1989, p. 409; Girmendonk
and Young 1997, pp. 16-44; Bezzerides and Bestgen 2002, pp. 6-9, 24-33;
Voeltz 2002, pp. 87-89). Dams, diversions, and groundwater pumping have
effectively eliminated much of the riverine habitat in Arizona that
roundtail chub once occupied simply by eliminating downstream flow and
drying much of the historical river courses (Tellman et al. 1997, pp.
164, 169; Voeltz 2002, pp. 19-22, 44-45). In 1904, Chamberlin noted
that a primary cause of fish extinctions in the lower Colorado River
basin was irrigation operations including water use, preclusion of
migration due to dams, and destruction of fish in ditches (Minckley
1999, p. 215). Groundwater pumping and water diversions continue to
pose a significant threat to the continued existence of the roundtail
chub by reducing the quantity and quality of habitat (Girmendonk and
Young 1997, p. 56), and by altering streamflow and reducing the
frequency and magnitude of floods. Diversions also impact fish
populations by creating barriers to fish movement and by entraining
drifting larvae and fish into irrigation canals where they may later
perish (Martinez et al. 1994, pp. 227-239). Chamberlin found that all
of the flow of the San Pedro River was diverted at two dams near
Fairbanks in 1904 (Minckley 1999, pp. 200-201). Reaches of the Verde
River near Tapco and the urban areas in the Verde Valley contain
numerous, significant diversion dams, and dead fishes have been
reported in surrounding pastures following irrigation (Girmendonk and
Young 1997, p. 56). Roundtail chubs are also diverted from the lower
Salt River into canals in the Phoenix area, where they likely perish as
a result of annual dewatering for canal maintenance, although some fish
are salvaged and returned to the Salt River.
The Service found that, in lotic systems (flowing water), roundtail
chub habitat is essentially eliminated when flow consistently drops
below 10 cubic feet per second (0.3 cubic meters per second) (Service
1989, pp. 32-33). In the Verde River, the lowered water level during
the summer irrigation season alters physical characteristics of the
river, changing stream width and depth (Girmendonk and Young 1997, p.
55-56), with much of the stream in the summer dry season reduced to
isolated pools, especially in the urbanized Verde Valley area. The
upper Gila River, in the vicinities of Cliff, Redrock, and Virden, New
Mexico, has been entirely dewatered on occasion by diversions for
agriculture (Bestgen 1985, p. 13). Water withdrawal alters stream flow
regime, in part by reducing flooding (Brouder 2001, p. 302; Freeman
2005, p. 1). Brouder (2001, p. 302) hypothesized that periodic flooding
in the Verde River is needed to maintain roundtail chub habitat, and
further that reductions in periodic flooding due to continued

[[Page 32361]]

water withdrawal and extended drought could lead to roundtail chub
recruitment failure and significant population declines.
To accommodate the needs of rapidly growing rural and urban
populations (see the ``Urban and Rural Development'' section), surface
water is commonly diverted to serve many industrial and municipal uses.
These water diversions have dewatered large reaches of once perennial
or intermittent streams, adversely affecting roundtail chub habitat
throughout its range in Arizona and New Mexico. Many tributaries of the
Verde River are permanently or seasonally dewatered by water diversions
for agriculture (Paradzick et al. 2006, pp. 104-110). Water withdrawal
(dams, diversions, and groundwater pumping) is a threat to most extant
populations of roundtail chub in the lower Colorado River basin
(Bestgen and Propst 1989, p. 409; Girmendonk and Young 1997, p. 56;
Propst 1999, p. 25; Voeltz 2002, pp. 23-81; Cantrell 2009, p. 15).
Increased urbanization and population growth results in an increase
in the demand for water and, therefore, water development projects.
Municipal water use in central Arizona has increased by 39 percent in
the last 8 years (American Rivers 2006, pp. 2-3). Areas of the Verde
River basin continue to experience explosive population growth and
concomitant demand for water. Traditionally rural portions of Arizona
are also predicted to experience significant growth. The populations of
developing cities and towns of the Verde watershed are expected to more
than double in the next 50 years, which may pose exceptional threats to
riparian and aquatic communities of the Verde Valley (Girmendonk and
Young 1993, p. 47; American Rivers 2006; Paradzick et al. 2006, p. 89).
Communities in Yavapai and Gila counties such as the Prescott-Chino
Valley and the City of Payson have seen rapid population growth in
recent years. For example, the population in the town of Chino Valley,
at the headwaters of the Verde River, grew by 22 percent between 2000
and 2004; Gila County, which includes reaches of Tonto Creek and the
Salt, White, and Black Rivers, grew by 20 percent between 2000 and 2003
(U.S. Census Bureau 2005). Voeltz (2002, p. 35) also considered
groundwater pumping from new development a serious threat for all
streams of the Burro Creek drainage in the Bill Williams River basin.
In the Verde River basin, water demands of increasing population
density and associated development have reduced the flow of the Verde
River, and seem likely to continue to do so. A number of researchers
have reported that groundwater in the Big Chino aquifer is connected to
the Verde River and that groundwater pumping of this aquifer affects
stream flow in the mainstem Verde River (Wirt and Hjalmarson 2000, pp.
44-47; Ford 2002, p. 1; Woodhouse et al. 2002, pp. 1-4). The
relationship between groundwater pumping in the lower Big Chino aquifer
and Verde River flow has been apparent since at least the early 1960s
when a surge of pumping due to new development caused Verde River flows
to drop significantly (Wirt and Hjalmarson 2000, p. 27). The Big Chino
aquifer is estimated to supply approximately 80 percent of the base
flow of the Upper Verde River (Wirt and Hjalmarson 2000, p. 44, Wirt et
al. 2004, p. G7; Blasch et al. 2006, updated 2007, pp. 1-2). Woodhouse
et al. (2004, pp. 1-4) also reported that numerous groundwater wells
throughout the upper Verde River watershed have reduced the water table
of the Verde River (Woodhouse et al. 2002, pp. 1-4). A proposed water
project in the area, the Big Chino Water Ranch Project, will include
infrastructure to pump groundwater in the Chino Valley and pipe it to
nearby communities. It will include a 30 mi (48 km), 36 in. (91 cm)
diameter pipeline that will deliver up to 2.8 billion gallons (gal)
(12,400 acre-feet (ac-ft)) of groundwater annually from the Big Chino
sub-basin aquifer to the rapidly growing area of Prescott Valley for
municipal use (McKinnon 2006c; Davis 2007, pp. 1-2). This potential
reduction or loss of baseflow in the Verde River could seasonally dry
up large reaches of the stream.
Roundtail chub habitat in Clear Creek and Chevelon Creek in the
Little Colorado River watershed appears severely threatened by
dewatering. Recent studies and assessments of the Little Colorado River
watershed and its underlying groundwater resources indicate that these
water resources are under increasing pressure from development (Bills
et al. 2005). The North Central Arizona Water Supply Study Report of
Findings (U.S. Bureau of Reclamation 2006) predicts that by the year
2050, the human demand for water will not be met in north-central
Arizona. Plans are underway to determine how additional water resources
can be developed to provide for this unmet demand. Protecting water
resources for environmental needs is included in these plans. However,
it is likely that, with the need for additional demand and use of water
for human uses, there will be additional stress on these aquatic
ecosystems. In addition, there is high potential that extended drought,
perhaps exacerbated through global climate change (see the ``Climate
Change'' section below), will further stress water resources. Two
hydrologic models developed to evaluate the impacts of additional
pumping on groundwater in the C-aquifer in Arizona support these
findings. The C-aquifer is located on the Colorado Plateau of
northeastern Arizona, western New Mexico, and southern Colorado and is
the aquifer that underlies the lower Colorado River Basin. Two
groundwater models, one developed by the U.S. Geological Survey (Leake
et al. 2005), and a second full-flow groundwater model developed to
evaluate cumulative effects to surface water flow (Papadopulos and
Associates 2005), have been developed for the area encompassing the C-
aquifer. Both models predicted depletion in baseflow from current and
proposed groundwater withdrawals in lower Chevelon and Clear Creeks
over the next 50 to 100 years. The flow model (Papadopulos and
Associates 2005) predicted that, based on current regional pumping, the
base flow of Lower Chevelon Creek would be zero in 60 years.
Water use from rapidly growing communities and agricultural and
mining interests have altered flows or dewatered significant reaches
during the spring and summer months in some of the Verde River's
larger, formerly perennial tributaries such as Wet Beaver Creek, West
Clear Creek, and the East Verde River (Girmendonk and Young 1993, pp.
45-47; Sullivan and Richardson 1993, pp. 38-39; Paradzick et al. 2006,
pp. 104-110). The upper Gila River is also threatened by water
diversions and water allocations. In New Mexico, a water settlement in
2004 allows New Mexico the right to withhold 4.5 billion gal (13,800
ac-ft) of surface water every year from the Gila and San Francisco
Rivers (McKinnon 2006d). Project details are still under development,
so the impact of this project on aquatic resources cannot yet be
evaluated.
The Arizona Department of Water Resources manages water supplies in
Arizona and has established five Active Management Areas across the
State (Arizona Department of Water Resources 2006). An Active
Management Area is established by the Arizona Department of Water
Resources when an area's water demand has exceeded the groundwater
supply and an overdraft has occurred. In these areas, groundwater use
has exceeded the rate that precipitation can recharge the aquifer.
Geographically, all five Active

[[Page 32362]]

Management Areas overlap the historical distribution of the roundtail
chub in Arizona. The declaration of these Active Management Areas
further illustrates the current and future threats to aquatic habitat
in these areas and is a cause of concern for the long-term maintenance
of historical and occupied roundtail chub habitat. Such overdrafts
reduce surface water flow of streams that are hydrologically connected
to the aquifer under stress, and this stress can be further exacerbated
by the surface water diversions.
Livestock Grazing
Historical accounts of livestock grazing and its effects in Arizona
are consistent: widespread overgrazing throughout the State in the mid-
to late-1880s denuded rangelands and so altered watersheds that the
landscape was changed forever. In fact, in 1906, F.M. Chamberlain
conjectured that the alteration of landscapes was so profound that it
had actually resulted in climate change to a more arid climate in the
region (as cited in Minckley 1999). Similarly, Croxen (1926) describes
changes to the Tonto National Forest resulting from poorly managed
livestock grazing as largely running their course by the late 1880s.
Between 1880 and 1890, the widespread improper grazing regimes that had
denuded the landscape for 10 to 20 years or so throughout the State was
followed by severe flooding. The end result was a rapid transition for
many aquatic habitats from permanent, meandering streams to
intermittent ``flashy'' arroyos (intermittent streams with higher peak
flows and lower base flows) (Minckley and Hendrickson 1984, pp. 131-
132; Cheney et al. 1990, pp. 5, 10).
Poorly managed livestock grazing has damaged approximately 80
percent of stream, cienega (marsh), and riparian ecosystems in the
western United States (Kauffman and Krueger 1984, pp. 433-435; Weltz
and Wood 1986, pp. 367-368; Waters 1995, pp. 22-24; Pearce et al. 1998,
p. 307; Belsky et al. 1999, p. 1) and severely altered many of the
habitats formerly and currently occupied by roundtail chub. Livestock
grazing today is much more strictly managed by Federal agencies and
Tribes because the effects of grazing and mismanagement are now better
understood and have been well documented. For example, Stromberg and
Chew (2002, p. 198) and Trimble and Mendel (1995, p. 243) discuss the
propensity for poorly managed cattle to remain within or adjacent to
riparian communities, a behavior that is more pronounced in arid
regions (Trimble and Mendel 1995, p. 243). In one rangeland study, it
was concluded that 81 percent of the vegetation that was consumed,
trampled, or otherwise removed was from a riparian area, which amounted
to only 2 percent of the total grazing space (Trimble and Mendel 1995,
p. 243). Additionally, grazing rates can be 5 to 30 times higher in
riparian areas (Trimble and Mendel 1995, p. 244). But as a direct
result of this research, management agencies now exclude livestock
grazing from many riparian areas and streams, or only permit light and
seasonal grazing in these areas. We summarize here the effects of
livestock grazing, but it is important to note that these effects only
become tangible if livestock grazing is poorly managed. If properly
managed, there is some evidence that affects to wildlife habitat can be
positive. In this respect, livestock grazing is largely a threat of the
past, and if properly managed, is not likely a threat. Although more
research is needed, livestock grazing strategies can be developed that
are compatible and even complementary with fisheries management (Platts
1989, p. 103; Vavra 2005, p. 128). The American Fisheries Society
Policy Statement on livestock grazing concludes that ``it is our strong
contention that when properly implemented and supervised, grazing could
become an important management tool benefiting fish and wildlife
riparian habitats'' (American Fisheries Society 2009).
Livestock grazing occurs throughout the range of roundtail chub in
the lower Colorado River basin in all drainages in which the species
occurs (Tellman et al. 1997, p. 167; Propst 1999, p. 25; Voeltz 2002,
pp. 23-88), and has resulted in the degradation of roundtail chub
habitat from a number of mechanisms. Livestock directly affect
roundtail chub habitat through removal of riparian vegetation (Clary
and Webster 1989, p. 1; Clary and Medin 1990, p. 1; Schulz and
Leininger 1990, p. 295; Armour et al. 1991, pp. 8-10; Fleishner 1994,
pp. 630-631), which can result in reduced bank stability, fewer pools,
and higher water temperatures (Kauffman and Krueger 1984, p. 432;
Minckley and Rinne 1985, p. 150; Schulz and Leininger 1990, p. 295;
Fleishner 1994, pp. 630-631; Belsky et al. 1999, pp. 8-12). Livestock
grazing can also cause increased sediment in the stream channel, due to
streambank trampling and riparian vegetation loss (Weltz and Wood 1986,
pp. 367-368; Waters 1995, pp. 22-24; Pearce et al. 1998, p. 307).
Livestock physically alter streambanks through trampling and shearing,
leading to bank erosion (Trimble and Mendel 1995, p. 244; Clary and
Webster 1989, pp. 7-8). In combination, loss of riparian vegetation and
bank erosion can alter channel morphology, including increased erosion
and deposition, downcutting, and an increased width/depth ratio, all of
which can lead to a loss of pool habitats and loss of shallow side and
backwater habitats (Trimble and Mendel 1995, pp. 243-250; Belsky et al.
1999, pp. 1-2). Pool habitats are required by the roundtail chub, and
shallow side and backwater habitats are used by larval chubs for
sheltering from larger bodied predators and for feeding (Minckley 1973,
p. 100; Brouder et al. 2000, pp. 6-7; Minckley and DeMarais 2000, p.
255).
Although livestock grazing is unlikely to be a threat if properly
managed, physical developments necessary to support livestock grazing
can also have direct effects on roundtail chub. Water sources are
essential to livestock operations, and numerous stock tanks, stream
diversions, and various types of groundwater pumps are utilized to
provide water for livestock (Valentine 1989, pp. 413-431). This diverts
water from natural surface waters, including streams supporting
roundtail chub (see ``Dams, Diversions, and Groundwater Withdrawal''
section above). In addition to livestock developments, thousands of
miles of fencing are needed to partition cattle into pastures or
rotation-type grazing systems (Valentine 1989, pp. 435-449).
Maintaining this infrastructure requires a substantial network of
roads. Road use and maintenance have been a major factor in altering
the morphology and habitat of streams in the Southwest (see ``Road
Construction, Use, and Maintenance'' section below).
Livestock can indirectly impact aquatic and riparian habitats at a
watershed level though soil compaction, altered soil chemistry, and
reductions in upland vegetation cover; these changes lead to an
increased severity of floods and sediment loading, lower water tables,
and altered channel morphology (Rich and Reynolds 1963, p. 222; Orodho
et al. 1990, p. 9; Schlesinger et al. 1990, p. 1043; Belsky et al.
1999, p. 1). One consequence of these changes in watershed function is
a reduction in the quantity and quality of pool habitat. Lowered water
tables result in the direct loss of pool habitats, simply because water
is not available to form pools. Increased erosion and sedimentation
results in filling of pools with sediments. Channel incision and
increased flood severity eliminate pools through bed scour, and reduce
habitat complexity by creating shallow, uniform streambeds (see Trimble
and Mendel

[[Page 32363]]

1995, pp. 245-251; Belsky et al. 1999, pp. 25-35). Much of Arizona's
rivers and streams were modified by livestock grazing in this way by
the mid 1900s (Miller 1961, pp. 394-395; Minckley 1999, p. 215), and
the effects to aquatic habitat from that historical modification remain
today.
Livestock use has been shown to alter the composition and community
structure of the aquatic fauna (regional animal life), which can also
indirectly impact roundtail chub by reducing the quantity and quality
of food sources. Altered stream channel characteristics, sediment
deposition, changes in substrate size, and nutrient cycle changes are
all potential effects of livestock grazing that can alter aquatic
invertebrate communities (Li et al. 1994, pp. 638-639; Hoorman and
McCutcheon 2005, p. 3), resulting in changes to the food base for
aquatic vertebrates, particularly fish. Few detailed studies of changes
in aquatic faunal communities have been completed on streams in the
range of the roundtail chub, but given the widespread occurrence of
ongoing and historical livestock grazing, changes in aquatic faunal
community has likely occurred in many streams within historical range
of roundtail chub.
Livestock grazing results in loss of aquatic habitat complexity,
thus reducing diversity of habitat types available and altering fish
communities (Li et al. 1987, pp. 627, 638-639). In the arid west, loss
of habitat complexity has been a major contributing factor in declines
of native fishes and amphibians and in the displacement of native fish
species by nonnative species (Bestgen and Propst 1986, p. 209; Minckley
and Rinne 1991, pp. 2-5; Baltz and Moyle 1993, p. 246; Lawler et al.
1999, p. 621). Livestock grazing has also contributed significantly to
the introduction and spread of nonnative aquatic species through the
proliferation of stock tanks (manmade ponds that are water sources for
livestock) which serve as created habitat for nonnative species (Rosen
et al. 2001, p. 24; Hedwall and Sponholtz 2005, pp. 1-5; Service 2008,
pp. 46-51). The spread of nonnative species is a threat to roundtail
chub because these nonnative species prey on and compete with roundtail
chub (see ``Nonnative Species'' section below for more discussion).
Another direct effect of livestock grazing in intermittent aquatic
habitats is the potential for livestock to drink occupied roundtail
chub habitat dry under certain conditions, completely eliminating all
habitat and killing any roundtail chub present. Vallentine (1989, pp.
413-431) states that cattle need an average of 12 to 15 gal (45 to 57
liters (L)) of water per day per animal, and that this varies
seasonally because of the moisture content of forage, ambient
temperature and humidity, and other factors. Griffith (1999, p. 1)
states that at 10 [deg]C (50 [deg]F), a cow may consume about 5 to 7
gal (19 to 26 L) per day, but the amount increases by 0.4 gal (1.5 L)
per day for every one-degree increase in air temperature; thus at 35
[deg]C (95 [deg]F) the same cow will drink an average of 24 gal (91 L)
per day. Roundtail chub can be limited to small isolated pool habitats
during the driest times of the year that can be as little as several
hundred gal (1-2000 L) in volume, and have flow so low that inflow is
essentially equal to or less than evaporation; several cows could
completely dry such habitats in a matter of days, especially in times
of drought. Gila chub, a related species, and its habitat, is believed
to have been eliminated in this manner from portions of Indian Creek in
2002-2003 (Service 2006, p. 10).
Livestock grazing also contributed to shrub invasion of grasslands
(Brown and Archer 1999, p. 2385). Shrub invasions decrease biodiversity
and create ecosystem instability in desert ecosystems (Baez and Collins
2008). Shrub invasion also can lead to a greater amount of water loss
through plants, which contributes to desertification (Knapp et al.
2008, p. 621). Fire regimes are also altered by shrub invasion
(Richburg et al. 2001, p. 104), and altered fire regimes pose a threat
to roundtail chub due to the effects of wildfire on watersheds and
direct effects of ash and sediment flows following wildfires (see
``High-Intensity Wildfires'' section below).
All extant populations of roundtail chub are subject to some level
of livestock grazing in the watershed, but specific problems associated
with livestock grazing have only been noted in four streams (Chevelon,
East Clear, Burro, and Salome Creeks) (Voeltz 2002; Cantrell 2009, p.
15). In Chevelon Creek, Arizona Department of Environmental Quality
water quality standards for sediment and turbidity (muddiness of water)
were not met due to grazing and high channel erosion, habitat
modification, and unsatisfactory watershed condition for the watershed
(Voeltz 2002, p. 27). In the Verde River, Girmendonk and Young (1997,
p. 53) noted cattle grazing had a major impact on both upland and
aquatic communities due to trampled banks and heavily grazed vegetation
from Sullivan Lake downstream to Cottonwood. However, we note that in
most streams currently occupied by roundtail chub, grazing has been
removed from the riparian area. For example, livestock grazing has
since been removed from that portion of the Verde River discussed by
Girmendonk and Young (1997).
The above discussion illustrates that poorly managed livestock
grazing can adversely affect roundtail chub in several ways, from
direct loss due to livestock water and vegetation consumption and
trampling, to indirect habitat alteration from changes in the
watershed. In general, properly managed livestock grazing utilizes
rest-rotation grazing systems that exclude riparian areas or limit
their use to the winter season, and utilize monitoring systems to
ensure that use of uplands and riparian areas are not overgrazed. When
livestock grazing is well managed in this manner it is not likely a
threat to the roundtail chub. The capability exists to create livestock
grazing strategies that are compatible and even complementary to
maintaining fisheries habitat, although more research is needed in this
regard (Platts 1989, p. 103; Vavra 2005, p. 128).
Urban and Rural Development
Urban and rural development are considered a threat in every stream
currently occupied by roundtail chub (Cantrell 2009, p. 18).
Development can affect roundtail chub and its habitat through direct
alteration of streambanks and floodplains from construction of homes
and businesses, as well as from numerous related impacts. Tellman et
al. (1997, pp. 92-93) listed the following impacts to rivers in Arizona
from urban and rural development: increased use of floodplain for homes
and businesses, sand and gravel mining in the floodplain for
construction materials, pollution from trash and wastewater in river
bed, depletion of water supplies, increased land covered by impervious
surfaces with greater surface runoff and less infiltration, building of
flood control structures, and increased recreational impacts. On a
broader scale, development alters the watershed with consequent changes
in the hydrology, sediment regimes, and pollution input (Leopold 1997,
pp. 97-102; Horak 1989, p. 42; Medina 1990, p. 351; Reid 1993, pp. 48-
51; Waters 1995, pp. 42-44; Wheeler et al. 2005, p. 141).
Development changes watersheds from land surfaces where
precipitation can infiltrate the soil and reach a stream slowly as
subsurface flow, to one with impervious surfaces such as rooftops,
asphalt, and compacted soils (Schueler 1994, p. 100; 1995, p. 233;
Wheeler et al. 2005, p. 151). These impervious surfaces capture
precipitation and route it quickly and directly into gutters,

[[Page 32364]]

storm drains, overland flow, and streams (Hollis 1975, p. 431; Wheeler
et al. 2005, p. 151). Similarly, precipitation falling on impervious
surfaces without direct hydraulic connections to streams may reach
streams quickly as overland flow (Horton 1945, p. 275; Leopold 1973, p.
1845; Wheeler et al. 2005, p. 151). Thus, urbanization fundamentally
alters the delivery of water to streams (Environmental Protection
Agency 2008, p. 1). These changes in precipitation delivery alter
stream flow regimes. Peak flow volume from precipitation events
increases (Hollis 1975, p. 431; Neller 1988, p. 1; Booth 1990, pp. 407-
417; Clark and Wilcock 2000, p. 1763; Rose and Peters 2001, p. 246;
Wheeler et al. 2005, p. 151). These changes increase the frequency and
magnitude of floods (Hollis 1975, p. 431; Wheeler et al. 2005, p. 151),
which cause a stream to increase its channel capacity by eroding its
banks, downcutting its channel, or both (Hammer 1972, p. 1530; Leopold
1973, p. 1845; Booth 1990, p. 1752; Pizzuto et al. 2000, p. 79; Brown
and Caraco 2001, pp. 16-19; Wheeler et al. 2005, p. 151). Because
natural surfaces in a watershed transmit water slowly to the stream as
subsurface flow, base flow in a stream is often from subsurface flow
and groundwater that steadily contributes flow between precipitation
events. The impervious surfaces caused by development alter this
process, preventing precipitation from infiltrating, and resulting in a
reduction in base flow of the stream (Simmons and Reynolds 1982, p.
1752; Wang et al. 2001, p. 255; 2003, p. 825; Wheeler et al. 2005, p.
151). Development within and adjacent to riparian areas has proven to
be a significant threat to riparian and aquatic biological communities
(Medina 1990, p. 351), with even low levels of development causing
adverse impacts within a watershed (Wheeler et al. 2005, p. 142).
Development can alter the nature of stream flow dramatically, changing
streams from perennial to ephemeral, which can have direct consequences
to stream fauna (Medina 1990, pp. 358-359). Medina (1990, pp. 358-359)
found that development reduced vegetation in streams and changed flow
regimes, which resulted in a decrease in abundance of fish.
Development in and near stream courses usually results in removal
of riparian vegetation, which leads to a number of changes to streams
(Wheeler et al. 2005, p. 151). Riparian vegetation stabilizes
streambanks and reduces bank erosion (Beeson and Doyle 1995, p. 983;
Wynn and Mostaghimi 2006, p. 400), and helps moderate urban stream
temperatures (LeBlanc et al. 1997, p. 445). Because riparian vegetation
contributes leaves, wood, organic debris, and terrestrial invertebrates
to streams, vegetation removal can often drastically alter food webs in
streams (Vannote et al. 1980, p. 130; Hawkins and Sedell 1981, p. 387;
Reid 1993, p. 74). Also, large woody debris can be an important
component of stream channels because the debris stabilizes stream banks
(Keller and Swanson 1979, p. 361), creates pools (Keller and Swanson
1979, p. 361; Rinne and Minckley 1985, p. 150), and provides habitat
for macroinvertebrates (Benke et al. 1985, pp. 8-13; Rinne and Minckley
1985, p. 150) and fishes (Angermeier and Karr 1984, p. 716; Flebbe and
Dolloff 1995, p. 579). Riparian vegetation also moderates stream
temperatures (LeBlanc et al. 1997, p. 445). In small and medium-sized
streams, riparian vegetation shades and cools the stream; loss of
riparian vegetation contributes to warming of the stream (Barton et al.
1985, p. 365; LeBlanc et al. 1997, p. 445). Wang et al. (2003, p. 825)
found that the maximum daily water temperature of streams in urbanized
settings in Wisconsin and Minnesota increased by 0.25 [deg]C (0.5
[deg]F) with every 1 percent increase in the impervious area of the
watershed.
Urban streams enlarge their channels by eroding their banks; this
erosion, together with runoff from urban construction activities, adds
fine sediment to the stream (Waters 1995, p. 43; Trimble 1997, p. 1442;
Wheeler et al. 2005, p. 151), increasing turbidity, which can alter
stream habitat productivity, adversely affect the food base for fish,
eliminate rearing habitats, and fill in pool habitat (Waters 1995, p.
43). Because urbanization typically results in loss of riparian
vegetation as areas near streams are cleared, riparian areas can lose
the natural ability to absorb and filter out metals, fine sediment, and
nutrients from overland runoff (McNaught et al. 2003, p. 7).
Development can affect water quality in a number of ways. Urban
runoff contains a variety of chemical pollutants including petroleum,
metals, and nutrients from a variety of sources such as automobiles and
building materials (Wheeler et al. 2005, p. 153). Some pollutants
contain the nutrients nitrogen and phosphorus, which can cause a body
of water to become nutrient-enriched and stimulate the growth of
aquatic plant life resulting in the depletion of dissolved oxygen. This
can adversely affect fish by reducing dissolved oxygen to lethal levels
(Hassler 1947, pp. 383-384; Cantrell 2009, p. 15). Development also
leads to increases in the number of dumps and landfills that leach
contaminants into ground and surface water, reducing water quality and
thereby degrading roundtail chub habitat. Similarly, wastewater
treatment plants that accompany development also can contaminate ground
and surface water (Winter et al. 1998, p. 66). Pharmaceuticals and
personal care products also may contain hormones, which are present in
wastewater, and can have significant adverse effects to fishes,
particularly fish reproduction (Kime 1995, p. 52; Rosen et al. 2007,
pp. 1-4). The use of pesticides is also a source of water quality
contamination from agricultural and residential use, which can have
lethal and sublethal effects to fish (Ongley 1996). The use of
pesticides occurs adjacent to 9 populations of roundtail chub in
Arizona (Cantrell 2009, p. 12).
The physical and chemical alterations of stream systems due to
urbanization cause significant changes to the stream biological
community (Wheeler et al. 2005, p. 153). Urbanized streams have fewer
numbers and species of macroinvertebrates (Richards and Host 1994, p.
195; Kemp and Spotila 1997, p. 55; Kennen 1998, p. 3), and exhibit
reduced biological health (Kennen 1998, p. 3). Urban streams also have
lower overall abundance and diversity of fishes (Tramer and Rogers
1973, p. 366; Scott et al. 1986, p. 555; Medina 1990, p. 351; Weaver
and Garman 1994, p. 162; Wang et al. 2000, p. 255; 2003, p. 825).
Little is known about how urban development and the corresponding
physical and chemical changes in streams result in changes in the
stream ecosystem, although the physical changes appear more important
in this process than the chemical changes (Wheeler et al. 2005, p.
154).
The net result of urbanization for roundtail chub is a decrease in
habitat suitability, most significantly through a reduction in stream
flow, although also through an increase in the probability of the
presence of nonnative aquatic species that prey on and compete with
roundtail chub (see ``Nonnative Species'' section below). As described
above, development typically involves increased water use in the form
of diversions of water from both surface flows and connected
groundwater (Glennon 1995, pp. 133-139). The physical changes
associated with development also result in a more ``flashy'' system, as
described above, where runoff from precipitation rapidly exits the
watershed, increasing flood flows, and decreasing base flow. These
hydrologic changes can lead to streams

[[Page 32365]]

changing from perennial to intermittent, and result in a corresponding
decrease in fish abundance (Medina 1990, p. 351).
The effects of urban and rural development are expected to increase
as human populations increase. Development has continually been
increasing in the southwestern United States. Arizona increased its
population by 394 percent from 1960 to 2000, and is second only to
Nevada as the fastest growing State in terms of human population
(Social Science Data Analysis Network 2000, p. 1). Growth rates in
Arizona counties with historical or extant roundtail chub populations
are also significant and increasing: Maricopa (463 percent); Cochise
(214 percent); Yavapai (579 percent); Gila (199 percent); Graham (238
percent); Apache (228 percent); Navajo (257 percent); Yuma (346
percent); LaPaz (142 percent); and Mohave (1,904 percent) (Social
Science Data Analysis Network 2000). Population growth trends in
Arizona are expected to continue into the future. The Phoenix
metropolitan area, founded in part due to its location near the
junction of the Salt and Gila Rivers, is a population center of 3.6
million people. The Phoenix metropolitan area is the sixth largest in
the United States and is located in the fastest growing county in the
United States since the 2000 census (McKinnon 2006a). Traditionally
rural portions of Arizona are also predicted to see huge increases in
human population. Developing cities and towns of the Verde watershed
are expected to more than double in the next 50 years, which, as
described above, is expected to threaten riparian and aquatic
communities of the Verde Valley where roundtail chubs occur (Girmendonk
and Young 1993, p. 47; American Rivers 2006; Paradzick et al. 2006, p.
89). Chino Valley, at the headwaters of the Verde River, grew by 22
percent between 2000 and 2004. Gila County, which includes reaches of
Tonto Creek and the Salt, White, and Black Rivers, grew by 20 percent
between 2000 and 2003 (U.S. Census Bureau 2005). In New Mexico, a water
settlement in 2004 allows New Mexico the right to withhold 4.5 billion
gal (13,800 ac-ft) of surface water every year from the Gila and San
Francisco Rivers (McKinnon 2006d). Project details are still under
development, so the impact of this project on aquatic resources has not
yet been evaluated; however, the project represents another potential
withdrawal of water from occupied habitat.
Given the arid nature of the Southwest, the predictions of further
growth in an already large population center, and the adverse impacts
to aquatic habitats that are associated with development, development
will continue to be a threat to the roundtail chub. Urban and rural
development are considered a threat in every stream currently occupied
by roundtail chub (Cantrell 2009, p. 15).
Road Construction, Use, and Maintenance
Roads are a threat to roundtail chub and its habitat due to a
variety of factors including fragmentation, modification, and
destruction of habitat; increase in genetic isolation; facilitation of
the spread of nonnative species via human vectors; increases in
recreational access and the likelihood of subsequent, decentralized
urbanization; and contributions of contaminants to aquatic communities
(Burns 1972, p. 1; Barrett et al. 1992, p. 437; Eaglin and Hubert 1993,
p. 884; Warren and Pardew 1998, p. 637; Waters 1995, p. 42; Jones et
al. 2000, pp. 82-84; Angermeier et al. 2004, pp. 19-24; Wheeler et al.
2005, pp. 145, 148-149).
Construction and maintenance of roads and highways near riparian
areas can be a source of sediment and pollutants (Waters 1995, p. 42;
Wheeler et al. 2005, pp. 145, 148-149). Sediment can adversely affect
fish populations by interfering with respiration; reducing the
effectiveness of fish's visually-based hunting behaviors; and filling
in interstitial spaces of the substrate, which reduces reproduction and
foraging success of fish (Wheeler et al. 2005, p. 145). Excessive
sediment also fills in intermittent pools that roundtail chub utilize
as habitat. Fine sediment pollution in streams impacted by highway
construction without the use of sediment control structures was 5 to 12
times greater than control streams (Wheeler et al. 2005, p. 144).
Excessive sediment can also affect the ability of roundtail chubs to
forage. Sedimentation can alter the aquatic macroinvertebrate
community, thereby reducing the food base for roundtail chubs.
Increased turbidity may impede the ability of roundtail chubs to forage
by reducing underwater visibility (Barrett et al. 1992, p. 437; Waters
1995, pp. 173-175).
Contaminants (hydrocarbons such as petroleum based products, and
metals, including iron, zinc, lead, cadmium, nickel, copper, and
chromium) are associated with highway construction and use (Foreman and
Alexander 1998, p. 220; Wheeler et al. 2005, pp. 146-149). Many of
these contaminants are suspected toxicants to aquatic organisms. Few
studies have addressed the toxicity of highway runoff, but some
comparisons of macroinvertebrate communities above and below highway
crossings indicate that there are reductions in diversity and
pollution-sensitive species below highway crossings, especially where
small streams receive runoff from large highway sections (Wheeler et
al. 2005, p. 148). In areas with cold winter weather conditions,
deicing is common to clear snow and ice from roadways. Deicing can
contribute sodium chloride and other chemical contaminants to water
ways, reducing water quality, which can cause fish stress or mortality
(Wheeler et al. 2005, p. 147). Roads also inevitably contribute to
contaminant spills from vehicle accidents. Most hazardous chemicals are
transported by trucks, and such spills are common and can contaminate
water bodies and cause fish kills (Wheeler et al. 2005, pp. 147-148).
Road construction can also impact roundtail chub through physical
changes to the stream channel. Channelization, often a necessary
component of urban road construction, can have numerous effects on the
natural structure and ecosystem function of stream systems (Poff et al.
1997, p. 773; Poole 2002, p. 641). As discussed in the ``Logging, Fuel
Wood Cutting, Mining, and Channelization'' section, channelization can
affect roundtail chub habitat by reducing its complexity, eliminating
cover, reducing nutrient input, improving habitat for nonnative
species, changing sediment transport, altering substrate size, and
reducing the length of the stream and therefore the amount of aquatic
habitat available (Gorman and Karr 1978, p. 507; Simpson et al. 1982,
pp. 122-132; Propst 1999, p. 25; Schmetterling et al. 2001, p. 6).
Roads can restrict the movement of stream fishes, resulting in
populations becoming more isolated and fragmented. Culverts, a common
feature of road stream crossings, are a well-known barrier to fish
movement. Culverts themselves provide poor fish habitat due to low-
bottom complexity and uniformly high-flow velocities (Slawski and
Ehlinger 1998, p. 676). Fish movement is inhibited or prevented by high
current velocities and shallow depths inside culverts, along with
vertical drops commonly associated with the culvert outflow (U.S.
Department of Transportation 2007, pp. 3-9). Warren and Pardew (1998,
p. 637) found that overall fish movement was an order of magnitude
lower through culverts than through other crossing types or natural
channels in small streams. Such barriers can isolate fish populations,
resulting in reduced

[[Page 32366]]

genetic diversity and increased probability of extinction due to
demographic instability and impeded recolonization. Fragmentation of
roundtail chub habitat increases the probability of local extirpation
(Fagan et al. 2002, p. 3250).
By definition, roads create access to otherwise inaccessible areas
or increase access to previously remote areas. This increased access
results in increased human visitation, thereby increasing the frequency
and significance of anthropogenic threats to aquatic ecosystems and
further fragmenting the landscape. Further, increased access often
leads to increased urban and agricultural development. Urbanization is
the most significant of these development activities; it alters a
watershed, such as through building construction, which changes rural
areas from such uses as farming and grazing to residential and
industrial areas. Wheeler et al. (2005; pp. 149-150) concluded that
``new highways clearly and purposely provide impetus for urban
development'' although they noted that few studies, if any, have
specifically documented this. Roads nonetheless do clearly have a
relationship to urban and rural development, which can alter physical
and chemical characteristics of streams due to increases in
contaminants and changes to the watershed that alter stream flow, as
discussed in the ``Urban and Rural Development'' section above.
Recreation
As discussed above, population growth trends are expected to
continue into the future throughout the range of the roundtail chub in
the lower Colorado River basin, dramatically increasing human
populations. Expanding population growth leads to higher demand for
recreational opportunities and recreational use. In the arid Southwest,
the human desire to recreate in or near water, and the relative
scarcity of such recreational opportunities, tends to focus impacts on
riparian areas. Recreation-related impacts to aquatic ecosystems are
particularly evident along stream reaches of the Salt and Verde River
watersheds near the Phoenix metropolitan area, which are visibly
degraded by ongoing use. Impacts of recreation are highly dependent on
the type of activity, with activities such as hiking having little
impact and activities such as off-highway vehicle (OHV) use potentially
having severe impacts on aquatic habitats.
An example of a recreation use impacted area within the existing
distribution of the roundtail chub is the Verde Valley. The reach of
the Verde River that winds through the Verde Valley receives a high
amount of recreational use from people living in central Arizona
(Paradzick et al. 2006, pp. 107-108). Increased human use results in
trampling of nearshore vegetation and reduced water quality.
Recreational impacts in Fossil Creek illustrate that such damage can be
quite severe. Fossil Creek is a tributary of the Verde River and an
extant locality of roundtail chub. A number of environmental groups
recently sent a letter to the Coconino National Forest requesting
emergency action to address the effects of ongoing recreational use in
Fossil Creek. The authors cited excessive and damaging impacts of
recreational uses on the creek and riparian habitat, including vehicles
crushing vegetation, proliferation of social trails, kayak impacts,
severe sanitation deficiencies, and an exceptional amount of trash
(American Rivers et al. 2007, pp. 1-4). The effects to roundtail chub
from these actions are unknown, but potentially adverse.
OHV use has grown considerably in Arizona, and is a recreational
use that can have severe adverse impacts to natural areas. As of 2007,
385,000 OHVs were registered in Arizona (a 350 percent increase since
1998) and 1.7 million people (29 percent of the Arizona's public)
engaged in off-road activity from 2005-2007. Over half of OHV users
reported that driving off-road was their primary activity, versus using
the OHV for the purpose of access or transportation to hunting,
fishing, or hiking. Ouren et al. (2007, pp. 16-22) provide additional
data on the effects of OHV use on wildlife. OHV trails often travel
through undeveloped habitat and cross directly through water bodies.
OHV use may also reduce vegetation cover and plant species diversity,
reducing infiltration rates, increasing erosion, and reducing habitat
connectivity (Ouren et al. 2007, pp. 6-7, 11, 16). As discussed above,
reducing vegetative cover and increasing sedimentation is a result of
other land uses as well, such as livestock grazing and urbanization,
and can have numerous adverse effects to roundtail chub. Voeltz (2002)
noted specific OHV use-related problems with recreation in two streams
with known populations of roundtail chub, the upper Gila River and Oak
Creek. Recreation occurs in every stream occupied by roundtail chub in
the lower Colorado River basin (Cantrell 2009, p. 15).
Logging, Fuel Wood Cutting, Mining, and Channelization
Logging and mining were more widespread historically and likely
were responsible for alteration of much of the roundtail chub's
historical habitat. Chamberlain in 1904 listed mining as one of three
primary causes of ``extinction'' of fishes in the lower Colorado River
basin (along with vegetation removal from grazing, logging and other
activities, and water use) (Minckley 1999, p. 215). The current mining
of sand, gravel, iron, gold, copper, or other materials remains a
potential threat to the habitat of roundtail chub for many of these
same reasons. Drilling for fuels such as oil and natural gas has very
similar effects (Hartman 2007, p. 1) and is occurring within the range
of the roundtail chub in Arizona (Cantrell 2009, p. 12). The effects of
mining activities on populations include adverse effects to water
quality and lowered flow rates due to dewatering of nearby streams
needed for mining operations (Arizona Department of Environmental
Quality 1993, pp. 61-63). Sand and gravel mining removes riparian
vegetation and destabilizes streambanks, resulting in habitat loss for
the roundtail chub (Brown et al. 1998, p. 979). Voeltz (2002, pp. 34-
35, 42) identified mining as a significant threat in Boulder, Burro,
and Eagle Creeks due to the release of toxic effluents into aquatic
systems from mining operations, and water depletion for use in mining
operations, and noted that contaminants in the form of acidified flows
originating from mining operations in Cananea, Mexico, have been
documented in the past in the San Pedro River, a stream in which the
roundtail chub no longer occurs. Girmendonk and Young (1997, p. 35)
noted that sand and gravel mining on West Clear Creek may have limited
the suitability of that stream to support roundtail chub near the mouth
of the Verde River. Mining is a land use in the basins of 24 out of 31
currently extant roundtail chub populations (Voeltz 2002; Cantrell
2009).
Logging and fuel wood cutting is largely a threat of the past
(resulting from previous management practices no longer in place),
although these activities resulted in profound changes in many streams
of the Southwest including those in which the roundtail chub occurs
(Minckley and Rinne 1985, pp. 150-151; Minckley 1999, p. 216). The
alteration of watersheds resulting from logging is deleterious to fish
and other aquatic life forms (e.g., Burns 1972, p. 1; Eaglin and Hubert
1993, p. 844), largely due to increases in surface

[[Page 32367]]

runoff, sedimentation, and mudslides, and the destruction of riparian
vegetation (Lewis 1998, p. 55; Jones et al. 2000, p. 81). All of these
effects negatively impact fish (Burns 1972, p. 15; Eaglin and Hubert
1993, p. 844; Barrett et al. 1992, p. 437; Warren and Pardew 1998, p.
637) by lowering water quality and reducing the quality and quantity of
pools, either by filling them with sediment, reducing the quantity of
large woody debris necessary to form pools, or imposing barriers to
movement. Logging is a land use in the watersheds of 17 of the
remaining 31 streams known to contain roundtail chub populations
(Voeltz 2002).
Channelization of streams is also a major factor in loss of habitat
for roundtail chub. The U.S. Environmental Protection Agency defines
channelization as: ``any activity that moves, straightens, shortens,
cuts off, diverts, or fills a stream channel, whether natural or
previously altered. Such activities include the widening, narrowing,
straightening, or lining of a stream channel that alters the amount and
speed of the water flowing through the channel. Examples of
channelization are: lining channels with concrete; pushing gravel from
the stream bed and placing it along the banks; and placing streams into
culverts'' (U.S. Environmental Protection Agency 2005, p. 1).
Channelization has occurred or is occurring in roundtail chub habitats
to drain marshes and reclaim bottomlands for agriculture or roads
(Hendrickson and Minckley 1984, p. 131; Propst 1999, p. 25); to create
irrigation diversions; to control mosquitoes; to reduce
evapotranspiration and speed water delivery to downstream metropolitan
and agricultural areas (U.S. Soil Conservation Service 1949, p. 3;
Burkham 1970, p. B1); and as flood control to protect fields,
buildings, or structures such as bridges (Pearthree and Baker 1987, p.
49). Channelization can affect roundtail chub habitat by reducing its
complexity, eliminating cover, reducing nutrient input, improving
habitat for nonnative species, changing sediment transport, altering
substrate size (usually from coarse sediments like gravel and sand to a
finer silt substrate), and reducing the length of the stream and
therefore the amount of aquatic habitat available (Gorman and Karr
1978, p. 513; Simpson et al. 1982, pp. 122-132; Propst 1999, p. 25;
Schmetterling et al. 2001, p. 6; U.S. Environmental Protection Agency
2005, pp. 1-4). Moyle (1976, p. 179) compared channelized and
unchannelized sections of a California stream and found a two-thirds
reduction in the biomass of fish and invertebrates in channelized
locations compared to unchannelized reaches, as well as differences in
fish and macroinvertebrate (animals lacking a vertebral column, such as
aquatic insects) species composition. Channelization may reduce the
recruitment of fishes by eliminating nursery habitat through the
removal of gradually sloping streambanks, reducing the extent of
nearshore habitats with low water velocity (Scheidegger and Bain 1995,
p. 125; M[eacute]rigoux and Ponton 1999, p. 177; Meng and Matern 2001,
p. 750).
High-Intensity Wildfires
Low-intensity fire has been a natural disturbance factor in
forested landscapes for centuries, and low-intensity fires were common
in southwestern forests and grasslands prior to European settlement
(Rinne and Neary 1996, pp. 135-136). Rinne and Neary (1996, p. 143)
discuss the current effects of fire management policies on aquatic
communities in Madrean Oak Woodland biotic communities, a community
type that comprises large portions of some watersheds occupied by
roundtail chub. They concluded that existing wildfire suppression
policies intended to protect the expanding number of human structures
on forested public lands have altered the fuel loads in these
ecosystems and increased the probability of devastating wildfires.
Other researchers have also found that fire suppression policies in
combination with other land uses have increased the probability of
high-intensity fire due to past land use, fire suppression, and
unnaturally high fuel loadings (Cooper 1960, pp. 161-162; Covington and
Moore 1994, pp. 45-46; Swetnam and Baison 1994, pp. 12-13; Touchan et
al. 1995, pp. 268-272; White 1985, p. 589). Not surprisingly, the
intensity (size and severity) of forest fires has increased in recent
times (Covington and Moore 1994, p. 40; Westerling et al. 2006, p.
940).
The effects of these catastrophic wildfires include the removal of
vegetation, the degradation of watershed condition, altered stream
behavior, and increased sediment and ash flows into streams. These
effects can harm fish communities, as observed in the 1990 Dude Fire,
when corresponding ash flows drastically reduced some fish populations
in Dude Creek and the East Verde River (Voeltz 2002, p. 77). Fire has
become an increasingly significant threat in lower-elevation
communities as well. Esque and Schwalbe (2002, pp. 180-190) discuss the
effect of wildfires in the upper and lower subdivisions of Sonoran
desertscrub. The widespread invasion of nonnative annual grasses, such
as brome (Bromus sp.) and Mediterranean grasses (Schismus sp.), appear
to be largely responsible for altered fire regimes that have been
observed in these communities, which are not adapted to fire (Esque and
Schwalbe 2002, p. 165). African buffelgrass (Pennisetum ciliare) is
recognized as another invading nonnative plant species throughout the
lower elevations of northern Mexico and Arizona. Nijhuis (2007, pp. 1-
7) discusses the spread of nonnative buffelgrass within the Sonoran
Desert of Arizona and adjoining Mexico, citing its ability to out-
compete native vegetation and present significant risks of fire in an
ecosystem that is not adapted to fire. In areas comprised entirely of
native plant species, ground vegetation density is mediated by barren
spaces that do not allow fire to carry itself across the landscape.
However, in areas where nonnative grasses have become established, the
fine fuel load is continuous, and fire is capable of spreading quickly
and efficiently (Esque and Schwalbe 2002, p. 175). These nonnative
grasses thus increase the potential for catastrophic wildfire.
After disturbances such as fire, nonnative grasses may exhibit
dramatic population explosions, which hasten their effect on native
vegetative communities. Additionally, with increased fire frequency,
these population explosions ultimately lead to a type-conversion of the
vegetative community from desertscrub to grassland (Esque and Schwalbe
2002, pp. 175-176). Fires carried by the fine fuel loads created by
nonnative grasses often burn at unnaturally high temperatures, which
may result in soils becoming hydrophobic (water repelling), exacerbate
sheet erosion, and contribute large amounts of sediment to receiving
water bodies, thereby affecting the health of the riparian community
(Esque and Schwalbe 2002, pp. 177- 178). The siltation of isolated,
remnant pools in intermittent streams significantly affects lower-
elevation species by increasing the water temperature, reducing
dissolved oxygen, and reducing or eliminating the permanency of pools,
as observed in pools occupied by lowland leopard frogs (Rana
yavapaiensis) and native fish (Esque and Schwalbe 2002, p. 190).
Fires in the Southwest frequently occur during the summer monsoon
season. As a result, fires are often followed by rain that washes ash-
laden debris into streams. Rinne (2004, p. 151) found significant
reductions in fish abundance as a result of these ash flows,

[[Page 32368]]

with reductions in fish abundance ranging from 70 to 100 percent.
Extreme summer fires, such as the 1990 Dude Fire, and corresponding ash
flows, have drastically reduced some fish populations. Some recent
examples of extreme summer fires that have reduced native fish
populations include the 2002 Rodeo-Chedeski Fire, the 2003 Aspen Fire,
and the 2004 Willow Fire, all of which burned parts of watersheds
occupied by roundtail chub. Carter and Rinne (unpubl. data) found that
the Picture Fire both benefited and eliminated headwater chub, a
closely related species that occurs in similar habitat, from portions
of Spring Creek. The fire eliminated chubs from Turkey Creek, a
tributary to Spring Creek. In other parts of Spring Creek, however,
chubs initially declined but later thrived after the fire, presumably
because most of the nonnative fishes were eliminated.
Dunham et al. (2003, pp. 189-190) examined how fire affects
nonnative species invasions; although habitat alteration over time can
facilitate nonnative species with wider habitat tolerances, native
species may be better able to withstand ash flows and flooding. Thus
immediately post-fire, nonnatives may be completely eliminated and the
few natives present can take advantage of the reduction in predators.
But such events, at a minimum, represent a genetic bottleneck (drastic
reduction in population size) for the species that could adversely
impact populations via genetic threats, such as inbreeding depression
(reduced health due to elevated levels of inbreeding) and genetic drift
(a reduction in gene flow within the species that can increase the
probability of unhealthy traits) (Meffe and Carrol 1994, pp. 156-167).
Many roundtail chub populations are fragmented and isolated. Fagan et
al (2002, p. 3254) found that, as a result of this fragmentation and
isolation, roundtail chub has moderately high risk of local
extirpation. Dunham et al. (2003, pp. 188-189) found that the threat of
fire to fish populations is much greater for highly fragmented and
isolated populations of fishes.
Undocumented Immigration and International Border Enforcement and
Management
Cantrell (2009, p. 12) indicated that undocumented immigration and
international border enforcement and management could be a threat in
nine areas occupied by roundtail chub. Because the roundtail chub is
extirpated from most of the southern portions of its range, such as the
San Pedro River, this threat is more likely to affect potential
recovery areas than currently occupied habitats, but is a possible
threat in some occupied streams. Undocumented immigrants and smugglers
attempt to cross the International border from Mexico into the United
States in areas historically and currently occupied by the roundtail
chub. These illegal border crossings and the corresponding efforts to
enforce U.S. border laws and policies have been occurring for many
decades with increasing intensity and have resulted in unintended
adverse effects to biotic communities in the border region. During the
warmest months of the year, many attempted border crossings occur in
riparian areas that serve to provide shade, water, and cover. Increased
U.S. border enforcement efforts that began in the early 1990s in
California and Texas have resulted in a shift in crossing patterns and
increasingly concentrated levels of attempted illegal border crossings
into Arizona (Segee and Neeley 2006, p. 6).
Traffic on new roads and trails from illegal border crossing and
enforcement activities, as well as the construction, use, and
maintenance of enforcement infrastructure (e.g., fences, walls, and
lighting systems), leads to compaction of streamside soils, and the
destruction and removal of riparian vegetation. Current border
infrastructure projects, including vehicle barriers and pedestrian
fences, are located specifically in valley bottoms and have resulted in
direct impacts to water courses and altered drainage patterns (Service
2008, p. 4). These activities also produce sediment in streams, which
affects their suitability as habitat for roundtail chub by reducing
their permanency and altering their physical and chemical parameters.
Riparian areas along the upper San Pedro River have been impacted by
abandoned fires that undocumented immigrants started to keep warm or
prepare food (Segee and Neeley 2006, p. 23).
Undocumented immigrants use wetlands for bathing, drinking, and
other uses (Segee and Neeley 2006, pp. 21-22). These activities can
contaminate the water quality of the wetlands and lead to reductions in
habitat quality for roundtail chub (Rosen and Schwalbe 1988, p. 43;
Segee and Neeley 2006, pp. 21-22). In addition, numerous observations
of littering and destruction of vegetation and wildlife occur annually
throughout the border region, which can adversely affect the quality of
habitat for the roundtail chub (Service 2006, p. 95).
Conservation Actions Relevant to Factor A
There are several existing conservation agreements for native fish
species that include roundtail chub (discussed in detail in Factor E
below): the Utah Department of Natural Resources' ``Range-wide
conservation agreement and strategy for roundtail chub (Gila robusta),
bluehead sucker (Catostomus discobolus), and flannelmouth sucker
(Catostomus latipinnis)'' (Range-wide Agreement; Utah Department of
Natural Resources 2002); the New Mexico Department of Game and Fish's
(NMDGF) ``Colorado River Basin Chubs Recovery Plan'' (New Mexico Plan;
Carman 2006), which includes the headwater and Gila chubs; and the
AGFD's ``Arizona Statewide Conservation Agreement for Roundtail Chub
(Gila robusta), Headwater Chub (Gila nigra), Flannelmouth Sucker
(Catostomus latipinnis), Little Colorado River Sucker (Catostomus
spp.), Bluehead Sucker (Catostomus discobolus), and Zuni Bluehead
Sucker (Catostomus discobolus yarrowi)'' (Arizona Agreement; AGFD
2006).
The Range-wide Agreement, Arizona Agreement, and New Mexico Plan
all include actions intended to reduce the threat of habitat loss. The
Range-wide Agreement recommends enhancing and maintaining habitat for
roundtail chub, including: Enhance and/or restore connectedness and
opportunities for migration of the subject species to disjunct
populations where possible; restore altered channel and habitat
features to suitable conditions; provide flows needed for all life
stages; maintain and evaluate fish habitat improvements; and install
regulatory mechanisms for the long-term protection of habitat (e.g.,
conservation easements, water rights). The Arizona Agreement identifies
the need to secure, enhance, and create habitat as one of its
conservation strategy tasks and includes these subtasks:
(1) Maintain instream flow;
(2) Manage detrimental nonnative fish and other aquatic species;
(3) Evaluate effectiveness of nonnative management efforts;
(4) Restore natural fire regimes;
(5) Manage the spread of infectious diseases and parasites to
habitats of the subject species;
(6) Enhance and/or restore connectedness;
(7) Develop appropriate flow recommendations for areas where
existing flow regimes are inadequate;
(8) Implement flow recommendations;
(9) Restore altered channel and habitat features;

[[Page 32369]]

(10) Create, maintain, and evaluate fish refugia throughout
historic range; and
(11) Maintain habitat quality.
The New Mexico Plan identifies the need to address habitat loss,
including:
(1) Identify and determine habitat requirements for all life
history stages of roundtail chub in the San Juan and Gila River basins;
(2) Support efforts within existing programs to enable habitat
restoration and protection for recovery;
(3) Identify and secure resources to promote habitat restoration
and protection;
(4) Rehabilitate, restore, and secure historical habitats where
chub restoration is possible;
(5) Inform private and public landowners about practices that
promote diverse, functional aquatic and riparian habitats;
(6) Inform private and public landowners about how to protect chub
habitat;
(7) Identify and secure funding to promote habitat restoration and
protection; and
(8) Establish formal agreements with willing participants to
enhance habitat and/or populations for recovery of roundtail chub.
Several actions are planned or have been implemented as a result of
the conservation agreements that address the threat of habitat loss.
They are discussed below.
The Nature Conservancy (Conservancy) is a signatory to the Arizona
Agreement. In Arizona, the Conservancy has launched its Nature Matters
fundraising campaign. This program raises private donations to support
cooperative land and water protection projects. The Conservancy
contacts landowners to explore their interest in placing their property
in a permanently protected status, then works cooperatively with its
agency partners to negotiate purchase and sale agreements and to
develop fundraising proposals and project financing. Properties are
identified and prioritized based on the quality of their riparian and
aquatic habitat as well as opportunities to secure surface water rights
or to file for new water rights to maintain instream flow.
In 2007, the Conservancy purchased the Upper Verde River Wildlife
Area, a 313-acre (ac) (127-hectare (ha)) parcel downstream from the
Verde River confluence with Granite Creek near Paulden, Arizona. The
Conservancy later received the donation of an additional 160 ac (65
ha). In total, the acquisition secured the largest remaining portion of
the Verde River headwaters still in private ownership and protects
roughly 1 mi (1.6 km) of high quality riparian and aquatic habitat from
development and improper livestock grazing. In 2008, the Conservancy
conveyed 293 ac (119 ha) of this property to the AGFD to be added to
the Upper Verde River Wildlife Area. In July of 2008, the Conservancy
and AGFD each filed for instream flow water rights with the Arizona
Department of Water Resources for the properties.
In 2008, the Conservancy completed two land acquisitions on the
middle Verde River within the 33-mi (53-km) stretch that Arizona State
Parks has designated for acquisition as the Verde River Greenway: a 20-
ac (8-ha) parcel upstream of Camp Verde that is adjacent to U.S. Forest
Service frontage on the river; and the 209-ac (85-ha) Rockin' River
Ranch property purchased with Arizona State Parks. The Rockin' River
property, located at the confluence of the Verde River and West Clear
Creek, includes 55 ac (22 ha) under irrigation with surface water
rights dating back to 1889. Protection of the property provides an
opportunity to retire and dedicate water rights to instream flow for
the benefit of wildlife including roundtail chub. The Conservancy
continues to meet with landowners on a willing-seller basis to explore
opportunities to protect additional lands along the river and in the
Big Chino Valley, which overlays the aquifer that is the primary
groundwater source for the upper Verde River, and to pursue private and
public funding to support land and water protection in the Verde
watershed. These actions could help secure instream flow and protect
riparian areas from harmful land uses, benefitting roundtail chub.
In 2006, the Conservancy received as a donation the Cobra Ranch
property at the headwaters of Aravaipa Creek near Klondyke, Arizona.
The addition of this property to the Conservancy's Aravaipa Canyon
Preserve protects over 1 mi (1.6 km) of stream channel and presents
significant habitat restoration opportunities. The Conservancy plans to
restore native vegetation on 100 ac (40 ha) of farm ground, and retire
irrigation, which will reduce draw-down of the aquifer and create
improved infiltration patterns on the farm. They will also
strategically plant native vegetation along the active channel to
restore the natural river channel. Fencing is being installed to remove
grazing from riparian areas, and planning is ongoing to restore a
natural fire regime. These actions will serve to restore a historical
cienega that once existed in the headwaters of Aravaipa Creek, and will
reduce overgrazing, dewatering, and sedimentation effects to the
roundtail chub in Aravaipa Creek.
The U.S. Forest Service is also a signatory to the Arizona
Agreement. The Tonto National Forest is working to establish an
instream flow water right on approximately 36 mi (58 km) of U.S. Forest
Service lands along Cherry Creek from its headwaters to the confluence
with the Salt River. Once in place, the water right should protect
enough flow to provide for roundtail chub habitat in perpetuity.
Similarly, through the Horseshoe and Bartlett Habitat Conservation
Plan, Salt River Project (SRP), a large water and electricity provider
for portions of Arizona, is implementing watershed management efforts
to maintain or improve stream flows in the Verde River, including
funding of stream gages and scientific studies, in-kind support for
watershed improvements, and administrative and legal efforts to curtail
stream flow reductions from illegal surface water diversions and
groundwater pumping.
The Arizona Agreement also includes provisions for addressing the
threat of catastrophic wildfire. A conservation strategy task is to
restore natural fire regimes in the watersheds of extant populations of
roundtail chub, including securing habitat through the use of
prescribed fire and noncommercial understory thinning to restore
natural fire regimes. Controlled prescribed fires reduce the risk of
catastrophic wild fires by reducing fuel loads. The New Mexico Plan
also identifies the need to support research to determine the tolerance
of roundtail chub to water quality parameters, particularly those that
may be altered during and after forest fires.
Summary of Factor A
Rivers, streams, and riparian habitats that are essential for the
survival of the roundtail chub are being adversely affected and
eliminated throughout the range of the species. Threats, including
water diversions, groundwater pumping, dams, channelization, and
erosion-related effects, are occurring that impact both the amount of
water available for habitat, as well as the water's suitability for
roundtail chub. Threats from flood control, development, roads, water
withdrawal, improper livestock grazing, recreation, and high-intensity
wildfire dry up, silt in, physically alter, and chemically pollute
habitats of the roundtail chub such that habitats become permanently
unsuitable. These threats have been documented historically and are
either occurring or likely to occur throughout the range of the
roundtail chub. These

[[Page 32370]]

threats reduce the habitat's suitability as cover for protection from
predators, as a foraging area, and as spawning and nursery areas.
Despite the conservation actions discussed above, the dewatering of
aquatic habitats in the arid lower Colorado River basin poses a
significant threat to all native fish of the region, including
roundtail chub. All of these threats are anthropogenic and can be
expected to continue, if not increase, given the predictions for
increases in human population expansion in the region. Efforts to
ameliorate these threats through established conservation agreements
have met with some success, but are in the early stages of
implementation.

Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes

Overutilization of roundtail chub for commercial, recreational,
scientific, or educational purposes is not considered a significant
threat to the roundtail chub in the lower Colorado River basin.
Roundtail chub is a permitted sport fish in Arizona (AGFD 2008). One
roundtail chub greater than 13 in. (33 cm) is allowed via angling per
day. The AGFD has also established a catch-and-release only, artificial
fly and lure only, single barbless hook, 7-month fishing season for
roundtail chub in Fossil Creek. A 4.5-mi (7.2-km) middle reach segment
of Fossil Creek will be open to catch-and-release fishing for roundtail
chub from Oct 3, 2009, through April 30, 2010. The remainder of the
year, the area is closed to all fishing. But angler use of roundtail
chub is light (C. Cantrell, AGFD, pers. comm. 2009), and we do not
believe that overutilization from current levels of angling is a threat
to the species in Arizona. In the upper Gila River in New Mexico, where
the species is not a legal sport fish (NMDGF 2008), there are reports
of anglers purposefully discarding chub species, which may be having a
negative effect on populations of roundtail chub locally (Voeltz 2002).
Several studies of fish species closely related to roundtail chub
indicate that handling for scientific purposes (research and
monitoring) may have some adverse effects on individual fish. Ruppert
and Muth (1997, p. 314) found that electrofishing caused spinal
hemorrhages in some juvenile humpback chub (Gila cypha), a closely
related species to roundtail chub, but did not affect short-term growth
or survival. Paukert et al. (2005, p. 649) found that use of hoop nets
affected fish growth and condition of bonytail; fish captured multiple
times grew less in length and weight than fish not recaptured. Fish
recaptured up to five times grew only 12.8 percent of their initial
weight compared to fish not recaptured, which grew 29.7 percent of
their initial weight. Ward et al. (in press) also found some mortality
from use of passive integrated transponder tags in related Gila chub
(G. intermedia) and bonytail, although mortality rate was low. We
believe the level of handling of roundtail chubs for scientific
purposes is low, and the results of these studies suggest that handling
roundtail chubs for scientific purposes is not a significant threat to
the species.
Conservation Actions Relevant to Factor B
Overutilization of roundtail chub is not believed to be a threat to
the species and is therefore not addressed in conservation planning
efforts. All three conservation agreements include action items to
identify threats; thus, if there is some unidentified threat from
overutilization or the degree of the threat has been underestimated,
the conservation agreements should serve to help identify this in the
future.
Summary of Factor B
Although roundtail chub is a legal sport fish in Arizona, available
information indicates that the species is not threatened by
overutilization as a game species from current levels of angling. There
is some information that collection for scientific purposes has some
adverse effects on individual fish; however, we do not believe that
handling roundtail chubs for scientific purposes is a significant
threat to the species.

Factor C. Disease or Predation

Nonnative Species
Nonnative species that compete with or prey on roundtail chub are a
serious and persistent threat to the continued existence of the
roundtail chub. Nonnative aquatic species include fishes, aquatic and
semi-aquatic mammals, reptiles, amphibians, crustaceans, mollusks
(snails and clams), insects, zooplankton, phytoplankton, parasites,
disease organisms, algae, and aquatic and riparian vascular plants. The
introduction and spread of nonnative species has long been identified
as one of the major factors in the continuing decline of native fishes
throughout North America and particularly in the Southwest (Miller
1961, p. 365; Lachner et al. 1970, pp. 1-4; Ono et al. 1983, p. 90;
Minckley and Deacon 1991; Carlson and Muth 1989, p. 220; Cohen and
Carlton 1995, p.1; Fuller et al. 1999, pp. 1-3; Clarkson et al. 2005,
p. 20; Mueller 2005, pp. 10-12; Olden and Poff 2005, p. 75). Nonnative
species may affect native fish and other aquatic fauna through numerous
means, including (all of which may be applicable to the roundtail
chub): Predation (Meffe et al. 1983, p. 316; Meffe 1985, p. 173; Marsh
and Brooks 1989, p. 188; Propst et al. 1992, p. 177; Blinn et al. 1993,
p. 139; Rosen et al. 1995, p. 251), competition (Lydeard and Belk 1993,
p. 370; Baltz and Moyle 1993, p. 246; Scoppotone 1993, p. 139; Douglas
et al. 1994, pp. 15-17), aggression (Meffe 1984, p. 1525; Karp and Tyus
1990, p. 25), habitat disruption (Hurlbert et al. 1972, p. 639;
Fernandez and Rosen 1996, p. 3), introduction of diseases and parasites
(Clarkson et al. 1997, p. 66; Robinson et al. 1998, p. 599), and
hybridization (Dowling and Childs 1992, p. 355; Echelle and Echelle
1997, p. 153). Because the impacts of competition with and predation by
nonnative species are often interrelated and difficult to discuss
separately, we will discuss all impacts of nonnative species in this
section.
In an evolutionary context, the native fish community of the lower
Colorado River basin, including roundtail chub, evolved with low
species diversity and with few predators and competitors and thus co-
evolved with few predatory fish species. In contrast, many of the
nonnative species co-evolved with high species diversity and many
predatory species (Clarkson et al. 2005, p. 21). A contributing factor
to the decline of native fish species cited by Clarkson et al. (2005,
p. 21) is that most of the nonnative species evolved behaviors, such as
nest guarding, to protect their offspring from these many predators,
while native species are generally broadcast spawners that provide no
parental care. In the presence of nonnative species, the reproductive
behaviors of native fish fail to allow them to compete effectively with
the nonnative species, and, as a result, the viability of native fish
populations is reduced.
In the Southwest, Miller et al. (1989, p. 22) concluded that
introduced nonnatives were a causal factor in 68 percent of the fish
extinctions in North America in the last 100 years. For 70 percent of
those fish still extant, but considered to be endangered or threatened,
introduced nonnative species are a primary cause of the decline
(Aquatic Nuisance Species Task Force 1994; Lassuy 1995, p. 391). The
widespread decline of native fish species from the arid southwestern
United States and Mexico from interactions with nonnative species has

[[Page 32371]]

been manifested in the listing rules of nine native species listed
under the Act whose historical ranges overlap with the historical and
current distribution of the roundtail chub: Bonytail (Gila elegans) (45
FR 27710; April 23, 1980), humpback chub (Gila cypha) (32 FR 4001;
March 11, 1967), Gila chub (Gila intermedia) (70 FR 66663; November 2,
2005), Colorado pikeminnow (Ptychocheilus lucius) (32 FR 4001; March
11, 1967), spikedace (Meda fulgida) (51 FR 23769; July 1, 1986), loach
minnow (Tiaroga cobitis) (51 FR 39468; October 28, 1986), razorback
sucker (Xyrauchen texanus) (56 FR 54957; October 23, 1991), desert
pupfish (Cyprinodon macularius) (51 FR 10842; March 31, 1986), and Gila
topminnow (Poeciliopsis occidentalis) (32 FR 4001; March 11, 1967). In
total within Arizona, 19 of 31 (61 percent) native fish species are
listed under the Act. Arizona ranks the highest of all 50 States in the
percentage of native fish species with declining trends (85.7 percent,
Stein 2002, p. 21; Warren and Burr 1994, pp. 6-18). In the Gila River
basin, introduction of nonnatives is considered a major factor in the
decline of all native fish species (Miller 1961, pp. 377-379; Williams
et al. 1985, p. 1; Minckley and Deacon 1991). In Arizona, release or
dispersal of new nonnative aquatic organisms is a continuing phenomenon
(Rosen et al. 1995, p. 259; Service 2008, p. 264).
Aquatic nonnative species are introduced and spread into new areas
through a variety of mechanisms, both intentional and accidental, and
authorized and unauthorized. Mechanisms for nonnative dispersal in the
southwestern United States include inter-basin water transfer (Service
2008, p. 1), sport fish stocking (Clarkson et al. 2005, p. 20),
aquaculture and aquarium releases (Courtenay 1993, pp. 35-62; Crossman
1991, p. 46; Crossman and Cudmore 2000, pp. 129-134; Mackie 2000, pp.
135-150), bait-bucket release (release of fish used as bait by anglers)
(Crossman 1991, p. 50; Litvak and Mandrak 1993, p. 6), and to control
other species (such as the introduction of herbivorous fish to control
aquatic plants) (Bailey 1978, p. 181; Courtney 1993, p. 37).
In the Verde River system alone, Rinne et al. (1998, p. 3)
estimated that over 5,300 independent stocking actions occurred that
involved 12 different species of nonnative fish species since the 1930s
and 1940s. If we extrapolate that effort over the same timeframe for
other historically occupied, larger-order systems known as recreational
fisheries (such as the Salt, upper Gila, Bill Williams, and San Pedro
Rivers, and Oak Creek and other tributaries with significant flow
throughout central and southern Arizona), in addition to the other
private stockings of stock tanks and other isolated habitat, the
magnitude of the nonnative species invasion over this timeframe becomes
clear. Subsequent to these efforts, but to a lesser extent, the spread
of bullfrogs and crayfish, both purposefully and incidentally,
commenced during the 1970s and 1980s (Tellman 2002, p. 43). We estimate
that nearly 100 percent of the habitat that historically supported
roundtail chub has been invaded over time, either purposefully or
indirectly through dispersal, by nonnative fishes and other aquatic
species.
Nonnative fishes known from within the historical range of
roundtail chub in the lower Colorado River basin include channel
catfish (Ictalurus punctatus), flathead catfish (Pylodictis olivaris),
red shiner (Cyprinella lutrensis), fathead minnow (Pimephales
promelas), green sunfish (Lepomis cyanellus), warmouth (L. gulosus),
bluegill (L. macrochiris), largemouth bass (Micropterus salmoides),
smallmouth bass (M. dolomieui), rainbow trout (Oncorynchus mykiss),
western mosquitofish (Gambusia affinis), carp (Cyprinus carpo), yellow
bullhead (Ameiurus natalis), black bullhead (A. melas), and goldfish
(Carassius auratus) (Bestgen and Propst 1989, pp. 409-410; Marsh and
Minckley 1990, p. 265; Sublette et al. 1990, pp. 112, 243, 246, 304,
313, 318; Abarca and Weedman 1993, pp. 6-12; Stefferud and Stefferud
1994, p. 364; Weedman and Young 1997, p. 1, Appendices B, C; Rinne et
al. 1998, pp. 3-6; Voeltz 2002, p. 88; Bonar et al. 2004, pp. 1-108;
Fagan et al. 2005, pp. 34, 38-39, 41). The fastest expanding nonnative
species are red shiner, fathead minnow, green sunfish, largemouth bass,
western mosquitofish, and channel catfish. These species are considered
to be the most invasive in terms of their negative impacts on native
fish communities (Olden and Poff 2005, p. 75).
Smaller size classes (juvenile and subadult fish) are more
vulnerable to predation because the size of a fish that a predatory
fish can consume is limited by the predator's gape size. Brouder et al.
(2000, p. 13) found that size class of native fishes consumed
(including roundtail chub) by predatory nonnative fishes in the Verde
River was 1.3 to 3.5 in (34 to 90 millimeters (mm)). This winnowing
effect results in a population of only large adult fish, which
eventually crashes. A spectacular example of this is the case of the
razorback sucker in Lake Mohave in Arizona and Nevada. For decades, no
recruitment was documented within the population, although large adults
(razorback sucker is a large species, with adults up to 20 in. (500 mm)
or longer in total length) remained common. This situation was possible
because razorback sucker are very long-lived, living 40 years or more
(McCarthy and Minckley 1987, p. 87). The population eventually crashed
in the 1990s because of a total lack of recruitment due to predation by
nonnative fish species on smaller, younger fish, although conservation
efforts have resulted in maintenance of a much smaller stocked
population (Service 2002a, pp. 9, 11; Mueller 2005, p. 11). A similar
population crash likely happened to bonytail, a species closely related
to roundtail chub, in Lake Mohave, with the crash happening sooner
because bonytail likely have a shorter life span (Service 2002b, p. 11,
A-6).
The introduction of more aggressive and competitive nonnative fish
has likely led to losses of roundtail chub (Voeltz 2002, p. 88). Dudley
and Matter (2000, p. 24) found that nonnative green sunfish prey on,
compete with, and virtually eliminate recruitment of Gila chub (a
closely related species to roundtail chub) in Sabino Creek in Arizona.
Similar effects of green sunfish on Gila chub have been documented in
Silver Creek in Arizona (Unmack et al. 2004, pp. 86-87), with
recruitment of Gila chub effectively eliminated by nonnative green
sunfish. In the Verde River mainstem, Bonar et al. (2004, p. 57) found
that nonnative fishes were approximately 2.6 times more dense per unit
volume of river than native fishes, and their populations were
approximately 2.8 times that of native fishes per unit volume of river.
Bonar et al. (2004, pp. 6-7) found that largemouth bass, smallmouth
bass, bluegill, green sunfish, channel catfish, flathead catfish, and
yellow bullhead all consumed native fish; although roundtail chub was
not detected in the diet of any nonnative fishes, this is likely only
due to the relative rarity of the species compared with other native
fish, as well as the short time necessary for a fish to be digested.
Roundtail chubs have been found in stomachs of largemouth bass in the
lower Salt River (P. Unmack, Arizona State University, pers. comm.
2008). Bestgen and Propst (1989, p. 406) reported that, of nonnatives
present in New Mexico, smallmouth bass, flathead catfish, and channel
catfish most impacted roundtail chub via predation. Native fishes,
including roundtail chub, have experienced significant declines in the
Salt River above Roosevelt Lake,

[[Page 32372]]

concurrent with a significant increase in flathead and channel catfish
numbers (Creef and Clarkson 1992, p. 5; Jahrke and Clark 1999 p. 9).
Brouder et al. (2000, p. 9), based on population estimates, determined
that nonnative species were likely suppressing roundtail chub
populations in two areas of the upper Verde River. Yard et al. (2008)
found that rainbow trout predation on humpback chub in Grand Canyon
likely resulted in significant levels of humpback chub mortality (Yard
et al. 2008, p. 53).
In some areas, the presence of nonnative species appears to be
limiting recruitment of roundtail chub, with only large adults
encountered during surveys (Cantrell 2009, p. 10). Red shiner is known
to compete with native southwestern cyprinids (Minckley and Deacon
1968, pp. 1427-1428; Minckley 1973, p. 138; Douglas et al. 1994, p. 9),
and prey on larval fishes (Ruppert et al. 1993, p. 397). In a study of
the roundtail chub population in the lower Salt and Verde Rivers, Bryan
and Hyatt (2004, p. 3) estimated adult population size of roundtail
chub to be 1,657, and found that this was a 74 percent decrease from
just 3 years earlier. Bryan and Hyatt (2004, pp. 12-13) concluded that
the roundtail chub population in the lower Salt and Verde Rivers was
declining rapidly due to low recruitment and high natural mortality,
and identified the ``negative impacts of competition and predation
[from the] introduction of nonnative fishes into roundtail chub
habitat'' as the likely cause of recruitment failure. They recommended
that stocking nonnative sport fish ``be carefully evaluated and
probably suspended, especially with regards to predatory species'' and
that stocking rainbow trout ``be thoroughly evaluated to determine its
economic impact and the specific impacts to the [roundtail] chub
population.''
Few if any studies of roundtail chub have effectively demonstrated
competition with nonnative fishes, although numerous authors have
considered it a threat (Bestgen and Propst 1989; Brouder et al. 2000;
Voeltz 2002; AGFD 2006, p. 5). Bestgen (1985, p. 53) found that diets
between rainbow trout and roundtail chub differed to an extent that
suggested interactive segregation of habitat and competition for food
resources, and although the health of the chub population indicated
competition was not severe, in higher densities, trout competition
could impact roundtail chub. Dudley and Matter (2000, p. 24) found that
green sunfish utilized the same habitats as Gila chub, a closely
related species to roundtail chub, and appeared to competitively
exclude them from preferred habitats. In the Colorado River in Grand
Canyon, Arizona, diet studies of humpback chub and rainbow trout show
strong overlap for aquatic invertebrates such as blackfly larvae
(Simuliidae) and Gammarus (Valdez and Ryel 1995; Yard et al. 2008), and
removal of nonnative trout is one factor suspected to be responsible
for a recent increase in humpback chub numbers in Grand Canyon (U.S.
Geological Survey 2006, p. 2). But because rainbow and brown trout
(Salmo trutta) have also been shown to prey on humpback chub in the
Grand Canyon (Yard et al. 2008), either a reduction in predation of
humpback chub, or a reduction in competition with humpback chub, or
both, may be responsible. Intuitively, both scenarios seem likely, and
this is the conventional wisdom of many researchers studying the
effects of nonnative fishes on natives in the southwest United States
(Marsh and Douglas 1997; Brouder et al. 2000; Voeltz et al. 2002; AGFD
2006, p. 5). Interestingly, Bestgen (1985, p. 53) noted that any
competition between rainbow trout and roundtail chub would likely be
significant only if rainbow trout occurred in high densities, and in
Grand Canyon, high densities of rainbow trout appear to be impacting
the humpback chub population (Yard et al. 2008; U.S. Geological Survey
2006). Marks et al. (in press) found that when nonnative fish species
were removed, roundtail chub numbers and recruitment increased
dramatically. Again, whether this is because nonnative species were
preying on or competing with roundtail chub is still a question, but
perhaps one that is not necessary to answer, for as Marks et al. (2008)
illustrate, the remedy for this threat is obvious.
Aquatic habitat alterations due to land use practices such as
livestock grazing and dams and dam operation may facilitate the spread
and persistence of nonnative fishes. Dams by their very purpose and
nature serve to reduce flood flows and increase base flows. Floods have
been identified as a potential means to disadvantage nonnative fishes
and thereby advantage native fishes (Meffe 1984, p. 1525). Haney et al.
(2008, p. 61) suggested that diminished river flow due to diversion may
be an important factor in loss of native fish from the Verde River.
Variation in river flows may provide both advantages and disadvantages
to aquatic species. The timing, duration, intensity, and frequency of
flood events has been altered to varying degrees by the presence of
dams along many stream courses within the range of the roundtail chub,
which affects fish communities. Flood pulses may help to reduce
populations of nonnative species because, unlike native fish that are
adapted to dramatic fluctuations in water conditions and flow regimes
(including random high-intensity events, such as flooding, extreme
water temperatures, and excessive turbidity), nonnative fishes appear
to be less well-adapted to such events. Dams, through their
amelioration of flood flows and increased base flows, may provide more
suitable habitat for nonnative fishes (Meffe 1984, p. 1525; Haney et
al. 2008, p. 61).
Livestock tanks also may facilitate the persistence and spread of
nonnative species of fish, amphibians, and crayfish that are
intentionally or unintentionally stocked by anglers and private
landowners (Rosen et al. 2001, p. 24). The management of stock tanks is
an important consideration for native fish restoration. Stock tanks
associated with livestock grazing can be intermediary ``stepping
stones'' in the dispersal of nonnative species from larger source
populations to new areas, and serve as source populations themselves
(Rosen et al. 2001, p. 24; Stone et al. 2007, p. 133).
Recent assessments of the fish fauna of the lower Colorado River
basin have provided additional insight into the importance of nonnative
fishes as a threat to native fish including the roundtail chub. The
Desert Fishes Team is an ``independent group of biologists and parties
interested in protecting and conserving native fishes of the Colorado
River basin'' and includes personnel from the U.S. Forest Service, U.S.
Bureau of Reclamation, Bureau of Land Management (BLM), University of
Arizona, Arizona State University, the Conservancy, and independent
experts (Desert Fishes Team 2003, p. 1). Desert Fishes Team (2003, p.
1) declared the native fish fauna of the Gila River basin to be
critically imperiled, citing habitat destruction and nonnative species
as the primary factors for the declines. The Desert Fishes Team
recommended control and removal of nonnative fish as an overriding need
to prevent the decline and ultimate extinction of native fish species
within the basin. Clarkson et al. (2005) discuss management conflicts
as a primary factor in the decline of native fish species in the
southwestern United States and declare the entire native fauna as
imperiled. The investigators cite nonnative species as the most
consequential factor leading to range-wide declines that prevent or
negate recovery efforts from being implemented or being successful

[[Page 32373]]

(Clarkson et al. 2005, p. 20). Clarkson et al. (2005, p. 20) note that
over 50 nonnative species have been introduced into the Southwest as
either sport fish or bait fish and are still being actively stocked,
managed for, and promoted by both Federal and State agencies as
nonnative recreational fisheries. To help resolve the conflicting
management mandates of native fish recovery and the promotion of
recreational fisheries, Clarkson et al. (2005, pp. 22-25) propose the
designation of entire watersheds as having either native or nonnative
fisheries and the management of watersheds to aggressively meet these
goals. Clarkson et al. (2005, p. 25) suggest that current management of
fisheries within the southwestern United States as status quo will have
serious adverse effects on native fish species and affect the long-term
viability of these species.
Mash and Pacey (2005, p. 59) concluded, ``The presence of nonnative
fishes alone precludes life-cycle completion by the natives. In the
absence of nonnatives, however, the natives thrive even in severely
altered habitats.'' This statement appears to apply well to roundtail
chub, and the best evidence is provided by the response of the species
when nonnative fishes are removed. Marks et al. (in press) examined the
effect of the removal of nonnative species on native species by
measuring fish abundance before and after a restoration project to
restore flow and chemically remove nonnative fishes (using the chemical
rotenone, a fish pesticide) to benefit native fish species including
the roundtail chub. They found that roundtail chub abundance increased
dramatically after restoration, and attributed most of this response to
the removal of nonnative fish species. Marks et al. (in press)
suggested that nonnative fish removal may be a more cost effective
method to restore native fish populations than flow restoration,
because the cost of chemical renovation was one-tenth the cost of flow
restoration at Fossil Creek. Roundtail chub is a stream species that
appears to require flow (Service 1987; Marks et al. in press). However,
AGFD has found that roundtail chub can thrive in pond habitats that are
free from nonnative species (AGFD 2009). Similarly, Mueller (2008, p.
2) examined the creation and performance of various nonnative fish-free
habitats for bonytail chub, a species closely related to the roundtail
chub, and found that recruitment occurred in hatchery-style holding
ponds, seemingly a less than optimal habitat for a species that occurs
in large rivers. Mueller (2008) concluded, ``In all cases, the common
denominator was not physical habitat conditions; it was simply the
absence of nonnative predators.'' As these findings illustrate, habitat
may not be the biggest concern for roundtail chub because the species
can thrive even in habitats that are seemingly less than ideal, as long
as nonnative species are not present. Despite some lack of direct
evidence of the effect of predation and recruitment on roundtail chub,
the results of removal of nonnative fish clearly demonstrate that
either predation or competition is occurring and is a serious threat to
the species.
Nonnative species predation may be having an effect on roundtail
chub that is known as the ``predator pit'' hypothesis (Messier 1994, p.
480). This hypothesis proposes that as a population of a species
decreases, especially when this happens rapidly, the predators of the
species will have an increasing impact on its survival due to the
relatively constant consumption amount, and thus increased consumption
rate. In situations where predator populations also increase, the
effect can be substantial. Given the variety of habitat-altering
activities that appear to be affecting roundtail chub throughout the
lower Colorado River basin, activities such as dewatering and
urbanization are likely reducing roundtail populations. With these
reductions, predation by nonnative species create a ``predator pit''
scenario.
At least two species of crayfish, the red swamp crayfish
(Procambaris clarki) and the northern or virile crayfish (Orconectes
virilis), have been introduced into Arizona aquatic ecosystems and are
now widely distributed and locally abundant in a broad array of natural
and artificial free-flowing and still-water habitats throughout the
State, including numerous streams within the historical and current
range of the roundtail chub (Inman et al. 1998, p. 3; Voeltz 2002, pp.
15-88). Crayfish appear to negatively impact native fishes and aquatic
habitats through habitat alteration by burrowing into stream banks and
removing aquatic vegetation, resulting in decreases in vegetative cover
and increases in turbidity (Lodge et al. 1994, p. 1270; Fernandez and
Rosen 1996, pp. 10-12). Carpenter (2005, pp. 338-340) documented that
crayfish may reduce the growth rates of native fish through competition
for food and noted that the significance of this impact may vary
between species. Crayfish also prey on fish eggs and larvae (Inman et
al. 1998, p. 17). Crayfish alter the abundance and structure of aquatic
vegetation by grazing on aquatic and semiaquatic vegetation, which
reduces the cover for fish (Fernandez and Rosen 1996, pp. 10-12). Creed
(1994, p. 2098) found that filamentous alga (Cladophora glomerata) was
at least 10-fold greater in aquatic habitat absent crayfish.
Filamentous alga is an important component of aquatic vegetation that
provides cover and food for fish, including roundtail chub.
Diseases and Parasites
Diseases, specifically parasite infestations, are a threat to the
roundtail chub. Asian tapeworm (Bothriocephalus acheilognathi) was
introduced into the United States via imported grass carp
(Ctenopharyngodon idella) in the early 1970s. Asian tapeworm has since
become well-established in the Southeast and mid-South and has been
recently found in the Southwest. The definitive host in the life cycle
of B. acheilognathi is cyprinid fishes, and, therefore, it is a
potential threat to the roundtail chub as well as to the other native
fishes in Arizona. The Asian tapeworm affects fish health in several
ways. Two direct impacts are by (1) impeding the digestion of food as
it passes through the intestinal track, and (2) causing emaciation and
starvation when large numbers of worms feed off of the fish. The Asian
tapeworm is present in the Colorado River basin in the Virgin River
(Heckman et al. 1986, p. 662) and the Little Colorado River (Clarkson
et al. 1997, p. 66). It has recently invaded the Gila River basin and
was found in 1998 in the Gila River near Ashurst-Hayden Dam. Research
and monitoring of the effects of Asian tapeworm on a related species,
the humpback chub, indicate that this parasite may be a significant
cause of mortality because large numbers of Asian tapeworm have been
detected in wild humpback chub, and laboratory studies indicate that
such infestations cause mortality in Gila species (U.S. Geological
Survey 2004, p. 1; 2005, pp. 2-3).
Anchor worm (Lernaea cyprinacea, Copepoda), an external parasite,
is unusual in that it has little host specificity, infecting a wide
range of fishes and amphibians. Severe Lernaea sp. infections have been
noted in a number of chub populations. Infections of Lernaea sp. may
have increased in recent years. James (1968, pp. 21-29) found that
Lernaea sp. was very rare in museum specimens collected prior to the
1930s, but increased in intensity from the 1930s to the 1960s, with
roundtail chubs exhibiting the greatest increase (10.8 percent).
Hendrickson (1993, pp. 45-46) noted very high infections of Lernaea sp.
during warm

[[Page 32374]]

periods in the Verde River, and Voeltz (2002, p. 69) reported that
headwater chubs found in Gun Creek in 2000, when surface flow was
almost totally lacking, ``showed signs of stress, and many had Lernaea,
black grub, lesions and an unidentified fungus.'' Girmendonk and Young
(1997, p. 55) concluded that ``parasitic infestations may greatly
affect the health and thus population size of native fishes.'' A die-
off of fish including roundtail chub in Trout Creek was likely due to
heavy infestations of black grub (Neascus sp.), an internal parasite,
which may have weakened the fish sufficiently to cause bacteria
hemorrhagic septicemia or blood poisoning (Voeltz 2002, p. 33).
The parasite Ichthyophthirius multifiliis, or ``Ich'', is a
potential threat to roundtail chub. ``Ich'' has occurred in some
Arizona streams, probably favored by high temperatures and crowding as
a result of drought (Mpoame 1982, p. 45). This protozoan becomes
embedded under the skin and within the gill tissues of infected fish.
When the ``Ich'' matures, it leaves the fish, causing fluid loss,
physiological stress, and sites that are susceptible to infection by
other pathogens. If the ``Ich'' are present in large enough numbers,
they can also impact respiration because of damaged gill tissue.
Conservation Actions Relevant to Factor C
All three of the conservation agreements have various provisions to
address the threat of nonnative species. The Range-wide Agreement
recommends that State conservation agreements include provisions to
control (as feasible and where possible) threats posed by nonnative
species that compete with, prey upon, or hybridize with roundtail chub.
The Arizona Agreement addresses the threat of predation and competition
from nonnative species, as well as the threat of disease and parasites,
in its provisions for habitat protection. These provisions include:
managing detrimental nonnative aquatic species in streams designated
for conservation of the subject species; evaluating effectiveness of
nonnative management efforts; and managing the spread of infectious
diseases and parasites to habitats of the subject species. The Arizona
Agreement also includes an indentified deliverable of a native fish
management plan that would also serve to address this threat.
The New Mexico Plan includes the following provisions to address
the threat of nonnative species:
(1) Determine the distribution and abundance of nonnative species
in the San Juan and Gila River watersheds and the physical barriers to
their expansion;
(2) Investigate the impacts, particularly competition, habitat
modification, and predation, of nonnative species on roundtail chub;
(3) Determine areas of the San Juan and Gila River watersheds where
limited nonnative species distribution and abundance may provide
opportunities for chub restoration;
(4) Work with sport fish managers to coordinate native and
nonnative fish management and identify stream areas expressly for
recovery of native species;
(5) When appropriate and feasible, remove nonnative species that
present a threat to roundtail, Gila, and headwater chubs;
(6) Prevent the introduction of nonnative species into the
watersheds utilizing existing information and programs when possible;
(7) Support efforts to re-establish the historical native aquatic
community in ecologically appropriate habitats in the San Juan and Gila
River basins utilizing existing programs when possible; and
(8) Inform local resource users about the impacts of nonnative
species on roundtail chub.
Specific actions implemented through the conservation agreements to
address the threats under Factor C include fisheries management
planning efforts and creation of new chub populations in nonnative-
fish-free habitats. AGFD convened a Statewide Fish Management Team in
2008, which developed a process to delineate fish management strategies
Statewide to address the dual mandates of providing native fish habitat
and sport fish angling opportunities for the public. AGDF intends that
this process will serve as the deliverable management plan for the
Arizona Agreement, and will facilitate sport fish and native fish
management decisions throughout Arizona. As discussed in the Status and
Distribution of the Lower Colorado River DPS section above, AGFD and
NMDGF have created four new populations of roundtail chub, two in
streams (Ash Creek and Roundtree Canyon) and two in pond refuges (the
Southwest Academy and Gila River Ranch Preserve refuge ponds). These
efforts are too new to evaluate their success, but such projects will
be essential to reversing the decline of the roundtail chub.
Summary of Factor C
Predation and competition with nonnative aquatic species, and in
particular fish, are, along with dewatering of habitat, the most
significant threats to the roundtail chub in the lower Colorado River
basin. Nonnative aquatic species are a threat to every population of
roundtail chub with the possible exception of recent transplants into
Roundtree Canyon and Ash Creek, and perhaps Fossil Creek and Aravaipa
Creek, based on long-term low levels of occurrence of nonnatives in
these streams and presence of natural or manmade fish barriers (Voeltz
2002, p. 47; U.S. Forest Service 2004, p. 1). No attempt has been made
to quantify the amount of range of these species affected by parasites,
however, parasites have been documented in numerous populations and
likely occur throughout the range of these species (Voeltz 2002, pp.
18-19). Although some actions have been implemented through
conservation agreements for roundtail chub to address this threat,
these actions are either not yet complete or too recently completed to
evaluate their success and contribution to the status of the roundtail
chub.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

Existing Regulatory Mechanisms
There are currently no specific Federal protections for roundtail
chub, and generalized Federal protections found in forest plans, Clean
Water Act dredge and fill regulations for streams, and other statutory,
regulatory, or policy provisions have been inadequate to ameliorate the
threats to roundtail chub in the lower Colorado River basin. Existing
Federal and State regulations and planning have not achieved
significant conservation of roundtail chub and its habitat. Although we
are aware that roundtail chub occurs on Tribal lands, we do not have
sufficient information to evaluate the effectiveness of Tribal
management.
As described in Factor C, introductions of nonnative fish are
likely a significant threat to roundtail chub. Fish introductions are
illegal unless approved by the respective States. However, enforcement
is difficult. Many nonnative fish populations are established through
illegal introductions. Nine species of fish, crayfish, and waterdogs or
tiger salamanders (Ambystoma pigrimum) may be legally used as bait in
Arizona, all of which are nonnative to the State of Arizona, and
several of which are known to have serious adverse effects on native
species. The portion of the State in which use of live bait is
permitted is limited. The use of live bait is restricted in some of the
Gila River system in Arizona (AGFD 2008, p. 28), but the use of live
bait species (such as green sunfish) is still permitted in areas such
as the Verde River that currently

[[Page 32375]]

have roundtail chub populations. New Mexico only allows the use of
fathead minnow as a live bait-fish in the Gila River drainage in New
Mexico, which covers the extent of the range of roundtail chub in the
lower Colorado River basin in New Mexico (NMDGF 2008, p. 8). Arizona
and New Mexico also continue to stock nonnative sport fishes, including
such likely predators and competitors as largemouth bass, channel
catfish, rainbow trout, and brown trout, for recreational angling
within areas that are connected to habitat of roundtail chub.
Although restrictions on use of live bait help reduce the input of
nonnative species into roundtail chub habitat, this does little to
reduce unauthorized bait use or other forms of ``bait-bucket'' transfer
(e.g., illegal stock of sport fish, dumping of unwanted aquarium fish)
not directly related to bait use. Such ``bait-bucket'' transfers can be
expected to increase as the human population of Arizona increases and
as nonnative species remain available to the public through aquaculture
and the aquarium trade.
AGFD also regulates nonnative species that can be legally brought
into the State. Prohibited nonnative species are put onto the
Restricted Live Wildlife List (Commission Order 12-4-406). However,
species are allowed unless they are prohibited by placement on the
list, rather than the more conservative approach of being prohibited
unless specifically allowed. This allows the opportunity for many
noxious nonnatives to be legally imported and introduced into Arizona.
New Mexico has adopted a more stringent approach; no live animal
(except domesticated animals or domesticated fowl or fish from
government hatcheries) is allowed to be imported without a permit (NMS
17-3- 32). However, the majority of the roundtail chub's range in the
lower Colorado River basin occurs within Arizona.
Existing water laws in Arizona and New Mexico are inadequate to
protect wildlife. The presence of water is clearly a requirement for
the roundtail chub. Gelt (2008, pp. 1-12) highlighted the fact that,
because existing water laws are old, they reflect a legislative
interpretation of the resource that is not consistent with what is
known today about hydrology. For example, over 100 years ago when
Arizona's water laws were written, the important connection between
groundwater and surface water was not known (Gelt 2008, pp. 1-12). Gelt
(2008, pp. 8-9) suggested that preserving stream flows and riparian
areas may be better accomplished by curtailing surface water uses
rather than groundwater uses, and that the prior appropriation doctrine
(appropriation of water rights based upon the water law concept of
``first in use, first in rights'') may be outdated and impractical for
arid areas like Arizona.
The Federal Land Policy and Management Act of 1976 (43 U.S.C. 1701
et seq.) and the National Forest Management Act of 1976 (16 U.S.C. 1600
et seq.) direct the Secretary of the Interior, through BLM, and Forest
Service, respectively, to prepare programmatic-level management plans
to guide long-term resource management decisions. In addition, the U.S.
Forest Service is required to manage habitat to provide appropriate
ecological conditions to support a diversity of native plant and animal
species (36 CFR 219.10). The Forest Service is the largest landowner
and manager of roundtail chub habitat and lists the roundtail chub as a
sensitive species in the lower Colorado River basin in the southwestern
region (Arizona and New Mexico). The BLM is updating its sensitive
species list for Arizona and has indicated they will add roundtail
chub. However, a sensitive species designation provides little
protection to the roundtail chub because it only requires the Forest
Service and BLM to analyze the effects of their actions on sensitive
species, but does not require that they choose environmentally benign
actions. Most of these areas where the majority of extant populations
of roundtail chub occur are managed by the Forest Service or BLM; thus
ongoing management by these agencies has not prevented adverse impacts
to roundtail chub habitat. Although both agencies have riparian
protection goals, neither agency has specific management plans for the
roundtail chub.
Wetland values and water quality of aquatic sites inhabited by the
roundtail chub are afforded varying protection under the Federal Water
Pollution Control Act of 1948 (Clean Water Act; 33 U.S.C. 1251-1376),
as amended; Federal Executive Orders 11988 (Floodplain Management) and
11990 (Protection of Wetlands); and section 404 of the Clean Water Act,
which regulates dredging and filling activities in waterways. Water
quality in the range of the roundtail chub has declined despite these
laws. The Arizona Department of Environmental Quality (2008) has
identified several streams with water quality problems occupied by
roundtail chub. Oak Creek exceeds the total maximum daily load for
Escherichia coli (E. coli) contamination, due to a combination of
recreation, septic systems, urban runoff, and livestock grazing.
Boulder Creek exceeds the total maximum daily load for benzene,
manganese, mercury, pH, arsenic, copper, and zinc as a result of mining
activities. The Verde River exceeds the total maximum daily load for
turbidity/sediment due to livestock grazing, urban development, and
road use and maintenance. The Arizona Department of Environmental
Quality is implementing actions through drainage water quality plans to
correct these problems, but they are ongoing and not likely to be
resolved in the near future. Our information indicates that the status
of the roundtail chub in these areas has declined, although it is
unclear whether this is due to these water quality issues (Voeltz 2002,
pp. 35, 72).
The NMDGF has adopted a wetland protection policy whereby they do
not endorse any project that would result in a net decrease in either
wetland acreage or wetland habitat values. This policy may afford some
protection to roundtail chub habitat, although it is advisory only and
destruction or alteration of wetlands is not regulated by State law.
The State of Arizona Executive Order Number 89-16 (Streams and Riparian
Resources), signed on June 10, 1989, directs State agencies to evaluate
their actions and implement changes, as appropriate, to allow for
restoration of riparian resources. Implementation of this regulation
may have reduced adverse effects of some State actions on the habitat
of the roundtail chub; however, we have no monitoring information on
the effects of this State Executive Order, nor do we have information
indicating that actions taken under it have been effective in reducing
adverse effects to the roundtail chub.
The National Environmental Policy Act of 1969 (NEPA) (42 U.S.C.
4321 et seq.) requires Federal agencies to consider the environmental
impacts of their actions. Most actions taken by the Forest Service,
BLM, and other Federal agencies that affect the roundtail are subject
to NEPA. NEPA requires Federal agencies to describe the proposed
action, consider alternatives, identify and disclose potential
environmental impacts of each alternative, and involve the public in
the decision-making process. However, Federal agencies are not required
to select the alternative having the least significant environmental
impacts. A Federal action agency may select an action that will
adversely affect sensitive species provided that these effects were
known and identified in a NEPA document.
The status of roundtail chub on Tribal lands is not well known. Any
regulatory or other protective measures for the

[[Page 32376]]

species on Tribal lands would be at the discretion of the individual
Tribe, and non-Tribal entities often have little information with which
to evaluate effectiveness. The San Carlos Apache Tribe has developed a
fisheries management plan that provides protection to roundtail chub,
although there are only two populations that potentially occur on San
Carlos Apache lands, representing a very small percentage of the
overall range of the species in the lower Colorado River basin. We have
limited information on threats to populations of roundtail chub on
Tribal lands, but land uses on Tribal lands include livestock grazing,
recreation, limited fuel wood harvest, limited agriculture, fisheries
and wildlife management, and localized municipal, urban, and rural
development and associated water use. The White Mountain Apache Tribe
is preparing a fisheries management plan that, when completed, could
benefit roundtail chub because 8 of the 31 populations occur wholly or
in part on White Mountain Apache Tribal lands.
The State of New Mexico lists the roundtail chub as ``State
Endangered'' under its Wildlife Conservation Act, which prohibits take
(New Mexico Wildlife Conservation Act 17-2-41(B)). In the State of New
Mexico, an ``Endangered Species'' is defined as ``any species of fish
or wildlife whose prospects of survival or recruitment within the State
are in jeopardy due to any of the following factors: (1) The present or
threatened destruction, modification, or curtailment of its habitat;
(2) overutilization for scientific, commercial or sporting purposes;
(3) the effect of disease or predation; (4) other natural or manmade
factors affecting its prospects of survival or recruitment within the
State; or (5) any combination of the foregoing factors'' as per New
Mexico Statutory Authority 17-2-38.D. ``Take,'' defined as ``to harass,
hunt, capture or kill any wildlife or attempt to do so'' by New Mexico
Statutory Authority 17-2-38.L., is prohibited without a scientific
collecting permit issued by the NMDGF as per New Mexico Statutory
Authority 17-2-41.C and New Mexico Administrative Code 19.33.6.
However, while the NMDGF can issue monetary penalties for illegal take
of roundtail chub, the same provisions are not in place for actions
that result in loss or modification of habitat (New Mexico Statutory
Authority 17-2-41.C and New Mexico Administrative Code 19.33.6).
The roundtail chub is identified on the AGFD draft document (never
finalized), Wildlife of Special Concern (AGFD 2006b, p. 5). The purpose
of the Wildlife of Special Concern list is to provide guidance in
habitat management implemented by land management agencies.
Additionally, the roundtail chub is considered a ``Tier 1b Species of
Greatest Conservation Need'' in the AGFD draft document, Arizona's
Comprehensive Wildlife Conservation Strategy (AGFD 2006c, p. 371). The
purpose for the Comprehensive Wildlife Conservation Strategy is to
``provide an essential foundation for the future of wildlife
conservation and a stimulus to engage the States, federal agencies, and
other conservation partners to strategically think about their
individual and coordinated roles in prioritizing conservation efforts''
(AGFD 2006c, p. 2). A ``Tier 1b Species of Greatest Conservation Need''
is one that requires immediate conservation actions aimed at improving
conditions through intervention at the population or habitat level
(AGFD 2006c, p. 32).
As discussed in Factor B, up to one roundtail chub may be taken and
possessed per day via angling Statewide in Arizona, with the exception
of Fossil Creek, which is catch and release only, from Oct 3, 2009,
through April 30, 2010. Take of roundtail chub is also permitted in
Arizona via issuance of a scientific collecting permit (Ariz. Admin.
Code R12-4-401 et seq.). While the AGFD can seek criminal or civil
penalties for illegal take of roundtail chub, the same provisions are
not in place for actions that result in destruction or modification of
roundtail chub habitat.
SRP has completed two habitat conservation plans (HCPs) for its
operation of Roosevelt Dam and Lake and its operation of Horseshoe and
Bartlett reservoirs (SRP 2006, 2008, 2009). Through implementation of
the Roosevelt Habitat Conservation Plan, SRP has permanently protected
and will manage land and water rights for more than 2,000 ac (809 ha)
of riparian and aquatic habitat along Tonto Creek and the middle Gila,
lower San Pedro, and Verde Rivers. Conservation measures on these
properties, such as increasing instream flows, excluding livestock,
improving channel integrity, excluding vehicle and off-road vehicle
traffic, abating wildfires, and promoting riparian ecosystem health,
will continue in perpetuity and will directly benefit native fishes,
including the roundtail chub. For example, one such SRP-owned and
maintained property is the Camp Verde Riparian Preserve near Camp
Verde, Arizona, on the Verde River, which contains a portion of the
Verde River occupied by roundtail chub (SRP 2006, pp. 26-28).
The HCP for Horseshoe and Bartlett Reservoirs specifically covers
the roundtail chub and includes numerous minimization and mitigation
measures that will benefit the species, including: rapid drawdown of
Horseshoe Lake annually to disadvantage nonnative fish species by
adversely affecting the recruitment and growth of these species;
providing funding to AGFD for creation and maintenance of fish rearing
facilities at its Bubbling Ponds State Fish Hatchery; providing funding
and support for native fish stocking, including stocking of roundtail
chub; watershed management efforts that serve to maintain quality and
quantity of instream flows; native fish monitoring; and public outreach
(SRP 2008, pp. 193-201). SRP is also a signatory to the Arizona
Agreement, and in this capacity, has funded roundtail chub genetics
research and development of roundtail chub broodstock. SRP also works
with AGFD to salvage roundtail chub from its canals (SRP 2009, pp. 6-
7).
Roundtail chub derives some conservation benefit from its co-
occurrence with other listed species and critical habitat in the lower
Colorado River basin. As an example, Bureau of Reclamation's
interagency consultation (section 7 compliance) on the operation and
maintenance of the Central Arizona Project (CAP), a water delivery
system designed to bring water from the Colorado River to portions of
Pima, Pinal, and Maricopa counties in Arizona, has greatly benefited
the species. Biological opinions on the CAP addressed the spread of
nonnative aquatic species through the project canals from the Colorado
River into the Gila and Santa Cruz River basins (Service 2001, 2008).
Conservation measures included in these biological opinions to benefit
listed fish and amphibian species (including the spikedace, loach
minnow, Gila topminnow, desert pupfish, Gila chub, and Chiricahua
leopard frog (Rana chiricahuensis)) have benefitted the roundtail chub
and likely will into the future. In 2004, nonnative fish were removed
from Fossil Creek through chemical renovation to benefit native fish
species including the roundtail chub. The Bureau of Reclamation, in
cooperation with AGFD, the Service, and the Forest Service, also
installed a fish barrier in lower Fossil Creek to prevent reinvasion of
nonnative fish. The Fossil Creek restoration project was a conservation
measure included in the CAP biological opinion issued to the Bureau of
Reclamation, and it resulted in the creation of the only stable-secure

[[Page 32377]]

population of roundtail chub currently in existence in the lower
Colorado River basin.
Conservation Actions Relevant to Factor D
The Range-wide Agreement recommends that the State plans include
provisions to assure adequate regulatory protection for the roundtail
chub, flannelmouth sucker, and bluehead sucker within the signatory
States, and to install regulatory mechanisms for the long-term
protection of habitat (e.g., conservation easements, water rights). The
Range-wide Agreement also recommends that States develop multi-State
nonnative stocking procedure agreements that protect all three species
and potential reestablishment sites from the threat of nonnative
species. The Arizona Agreement includes the provision to maintain
instream flow by securing habitat through acquisition of water rights
or agreements with water rights holders to maintain instream flow.
Implementation of these provisions so far has resulted in the U.S.
Forest Service application for an instream flow right on Cherry Creek,
which contains roundtail chub, and SRP and Conservancy applications to
the Arizona Department of Water Resources for instream flow rights on
the Verde River. These measures and actions may result in further
regulatory protection for roundtail chub by legally protecting flows
for the species.
Summary of Factor D
Existing regulations within the range of the roundtail chub address
the direct take of individuals without a permit, and unpermitted take
is not thought to be a threat to roundtail chub. However, Arizona and
New Mexico statutes do not provide protection of habitat and
ecosystems. Currently, there are no regulatory mechanisms in place that
specifically target the conservation of roundtail chub or its habitat.
General regulatory mechanisms protecting the quantity and quality of
water in riparian and aquatic communities are inadequate to protect
water resources for the roundtail chub, particularly in the face of the
significant human population growth expected within the historical
range of the chub discussed under Factor A. Conservation actions
defined in existing conservation agreements may provide some additional
regulatory protection, in particular through development of instream
flow rights to protect habitat for the roundtail chub, but no instream
flow rights have yet been acquired, although several applications for
specific waters have been submitted.

Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence

Fragmented Populations and Stochastic Events
The rarity of roundtail chub increases the possible extinction risk
associated with stochastic events such as drought, flood, and wildfire.
Roundtail chub populations have been fragmented and isolated to smaller
stream segments and may be vulnerable to natural or manmade factors
(e.g., drought, groundwater pumping) that might further reduce their
population sizes. Maintaining several populations with relatively
independent susceptibility to threats is an important consideration in
the long-term viability of a species (Shaffer 1987; Goodman 1987).
Redundant populations provide security from catastrophic events or
repeated recruitment failure. For example, consider that a single
hypothetical population has a probability of extinction from a
catastrophic event of 10 percent in 200 years. If two populations are
independent, the probability of both going extinct is 1 percent (0.12).
For three populations, the probability reduces to 0.1 percent (0.13).
Even with an extinction probability of 25 percent for one population,
the probability of extinction for two and three populations is 6.3
percent and 1.6 percent, respectively (Casagrandi and Gatto 1999).
Fagan et al. (2002) determined that individual roundtail chub
populations have a 0.41 percent probability of extirpation given
current status and levels of fragmentation and isolation. Providing for
multiple populations that are secure and stable (as defined above in
Table 1, a population that is recruiting with multiple age classes and
that is free from threats) in a single drainage basin will provide
increased redundancy and reduce the likelihood of extirpation. We
consider a particular basin or management area to be at risk of
extirpation if there are fewer than a minimum of two stable-secure
populations because any single population can be eliminated by
stochastic events or catastrophic disturbance, such as fire. We only
consider roundtail chub to be stable-secure in one stream, Fossil
Creek.
In general, Arizona is an arid State; about one-half of Arizona
receives less than 10 in. (25 cm) of rain a year. Dewatering and other
forms of habitat loss have resulted in fragmentation of roundtail chub
populations. We anticipate that water demands from a rapidly increasing
human population may further reduce habitat available to this species,
and could further fragment populations. In examining the relationship
between species distribution and extinction risk in southwestern
fishes, Fagan et al. (2002, p. 3250) found that the number of
occurrences or populations of a species is less significant a factor in
determining extinction risk than is habitat fragmentation.
Fragmentation of habitat may also cause the roundtail chub to be
vulnerable to extinction from threats of further habitat loss and
competition from nonnative fish because immigration and recolonization
from adjacent populations is less likely. The risk of extirpation of
individual populations of this species appears to be quite high given
the degree of fragmentation (Fagan et al. 2002, p. 3254), that only one
population is considered stable and secure, and that many threats are
predicted to increase in severity in the future.
Climate Change
Several recent studies predict continued drought in the
southwestern United States, including the lower Colorado River basin,
due to global climate change. Seager et al. (2007, pp. 1181-1184)
analyzed 19 different computer models of differing variables to
estimate the future climatology of the southwestern United States and
northern Mexico in response to predictions of changing climatic
patterns. All but one of the 19 models predicted a drying trend within
the Southwest (Seager et al. 2007, p. 1181). A total of 49 projections
were created using the 19 models, and all but 3 predicted a shift to
increasing aridity (dryness) in the Southwest as early as 2021-2040
(Seager et al. 2007, p. 1181). Recently published projections of
potential reductions in natural flow in the Colorado River basin by the
mid-21st century range from approximately 45 percent by Hoerling and
Eischeid (2006, p. 3989) to approximately 6 percent by Christensen and
Lettenmaier (2006, pp. 3727-3729). The U.S. Climate Change Science
Program recently completed a report entitled ``Abrupt Climate Change, A
report by the U.S. Climate Change Science Program and the Subcommittee
on Global Change Research'' (U.S. Climate Change Science Program
2008a). Regarding the southwest United States, the summary and findings
concluded: ``Climate model studies over North America and the global
subtropics indicate that subtropical drying will likely intensify and
persist in the future due to

[[Page 32378]]

greenhouse warming. This drying is predicted to move northward into the
southwestern United States. If the model results are correct, then the
southwestern United States may be beginning an abrupt period of
increased drought'' (U.S. Climate Change Science Program 2008b, p. 2).
If predicted effects of climate change result in persistent drought
conditions in the Colorado River basin similar or worse than those seen
in recent years, water resources will become increasingly taxed as
supplies dwindle and demand stays the same or increases. Likewise,
there would be increased demand on surface and groundwater supplies in
Arizona. Clearly, permanent water is crucial for the continued survival
of native fish in the region, including roundtail chub. Essentially the
entire range of the roundtail chub in the lower Colorado River basin is
predicted to be at risk of becoming more arid (Seager et al. 2007, pp.
1183-1184), which has severe implications to the integrity of aquatic
and riparian ecosystems and the water that supports them. Perennial
streams in the region may become intermittent and streams that are
currently intermittent may become unsuitable or dry completely.
Changes to climatic patterns may warm water temperatures, alter
stream flow events, and increase demand for water storage and
conveyance systems (Rahel and Olden 2008, pp. 521-522). Warmer water
temperatures across temperate regions are predicted to expand the
distribution of existing aquatic nonnative species by providing 31
percent more suitable habitat for aquatic nonnative species. This
conclusion is based upon studies that compared the thermal tolerances
of 57 fish species with predictions made from climate change
temperature models (Mohseni et al. 2003, p. 389). Eaton and Scheller
(1996, p. 1111) reported that while several cold-water fish species in
North America are expected to have reductions in their distribution
from effects of climate change, several warmwater fish species are
expected to increase their distribution. In the southwestern United
States, this situation may occur where water persists but water
temperature warms to a level suitable for nonnative species that were
previously physiologically precluded from occupation of these areas.
Species that are particularly harmful to roundtail chub populations
such as the green sunfish, channel catfish, largemouth bass, and
bluegill are expected to increase their distribution by 7.4 percent,
25.2 percent, 30.4 percent, and 33.3 percent, respectively (Eaton and
Scheller 1996, p. 1111). Rahel and Olden (2008, p. 526) expect that
increases in water temperatures in drier climates such as the
southwestern United States will result in periods of prolonged low
flows and stream drying. These effects from changing climatic
conditions may have profound effects on the amount, permanency, and
quality of habitat for the roundtail chub. Warmwater nonnative species
such as red shiner, common carp, mosquitofish, and largemouth bass are
expected to benefit from prolonged periods of low flow (Rahel and Olden
2008, p. 527).
Rahel et al. (2008, p. 551) examined climate change models,
nonnative species biology, and ecological observations, and concluded
that climate change could foster the expansion of nonnative aquatic
species into new areas, magnify the effects of existing aquatic
nonnative species where they currently occur, increase nonnative
predation rates, and heighten the virulence of disease outbreaks in
North America. Many of the nonnative species have similar, basic
ecological requirements as our native species, such as the need of
nonnative fish species for permanent or nearly permanent water. Rahel
et al. (2008, pp. 554-555; and from Carveth et al. 2006, p. 1435) found
that climate change will likely favor nonnative fish species such as
largemouth bass, yellow bullhead, and green sunfish over roundtail
chub, in part because they have higher temperature tolerances. Also,
drying of stream channels will create less habitat and greater
competition due to limited space and habitat. Thus climate change can
eliminate roundtail chub habitat through at least two mechanisms:
directly, by drying up aquatic habitats due to decreases in
precipitation and stable or increasing human demand for water
resources; and indirectly by improving conditions for nonnative
species, increasing their proliferation, and thereby increasing the
threat from nonnative fish predation and competition.
Rahel et al. (2008, p. 555) also noted that climate change could
facilitate expansion of nonnative parasites. This could be an important
threat to roundtail chub. Optimal Asian tapeworm development occurs at
25-30 [deg]C (77-86 [deg]F) (Granath and Esch 1983, p. 1116), and
optimal anchorworm temperatures are 23-30 [deg]C (73-86 [deg]F) (Bulow
et al. 1979, p. 102). Cold water temperatures in parts of the range of
the roundtail chub may have prevented these parasites from completing
their life cycles and limited their distribution. Warmer climate trends
could result in warmer overall water temperatures, increasing the
prevalence of these parasites.
The effects of the water withdrawals discussed above may be
exacerbated by the current, long-term drought facing the arid
southwestern United States. Philips and Thomas (2005, pp. 1-4) provided
streamflow records that indicate that the drought Arizona experienced
between 1999 and 2004 was the worst drought since the early 1940s and
possibly earlier. The Arizona Drought Preparedness Plan Monitoring
Technical Committee (2008) assessed Arizona's drought status through
June of 2008 in watersheds where the roundtail chub occurs or
historically occurred. They found that the Verde and San Pedro
watersheds continue to experience moderate drought (Arizona Drought
Preparedness Plan Monitoring Technical Committee 2008), and the Salt,
Upper Gila, Lower Gila, and Lower Colorado watersheds were abnormally
dry (Arizona Drought Preparedness Plan Monitoring Technical Committee
2008). Ongoing drought conditions have depleted recharge of aquifers
and decreased baseflows in the region. While drought periods have been
relatively numerous in the arid Southwest from the mid-1800s to the
present, the effects of human-caused impacts on riparian and aquatic
communities may compromise the ability of these communities to function
under the additional stress of prolonged drought conditions.
Conservation Agreements
As discussed in the ``Conservation Actions Relevant to Factor A''
section above, there are three wide-ranging plans that address the
ongoing conservation of the roundtail chub. The Utah Department of
Natural Resources' Range-wide Agreement was finalized and signed by all
the Colorado River basin States in 2004. The Range-wide Agreement
depends heavily on individual State plans for its implementation. The
objectives of the Range-wide Agreement are to:
(A) Establish or maintain populations sufficient to ensure the
conservation of each species within the State;
(B) Establish or maintain sufficient connectivity between
populations so that viable metapopulations are established or
maintained;
(C) As feasible, identify, significantly reduce or eliminate
threats to the conservation of these species.
To meet its obligations under the Range-wide Agreement, New Mexico
completed a recovery plan for the roundtail chub in November of 2006,
the ``Colorado River Basin Chubs Recovery Plan'' (New Mexico Plan)

[[Page 32379]]

(Carman 2006, p. 39). The New Mexico Plan includes a management
strategy with the goal of establishing roundtail chub populations that
are secure and self-sustaining throughout their historical ranges in
New Mexico, and the objective for at least one sufficient, self-
sustaining, secure population of roundtail chub in the mainstem of the
Gila River in New Mexico (Carman 2006, p. 49). The New Mexico Plan
management strategy also includes specific and comprehensive management
issues and strategies with corresponding implementation tasks and a
timeline for completion. The implementation tasks provide a
comprehensive list of conservation measures including: compiling
information on status and potential habitat; improving knowledge of
historical and current population dynamics; creating refuge populations
of chub lineages; restoring and securing habitats; if necessary,
augmenting populations; if possible, establishing additional
populations; restricting angling take of headwater chub; controlling
nonnative species; identifying and reducing information gaps; and
establishing agreements and partnerships to implement the plan (Carman
2006, pp. 55-57). Actions taken to date in implementation of the New
Mexico Plan include the creation of a new refuge population of
roundtail chub at the Conservancy's Gila River Preserve farm pond in
2008 using offspring of wild-caught Verde River fish from the AGFD
Bubbling Ponds Fish Hatchery. The NMDGF plans to complete health and
genetic studies on these fish, and if appropriate, their offspring will
be stocked into the mainstem Gila River in New Mexico. The NMDGF has
also been working with partners to secure habitat through purchases and
land management. In 2007, the Department and the Conservancy purchased
168 ac (68 ha) of riparian and river habitat in the Gila-Cliff Valley.
The goal of the Arizona Agreement is to ensure the conservation of
roundtail chub, headwater chub, flannelmouth sucker, Little Colorado
River sucker, bluehead sucker, and Zuni bluehead sucker populations
throughout Arizona. The Arizona Agreement's objective is to address and
ameliorate the five listing factors in accordance with section 4(a)(1)
of the Act; the Arizona Agreement objectives also correspond to those
in the Range-wide Agreement (see above). The Arizona Agreement includes
a strategy that is comprehensive and includes numerous conservation
strategy tasks. Key tasks include: create a management plan; create a
Statewide management team; conduct status assessments; identify
threats; conduct research; secure, enhance, maintain, and create
habitat; manage detrimental nonnative fish/aquatic species; manage the
spread of infectious diseases and parasites; enhance or restore
connectedness and opportunities for migration; create, maintain and
evaluate fish refugia; establish and enhance populations; monitoring;
and outreach (AGFD 2006a, pp. 45-52). The Arizona Agreement also
includes success criteria, including: population stability criteria for
sizes and numbers of populations to maintain roundtail chub; threat
reduction success criteria, to determine if threats have been
adequately mitigated or eliminated, and monitoring to evaluate status
and trend of populations, and determine if habitat is being adequately
maintained.
AGFD has established a Statewide Management Team to implement the
Arizona Agreement; signatories include the Bureau of Reclamation, the
Hualapai Tribe; SRP; BLM; the Arizona State Lands Department; the
Arizona Department of Water Resources; the Conservancy; the Forest
Service; and the Fish and Wildlife Service. Under the Arizona
Agreement, AGFD and its partners have implemented several conservation
actions that have benefited the roundtail chub, including stocking
roundtail chub into two new habitats that are free from nonnative
fishes, Roundtree Canyon and Ash Creek. These stockings are too new to
evaluate whether roundtail chub has become established, but if
successful, these efforts will help conserve the species by creating
two new populations that are largely free from significant threats.
AGFD plans to establish another new population of roundtail chub in
Houston Creek in 2009. AGFD is also working with various partners to
develop operating criteria for Alamo Dam on the Bill Williams River to
conserve roundtail chub, and is finalizing broodstock and fishery
management plans, which will guide the maintenance and propagation of
different stocks for use in restoration of populations throughout the
range of the DPS and management of individual population units,
management areas, and conservation units.
The Range-wide Agreement and the Arizona Agreement depend on good-
faith efforts from signatories for their implementation, and identify
the need to develop funding sources for their implementation. Likewise,
the New Mexico Plan commits to using existing resources and funding
sources, to the extent possible, to implement the plan, and also
identifies the need for additional sources for full implementation. No
funding agreements are in place to support these efforts. Although a
few conservation actions have been implemented to benefit roundtail
chub, as discussed above, the Range-wide Agreement, the Arizona
Agreement, and the New Mexico Plan, and their comprehensive lists of
tasks, which if fully implemented would significantly aid in the
conservation of roundtail chub, are in the early stages of
implementation at this point in time. Specific actions identified in
these plans, either planned or implemented, that address individual
threats are identified in Factors A to E as appropriate.
The Arizona Agreement has resulted in two new populations of
roundtail chub, one in a 1.2-mi (2-km) tributary to the Verde River,
Roundtree Canyon, and one in a 0.6-mi (1-km) tributary of the Salt
River, Ash Creek. These translocations are too new to evaluate their
success, having been completed in 2008 and 2007 respectively, but they
could potentially benefit the species. AGFD is also planning to execute
a translocation into a second tributary of the Verde River, Houston
Creek, on the Tonto National Forest, in 2009. Another conservation
measure being undertaken as a result of the conservation agreements is
the establishment of refuge populations and broodstock. Refuge or
sanctuary populations have proven to be important in the conservation
of native fish in the Southwest by creating predator-free habitats
(Mueller 2008), and use of broodstock populations has prevented the
extinction of bonytail (Hedrick et al. 2000). AGFD has developed
broodstock management plans for the Verde River and Chevelon Creek
(Cantrell 2009, p. 5). Refuge populations provide both broodstock and a
secure population to preserve the genetic integrity of a population.
AGFD and the NMDGF recently created a refuge population in New Mexico
at the Conservancy Gila River Preserve refuge pond near the Gila River.
AGFD has also created a refuge at the Southwest Academy on Wet Beaver
Creek near Camp Verde, Arizona. Both of these refuges were created with
Verde River broodstock from a broodstock population at the AGFD
Bubbling Ponds fish hatchery. AGFD plans to create additional refuge/
broodstock populations for other conservation management units, with a
minimum of one for each management area (Cantrell 2009, p. 5).

[[Page 32380]]

Conservation Actions Relevant to Factor E
The Arizona Agreement includes provisions to address the threat of
population fragmentation, identifying the need to maintain
connectivity, or at least gene flow, even by artificial means, between
populations. If connectivity between occupied habitats cannot be
maintained via natural connection, the Arizona Agreement recommends
considering the practice of moving individuals of the subject species
between fragmented populations. Further, reducing existing stressors by
implementing the conservation agreements will give existing populations
additional resiliency to face the stresses presented by climate change.
Summary of Factor E
Threats to roundtail chub are magnified by the fragmentation of
existing populations. All but one model evaluating changing climatic
patterns for the southwestern United States and northern Mexico predict
a drying trend for the region (Seagar et al. 2007, pp. 1181-1184). We
acknowledge that drought and the loss of surface water in riparian and
aquatic communities are related to changing climatic conditions (Seagar
et al. 2007, pp. 1181-1184). The extent to which changing climate
patterns will affect the roundtail chub is not known with certainty at
this time. However, threats to the roundtail chub identified in Factors
A and C will likely be exacerbated by changes to climatic patterns in
the southwestern United States due to increasing drought and reduction
of surface waters if the predicted patterns are realized. Conservation
agreements and associated plans have been developed for roundtail chub
in the lower Colorado River basin, and some actions have been
implemented as a result that benefit and help conserve the roundtail
chub, such as the establishment of new populations in nonnative fish-
free habitats and the development of broodstock for use in establishing
and augmenting populations. These plans also include numerous actions
to help reduce the threats to the roundtail chub. While we recognize
the importance of working with our partners in conserving the roundtail
chub through the implementation of these plans, and recognize that if
implemented, they will greatly assist in the conservation of roundtail
chub, these agreements have only recently been completed and are in the
early stages of implementation.

Summary of Status and Threats

The following discussion illustrates how the threats to the species
have affected and are affecting the roundtail chub across the DPS.
Based on museum records documented in Voeltz (2002, Appendices), we
suspect that the roundtail chub retained much of its historical
distribution in the lower Colorado River basin within the United States
up to and likely through the 1920s. Activities such as the construction
of dams and water diversions that occurred throughout the early to mid-
1900s for agriculture and regional economic development likely
eliminated surface flow throughout stream reaches with occupied
habitat, which led to widespread extirpations of roundtail chub
populations in areas such as the lower Gila and Salt Rivers in Arizona.
After the period of dam construction and the subsequent creation of
reservoirs, widespread nonnative fish stocking efforts ensued
throughout Arizona beginning in mid 1900s. The effects from this influx
of nonnative species throughout the Southwest resulted in significant
declines in native fish and ranid frog distribution and abundance, and
the subsequent listing of 19 of Arizona's 31 native fish species
throughout the last 35 years (see discussion in the ``Nonnative
Species'' section above).
Currently, there are three specific Management Areas of the DPS.
Management Area A contains three river basins with the same lineage of
roundtail chub: The Gila, Salt, and Verde Rivers (Dowling et al. 2008).
However, these three basins have very limited connectivity between them
today, and the status of each basin may best be described separately.
We will therefore discuss each of these river basins separately to
better understand the status of the Management Area.
The roundtail chub populations in the Verde River basin have the
best hydrological connectivity between populations of any basin and the
only ``stable-secure'' population, in Fossil Creek (Table 2). However,
the Verde River is fragmented due to the presence of Horseshoe and
Bartlett reservoirs. Fossil Creek was restored in 2004, and has been
stocked with native fishes including roundtail chub. Of the other five
natural populations in the Verde River, one is extirpated, two are
``stable-threatened'' and two are ``unstable-threatened.'' Reproduction
and recruitment is documented in the two ``stable-threatened''
populations, but even in these, appears sporadic over time (Brouder et
al. 2001, p. 9). As discussed above (see the Summary of Factors
Affecting the Species section), the Verde River is experiencing threats
from numerous land uses, especially water withdrawal with increasing
demand for the Big Chino aquifer, the source of the Verde River.
Nonnative species are present in all populations with the exception of
Fossil Creek. Throughout the Verde River basin, populations seem at
risk of not achieving long-term persistence due to threats, as only
sporadic recruitment documented.
The Salt River populations are difficult to assess due to land
ownership. The success of Tribal fisheries management plans is
uncertain. The San Carlos Apache Tribe Fisheries Management Plan is
complete, but the species has limited occurrence on that reservation.
The White Mountain Apache Tribe has begun work on a fisheries
management plan, which is not yet complete. Tribal management affects
all but two populations in the Salt River basin. Of the two completely
non-Tribal populations, one is ``stable-threatened'' and one is
``unstable-threatened.'' Cherry Creek, the lone ``stable-threatened''
population, is disconnected from other populations in the Management
Area, and a single stochastic event, such as wildfire, which has
recently affected nearby populations, could eliminate the population.
The roundtail chub populations in the Gila River are almost
completely extirpated, with the only ``stable-threatened'' population
in Aravaipa Creek. Aravaipa Creek is protected by fish barriers,
erected by the Bureau of Reclamation as a result of the CAP biological
opinions (Service 2001, 2008). Thus the roundtail chub in Aravaipa
Creek has also benefited from its co-occurrence with the Federally
listed spikedace and loach minnow. Aravaipa Creek has also benefitted
from other conservation actions, including those undertaken through
conservation agreements, such as actions of the Conservancy taken for
its protection, discussed above (see Conservation Actions Relevant to
Factor A). But nonnative fish species do occur above the barrier in
Aravaipa Creek and could conceivably spread. The only other populations
in the Management Area are Eagle Creek and the upper Gila River in New
Mexico. Roundtail chub in both of these locations has become very rare
in recent years (Carman 2006, p. 7; Cantrel 2009, p. 9). Both of these
populations are subject to numerous threats, including abundant
nonnative species and dewatering due to ongoing mining operations and
potential water

[[Page 32381]]

projects resulting from recent water rights settlements.
Management Area A is thus at a high risk of extirpation for several
reasons. The management area is made up of fractured basins, the Gila,
Salt, and Verde Rivers. Many populations have been extirpated, and
roundtail chub in Eagle Creek and the Upper Gila River has become very
rare. A number of populations are on Tribal lands and are difficult to
evaluate in terms of status and future management. Two populations are
fairly well protected and have a stable status, Fossil and Aravaipa
Creeks. However, these two locations are no longer connected, and we
find that their current status is largely due to special management
resulting from their co-occurrence with already listed fish species.
All of the other populations apart from Fossil and Aravaipa Creeks in
Management Area A are likely at significant risk from Factors A and C,
and in particular, predation from nonnative fish species and
dewatering.
Management Area B is the Bill Williams River Basin. Streams in the
Bill Williams Management Area are highly fragmented and subject to
summer drying, even under normal conditions, because the area is in the
driest part of the DPS (Green and Sellers 1964, Figs. 3-5). It is
likely that all populations in Management Area B are fragmented and
isolated during the dry season. Remaining populations face increasing
groundwater development particularly in the Boulder Creek sub-basin,
and in Kirkland Creek in particular. Only four of the nine extant
populations are ``stable-threatened'' and those are in isolated
portions of the drainage. Trout Creek is completely isolated, and the
Big Sandy River is extirpated. The Burro Creek drainage, which includes
Boulder and Conger Creeks, has some redundancy, but effluent from
mining operations and the presence of green sunfish, red shiner, and
yellow bullhead in Boulder Creek pose a threat to these populations.
The Santa Maria sub-basin contains three populations, including
Kirkland and Sycamore Creeks, all of which are considered ``unstable-
threatened'' and at risk from increased groundwater pumping and the
presence of nonnative fish species. According to AGFD, these streams
may dry completely in drought and are more vulnerable to the effects of
climate change (A. Clark, AGFD, pers. comm. 2009). Thus, Management
Area B is a collection of highly isolated, threatened populations, in a
very dry region of the DPS.
Management Area C is the Little Colorado River Basin. Only two
populations remain: Clear Creek (East Clear Creek) and Chevelon Creek.
Both are ``unstable-threatened.'' Recent surveyors have commented with
surprise that these populations persist. For example, Clarkson and
Marsh (2005b, p. 9) remarked that the occurrence of roundtail chub and
juvenile roundtail chub in Clear Creek was shocking given the lack of
occurrence in surveys a year before, and especially given the co-
occurrence and dominance of nonnative fish species in the area. The
authors would not even speculate on why this rare situation existed,
but noted that in similar situations in the Southwest, ``natives
eventually decline and succumb in the presence of nonnative fish
populations (Marsh and Pacey 2005).'' Further, they found that other
natives including speckled dace (Rhinichthys osculus), bluehead sucker,
and Little Colorado spinedace (Lepidomeda vittata) were absent from
Clear Creek, which Clarkson and Marsh (2005b, p. 9) state ``is likely
testament to the continuing deterioration of the native fish fauna in
this area.'' Threats to these two populations include both nonnative
species and water use. The aquifer that feeds these streams in their
lower reaches has recently been the subject of study for its use as a
water supply for nearby mining operations and future development in
towns of the region such as Flagstaff, Winslow, and Holbrook.
Therefore, further strain on these systems from increased surface and
groundwater diversions is likely. Of the three management areas,
Management Area C appears to be the most threatened and has the poorest
status. Given the lack of redundancy and resiliency in these
populations, the loss of the two populations seems very likely in the
near future without aggressive conservation to reduce threats.
Foreseeable Future
The Act does not define the term ``foreseeable future.'' However,
in a January 16, 2009, memorandum addressed to the Acting Director of
the U.S. Fish and Wildlife Service, the Office of the Solicitor,
Department of the Interior, concluded, ``* * * as used in the [Act],
Congress intended the term `foreseeable future' to describe the extent
to which the Secretary can reasonably rely on predictions about the
future in making determinations about the future conservation status of
the species.'' In discussing the concept of foreseeable future for the
lower Colorado River basin DPS of the roundtail chub, we considered:
(1) The biological and demographic characteristics of the species (such
as generation times, population genetics, trends in evidence of
recruitment within current populations, etc.); (2) our ability to
predict or extrapolate the effects of threats facing the DPS into the
future; and (3) the relative permanency or irreversibility of these
threats.
Of the threats to the roundtail chub described in our analysis, the
threats of habitat loss and nonnative species are the most significant.
Habitat loss has resulted in the loss of large sections of the species'
former range in the lower Colorado River basin because suitable habitat
is now gone or so altered as to be permanently unsuitable, and the same
land use practices that have led to this habitat loss are still
occurring throughout the range of the DPS and therefore continue to
constitute a significant threat. The threat of habitat loss is likely
to not only continue in the future but increase in severity given the
environmental changes resulting from climate change and increasing
human populations. The widespread, imminent, and serious threat to the
long-term sustainability of roundtail chub in the lower Colorado River
basin from the presence of nonnative aquatic species, especially
nonnative fishes, compounds the threat of habitat loss. The elimination
of the single threat of nonnative species, especially fishes, may
lessen the severity of all other threats. We find that because of the
potential for habitat loss due to various land uses, in particular
dewatering, the presence of significant levels of nonnative fish in all
but one population, and the extent of threats and lack of stability to
populations throughout the lower Colorado River basin, the viability of
the DPS is in question into the foreseeable future.
In response to the impacts to the roundtail chub discussed above
and in our analysis of threats, the roundtail chub in the lower
Colorado River basin has been eliminated from approximately 68 to 82
percent of its historical range over the last 80 years (Voeltz 2002, p.
83). The most significant period of declines and subsequent
extirpations of entire populations of roundtail chub likely coincided
with the proliferation of nonnative species beginning in the 1940s and
1950s, most notably with the widespread introduction and expansion of
nonnative fish such as common carp, largemouth bass, green sunfish, and
channel and flathead catfish. In some areas, the presence of these
nonnative species appears to be limiting recruitment of roundtail chub,
with only large adults encountered during surveys (Cantrell 2009, p.
10).

[[Page 32382]]

Voeltz (2002, p. 5) defined ``unstable-threatened'' populations of
roundtail chub as those which exhibited over the past 5-10 years a
declining population with limited recruitment, and noted 13 such
populations. Specific instances of apparent recruitment failure have
been noted in the Verde and Salt Rivers, and in Wet Beaver Creek
(Girmendonk and Young 1997, pp. 21, 25, 34; Voeltz 2002, p. 71; Bryan
and Hyatt 2004, p. 3). Based on the best available information, we
consider 13 populations to be lacking recruitment, and are thus
``unstable-threatened.'' Also, there are nine populations for which we
have limited status information and must consider ``unknown.'' Since
roundtail chubs appear to live 5 to 7 years (Bestgen 1985, pp. 72-75;
Brouder et al. 2000, p. 10; Brouder 2005, p. 866), total recruitment
failure over a 10-year timeframe could extirpate a population. Because
this is a relatively short period of time (compared to longer-lived
species like the razorback sucker or bonytail), recruitment failure may
be difficult to detect without significant monitoring efforts.
Recruitment failure is particularly apparent in areas where habitat
remains structurally intact, but where nonnative species maintain
stable populations and native species persist at low levels. In Fossil
Creek, a restoration effort in 2004 created a nonnative fish barrier
and renovated 9.5 mi (15.3 km) of stream (U.S. Forest Service 2004, p.
9), which removed all nonnative fish species, which were previously
abundant, from Fossil Creek. Roundtail chub abundance increased
dramatically after the restoration effort, illustrating clearly the
significance of predation by and competition from nonnative fish
species on limiting recruitment and abundance of the chub populations
(Marks et al. in press, pp. 22-24). The observed effects of nonnative
species on age-class distribution and recruitment are an important
influence on the maintenance of current populations to be considered in
our evaluation of the foreseeable future for this species.
Predicting how current populations will fare over time is
confounded by a lack of monitoring data and population and survivorship
estimates. Although roundtail chub has persisted in many currently
occupied locations for some time, there is little information on status
over time, with often only one or two surveys to determine status.
There is no status information available for one third of the
populations. Of the remainder, many appear to be in a downward trend.
Voeltz (2002) found that roundtail chub was extirpated from the Little
Colorado River, Bill Williams River, Big Sandy River, Lower Gila River,
San Pedro River, San Francisco River, Dry Beaver Creek, Zuni River, and
Blue River (Voeltz 2002; see Table 2). All of these extirpated
populations experienced reductions in flow, and many of the remaining
populations are subjected to this threat. All of the remaining
established populations are also subject to the threat of nonnative
species with the exception of Fossil Creek, Ash Creak, and Roundtree
Canyon. Generally, population trends appear to be declining throughout
the lower Colorado River basin (Voeltz 2002, p. 85; Cantrell 2009, pp.
10-11). Few efforts specifically examining trend have been conducted;
two population estimate studies conducted for the species in the lower
Colorado River basin indicated a declining trend (Brouder et al. 2000,
p. 8-9; Bryan and Hyatt 2004, p. 3). For the lone ``stable-secure''
population, a recently completed study of Fossil Creek indicates a
significant increase in abundance of roundtail chub as a result of flow
increases and nonnative species removal (Marks et al. in press).
We conclude that remaining populations are subject to a high risk
of extirpation, given that: (1) Roundtail chub have a relatively high
risk of localized extirpation due to habitat fragmentation (Fagan et
al. 2002, p. 3254); (2) remaining populations are highly vulnerable to
the effects of threats discussed in detail in Factors A through E
above; (3) the significant threat of predation from nonnative fish
species; (4) nonnative species show an alarming trend of eventually
completely overtaking native species where they co-occur (Marsh and
Pacey 2005, p. 59); (5) all but three existing established population
of roundtail chub is believed to contain nonnative fish species (Voeltz
2002); (6) the few existing studies of population trend and overall
status assessments indicate a continuing decline in abundance, likely
due to low recruitment as a result of predation from nonnative fishes
(Voeltz 2002, pp. 83-88; Bryan and Hyatt, 2004, pp. 3, 12-13); and (7)
many threats are projected to increase over time, including those most
detrimental to the long-term viability of the DPS, such as the
continued proliferation of nonnative species, and projected increases
in human population and water use, both of which are likely to be
exacerbated by the environmental effects resulting from climate change.

Finding

We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
faced by the lower Colorado River basin roundtail chub. We reviewed the
petition, information available in our files, and other published and
unpublished information submitted to us by the public following our 90-
day petition finding, and consulted with recognized roundtail chub
experts and other Federal and State resource agencies. On the basis of
the best scientific and commercial information available, we find that
the population segment satisfies the discreteness and significance
elements of the DPS policy, and therefore qualifies as a DPS under our
policy. We further find that listing the lower Colorado River basin DPS
of roundtail chub is warranted. However, listing the lower Colorado
River basin DPS of roundtail chub is precluded by higher priority
listing actions at this time, as discussed in the Preclusion and
Expeditious Progress section below.
In making this finding, we recognize that there have been declines
in the distribution and abundance of the roundtail chub, primarily
attributed to the introduction of and subsequent predation by nonnative
fishes, as documented in the body of scientific research on the
distributions and impact of introduced fishes in relation to the
roundtail chub. Direct predation by nonnative fishes on this species
has resulted in rangewide population declines and local extirpations.
Because nonnative species are present in all but one of the remaining
established populations of this species, we conclude that remaining
populations are at risk of declines and extirpation as a result of
predation by nonnative species. Furthermore, the result of the past
effects of these threats is that many of the remaining populations are
fragmented and isolated, making them vulnerable to further declines and
local extirpations from other factors (Fagan et al. 2002, p. 3250).
Populations that go extinct following habitat fragmentation and
population isolation are unlikely to be naturally recolonized due to
both the isolation from, and lack of connectivity to, potential source
populations.
The isolation of remaining roundtail chub populations and habitat
fragmentation as a result of nonnative fish introductions and habitat
alteration has made remaining populations vulnerable to extinction from
stochastic events. Stochastic events such as fire have only recently
been recognized as an important factor in the decline of this species
(Dunham et al. 2003, p. 183; Rinne 2004, p. 151). Other factors include
parasitism and the inadequacy of existing regulatory mechanisms. These
factors may contribute to declines

[[Page 32383]]

or extirpations of roundtail chub. In addition, these factors are
exacerbated by the effects that have been caused by nonnative fishes.
Also, a significant new threat appears to be environmental changes that
result from climate change, which may have the potential to drastically
reduce existing habitat through further stream dewatering, as well as
result in habitat change by, for example, increasing water temperatures
that will aid the spread and establishment of nonnative predators and
parasites.
A number of habitat altering land uses further threaten remaining
populations of roundtail chub. These include dams, diversions, and
groundwater withdrawal; livestock grazing; logging, fuel wood cutting,
mining, and channelization; road construction, use, and maintenance;
urban and rural development; recreation; and high-intensity wildfires.
These threats negatively impact the rivers, streams, and riparian
habitats that are essential for the survival of the roundtail chub.
These threats have been documented historically, are either ongoing or
likely to occur throughout the range of the roundtail chub in the lower
Colorado River basin, and will reduce the suitability of roundtail chub
habitat as cover for protection from predators, as a foraging area, and
as spawning and nursery areas. Despite the conservation actions
discussed above, the dewatering of aquatic habitats in the arid lower
Colorado River basin poses a significant threat to all native fish of
the region, including roundtail chub. All of these threats are
anthropogenic and can be expected to continue, if not increase, given
the predictions for increases in human population in the region.
Efforts to improve the status of the roundtail chub in the lower
Colorado River basin began in earnest in 2006. These conservation
efforts, notably the Arizona Agreement and New Mexico Plan, include
many actions to stabilize populations, establish new populations,
increase the range of the species, and ameliorate threats. The
conservation agreements have met with some success in this regard. Two
populations have been created, as have two refuge populations and a
refuge-broodstock population at a hatchery. Efforts to purchase land
and water rights to reduce threats to habitat have met with some
limited success. These conservation efforts can conserve the roundtail
chub if fully implemented. Currently, however, they are in the early
stages of implementation.

Preclusion and Expeditious Progress

Preclusion is a function of the listing priority of a species in
relation to the resources that are available and competing demands for
those resources. Thus, in any given fiscal year (FY), multiple factors
dictate whether it will be possible to undertake work on a proposed
listing regulation or whether promulgation of such a proposal is
warranted but precluded by higher- priority listing actions.
The resources available for listing actions are determined through
the annual Congressional appropriations process. The appropriation for
the Listing Program is available to support work involving the
following listing actions: proposed and final listing rules; 90-day and
12-month findings on petitions to add species to the Lists of
Endangered and Threatened Wildlife and Plants (Lists) or to change the
status of a species from threatened to endangered; annual
determinations on prior ``warranted but precluded'' petition findings
as required under section 4(b)(3)(C)(i) of the Act; proposed and final
rules designating critical habitat; and litigation-related,
administrative, and program management functions (including preparing
and allocating budgets, responding to Congressional and public
inquiries, and conducting public outreach regarding listing and
critical habitat). The work involved in preparing various listing
documents can be extensive and may include, but is not limited to:
gathering and assessing the best scientific and commercial data
available and conducting analyses used as the basis for our decisions;
writing and publishing documents; and obtaining, reviewing, and
evaluating public comments and peer review comments on proposed rules
and incorporating relevant information into final rules. The number of
listing actions that we can undertake in a given year also is
influenced by the complexity of those listing actions; that is, more
complex actions generally are more costly. For example, during the past
several years, the cost (excluding publication costs) for preparing a
12-month finding, without a proposed rule, has ranged from
approximately $11,000 for one species with a restricted range and
involving a relatively uncomplicated analysis to $305,000 for another
species that is wide-ranging and involving a complex analysis.
We cannot spend more than is appropriated for the Listing Program
without violating the Anti-Deficiency Act (see 31 U.S.C.
1341(a)(1)(A)). In addition, in FY 1998 and for each fiscal year since
then, Congress has placed a statutory cap on funds which may be
expended for the Listing Program, equal to the amount expressly
appropriated for that purpose in that fiscal year. This cap was
designed to prevent funds appropriated for other functions under the
Act (for example, recovery funds for removing species from the Lists),
or for other Service programs, from being used for Listing Program
actions (see House Report 105-163, 105th Congress, 1st Session, July 1,
1997).
Recognizing that designation of critical habitat for species
already listed would consume most of the overall Listing Program
appropriation, Congress also put a critical habitat subcap in place in
FY 2002 and has retained it each subsequent year to ensure that some
funds are available for other work in the Listing Program: ``The
critical habitat designation subcap will ensure that some funding is
available to address other listing activities'' (House Report No. 107-
103, 107th Congress, 1st Session, June 19, 2001). In FY 2002 and each
year until FY 2006, the Service has had to use virtually the entire
critical habitat subcap to address court-mandated designations of
critical habitat, and consequently none of the critical habitat subcap
funds have been available for other listing activities. In FY 2007, we
were able to use some of the critical habitat subcap funds to fund
proposed listing determinations for high-priority candidate species. In
FY 2008, while we were unable to use any of the critical habitat subcap
funds to fund proposed listing determinations, we did use some of this
money to fund the critical habitat portion of some proposed listing
determinations, so that the proposed listing determination and proposed
critical habitat designation could be combined into one rule, thereby
being more efficient in our work. In FY 2009, we anticipate being able
to do the same.
Thus, through the listing cap, the critical habitat subcap, and the
amount of funds needed to address court-mandated critical habitat
designations, Congress and the courts have in effect determined the
amount of money available for other listing activities. Therefore, the
funds in the listing cap, other than those needed to address court-
mandated critical habitat for already listed species, set the limits on
our determinations of preclusion and expeditious progress.
Congress also recognized that the availability of resources was the
key element in deciding whether, when making a 12-month petition
finding, we would prepare and issue a listing proposal or instead make
a ``warranted

[[Page 32384]]

but precluded'' finding for a given species. The Conference Report
accompanying Public Law 97-304, which established the current statutory
deadlines and the warranted-but-precluded finding, states (in a
discussion on 90-day petition findings that by its own terms also
covers 12-month findings) that the deadlines were ``not intended to
allow the Secretary to delay commencing the rulemaking process for any
reason other than that the existence of pending or imminent proposals
to list species subject to a greater degree of threat would make
allocation of resources to such a petition [that is, for a lower-
ranking species] unwise.''
In FY 2009, expeditious progress is that amount of work that can be
achieved with $8,808,000, which is the amount of money that Congress
appropriated for the Listing Program (that is, the portion of the
Listing Program funding not related to critical habitat designations
for species that are already listed). Our process is to make our
determinations of preclusion on a nationwide basis to ensure that the
species most in need of listing will be addressed first and also
because we allocate our listing budget on a nationwide basis. The
$8,808,000 is being used to fund work in the following categories:
compliance with court orders and court-approved settlement agreements
requiring that petition findings or listing determinations be completed
by a specific date; section 4 (of the Act) listing actions with
absolute statutory deadlines; essential litigation-related,
administrative, and listing program management functions; and high-
priority listing actions for some of our candidate species. The
allocations for each specific listing action are identified in the
Service's FY 2009 Allocation Table (part of our administrative record).
In FY 2007, we had more than 120 species with an LPN of 2, based on
our September 21, 1983, guidance for assigning an LPN for each
candidate species (48 FR 43098). Using this guidance, we assign each
candidate an LPN of 1 to 12, depending on the magnitude of threats
(high vs. moderate to low), immediacy of threats (imminent or
nonimminent), and taxonomic status of the species (in order of
priority: monotypic genus (a species that is the sole member of a
genus); species; or part of a species (subspecies, distinct population
segment, or significant portion of the range)). The lower the listing
priority number, the higher the listing priority (that is, a species
with an LPN of 1 would have the highest listing priority). Because of
the large number of high-priority species, we further ranked the
candidate species with an LPN of 2 by using the following extinction-
risk type criteria: International Union for the Conservation of Nature
and Natural Resources (IUCN) Red list status/rank, Heritage rank
(provided by NatureServe), Heritage threat rank (provided by
NatureServe), and species currently with fewer than 50 individuals, or
4 or fewer populations. Those species with the highest IUCN rank
(critically endangered), the highest Heritage rank (G1), the highest
Heritage threat rank (substantial, imminent threats), and currently
with fewer than 50 individuals, or fewer than 4 populations, comprised
a list of approximately 40 candidate species (``Top 40''). These 40
candidate species have had the highest priority to receive funding to
work on a proposed listing determination. As we work on proposed and
final listing rules for these 40 candidates, we are applying the
ranking criteria to the next group of candidates with LPN of 2 and 3 to
determine the next set of highest priority candidate species.
To be more efficient in our listing process, as we work on proposed
rules for these species in the next several years, we are preparing
multi-species proposals when appropriate, and these may include species
with lower priority if they overlap geographically or have the same
threats as a species with an LPN of 2. In addition, available staff
resources are also a factor in determining high-priority species
provided with funding. Finally, proposed rules for reclassification of
threatened species to endangered are lower priority, because as listed
species, they are already afforded the protection of the Act and
implementing regulations.
We assigned the lower Colorado River basin DPS of the roundtail
chub an LPN of 9, based on our finding that the subspecies faces
threats that are imminent and of moderate magnitude, including the
present or threatened destruction, modification or curtailment of its
habitat; the impacts of nonnative species; and the inadequacy of
existing regulatory mechanisms. We consider the threat magnitude
moderate because, while all populations are experiencing threats, the
populations occur in multiple watersheds, and the threats acting on the
DPS are not occurring uniformly throughout the range of the species;
therefore not all populations are likely to be impacted simultaneously
by any of the known threats. Additionally, the existence of
conservation agreements has resulted in the implementation of actions
to improve the status of the DPS and reduce the severity of threats. We
anticipate that these conservation agreements will continue to benefit
the species with additional actions to improve status and reduce or
eliminate threats. Although implemented too recently to assess, recent
efforts to create new populations of the DPS in relatively threat-free
habitats may prove to be successful, and additional restoration efforts
are being planned.
We consider the threats imminent because they are currently
occurring in all of the existing populations. Under the 1983 Guidelines
(48 FR 43098), a subspecies or DPS receives a lower priority than a
full species and a full species receives a lower priority than a
monotypic genus, thus a DPS facing imminent moderate-magnitude threats
is assigned an LPN of 9. Therefore, work on a proposed listing
determination for the lower Colorado River basin DPS of roundtail chub
is precluded by work on higher priority candidate species (i.e.,
entities with LPN of 8 or lower); listing actions with absolute
statutory, court ordered, or court-approved deadlines; and final
listing determinations for those species that were proposed for listing
with funds from FY 2008. This work includes all the actions listed in
the tables below under expeditious progress.
As explained above, a determination that listing is warranted but
precluded must also demonstrate that expeditious progress is being made
to add or remove qualified species to and from the Lists of Endangered
and Threatened Wildlife and Plants. (Although we do not discuss it in
detail here, we are also making expeditious progress in removing
species from the list under the Recovery program, which is funded by a
separate line item in the budget of the Endangered Species Program. As
explained above in our description of the statutory cap on Listing
Program funds, the Recovery Program funds and actions supported by them
cannot be considered in determining expeditious progress made in the
Listing Program.) As with our ``precluded'' finding, expeditious
progress in adding qualified species to the Lists is a function of the
resources available and the competing demands for those funds. Given
that limitation, we find that we are making progress in FY 2009 in the
Listing Program. This progress included preparing and publishing the
following determinations:

[[Page 32385]]

FY 2009 Completed Listing Actions
----------------------------------------------------------------------------------------------------------------
Publication date Title Actions FR pages
----------------------------------------------------------------------------------------------------------------
10/15/2008.................. 90-Day Finding on a Notice of 90-day 73 FR 61007-61015
Petition To List the Petition Finding,
Least Chub Substantial.
10/21/2008.................. Listing 48 Species on Proposed Listing, 73 FR 62591-62742
Kauai as Endangered Endangered; Proposed
and Designating Critical Habitat.
Critical Habitat
10/24/2008.................. 90[dash]Day Finding on Notice of 90-day 73 FR 63421-63424
a Petition to List the Petition Finding, Not
Sacramento Valley substantial.
Tiger Beetle as
Endangered
10/28/2008.................. 90-Day Finding on a Notice of 90-day 73 FR 63919-63926
Petition To List the Petition Finding,
Dusky Tree Vole as Substantial.
Threatened or
Endangered
11/25/2008.................. 12-Month Finding on a Notice of 12-month 73 FR 71787-71826
Petition To List the petition finding,
Northern Mexican Warranted but
Gartersnake as precluded.
Threatened or
Endangered With
Critical Habitat;
Proposed Rule
12/02/2008.................. 90-Day Finding on a Notice of 90-day 73 FR 73211-73219
Petition To List the Petition Finding,
Black-tailed Prairie Substantial.
Dog as Threatened or
Endangered
12/05/2008.................. 90-Day Finding on a Notice of 90-day 73 FR 74123-74129
Petition To List the Petition Finding,
Sacramento Mountains Substantial.
Checkerspot Butterfly
as Endangered with
Critical Habitat
12/18/2008.................. 90-Day Finding on a Notice of 90-day 73 FR 76990-76994
Petition to Change the Petition Finding,
Listing Status of the Substantial.
Canada Lynx
1/06/2009................... Partial 90-Day Finding Notice of 90-day 74 FR 419-427
on a Petition To List Petition Finding, Not
475 Species in the substantial.
Southwestern United
States as Threatened
or Endangered With
Critical Habitat
2/05/2009................... Partial 90-Day Finding Notice of 90-day 74 FR 6122-6128
on a Petition To List Petition Finding, Not
206 Species in the in substantial.
the Midwest and
Western United States
as Threatened or
Endangered With
Critical Habitat
2/10/2009................... 90-Day Finding on a Notice of 90-day 74 FR 6558-6563
Petition To List the Petition Finding,
Wyoming Pocket Gopher Substantial.
as Threatened or
Endangered With
Critical Habitat
3/17/2009................... Listing Phyllostegia Final Listing 74 FR 11319-11327
hispida as Endangered Endangered.
Throughout Its Range
3/25/2009................... 12-Month Finding on a Notice of 12-month 74 FR 12931-12968
Petition to List the petition finding,
Yellow-Billed Loon as Warranted but
Threatened or precluded.
Endangered
4/09/2009................... 12-Month Finding on a Notice of 12-month 74 FR 16169-16175
Petition to List the petition finding, Not
San Francisco Bay- warranted.
Delta Population of
the Longfin Smelt as
Endangered
4/22/2009................... 90-Day Finding on a Notice of 90-day 74 FR 18336-18341
Petition To List the Petition Finding,
Tehachapi Slender Substantial.
Salamander as
Threatened or
Endangered
5/07/2009................... 90-Day Finding on a Notice of 90-day 74 FR 21301-21310
Petition To List the Petition Finding,
American Pika as Substantial.
Threatened or
Endangered with
Critical Habitat
5/-/2009.................... 12-Month Finding on a Notice of 12-month 74 FR 23376 23376-23388
Petition to List the petition finding, Not
Coaster Brook Trout as warranted.
Endangered
6/09/2009................... 90-Day Finding on a Notice of 90-day 74 FR 27266-27271
Petition to List Petition Finding, Not
Oenothera acutissima substantial.
as Threatened or
Endangered
----------------------------------------------------------------------------------------------------------------

Our expeditious progress also included work on listing actions,
which we funded in FY 2009 but have not yet been completed to date.
These actions are listed below. Actions in the top section of the table
are being conducted under a deadline set by a court. Actions in the
middle section of the table are being conducted to meet statutory
timelines, that is, timelines required under the Act. Actions in the
bottom section of the table are high priority listing actions. These
actions include work primarily on species with an LPN of 2, and
selection of these species is partially based on available staff
resources, and when appropriate, include species with a lower priority
if they overlap geographically or have the same threats as the species
with the high priority. Including these species together in the same
proposed rule results in considerable savings in time and funding, when
compared to preparing separate proposed rules for each of them in the
future.

Actions Funded in FY 2009 But Not Yet Completed
------------------------------------------------------------------------
Species Action
------------------------------------------------------------------------
Actions Subject to Court Order/Settlement Agreement
------------------------------------------------------------------------
Slickspot peppergrass......... Final listing determination.
Coastal cutthroat trout....... Final listing determination.
Mono basin sage-grouse........ 12-month petition finding.
Sacramento Mtns. checkerspot 12-month petition finding.
butterfly.

[[Page 32386]]

SW Bald eagle population...... 12-month petition finding.
Black-tailed prairie dog...... 12-month petition finding.
Lynx (include New Mexico in 12-month petition finding.
listing.).
White-tailed prairie dog...... 12-month petition finding.
Big Lost River whitefish...... 12-month petition finding.
Hermes copper butterfly....... 90-day petition finding.
Thorne's hairstreak butterfly. 90-day petition finding.
------------------------------------------------------------------------
Actions With Statutory Deadlines
------------------------------------------------------------------------
48 Kauai species.............. Final listing determination.
Black-footed albatross........ 12-month petition finding.
Mount Charleston blue 12-month petition finding.
butterfly.
Goose Creek milk-vetch........ 12-month petition finding.
Mojave fringe-toed lizard \1\. 12-month petition finding.
Pygmy rabbit (rangewide) \1\.. 12-month petition finding.
Kokanee--Lake Sammamish 12-month petition finding.
population \1\.
Ashy storm petrel............. 12-month petition finding.
Delta smelt (uplisting)....... 12-month petition finding.
Cactus ferruginous pygmy owl 12-month petition finding.
\1\.
Tucson shovel-nosed snake \1\. 12-month petition finding.
Northern leopard frog......... 12-month petition finding.
Tehachapi slender salamander.. 12-month petition finding.
Northern leopard frog......... 90-day petition finding.
4 subspecies of 90-day petition finding.
Pseudocopaeodes enunus.
Southeastern pop snowy plover 90-day petition finding.
& wintering pop. of piping
plover.
Berry Cave salamander \1\..... 90-day petition finding.
Ozark chinquapin \1\.......... 90-day petition finding.
Smooth-billed ani............. 90-day petition finding.
Bay Springs salamander \1\.... 90-day petition finding.
Mojave ground squirrel \1\.... 90-day petition finding.
Llanero coqui................. 90-day petition finding.
Gopher tortoise--eastern 90-day petition finding.
population.
Mojave ground squirrel........ 90-day petition finding.
Pacific walrus................ 90-day petition finding.
32 species of snails and slugs 90-day petition finding.
Calopogon oklahomensis........ 90-day petition finding.
Susan's purse-making caddisfly 90-day petition finding.
Striped newt.................. 90-day petition finding.
American dipper--Black Hills 90-day petition finding.
population.
Sprague's pipit............... 90-day petition finding.
Southern hickorynut........... 90-day petition finding.
5 Southwest mussel species.... 90-day petition finding.
Sonoran desert tortoise....... 90-day petition finding.
Chihuahua scarfpea............ 90-day petition finding.
Jemez Mtns. salamander........ 90-day petition finding.
White-sided jackrabbit........ 90-day petition finding.
Wrights marsh thistle......... 90-day petition finding.
White-bark pine............... 90-day petition finding.
Puerto Rico harlequin......... 90-day petition finding.
Fisher--Northern Rocky Mtns. 90-day petition finding.
population.
42 snail species (Nevada & 90-day petition finding.
Utah).
HI yellow-faced bees.......... 90-day petition finding.
206 species (partially 90-day petition finding.
completed).
475 Southwestern species 90-day petition finding.
(partially completed).
------------------------------------------------------------------------
High Priority Listing Actions \3\
------------------------------------------------------------------------
19 Oahu candidate species (16 Proposed listing.
plants, 3 damselflies) (15
with LPN = 2, 3 with LPN = 3,
1 with LPN = 9).
2 HI damselflies (LPN = 2).... Proposed listing.
17 Maui-Nui candidate species Proposed listing.
(14 plants, 3 tree snails)
(12 with LPN = 2, 3 with LPN
= 3, 3 with LPN = 8).
Sand dune lizard (LPN = 2).... Proposed listing.
2 Arizona springsnails Proposed listing.
(Pyrgulopsis bernadina (LPN =
2), Pyrgulopsis trivialis
(LPN = 2)).
2 New Mexico springsnails Proposed listing.
(Pyrgulopsis chupaderae (LPN
= 2), Pyrgulopsis thermalis
(LPN = 11)).
2 mussels (rayed bean (LPN = Proposed listing.
2), snuffbox No LPN).
2 mussels (sheepnose (LPN = Proposed listing.
2), spectaclecase (LPN = 4),).
Ozark hellbender \2\ (LPN = 3) Proposed listing.
3 southeast aquatic species Proposed listing.
\1\ (Georgia pigtoe,
interrupted rocksnail, rough
hornsnail) (all with LPN = 2).
Altamaha spinymussel (LPN = 2) Proposed listing.
5 southeast fish (rush darter Proposed listing.
(LPN = 2), chucky madtom (LPN
= 2), yellowcheek darter (LPN
= 2), Cumberland darter (LPN
= 5), laurel dace (LPN = 5)).

[[Page 32387]]

8 southeast mussels (southern Proposed listing.
kidneyshell (LPN = 2), round
ebonyshell (LPN = 2), Alabama
pearshell (LPN = 2), southern
sandshell (LPN = 5), fuzzy
pigtoe (LPN = 5), Choctaw
bean (LPN = 5), narrow pigtoe
(LPN = 11), and tapered
pigtoe (LPN = 11)).
3 Colorado plants (Pagosa Proposed listing.
skyrocket (Ipomopsis
polyantha) (LPN = 2),
Parchute beardtongue
(Penstemon debilis) (LPN =
2), Debeque phacelia
(Phacelia submutica) (LPN =
8)).
Casey's june beetle (LPN = 2). Proposed listing.
------------------------------------------------------------------------
\1\ Funds for listing actions for these species were provided in
previous FYs.
\2\ We funded a proposed rule for this subspecies with an LPN of 3 ahead
of other species with LPN of 2, because the threats to the species
were so imminent and of a high magnitude that we considered emergency
listing if we were unable to fund work on a proposed listing rule in
FY 2008.
\3\ Funds for these high priority listing actions were provided in FY
2008 and 2009.

We have endeavored to make our listing actions as efficient and
timely as possible, given the requirements of the relevant law and
regulations, and constraints relating to workload and personnel. We
are continually considering ways to streamline processes or achieve
economies of scale, such as by batching related actions together.
Given our limited budget for implementing section 4 of the Act,
these actions described above collectively constitute expeditious
progress.

The lower Colorado River basin DPS of roundtail chub will be added
to the list of candidate species upon publication of this 12-month
finding. We will continue to monitor the status of this species as new
information becomes available. This review will determine if a change
in status is warranted, including the need to make prompt use of
emergency listing procedures.
We intend that any proposed listing action for the lower Colorado
River basin DPS of roundtail chub will be as accurate as possible.
Therefore, we will continue to accept additional information and
comments from all concerned governmental agencies, the scientific
community, industry, or any other interested party concerning this
finding.

References Cited

A complete list of all references cited in this document is
available upon request from the Field Supervisor at the Arizona
Ecological Services Office (see ADDRESSES section).

Author

The primary authors of this document are the staff members of the
Arizona Ecological Services Office (see ADDRESSES section).

Authority

The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).

Dated: June 24, 2009.
Marvin E. Moriarty,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. E9-15828 Filed 7-6-09; 8:45 am]
BILLING CODE 4310-55-P