[Federal Register Volume 70, Number 65 (Wednesday, April 6, 2005)]
[Proposed Rules]
[Pages 17386-17401]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-6611]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 223
[Docket No. 050323081-5081-01; I.D. 031505C]
RIN 0648-AT02
Endangered and Threatened Wildlife and Plants: Proposed
Threatened Status for Southern Distinct Population Segment of North
American Green Sturgeon
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Proposed rule; request for comments.
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SUMMARY: We, the NMFS, have completed an update of an Endangered
Species Act (ESA) status review for the North American green sturgeon
(Acipenser medirostris; hereafter ``green sturgeon''). After reviewing
new and updated information on the status of green sturgeon and
considering whether green sturgeon is in danger of extinction
throughout all or a significant portion of its range, or is likely to
become endangered within the foreseeable future throughout all or a
significant portion of its range, we confirm our earlier determination
that the species is comprised of two distinct population segments
(DPSs) that qualify as species under the ESA, the Northern and Southern
DPSs. We reaffirm our earlier determination that the Northern DPS does
not warrant listing as threatened or endangered at this time, and we
will maintain the DPS on the Species of Concern List due to remaining
uncertainties about its status and threats. We revise our previous
``not warranted'' finding for the Southern DPS and propose to list it
as threatened. This revision is based on: new information showing that
the majority of spawning adults are concentrated into one spawning
river (i.e., Sacramento River), thus increasing the risk of extirpation
due to catastrophic events; threats that have remained severe since the
last status review and have not been adequately addressed by
conservation measures currently in place; fishery-independent data
exhibiting a negative trend in juvenile green sturgeon abundance; and
new information showing evidence of lost spawning habitat in the upper
Sacramento and Feather Rivers. We will reevaluate the status of the
Northern DPS in 5 years. If the proposed listing is finalized, a
recovery plan will be prepared and implemented for the Southern DPS.
Protective regulations under ESA section 4(d) and critical habitat will
be proposed in a subsequent Federal Register notice.
DATES: Comments on this proposal must be received by July 5, 2005. A
public hearing will be held promptly if any person so requests by May
23, 2005. Notice of the location and time of any such hearing will be
published in the Federal Register not less than 15 days before the
hearing is held.
ADDRESSES: You may submit comments by any of the following methods:
E-Mail: [email protected]
Federal e-Rulemaking Portal: http://www.regulations.gov.
Follow the instructions for submitting comments.
Mail: Submit written comments to Chief, Protected
Resources Division, Southwest Region, National Marine Fisheries
Service, 501 West Ocean Blvd., Suite 4200, Long Beach, CA, 90802-4213.
The updated green sturgeon status review and other reference
materials regarding this determination can be obtained via the Internet
at: http://www.nmfs.noaa.gov or by submitting a request to the
Assistant Regional Administrator, Protected Resources Division,
Southwest Region, NMFS, 501 West Ocean Blvd., Suite 4200, Long Beach,
CA 90802-4213, or the Assistant Regional Administrator, Protected
Resources Division, Northwest Region, NMFS, 1201 NE Lloyd Avenue, Suite
1100, Portland, OR 97232.
FOR FURTHER INFORMATION CONTACT: Melissa Neuman, NMFS, Southwest Region
(562) 980-4115; Scott Rumsey, NMFS, Northwest Region (503) 872-2791; or
Lisa Manning, NMFS, Office of Protected Resources (301) 713-1401.
SUPPLEMENTARY INFORMATION:
Background
On June 12, 2001, we received a petition from the Environmental
Protection Information Center, Center
[[Page 17387]]
for Biological Diversity, and WaterKeepers Northern California
requesting that we list the green sturgeon as threatened or endangered
under the ESA and that critical habitat be designated for the species
concurrently with any listing determination. On December 14, 2001, we
provided notice of our determination that the petition presented
substantial scientific information indicating that the petitioned
action may be warranted and requested information to assist with a
status review to determine if green sturgeon warranted listing under
the ESA (66 FR 64793). To assist in the status review, we formed a
Biological Review Team (BRT) comprised of scientists from our Northwest
and Southwest Fisheries Science Centers and from the United States
Geological Survey (USGS). We also requested technical information and
comments from State and Tribal co-managers in California, Oregon, and
Washington, as well as from scientists and individuals having research
or management expertise pertaining to green sturgeon from California
and the Pacific Northwest. The BRT considered the best available
scientific and commercial information, including information presented
in the petition and in response to our request for information
concerning the status of and efforts being made to protect the species
(66 FR 64793; December 14, 2001). The BRT presented its findings in a
final status review report for North American green sturgeon (Adams et
al., 2002). Under the ESA, a listing determination may address a
species, subspecies, or a DPS of any vertebrate species which
interbreeds when mature (16 U.S.C. 1532(16)). On February 7, 1996, the
U.S. Fish and Wildlife Service (FWS) and NMFS adopted a policy
describing what constitutes a DPS of a taxonomic species (61 FR 4722).
The joint DPS policy identified two elements that must be considered
when making DPS determinations: (1) The discreteness of the population
segment in relation to the remainder of the species (or subspecies) to
which it belongs; and (2) the significance of the population segment to
the remainder of the species (or subspecies) to which it belongs. After
conducting the status review, we determined that green sturgeon is
comprised of two DPSs that qualify as species under the ESA: (1) a
northern DPS consisting of populations in coastal watersheds northward
of and including the Eel River (``Northern DPS''); and (2) a southern
DPS consisting of coastal and Central Valley populations south of the
Eel River, with the only known population in the Sacramento River
(``Southern DPS'').
The BRT considered the following information in order to assess
risk factors for each green sturgeon DPS: (1) abundance trends from
fisheries data; (2) the effects of fishing bycatch; (3) the possible
loss of spawning habitat in rivers where spawning is reported to have
occurred historically, but apparently no longer does; (4) concentration
of spawning in the Klamath and Sacramento River systems; (5) lack of
adequate population abundance data; (6) potentially lethal water
temperatures and adverse effects of contaminants; (7) entrainment
(defined here as loss of green sturgeon due to water diversion) by
water projects; and (8) adverse effects of non-native species. Based on
the 2002 risk assessment, we determined on January 23, 2003, that
neither DPS warranted listing as threatened or endangered (68 FR 4433).
Uncertainties in the structure and status of both DPSs led us to add
them to the Species of Concern List (formerly the candidate species
list; 69 FR 19975; April 15, 2004). Along with the finding, we
announced that we would reevaluate the status of green sturgeon in 5
years.
On April 7, 2003, the Environmental Protection Information Center
(and other Plaintiffs) challenged our ``not warranted'' finding for
green sturgeon. The U.S. District Court for the Northern District of
California issued an order on March 2, 2004, which set aside our ``not
warranted'' finding and remanded the matter to us for redetermination
of whether green sturgeon is in danger of extinction throughout all or
a significant portion of its range, or is likely to become endangered
within the foreseeable future throughout all or a significant portion
of its range. The U.S. District Court's March 2004 remand was issued
because the Court was not satisfied with our examination of whether
purported lost spawning habitat constituted a significant portion of
either DPS' range. We reestablished the BRT in the early summer of 2004
and added a new member from USGS who possessed considerable knowledge
of green sturgeon. The BRT was asked to consider recent scientific and
commercial information available regarding the biological status of
green sturgeon and to assist us in assessing the viability of the
species throughout all or a significant portion of its range. We
published a notice on June 18, 2004, soliciting information from the
public to assist us in updating our status review and making a new
listing determination (69 FR 34135).
In addition to the information solicited during the first status
review, we solicited any new information beyond that considered in the
2002 green sturgeon status review or the January 2003 1-year ``not
warranted'' finding on the following topics for the Northern and
Southern DPSs of green sturgeon: (1) new genetic, morphological,
physiological, or ecological information relevant to DPS
identification; (2) current or historic information documenting the
geographic extent (e.g., area, river mile distance) and magnitude
(e.g., abundance of spawning females, reproductive output) of spawning
in particular river systems (e.g., Fraser River, Umpqua River, South
Fork Trinity River, Eel River, Feather River, and San Joaquin River);
(3) information documenting the current geographic extent and magnitude
of spawning in areas other than where it is known to presently occur
(i.e., areas other than the Sacramento River, Klamath River and Rogue
River); (4) the legitimacy of references used to support information
regarding current or historic spawning in the systems mentioned above
in (2) and (3), particularly citations by Houston (1988) for the Fraser
River; Lauman et al. (1972) and the Oregon Department of Fish and
Wildlife (ODFW) (2002) for the Umpqua River; Moyle et al. (1992) and
references therein for the South Fork Trinity River; Puckett (1976),
Moyle et al. (1992) and references therein for the Eel River; Wang
(1986) and FWS (1995) for the Feather River; and Moyle et al. (1992)
and references therein for the San Joaquin River; (5) historic, current
or future factors that may be responsible for the reported loss of
spawning habitat and associated spawning populations; and (6) fishery-
dependent and -independent abundance data for analysis of population
trends.
The public comment period closed on August 17, 2004. The BRT
convened to draft an updated status review in November 2004.
On January 27, 2005, we distributed the updated status review to
co-managers (i.e., States of Washington, Oregon and California, Yurok
and Hoopa Tribes, FWS, and the California Bay-Delta Program) for
review. The final updated status review for green sturgeon was
completed by the BRT on February 22, 2005, and submitted to NMFS
Regional Offices for further consideration prior to the publication of
this notice.
[[Page 17388]]
Biology and Life History of Green Sturgeon
A thorough account of green sturgeon biology and life history may
be found in the previous 1-year finding (68 FR 4433; January 23, 2003)
and the updated status review (Adams et al., 2005), which are
incorporated here by reference. The following is a summary of that
information.
Adult Distribution and Feeding
The green sturgeon is the most widely distributed member of the
sturgeon family Acipenseridae. Like all sturgeon species it is
anadromous, but it is also the most marine-oriented of the sturgeon
species. Green sturgeon are known to range in nearshore marine waters
from Mexico to the Bering Sea and are commonly observed in bays and
estuaries along the western coast of North America, with particularly
large concentrations entering the Columbia River estuary, Willapa Bay,
and Grays Harbor during the late summer (Moyle et al., 1992). The
reasons for these concentrations are unclear, but do not appear to be
related to spawning or feeding (Beamesderfer, 2000).
Little is known about adult green sturgeon feeding. Adults in the
Sacramento-San Joaquin Delta are reported to feed on benthic
invertebrates including shrimp, mollusks, amphipods, and even small
fish (Moyle et al., 1992). One hundred and twenty-one green sturgeon
stomach samples from the Columbia River gillnet fishery were empty with
the exception of one fish, while all white sturgeon stomachs contained
digested material (ODFW 2002).
Spawning
Adult green sturgeon are thought to spawn every 3 to 5 years
(Tracy, 1990), but new information suggests that spawning could occur
as frequently as every 2 years (Lindley and Moser, pers. comm., 2004).
Adults typically migrate into fresh water beginning in late February
(Moyle et al., 1995); spawning occurs from March July, with peak
activity from April June (Moyle et al., 1995). Confirmed spawning
populations in North America are in the Rogue (Erickson et al., 2001,
Rien et al., 2001), Klamath, and Sacramento Rivers (Moyle et al., 1992;
CDFG, 2002). Green sturgeon females produce 60,000 - 140,000 eggs
(Moyle et al., 1992), and they are the largest eggs (diameter 4.34mm)
of any sturgeon species (Cech et al., 2000). Spawning occurs in deep
turbulent river mainstems. Klamath and Rogue River populations appear
to spawn within 100 miles (161 km) of the ocean, while the Sacramento
spawning run may travel over 200 miles (322 km). Specific spawning
habitat preferences are unclear, but eggs likely are broadcast over
large cobble where they settle into the cracks (Moyle et al., 1995).
Optimum flow and temperature requirements for spawning and incubation
are unclear, but spawning success in most sturgeons is related to these
factors (Dettlaff et al.,1993). Temperatures above 68 F (20[deg]C) were
lethal to embryos in laboratory experiments (Cech et al., 2000).
Early Life History and Maturation
Green sturgeon larvae first feed at 10 days post hatch and grow
quickly reaching a length of 66mm and a weight of 1.8 g in 3 weeks of
exogenous feeding. Metamorphosis to the juvenile stage is complete at
45 days. Juveniles continue to grow rapidly, reaching 300mm in 1 year
and over 600mm within 2 3 years for the Klamath River (Nakamoto et al.,
1995). Juveniles spend from 1 4 years in fresh and estuarine waters and
disperse into salt water at lengths of 300-750mm. The little that is
known regarding juvenile green sturgeon feeding habits comes from a
study conducted in the Sacramento-San Joaquin Delta, where juveniles
fed on opossum shrimp and amphipods (Radtke, 1966).
Green sturgeon disperse widely in the ocean after their out-
migration from freshwater (Moyle et al., 1992). Tagged green sturgeon
from the Sacramento and Columbia Rivers are primarily captured to the
north in coastal and estuarine waters, with some fish tagged in the
Columbia River being recaptured as far north as British Columbia (WDFW,
2002a). While there is some bias associated with recovery of tagged
fish through commercial fishing, the pattern of a northern migration is
supported by the large concentration of green sturgeon in the Columbia
River estuary, Willapa Bay, and Grays Harbor, which peaks in August.
These fish tend to be immature; however, mature fish and at least one
ripe fish have been found in the lower Columbia River (WDFW, 2002a).
Genetic evidence suggests that Columbia River green sturgeon are a
mixture of fish from at least the Sacramento, Klamath, and Rogue Rivers
(Israel et al., 2002). Mature males range from 139 199cm in fork length
(FL) and 15 to 30 years of age (VanEenennaam, 2002). Mature females
range from 157 223cm FL and 17 to 40 years of age. Maximum ages of
adult green sturgeon are likely to range from 60-70 years (Moyle,
2002).
Summary of New Information
Consideration as a ``Species'' Under the ESA
The ESA defines species as ``any subspecies of fish or wildlife or
plants, and any distinct population segment of any species of
vertebrate fish or wildlife that interbreeds when mature'' 16 U.S.C.
1532(16). This definition allows for the recognition of DPSs at levels
below taxonomically recognized species or subspecies. On February 7,
1996, the FWS and NMFS published a joint policy to clarify the phrase
``distinct population segment'' for the purposes of listing, delisting
and reclassifying species under the ESA (61 FR 4722). This policy
identifies two criteria that must be met for a population segment to be
considered a DPS under the ESA: (1) The discreteness of the population
segment in relation to the remainder of the species or subspecies to
which it belongs; and (2) the significance of the population segment to
the species or subspecies to which it belongs.
New genetic information in combination with the tendency of
sturgeon to exhibit high spawning site fidelity confirms the
conclusions drawn during the previous 1-year ``not warranted'' finding
(68 FR 4433; January 29, 2003) that the northern and southern
populations of green sturgeon are ``discrete'' and ``significant'' as
defined in the DPS policy. (For a complete discussion of the
discreteness and significance of the U.S. population of green sturgeon
see 68 FR at 4437).
Genetic Information
Updated analyses of green sturgeon genetic structure were made
available from University of California - Davis (J. Israel and B. May,
pers. comm., 2004). These results incorporated a greater number of
samples including new adult samples from the Umpqua River, new juvenile
samples from the Sacramento River, and an increase in microsatellite
DNA loci to nine over the six reported in the previous status review
and discussed in Israel et. al. (2004). Green sturgeon samples
demonstrate a strong division between a grouping of the Rogue, Klamath,
and Umpqua Rivers versus a grouping of the Sacramento and Columbia
Rivers and San Pablo Bay samples. The northern group included mixed
stock green sturgeon samples from the Umpqua River as well as single
stock samples from the Rogue and Klamath Rivers and the southern group
included mixed stock samples from the Columbia River, samples from San
Pablo Bay that may be either mixed or single stock, and single stock
samples from the Sacramento River.
[[Page 17389]]
Oceanic Distribution and Behavior
New oceanic distribution and behavior information came from pop-off
archival tags (7 fish), Oregon trawl logbook analysis, and acoustic
tags (168 fish). These data indicated that green sturgeon generally
make northward migrations, to points as far north as northwest
Vancouver Island, Canada, upon returning to the ocean. During oceanic
migrations, archival tagged fish occupied depths of 40-70 m and
remained exclusively inside the 110 m contour. These results are
confirmed by Oregon trawl logbook records (Erickson and Hightower,
2004). Fish marked in spawning areas (Rogue and Klamath Rivers and San
Pablo Bay) and in mixed stock areas (Columbia River and Willapa Bay)
with acoustic tags in 2002, 2003, and 2004 sustained migrations of 100
km per day. Several fish tagged in 2002 returned to the Rogue River in
2004, suggesting a minimal spawning periodicity of 2 years if it is
assumed that these fish were ripe and returning to the River to spawn
(S. Lindley and M. Moser, pers. comm., 2004).
Freshwater Distribution Information
We requested new historic and/or current information for particular
river systems where historic and current spawning status is uncertain
(e.g., Fraser River, Umpqua River, South Fork Trinity River, Eel River,
Feather River, and San Joaquin River; 69 FR 34135). New information was
received for the Chehalis, Umpqua, Rogue, and Eel Rivers within the
Northern DPS and the Sacramento, Feather, and San Joaquin Rivers within
the Southern DPS.
Northern DPS
Washington Department of Fish and Wildlife (WDFW) investigated the
Chehalis River as potential green sturgeon habitat, and while it
appears to possess suitable habitat features for green and white
sturgeon spawning, there has not been evidence of spawning occurring in
this basin (WDFW, 2004). Data summarized from catch record cards
suggest that a few green sturgeon were caught in sport fisheries as far
upriver as 60 kilometers during July 2002, March 2003, and December
2003, but these may be misidentifications of white sturgeon, which are
much more common within the basin. Sport anglers have reported small
green sturgeon in Grays Harbor; however, these fish were most likely of
a post-migratory size and therefore were not fish rearing in the
estuary. Green and white sturgeon eggs and larvae have not been
observed in the Chehalis River or Grays Harbor.
There are two confirmed records of green sturgeon captured above
tidal influence in the Umpqua River (T. Rien, pers. comm., 2004). In
July 2000, two juvenile green sturgeon (each approximately 10-cm long)
were regurgitated from two smallmouth bass caught at river kilometer
(rkm) 134 on the Umpqua River. The ODFW interviewed the local angling
guide, and the one available regurgitated fish was positively
identified as a green sturgeon. The other regurgitated sturgeon was not
available to examine. In April 1979, a 1.8 m green sturgeon was caught
at rkm 164 on the Umpqua River. A picture of the fish was published in
the Roseburg News Review (May 3, 1979) and it was visually identified
as a green sturgeon by ODFW. ODFW has sampled the Umpqua River in 2002,
2003, and 2004 using gill nets, beach seines, snorkeling, and
underwater video, and their sampling efforts did not capture any green
sturgeon above tidal influence in the Umpqua River.
A putative green juvenile sturgeon was captured at Big Butte Creek
(rkm 254) near Lost Creek Dam on the Rogue River (R. Reisenbichler,
pers. comm., 2004). This is unusual because it is very high in the
system and above two major dams with fish ladders (Savage Rapids and
Gold Ray) and several smaller dams.
Adult green sturgeon were sighted on the mainstem Eel River near
Fort Seward, California (rkm 101) during snorkel surveys in 1995 and
1996 (S. Downie, pers. comm., 2004). Three sturgeon were sighted each
year at a place locally known as ``The Sturgeon Hole.'' Two juvenile
green sturgeon were captured in the Eel River estuary in 1994 by trawl
(S. Cannata, pers. comm., 2004). The first one was 282mm FL and the
second was 510mm. This is in addition to the previously reported
capture of 26 juvenile green sturgeon near Fort Seward in 1967 and 1968
(Pluckett, 1976).
Southern DPS
Recent habitat evaluations conducted in the upper Sacramento and
Feather Rivers for salmonid recovery planning suggest that significant
potential green sturgeon spawning habitat was made inaccessible or
altered by dams (historical habitat characteristics, temperature, and
geology summarized in Lindley et al., 2004). This spawning habitat may
have extended up into the three major branches of the Sacramento River,
the Little Sacramento River, the Pit River system, and the McCloud
River.
Green and white sturgeon adults have been observed periodically in
small numbers in the Feather River (Beamesderfer et al., 2004). There
are at least two confirmed records of adult green sturgeon in 2004.
There are no records of larval or juvenile sturgeon of either species,
even prior to the 1960's when Oroville Dam was built. There are reports
that green sturgeon may reproduce in the Feather River during high flow
years (CDFG, 2002), but these are not specific and are unconfirmed.
Small fisheries for sturgeon occur in spring on the San Joaquin
River between Mossdale and the Merced River (Kohlhorst, 1976). Though
sturgeon are known to migrate into the San Joaquin River, no efforts
have been made to document sturgeon reproduction (FWS, 1995). In
addition, data are not regularly collected at diversions on the San
Joaquin River, and when sturgeon have been collected, species
differentiation rarely occurred. Information exists through interviews
with biologists, wardens, and anglers regarding the presence and
potential spawning of white sturgeon on the San Joaquin River (FWS,
1995). Two juvenile white sturgeon caught at Woodbridge on the
Mokelumne River (rkm 63) in 2003 are the first confirmation of white
sturgeon reproduction in the San Joaquin River system (Beamesderfer et
al., 2004). Though no green sturgeon have ever been documented in the
San Joaquin River upstream of the Delta or in the Stanislaus, Tuolumne,
and Merced Rivers (CDFG, 2002; Beamesderfer et al., 2004), the San
Joaquin River and its tributaries have been heavily modified in ways
that reduce suitability for sturgeon since the 1940s, so the lack of
contemporary information cannot be considered evidence of historical
green sturgeon absence. Moreover, species with a similar dependence on
historic deep cool waters of the San Joaquin for spawning (i.e.,
spring-run Chinook salmon; Yoshiyama et al., 2001; and white sturgeon,
FWS, 1995) are either extirpated or nearly so on the San Joaquin River,
indicating that a once self-sustaining green sturgeon population on the
San Joaquin River may have been possible.
Catch Information
The coastwide bycatch of green sturgeon continues to be reduced
over time as noted in the previous status review (Adams et al., 2002).
Based on updated and corrected bycatch numbers, green sturgeon take has
been reduced from a high of 9,065 in 1986 to 862 in 2001, the last year
in the previous status review, to 512 in 2003. The greatest reductions
in bycatch (direct and indirect) were for the commercial fisheries in
the Northern
[[Page 17390]]
DPS, specifically the Columbia River, Willapa Bay, and Grays Harbor.
This reduction has occurred due to regulatory changes summarized in
Adams et al. (2002), Appendix 1 Table 2. Yurok and Hoopa tribal green
sturgeon fisheries have remained constant, with relatively constant
effort, and together account for 59 percent of the coastwide green
sturgeon catch in 2003.
Historic Spawning Status
Information presented in the first status review (Adams et al.,
2002) and new information presented here regarding the historic and
current spawning status of green sturgeon were analyzed.
Conclusions from New Information
In earlier technical memos and Federal Register publications (66 FR
64793, December 14, 2001; 68 FR 4433, January 23, 2003), we reported
the loss of green sturgeon spawning habitat in the Umpqua, Fraser,
South Fork Trinity, Eel (Northern DPS), Upper Sacramento, Feather, and
possibly San Joaquin Rivers (Southern DPS) based on information
presented in the petition. These claims prompted us to report that
green sturgeon experienced a significant reduction in spawning area.
New analysis of existing information and the submission of new
information to us in August 2004 (69 FR 34135) leads us to revise these
earlier judgments in the following ways.
Northern DPS
There is no evidence of historic or current spawning in the Fraser
or Chehalis Rivers (D. Lane, pers. comm., 2004; WDFW, 2004). Based on
the lack of data, we cannot conclude that there has been a loss of
spawning habitat over time in these systems.
Known historic and current spawning, based primarily on the
presence of juvenile green sturgeon, occurs in the Umpqua, Rogue,
Klamath and Trinity Rivers, and, therefore, we conclude that
populations have not been extirpated from these systems (T. Rein, pers.
comm., 2004; Erickson et al., 2002; Moyle, 2002; Sheiff et al., 2001).
We are uncertain as to whether spawning habitat has been lost in the
Umpqua River. A significant reduction in spawning habitat is not likely
to have occurred in the Rogue River because there are no impassable
barriers along green sturgeon migration routes. Although the Klamath
River has undergone human alteration, data suggest that the geographic
extent of spawning in the system has not been reduced over time. A
paucity of data for the Trinity River limits our ability to comment on
the magnitude of loss of spawning habitat in this system.
There is evidence to suggest that green sturgeon spawned in the
South Fork Trinity River and continue to spawn there to some degree,
based on the presence of adults in freshwater areas above tidal
influence (CDFG, 1978; Moyle et al., 1992). We suspect that spawning
habitat still exists in this system, but have no evidence to comment on
whether spawning habitat has been reduced over time.
The Eel River is the only system in the Northern DPS where the
status of spawning since historic times is believed to have changed.
Spawning is known to have occurred in the past based on the presence of
juveniles (Plunkett, 1976), but recently, only adults have been present
in the River (S. Downie, pers. comm., 2004) and one juvenile, whose
natal stream origin is uncertain, was collected in the estuary. Despite
Moyle et al.'s (2002) claim that green sturgeon have been extirpated
from the Eel River, we determined that our ability to make a conclusion
regarding extirpation is limited by: (1) low sampling effort in recent
times (see Status of Green Sturgeon DPSs: Northern DPS); and (2) our
inability to determine how much spawning habitat or reproductive
potential may have been lost.
Southern DPS
Known historic and current spawning, based on the presence of
juvenile green sturgeon, occurs in the Sacramento River (Adams et al.,
2002). We have indirect evidence, based on habitat assessments of
Chinook salmon, that the geographic extent of spawning has been reduced
due to impassable barriers (the Keswick and Shasta dams) in the upper
Sacramento River. We have not been able to quantify the reduction of
habitat to date, and are uncertain how reduction in spawning habitat
has affected the population's viability.
Spawning is suspected to have occurred in the Feather River due to
the presence of adults in the system (CDFG, 2002). Although there is no
evidence of spawning in the past or now, the continued presence of
adults in the system suggests that green sturgeon are trying to migrate
into presumed spawning areas now blocked by the Oroville Dam.
Therefore, we conclude that spawning habitat may have been lost in the
Feather River, but we were not able to determine how much habitat or
reproductive potential was lost.
There is no evidence of historic or current spawning in the San
Joaquin River (Beamesderfer, 2004; Adams et al., 2002; CDFG, 2002).
While we cannot make any conclusions regarding loss of spawning habitat
over time in the San Joaquin River, indirect evidence from a variety of
sources (Moyle, 2002; Lindley et al., 2004; L. Hess, pers. comm., 2004)
suggests that both adult and juvenile green sturgeon may have been
present in this system in the past. If spawning did occur in the San
Joaquin River in the past, there may have been a reduction in spawning
habitat again due to reasons mentioned above for the Sacramento and
Feather Rivers.
Summary of Factors Affecting the Species
Section 4 of the ESA (16 U.S.C. 1533) and regulations promulgated
to implement the listing provisions of the ESA (50 CFR part 424) set
forth the procedures for adding species to the Federal list of
threatened and endangered species. Section 4 requires that listing
determinations be based solely on the best scientific and commercial
data available, without consideration of possible economic or other
impacts of such determinations. A species may be determined to be
endangered or threatened due to one or more of the five factors
described in section 4(a)(1) of the ESA. We must determine if either
DPS of green sturgeon is endangered or threatened because of any one or
a combination of the following factors: (1) the present or threatened
destruction, modification, or curtailment of its habitat or range; (2)
overutilization for commercial, recreational, scientific, or
educational purposes; (3) disease or predation; (4) inadequacy of
existing regulatory mechanisms; or (5) other natural or human-made
factors affecting its continued existence.
Species-wide Factors
Ocean and estuarine bycatch of green sturgeon in the white sturgeon
and salmonid fisheries was considered a species-wide factor for decline
since its impact could not be apportioned to one DPS or the other.
Current total catch of green sturgeon has been reduced to 6 percent of
its 1986 high value of 9,065 fish; this does not, however, necessarily
represent a reduction in green sturgeon abundance. The recent reduction
is due to newly imposed fishing regulations in Oregon and Washington.
Commercial fisheries targeting sturgeon have not been allowed in the
Columbia River or Willapa Bay since 2001, and recreational fishing
remains negligible (WDFW, 2004). Yurok and Hoopa tribal catch has
remained relatively constant during the entire time series. The
reduction in catch through protective
[[Page 17391]]
management measures represents a reduction in risk to the Northern
DPS. CDFG (2002) estimated an average fishing mortality of 2.2 percent
for green sturgeon based on tag return data in the Sacramento-San
Joaquin Estuary. The impact of this fishing mortality rate is unknown.
A summary of DPS-specific factors for decline is presented below
(Tables 1 and 2). These factors were only considered for those river
systems with known or suspected historical or current spawning
activity.
Northern DPS Factors
The potential factors for decline in the Northern DPS are reduced
flows, changed flow regimes, increased temperatures, and reduced oxygen
concentrations, principally in the Klamath-Trinity and Eel River
systems (Table 1). The impact of these factors is uncertain. This DPS
also has the only major in-river fishery for green sturgeon (Yurok and
Hoopa tribal fisheries in the Klamath-Trinity River system), the
effects of which are uncertain, but catch data show no obvious signs of
decline. As mentioned in the previous section, species-wide reduction
in bycatch fishing mortality through protective management measures
reduces the threat of overfishing in the Northern DPS. No risks due to
disease, predation, or inadequacy of existing regulatory mechanisms
were identified. The Northern DPS has two known major spawning
populations (e.g., the Klamath-Trinity River system and the Rogue
River) that are not close to one another geographically, thus spreading
risks of extinction over more than one spawning area. Spawning also
appears to occur infrequently in the Umpqua River. This gives the
Northern DPS some additional protection.
Southern DPS Factors
The principal factor for decline for this DPS comes from the
reduction of green sturgeon spawning area to a limited area of the
Sacramento River (Table 2). Keswick Dam provides an impassible barrier
blocking green sturgeon access to what were likely historic spawning
grounds upstream (FWS, 1995). A substantial amount of habitat in the
Feather River above Oroville Dam also was lost, and threats to green
sturgeon on the Feather River are similar to those faced in the
Sacramento River (NMFS, 2004). The BRT concluded that a viable spawning
population of green sturgeon no longer exists in the Feather River and
was likely lost due to the habitat blockage as a result of Oroville Dam
and from thermal barriers associated with the Thermalito Afterbay
Facility (Table 2). Any observations of adult green sturgeon likely
represent individuals that were stranded as a result of these barriers.
Potential adult migration barriers to green sturgeon include the
Red Bluff Diversion Dam (RBDD), Sacramento Deep Water Ship Channel
locks, Fremont Weir, Sutter Bypass, and the Delta Cross Channel Gates
on the Sacramento River, and Shanghai Bench and Sunset Pumps on the
Feather River. The threat of screened and unscreened agricultural,
municipal, and industrial water diversions in the Sacramento River and
Delta to green sturgeon are largely unknown as juvenile sturgeon are
often not identified, and current California Department of Fish and
Game (CDFG) and NMFS screen criteria do not address sturgeon. Based on
the temporal occurrence of juvenile green sturgeon and the high density
of water diversion structures along rearing and migration routes, we
find the potential threat of these diversions to be serious and in need
of study (Table 2 NMFS, 2005).
CDFG (1992) and FWS (1995) found a strong correlation between mean
daily freshwater outflow (April to July) and white sturgeon year class
strength in the Sacramento-San Joaquin Estuary (these studies primarily
involve the more abundant white sturgeon; however, the threats to green
sturgeon are thought to be similar), indicating that insufficient flow
rates are likely to pose a significant threat to green sturgeon (Table
2). This association of year class strength with outflow is also found
in other anadromous fishes inhabiting the Estuary, such as striped
bass, Chinook salmon, American shad, and longfin smelt (Stevens and
Miller, 1983). Mean April-May flow rates of 566 cubic meters per second
appear to be the minimum required for the production of good year class
strength based on approximately 20 years of sturgeon salvage data at
the Skinner Fish Facility (CDFG, 2002). According to this criterion,
low flow rates occurred slightly more than 50 percent of the time
during the years spanning 1968-1987 (CDFG, 2002). The FWS (1995) used
water year types, based on an index developed for the Sacramento Basin
(California Department of Water Resources, 2004), to suggest that low
flow conditions occurred 53 percent of the time during the years
spanning 1944-2004. It is postulated that low flow rates could dampen
survival by hampering the dispersal of larvae to areas of greater food
availability, hampering the dispersal of larvae to all available
habitat, delaying the transportation of larvae downstream of water
diversions in the Delta, or decreasing nutrient supply to the nursery,
thus stifling productivity (CDFG, 1992). There are no current
indications that flow rates will increase over time.
High temperatures no longer seem to be the problem that they once
were with the installation of the Shasta Dam temperature control device
in 1997, although Shasta Dam has a limited storage capacity and cold
water reserves could be depleted in long droughts (Table 2).
Temperatures at RBDD have not been higher than 16[deg] C since 1995
(California Data Exchange Center) and are within the green sturgeon egg
and larvae optimum for growth and survival of 15[deg] to 19[deg] C
(Mayfield and Cech, 2004). However, green sturgeon reproduction before
1995 may well have been adversely affected by temperature and these
earlier high temperatures may have caused population reductions that
would still affect the overall population size and age-structure (Table
2). Water temperatures on Feather River downstream of the Thermalito
Afterbay outlet are considerably higher than temperatures in the low-
flow channel (FWS, 1995). It is likely that high water temperatures
(greater than 17.2[deg] C) may deleteriously affect sturgeon egg and
larval development, especially for late-spawning fish in drier water
years (FWS, 1995). CDFG (2002) also indicated water temperatures may be
inadequate for spawning and egg incubation in the Feather River during
many years as the result of releases of warmed water from Thermalito
Afterbay. CDFG believed this may be one reason neither green nor white
sturgeon are found in the river in low-flow years. It is not expected
that water temperatures will become more favorable in the near future
(CDFG, 2002) and thus elevated water temperature continues to be a
threat.
Sturgeon have high vulnerability to fisheries, and the trophy
status of large white sturgeon makes these fishes a high priority for
enforcement to protect against poaching (Table 2; CDFG, 2002). Green
sturgeon are caught incidentally in these white sturgeon fisheries.
Non-native species are an ongoing problem in the Sacramento-San
Joaquin River and Delta systems (Table 2; CDFG, 2002). One risk for
green sturgeon associated with the introduction of non-native species
involves the replacement of relatively uncontaminated food items with
those that may be contaminated. For example, the non-native overbite
clam, Potamocorbula amurensis, introduced in 1988, has become the most
common food of white sturgeon and was found in the only green
[[Page 17392]]
sturgeon examined thus far (CDFG, 2002). The overbite clam is known to
bioaccumulate selenium, a toxic metal (CDFG, 2002; Linville et al.,
2004). Green sturgeon may also experience predation by introduced
species including striped bass.
Contamination of the Sacramento River increased substantially in
the mid-1970s when application of rice pesticides increased (FWS,
1995). Estimated toxic concentrations for the Sacramento River during
1970-1988 may have deleteriously affected striped bass larvae (Bailey,
1994). White sturgeon may also accumulate PCBs and selenium (White et
al., 1989). While green sturgeon spend more time in the marine
environment than white sturgeon and, therefore, may have less exposure,
the BRT concluded that some degree of risk from contaminants probably
also occurs for green sturgeon (Table 2).
The previous status review (Adams et al., 2002) summarized juvenile
entrainment and change in annual mean number over time. Juvenile
entrainment is considered a type of threat imposed by water diversion
(Table 2).
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Status of Green Sturgeon DPS
Northern DPS
The Fraser River in Canada currently has a catch and release
fishery for sturgeon, but the number of green sturgeon captured is
extremely small. A tagging study in 1992-1993 tagged 2300 sturgeon and
only one was a green sturgeon (D. Lane, pers. comm., 2004). Green
sturgeon occur off the West Coast of Vancouver Island where they are
taken in the trawl fishery. These fish are thought to be from spawning
areas in the United States, and this idea is supported by the recent
acoustic and pop-off archival tagging. WDFW has investigated the
possibility of green sturgeon spawning in the Chehalis River as it
appears to provide suitable habitat features to support spawning.
However, no evidence of spawning in this system has occurred to date.
Currently, there is limited fishing in Grays Harbor, but no evidence of
spawning has been found (WDFW, 2004).
Spawning does appear to take place in the Umpqua River, but is
probably rare. Juvenile green sturgeon were identified in the system in
2000. Spawning in the Umpqua River apparently is not common since
substantial sampling efforts in 2002, 2003, and 2004 failed to find any
evidence of green sturgeon spawning.
The presence of green sturgeon spawning in the Rogue River has been
only recently discovered. The river is less manipulated and habitat
seems to be of better quality than in other green sturgeon spawning
rivers. Blockages to migration of anadromous fish are likely to be
upriver of the historical extent of green sturgeon spawning habitat
and, therefore, do not seem to be limiting; habitat seems to be roughly
what it was historically. Other anadromous salmonid fishes are
generally doing well in the Rogue River (Weitkamp et al., 1995; Busby
et al., 1996; and Myers et al., 1998).
The Klamath River has the largest green sturgeon spawning
population. Spawning still occurs upstream to the historical limit of
its habitat range (Ishi Pishi Falls). Out-migrant juvenile green
sturgeon are captured each year in screw traps at Big Bar (Schieff et
al., 2001). The BRT expressed concerns over recent fish kills in the
Klamath River, but reached no conclusions regarding whether or not the
temperature regime in the system played a part in this mortality event.
The Yurok tribal fishery comprises the majority of green sturgeon catch
coastwide. There is no new information regarding abundance trends since
the last status review (Adams et al., 2002). As discussed in the
previous status review, the trends in numbers and size are difficult to
interpret, but do not appear to indicate population decline.
There are few available data regarding the status of green sturgeon
in the Trinity River system. The Hoopa Tribe has a small in-river
fishery which takes fewer than 30 adult green sturgeon each year.
Juvenile out-migrant green sturgeon are captured in most years in small
numbers at Willow Creek (Schieff et al., 2001). Due to the continued
presence of juveniles within the system, the BRT was not convinced that
green sturgeon were extirpated from the South Fork Trinity River by the
1964 flood as suggested by Moyle (2002).
The Eel River is the southern-most known spawning area in the
Northern DPS. Moyle et al. (1992) suggested that green sturgeon were
extirpated from the Eel River following the 1964 flood. The 1955 and
1964 floods delivered large amounts of sediment into the Eel River.
These historical flood events, combined with land use practices, have
resulted in persisting high sediment levels. Some portion of the deep
holes that green sturgeon use during spawning were filled in by the
1955 and 1964 flood events, but the extent of sturgeon habitat loss is
unknown. The BRT was not convinced that green sturgeon have been
extirpated from the Eel River. Sightings of adults in both 1995 and
1996 and of juveniles in the estuary in 1994 suggest that a green
sturgeon population persists in the Eel River, although severely
reduced from historical levels. Sampling was limited with adult surveys
conducted only in 1995 and 1996 and estuarine surveys conducted only in
1993 and 1994.
The evaluation of extinction risk over a ``significant portion of
its range'' is difficult for this DPS because of the lack of historical
data about green sturgeon spawning areas. As explained above, in
earlier technical memos and Federal Register publications (66 FR 64793,
December 14, 2001; 68 FR 4433, January 23, 2003) we had discussed the
possibility that spawning habitat in the Fraser, Umqua, South Fork
Trinity, and Eel Rivers had beenseverely reduced. However, after
reviewing both existing and new information, we have revised those
earlier judgments and now conclude that the Eel River is the only
system in the Northern DPS where the status of spawning since historic
times is believed to have changed. All BRT members felt that the
historic spawning area of the DPS had been larger than the current
spawning area, but with no historical data describing spawning areas,
there was a range of thought about how much larger.
The BRT was unable to come to firm consensus on what should be
considered ``a significant portion'' for this DPS, however, they
generally agreed that ``a significant portion'' of the DPS's range
would include either the Klamath or Rogue Rivers, and that the South
Fork Trinity and Eel Rivers do not represent a significant portion of
the DPS's range. The BRT's opinion regarding ``significant portion of
its range'' is supported by drawing analogies from salmonid habitat use
and estimated abundance in the Klamath, Rogue, South Fork Trinity and
Eel Rivers (Lindley et al., 2004). Salmonid spawning habitat is more
extensive and estimated population abundance is higher in the Klamath
and Rogue Rivers than in the South Fork Trinity and Eel Rivers, and we
expect that green sturgeon habitat requirements and population size are
correlated with those of salmonids, both historically and today. Also,
the geology of the Eel River, in particular, is more erosive and prone
to sedimentation events, suggesting that spawning habitat in the Eel
River is of poorer quality than that in the Klamath and Rogue Rivers.
Finally, evidence suggests that the Klamath and Rogue Rivers played a
more important role in historic Yurok and Hoopa tribal sturgeon
fisheries than the Eel and South Fork Trinity Rivers (FWS, 1981), again
supporting the BRT's conclusion that neither the Eel nor South Fork
Trinity Rivers constitute a significant portion of the Northern DPS'
range.
Conclusion-Northern DPS
Based on the input provided by the BRT, we conclude that the
Northern DPS of green sturgeon is not in danger of extinction, nor
likely to become endangered in the foreseeable future, in all or a
significant portion of its range. While a significant portion of the
DPS' range would include either the Klamath or the Rogue Rivers,
neither of these populations is regarded as being at risk of
extirpation now or in the foreseeable future. The BRT was not convinced
that green sturgeon were extirpated from the South Fork Trinity or Eel
Rivers, even though it is likely that the Eel River population, in
particular, has suffered a severe reduction since historic times.
Reference data from salmonid habitat assessments and tribal fisheries
data suggest that even though green sturgeon populations in the Eel and
South Fork Trinity Rivers are likely low, these rivers do not represent
a significant portion of the DPS' range. The majority of the BRT felt
that the presence of two
[[Page 17396]]
well-separated and significant spawning populations in the Klamath and
Rogue Rivers, and the effective reduction in green sturgeon catch due
to implemented regulatory mechanisms, confer a low level of risk to the
DPS. A minority felt that overall paucity of data generates such
uncertainty in green sturgeon status that the DPS' level of extinction
risk may be higher than available data appear to indicate. The BRT
expressed concern regarding the lack of data and monitoring efforts to
adequately monitor the status of, and manage potential threats to,
green sturgeon populations in this DPS. The BRT recommended that the
Northern DPS be placed on the Species of Concern List, that their
status be reviewed in at least 5 years, and that population status
monitoring be implemented immediately.
Southern DPS
The BRT concluded that the Sacramento River contains the only known
green sturgeon spawning population in this DPS. There are no updated
population trends data since the last status review. The BRT concluded
that there was almost certainly a substantial loss of spawning habitat
behind Keswick and Shasta dams (FWS, 1995b, historical habitat data
summarized in Lindley et al., 2004 for salmonids). Green sturgeon
currently occur up to the impassible barrier at Keswick Dam (FWS,
1995b). It is unlikely that green sturgeon reproduced in their current
spawning area under the historical temperature regime that occurred
before the construction of Shasta and Keswick dams. At present, water
temperatures in the current spawning area are lower than they were
historically due to releases from Shasta Dam. Prior to dam
construction, green sturgeon would have had to migrate farther up the
mainstem than they do now in order to encounter water temperatures cool
enough to trigger spawning. The BRT considered it possible that the
additional habitat behind Shasta Dam in the Pit, McCloud, and Little
Sacramento systems would have supported separate populations or at
least a single, larger Sacramento River population less vulnerable to
catastrophes than one confined to a single mainstem, but the BRT was
unable to be specific due to the paucity of historical information. The
BRT expressed concern about the habitat limitation and potential
threats that green sturgeon faced in the Sacramento River and again
expressed particular concern about the high numbers of juveniles
entrained prior to 1986.
Juvenile entrainment data provide an indication of how abundance
has changed over time (1968-present). For the State facility (John
Skinner Fish Facility; 1968-2001), the estimated average number of
green sturgeon taken per year prior to 1986 was 732; from 1986 on, the
average number was 47. For the Federal facility (Tracy Fish Collection
Facility; 1980-2001), the average number prior to 1986 was 889; from
1986 on, the average was 32. The significant reduction in numbers is
consistent across the State and Federal facilities and is also
consistent with significant reductions in estimated white sturgeon take
within the same time periods (NMFS, 2005). In addition, evidence
indicates export levels at both facilities have increased
substantially, particularly at the State facility since the 1970s and
1980s (as exhibited by yearly acre-feet exported from Federal and State
facilities, NMFS, 2005). Though there are many assumptions associated
with fish salvage estimates at these facilities (i.e., estimates are
expanded catches from brief sampling periods; CDFG, 2002), this
information may be the best available data in determining the
population trends of the Southern DPS.
The BRT concluded that an effective population of spawning green
sturgeon does not exist in the Feather River. Although there is no
evidence of spawning in the Feather River either in the past or now,
the continued presence of adults in the system suggests that green
sturgeon are trying to migrate ito presumed spawning areas now blocked
by Oroville Dam, suggesting in turn that spawning habitat on the Fraser
River may bave been lost. A substantial amount of habitat in the
Feather River was lost with the construction of Oroville Dam
(constructed in 1961) and from thermal barriers at the Thermalito
Afterbay facility (CDFG, 2002). FWS (1995b) stated that ``Evidence also
suggests that [white] sturgeon reproduction occurs in both the Feather
and Bear rivers.'' Again, the BRT assumed that a similar suggestion
could be made for green sturgeon in the face of the paucity of data.
Sturgeon (including some documented green sturgeon) still regularly
occur in the Bear and Yuba Rivers (CDFG, 2002; Beamesderfer et al.,
2004) and, therefore, must migrate through the Feather River. Threats
to green sturgeon are similar to those faced in the Sacramento River.
Though the BRT concluded that there was not sufficient information
to establish whether the San Joaquin River system once supported a
viable green sturgeon population, we see no reason to exclude the San
Joaquin River system as a possibly occupied watershed in the past based
on similar conclusions reached for Chinook salmon habitat assessments
in the Sacramento and Feather Rivers. While some authors indicate that
there is no evidence of green sturgeon occurrence or spawning in the
San Joaquin River (Beamesderfer et al., 2004; Adams et al., 2002; CDFG,
2002), sampling effort has been extremely limited. Thus, no evidence of
presence does not necessarily mean that green sturgeon do not occur in
this system. Moyle (2002) suggested that green sturgeon reproduction
may have taken place in the San Joaquin River because numerous juvenile
green sturgeon have been captured at Santa Clara Shoal and Brannan
Island Recreational Area in the Delta. Both adult and juvenile green
sturgeon salvage recoveries at the Federal facility, located closest to
the San Joaquin River, also provide some evidence that the San Joaquin
River system may at least be occupied by green sturgeon during parts of
the year. The potential threats faced by green sturgeon if they do
occur or occurred in the past in the San Joaquin system would be
similar in nature to those faced in the Sacramento River, but would
likely be more extreme because there are a greater number of impassable
barriers in this system, many of which lack fish passage structures,
and flow rates are lower in the San Joaquin than those in the
Sacramento.
Conclusion-Southern DPS
The majority of the BRT concluded that the Southern DPS is likely
to become endangered in the foreseeable future throughout all of its
range. The BRT felt that the blockage of green sturgeon spawning from
what were historic spawning areas above Shasta Dam (although it is
unclear whether these were separate populations) and the accompanying
decrease in spawning area with the loss of a potential spawning area in
the Feather River make green sturgeon in the Southern DPS likely to
become endangered within the foreseeable future. We believe that the
loss of potential spawning habitat in the San Joaquin River system also
may have contributed to the overall decline of the Southern DPS. The
majority of the BRT also felt that the concentration of spawning adults
in the Sacramento River places this DPS at even greater risk of
extinction. No BRT members felt that the DPS was at imminent risk of
extinction.
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Efforts Being Made to Protect Green Sturgeon
Section 4(b)(1)(A) of the ESA requires the Secretary of Commerce to
make listing determinations solely on the basis of the best scientific
and commercial data available after taking into account efforts being
made to protect a species. Therefore, in making its listing
determinations, we first assess a DPS's level of extinction risk and
identify factors that have led to its decline. We then assess existing
efforts being made to protect the species to determine if those
measures ameliorate the risks faced by the DPS.
In judging the efficacy of existing protective efforts, we rely on
the joint NMFS-FWS ``Policy for Evaluation of Conservation Efforts When
Making Listing Decisions'' (``PECE;'' 68 FR 15100; March 28, 2003).
PECE provides direction for the consideration of protective efforts
identified in conservation agreements, conservation plans, management
plans, or similar documents (developed by Federal agencies, state and
local governments, Tribal governments, businesses, organizations, and
individuals) that have not yet been implemented, or have been
implemented but have not yet demonstrated effectiveness. The policy
articulates several criteria for evaluating the certainty of
implementation and effectiveness of protective efforts to aid in
determining whether a species should be listed as threatened or
endangered. Evaluations of the certainty an effort will be implemented
include whether: the necessary resources (e.g., funding and staffing)
are available; the requisite agreements have been formalized such that
the necessary authority and regulatory mechanisms are in place; there
is a schedule for completion and evaluation of the stated objectives;
and (for voluntary efforts) the necessary incentives are in place to
ensure adequate participation. The evaluation of the certainty of an
effort's effectiveness is made on the basis of whether the effort or
plan: establishes specific conservation objectives; identifies the
necessary steps to reduce threats or factors for decline; includes
quantifiable performance measures for the monitoring of compliance and
effectiveness; incorporates the principles of adaptive management; and
is likely to improve the species' viability at the time of the listing
determination.
PECE also notes several important caveats. Satisfaction of the
above mentioned criteria for implementation and effectiveness
establishes a given protective effort as a candidate for consideration,
but does not mean that an effort will ultimately change the risk
assessment. The policy stresses that just as listing determinations
must be based on the viability of the species at the time of review, so
they must be based on the state of protective efforts at the time of
the listing determination. PECE does not provide explicit guidance on
how protective efforts affecting only a portion of a species' range may
affect a listing determination, other than to say that such efforts
will be evaluated in the context of other efforts being made and the
species' overall viability. There are circumstances where threats are
so imminent, widespread, and/or complex that it may be impossible for
any agreement or plan to include sufficient efforts to result in a
determination that listing is not warranted.
Conservation measures that may apply to listed species include
conservation measures implemented by tribes, states, foreign nations,
local governments, and private organizations. Also, Federal, tribal,
state, and foreign nations' recovery actions (16 U.S.C. 1533(f)),
Federal consultation requirements (16 U.S.C. 1536), and prohibitions on
taking (16 U.S.C. 1538) constitute conservation measures. In addition,
recognition through Federal government or state listing promotes public
awareness and conservation actions by Federal, state, tribal
governments, foreign nations, private organizations, and individuals.
Fishing Regulations
Recent management strategies in Oregon and Washington have
considerably reduced the catch of green sturgeon. There are no targeted
commercial fisheries on green sturgeon, and recreational fishing
remains negligible. Commercial by-catch of green sturgeon occurs
predominantly during the early fall salmon and white sturgeon fisheries
in the lower Columbia River, when the green sturgeon have migrated into
the estuary and lower river mainstem. Fisheries are timed to avoid
coinciding with peak periods of green sturgeon presence. Since 2002,
Oregon and Washington have adopted daily landing limits for sturgeon
during fall Columbia River commercial salmon seasons. This management
action has resulted in a significant decrease in green sturgeon catch
due to the higher value (price per pound) of white sturgeon on the
commercial market. Harvesters now typically release all green sturgeon
(alive) to fill their weekly or daily landing limit with the more
valuable white sturgeon. Additionally, this management approach has
allowed the commercial fishery to access its allocation of white
sturgeon prior to periods of peak green sturgeon presence and without
any fisheries targeting sturgeon, further minimizing green sturgeon by-
catch.
Protective efforts on the Klamath and Trinity Rivers began with
take limits and maximum size ranges through the late 1970s, and between
1978 and 1993 seasonal limits were imposed to prohibit the take of
sturgeon in the Klamath River upstream of and including the Trinity
River. All sturgeon fishing has been prohibited in the Klamath-Trinity
system since 1993. Sturgeon fishing also has been prohibited since 1993
in all waters of the Eel River from the mouth to rkm 153 including all
waters of the South Fork Eel River downstream of Benbow Dam (CDFG,
2002). Sturgeon fishing in rivers and bays in Del Norte and Humboldt
Counties, including the Smith River, Humboldt and Arcata Bays, and all
tidal waters, has been prohibited since 1993. General angling
regulations apply to sturgeon angling from Mendocino County south (one
fish per day between 117 and 183cm TL).
Both white and green sturgeon are protected by the same fishing
regulations in the Sacramento-San Joaquin system. No commercial take is
permitted and angling take is restricted to one fish per day between
117 and 183cm TL. An additional closure in central San Francisco Bay
occurs between January 1 and March 15, coinciding with the herring
spawning season to protect sturgeon feeding on herring eggs (CDFG,
2002). Active sturgeon enforcement is often employed in areas where
sturgeon are concentrated and particularly vulnerable to the fishery.
There is no commercial fishery for green sturgeon in Canada,
although the species is taken as by-catch in white sturgeon and salmon
fisheries.
Habitat Protection Efforts
In the United States, the Central Valley Project Improvement Act
(CVPIA) is a Federal act directing the Secretary of the Interior to
amend previous authorizations of California's Central Valley Project to
include fish and wildlife protection, restoration, and mitigation as
project purposes having equal priority with irrigation and domestic
use, and fish and wildlife enhancement as a project purpose equal to
power generation. As a result of the CVPIA enacted in 1992, the FWS and
U.S. Bureau of Reclamation have led an effort to implement a
significant number of activities across the Central Valley including
projects such as: river restoration; land purchases; fish screen
projects; water acquisitions for the
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environment; and special studies and investigations. The Anadromous
Fish Restoration Program (AFRP), a component of the CVPIA, implements a
doubling program in an attempt to ``implement a program which makes all
reasonable efforts to ensure that, by the year 2002, natural production
of anadromous fish in Central Valley rivers and streams will be
sustainable, on a long-term basis, at levels not less than twice the
average levels attained during the period of 1967-1991.'' The AFRP
specifically applies the doubling effort toward Chinook salmon, Central
Valley steelhead, striped bass, and white and green sturgeon. Though
most efforts of the AFRP have primarily focused on Chinook salmon as a
result of their listing history and status, green sturgeon may receive
some unknown amount of benefit from these restoration efforts. For
example, the acquisition of water for flow enhancement on tributaries
to the Sacramento River, fish screening for the protection of Chinook
salmon and Central Valley steelhead, or riparian revegetation and
instream restoration projects would likely have some ancillary benefits
to sturgeon. The AFRP has also invested in one green sturgeon research
project that has helped improve our understanding of the life history
requirements and temporal patterns of green sturgeon within the
Southern DPS.
The California Bay-Delta Program (CALFED) is a cooperative effort
of more than 20 State and Federal agencies designed to improve water
quality and reliability of California's water supply while recovering
the Central Valley ecosystem. The CALFED program contains four key
objectives which include water quality, ecosystem quality, water supply
and levee system integrity. Many notable beneficial actions have
originated and been funded by the CALFED program including such
projects as floodplain and instream restoration, riparian habitat
protection, fish screening and passage projects, research regarding
non-native invasive species and contaminants, restoration methods, and
watershed stewardship and education and outreach programs. Prior
Federal Register notices have reviewed the details of CVPIA and CALFED
programs and potential benefits towards anadromous fish, particularly
Chinook salmon and Central Valley steelhead (50 FR 33102).
Information received from CALFED regarding potential projects that
could be regarded as conservation measures for green sturgeon indicated
a total of 118 projects of various types and levels of progress funded
between 1995 and 2004. Projects primarily consisted of fish screen
evaluation and construction projects, restoration evaluation and
enhancement activities, contaminations studies, and dissolved oxygen
investigations related to the San Joaquin River Deep Water Ship
Channel. Two evaluation projects specifically addressed green sturgeon
while the remaining projects primarily address anadromous fish in
general, particularly listed salmonids. The new green sturgeon
information from research will be used to enhance our understanding of
the risk factors affecting the species, thereby improving our ability
to develop effective management measures. However, at present they do
not directly help to alleviate threats that this species faces in the
wild. All ongoing fish screen and passage studies are designed
primarily to meet the minimum qualifications outlined by the NMFS and
CDFG fish screen criteria. Though these improvements will likely
benefit salmonids, there is no evidence showing that these measures
will decrease the likelihood of green sturgeon mortality. While one of
CALFED's goals is to recover a number of at-risk species (including
green sturgeon) and the program has and continues to provide funding
for a variety of laboratory-based research projects, there are no
specific actions aimed at alleviating the primary risks that threaten
the continued existence of green sturgeon in the wild.
Other potential conservation measures such as the opening of the
RBDD gates have helped green sturgeon passage in the Sacramento River
during the early part of their spawning season, but it is not known how
effective this measure has been. In addition, fish ladders in place are
probably too small for green sturgeon to negotiate during the latter
part of the spawning season when the RBDD gates are closed (FWS,
1995b). The Glenn-Colusa Irrigation District plans to help reduce fish
loss and enhance long-term fish passage, but these measures are not yet
underway. Fish salvaging efforts at the Tracy Fish Collection Facility
and the Skinner Delta Fish Protective Facility in the South Delta have
been operating for decades, but it is unknown whether efforts to
relocate adults have resulted in restoration of spawning potential and
whether the salvage of juveniles is effective.
As evaluated pursuant to PECE, the above described protective
efforts do not as yet, individually or collectively, provide sufficient
certainty of implementation and effectiveness to counter the extinction
risk assessment conclusion that the Southern DPS is likely to become an
endangered species in the foreseeable future throughout its range.
Green sturgeon are listed as Species of Special Concern under
Canada's Species at Risk Act (SARA). Under SARA a Species of Special
Concern is a wildlife species that may become a threatened or an
endangered species because of a combination of biological
characteristics and identified threats. There are no specific
conservation measures directed at green sturgeon in Canada to alleviate
the recognized threats of habitat degradation and alteration.
Proposed Determinations
Section 4(b)(1) of the ESA requires that the listing determination
be based solely on the best scientific and commercial data available,
after conducting a review of the status of the species and after taking
into account those efforts, if any, being made by any state or foreign
nation to protect and conserve the species. We have reviewed the
petition, the reports of the BRT (NMFS, 2002, 2004), co-manager
comments, and other available published and unpublished information,
and we have consulted with species experts and other individuals
familiar with green sturgeon. On the basis of the best available
scientific and commercial information, the southern and northern
populations of green sturgeon meet the discreteness and significance
criteria for distinct DPSs.
Northern DPS
Informed by the BRT's risk assessment, we conclude that the
Northern DPS is not presently in danger of extinction or likely to
become so in the foreseeable future throughout all or a significant
portion of its range. Accordingly, the DPS does not warrant listing
under the ESA at this time. Our review indicates that: (1) there is no
evidence for reductions in spawning habitat in the South Fork Trinity
River; and (2) the Eel River population may have experienced declines
and loss of spawning habitat. Nevertheless, the BRT concluded that
neither the South Fork Trinity nor the Eel River constitute a
significant portion of the DPS' range because: (1) analogies drawn from
salmonid research suggest that the South Fork Trinity and Eel Rivers do
not support large salmonid populations; (2) habitat in the Eel River is
of poorer quality compared to that of the Klamath and Rogue Rivers; and
(3) tribal fisheries data do not suggest that the South Fork Trinity or
Eel River supported significant numbers of green sturgeon in the past.
Due to the poor availability of data and attendant uncertainties
[[Page 17399]]
regarding the status of and threats facing the species, we will
maintain the Northern DPS on the Species of Concern List. We will re-
evaluate the status of the Northern DPS in 5 years provided sufficient
new information becomes available indicating that a status review
update is warranted.
Southern DPS
We propose to find that the Southern DPS is not presently in danger
of extinction throughout all of its range. Fishing regulations in place
in California, the implementation of studies aimed at increasing our
understanding of the ecological requirements of green sturgeon in the
wild, and efforts to ameliorate threats to salmonids in the wild, thus
conferring some possible benefits to green sturgeon, indicate that the
Southern DPS is not presently in danger of extinction throughout all of
its range. We also propose to find that the Southern DPS is not in
danger of extinction throughout a significant portion of its range. We
feel that spawning habitat may have been lost in the Sacramento and
Feather Rivers, but due to a paucity of data, we are unable to
determine the geographic extent and demographic consequences of this
loss. We have no evidence of historic or current spawning in the San
Joaquin River and therefore we have no evidence of lost spawning
habitat.
Based on our evaluation of the best available scientific
information and the ongoing state and Federal conservation efforts, we
propose to find that the Southern DPS is likely to become endangered in
the foreseeable future throughout all of its range and should therefore
be listed as threatened. This proposal is based on the reduction of
potential spawning habitat, the threats to the single remaining
spawning population remaining severe and unlikely to be sufficiently
alleviated by conservation measures currently in place, and the
downward trend of sturgeon salvage estimates from State (1968-2003) and
Federal (1980-2003) facilities.
Take Prohibitions and Protective Regulations
Section 9 of the ESA prohibits certain activities that directly or
indirectly affect endangered species. In the case of threatened
species, ESA section 4(d) authorizes the Secretary to issue regulations
he considers necessary and appropriate for the conservation of the
species. We have flexibility under section 4(d) to tailor protective
regulations based on the contents of available conservation measures.
The 4(d) protective regulations may prohibit, with respect to
threatened species, some or all of the acts which section 9(a) of the
ESA prohibits with respect to endangered species. These 9(a)
prohibitions and 4(d) regulations apply to all individuals,
organizations, and agencies subject to U.S. jurisdiction. We will
evaluate protective regulations pursuant to section 4(d) for the
Southern green sturgeon DPS and propose any thought to be necessary and
appropriate for conservation of the species in a forthcoming notice of
proposed rulemaking that will be published in the Federal Register.
Other Protective Regulations
Section 7(a)(2) of the ESA and NMFS/FWS regulations require Federal
agencies to confer with us on actions likely to jeopardize the
continued existence of species proposed for listing or result in the
destruction or adverse modification of proposed critical habitat. If a
proposed species is ultimately listed, Federal agencies must consult on
any action they authorize, fund, or carry out if those actions may
affect the listed species or its critical habitat. Examples of Federal
actions that may affect the Southern green sturgeon DPS include: water
diversion for human use; point and non-point source discharge of
persistent contaminants; contaminated waste disposal; water quality
standards; and fishery management practices.
Service Policy on the Role of Peer Review
On July 1, 1994, we and FWS published a series of policies
regarding listings under the ESA, including a policy for peer review of
scientific data (59 FR 34270). The intent of the peer review policy is
to ensure that listings are based on the best scientific and commercial
data available. Prior to a final listing, we will solicit the expert
opinions of three qualified specialists, concurrent with the public
comment period. Independent specialists will be selected from the
academic and scientific community, Federal and state agencies, and the
private sector.
Critical Habitat
Critical habitat is defined in section 3 of the ESA as: ``(i) the
specific areas within the geographical area occupied by the species, at
the time it is listed in accordance with the provisions of section 4 of
this Act, on which are found those physical or biological features (I)
essential to the conservation of the species and (II) which may require
special management considerations or protection; and (ii) specific
areas outside the geographical area occupied by the species at the time
it is listed in accordance with the provisions of section 4 of this
Act, upon a determination by the Secretary that such areas are
essential for the conservation of the species'' (16 U.S.C. 1532(5)(A)).
``Conservation'' means the use of all methods and procedures needed to
bring the species to the point at which listing under the ESA is no
longer necessary (16 U.S.C. 1532(3)). Section 4(a)(3)(A) of the ESA
requires that, to the maximum extent prudent and determinable, critical
habitat be designated concurrently with the listing of a species (16
U.S.C. 1533(a)(3)(A)(i)). Designations of critical habitat must be
based on the best scientific data available and must take into
consideration the economic, national security, and other relevant
impacts of specifying any particular area as critical habitat. Once
critical habitat is designated, section 7 of the ESA requires Federal
agencies to ensure that they do not fund, authorize or carry out any
actions that are likely to destroy or adversely modify that habitat.
This requirement is in addition to the section 7 requirement that
Federal agencies ensure that their actions do not jeopardize the
continued existence of listed species. We are currently compiling
information to prepare a critical habitat proposal for the Southern
DPS. In a previous Federal Register notice (66 FR 64793; December 14,
2001) we requested specific information on critical habitat and are
again seeking public input and information to assist in gathering and
analyzing the best available scientific data to support a critical
habitat designation. We will continue to meet with co-managers and
other stakeholders to review this information and the overall
designation process. We will then initiate rulemaking with the
publication of a proposed designation of critical habitat, opening a
period for public comment and the opportunity for public hearings.
Joint NMFS/FWS regulations for listing endangered and threatened
species and designating critical habitat at 50 CFR 424.12(b) state that
the agency ``shall consider those physical and biological features that
are essential to the conservation of a given species and that may
require special management considerations or protection'' (hereafter
also referred to as ``essential features.'' Pursuant to the
regulations, such requirements include, but are not limited to the
following: (1) space for individual and population growth, and for
normal behavior; (2) food, water, air, light, minerals, or other
[[Page 17400]]
nutritional or physiological requirements; (3) cover or shelter; (4)
sites for breeding, reproduction, rearing of offspring, germination, or
seed dispersal; and generally; (5) habitats that are protected from
disturbance or are representative of the historic geographical and
ecological distributions of a species. These regulations go on to
emphasize that the agency shall focus on essential features within the
specific areas considered for designation. These features ''may
include, but are not limited to, the following: spawning sites, feeding
sites, seasonal wetland or dryland, water quality or quantity,
geological formation, vegetation type, tide, and specific soil types.''
Public Comments Solicited
We recognize that there are serious limits to the quality of
information available, and, therefore, we exercised our best
professional judgment in developing this proposal to list the Southern
DPS. To ensure that the final action resulting from this proposal will
be as accurate and effective as possible, we are soliciting comments
and suggestions from the public, other governmental agencies, the
Government of Canada, the scientific community, industry, environmental
groups, and any other interested parties. Comments are encouraged on
this proposal (See DATES and ADDRESSES). Specifically, we are
interested in information regarding: (1) green sturgeon spawning
habitat within the range of the Southern DPS that was present in the
past, but may have been lost over time (2) biological or other relevant
data concerning any threats to the Southern green sturgeon DPS; (3) the
range, distribution, and abundance of the Southern DPS; (4) current or
planned activities within the range of the Southern DPS and their
possible impact on the Southern DPS; and (5) efforts being made to
protect the Southern DPS.
We are also requesting quantitative evaluations describing the
quality and extent of freshwater and marine habitats for juvenile and
adult green sturgeon as well as information on areas that may qualify
as critical habitat in California for the proposed Southern DPS.
Specific areas that include the physical and biological features
essential to the recovery of the DPS should be identified. We recognize
that there are areas within the proposed boundaries of the Southern DPS
that historically constituted green sturgeon habitat, but may not be
currently occupied by green sturgeon. We are requesting information
about these currently unoccupied areas to help us determine whether
these areas are essential to the recovery of the species or excluded
from designation. For areas potentially qualifying as critical habitat,
we are requesting information describing: (1) the activities that
affect the area or could be affected by the designation, and (2) the
economic costs and benefits of additional requirements of management
measures likely to result from the designation. The economic cost to be
considered in the critical habitat designation under the ESA is the
probable economic impact ``of the [critical habitat] designation upon
proposed or ongoing activities'' (50 CFR 424.19). Economic effects
attributable to listing include actions resulting from section 7
consultations under the ESA to avoid jeopardy to the species. Comments
concerning economic impacts should attempt to distinguish the costs of
listing from the incremental costs that can be directly attributed to
the designation of specific areas as critical habitat.
We will review all public comments and any additional information
regarding the status of, and critical habitat for, the Southern green
sturgeon DPS in developing a final listing determination as well as
proposed critical habitat and, potentially, section 4(d) regulations.
Public Hearings
Public hearings will be held in several locations within the range
of the proposed Southern DPS; details regarding locations, dates, and
times will be published in a forthcoming Federal Register notice.
References
A complete list of all references cited herein is available upon
request (see ADDRESSES section).
Classification
National Environmental Policy Act
The 1982 amendments to the ESA, in section 4(b)(1)(A), restrict the
information that may be considered when assessing species for listing.
Based on this limitation of criteria for a listing decision and the
opinion in Pacific Legal Foundation v. Andrus, 675 F. 2d 825 (6th Cir.
1981), we have concluded that ESA listing actions are not subject to
the environmental assessment requirements of the National Environmental
Policy Act. (See NOAA Administrative Order 216 6.)
Executive Order 12866, Regulatory Flexibility Act and Paperwork
Reduction Act
As noted in the Conference Report on the 1982 amendments to the
ESA, economic impacts cannot be considered when assessing the status of
a species. Therefore, the economic analysis requirements of the
Regulatory Flexibility Act are not applicable to the listing process.
In addition, this rule is exempt from review under Executive Order
12866. This proposed rule does not contain a collection-of-information
requirement for the purposes of the Paperwork Reduction Act.
Federalism
In keeping with the intent of the Administration and Congress to
provide continuing and meaningful dialogue on issues of mutual State
and Federal interest, this proposed rule will be given to the relevant
state agencies in each state in which the species is believed to occur,
who will be invited to comment. We have conferred with the States of
Washington, Oregon and California in the course of assessing the status
of the Southern DPS, and considered, among other things, Federal, state
and local conservation measures. As we proceed, we intend to continue
engaging in informal and formal contacts with the States, and other
affected local or regional entities, giving careful consideration to
all written and oral comments received. We also intend to consult with
appropriate elected officials in the establishment of a final rule.
List of Subjects in 50 CFR Part 223
Endangered and threatened species, Exports, Imports,
Transportation.
Dated: March 28, 2005.
William T. Hogarth,
Assistant Administrator for Fisheries, National Marine Fisheries
Service.
For the reasons set out in the preamble, 50 CFR part 223 is
proposed to be amended as follows:
PART 223--THREATENED MARINE AND ANADROMOUS SPECIES
1. The authority citation for part 223 continues to read as
follows:
Authority: 16 U.S.C. 1531 1543; subpart B, Sec. 223.12 also
issued under 16 U.S.C. 1361 et seq.
2. In Sec. 223.102, amend paragraph (a) by adding and reserving
paragraph (a)(23) and paragraph (a)(24) and adding a new paragraph
(a)(25) to read as follows:
Sec. 223.102 Enumeration of threatened marine and anadromous species.
(a) * * *
(25) North American green sturgeon-southern DPS (Acipenser
medirostris). California. The southern DPS includes all spawning
populations of green
[[Page 17401]]
sturgeon south of the Eel River (exclusive), principally including the
Sacramento River green sturgeon spawning population.
* * * * *
[FR Doc. 05-6611 Filed 4-5-05; 8:45 am]
BILLING CODE 3510-22-S