[Federal Register Volume 60, Number 192 (Wednesday, October 4, 1995)]
[Rules and Regulations]
[Pages 51928-51932]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-24698]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 227
[I.D. 092895B]
Endangered and Threatened Species; West Coast Pink Salmon
Petition Determination
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of determination.
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SUMMARY: NMFS has determined that neither Elwha River nor lower
Dungeness River pink salmon, as petitioned, constitute a ``species''
under the Endangered Species Act of 1973 (ESA). However, Elwha River
and lower Dungeness River pink salmon are part of a larger
evolutionarily significant unit (ESU) that includes all odd-year pink
salmon stocks in Washington as far west as the Elwha River and in
southern British Columbia, Canada (including the Fraser River and
eastern Vancouver Island), as far north as Johnstone Strait. Further,
NMFS has identified a second pink salmon ESU which includes even-year
pink salmon residing in the Snohomish River, WA. NMFS has determined
that, at the present time, neither of these ESUs warrant listing as a
threatened or endangered species.
ADDRESSES: Environmental and Technical Services Division, NMFS, 525 NE
Oregon Street, Suite 500, Portland, OR 97232.
FOR FURTHER INFORMATION CONTACT: Garth Griffin, Environmental and
Technical Services Division, 503/231-2005 or Marta Nammack, Protected
Species Management Division, 301/713-1401.
SUPPLEMENTARY INFORMATION:
Petition Background
On March 14, 1994, the Secretary of Commerce received a petition
from Professional Resources Organization-Salmon (PRO-Salmon), to list
as threatened or endangered nine naturally spawning populations of
salmon indigenous to northwestern Washington and to designate critical
habitat under the ESA (PRO-Salmon, 1994). Two of the petitioned
populations included pink salmon (Oncorhynchus gorbuscha) stocks
residing in the Elwha River and the lower Dungeness River on
Washington's Olympic Peninsula. NMFS published a document on September
12, 1994 (59 FR 46808) that the petition presented substantial
scientific information indicating that listings may be warranted.
Concurrently, NMFS also announced its intention to initiate
comprehensive status reviews of all species of Pacific salmon and
anadromous trout in Washington, Oregon, Idaho, and California.
In announcing these comprehensive status reviews, NMFS requested
comments from any party having relevant information concerning (1)
whether any salmon stock qualifies as a ``species'' under the ESA and
(2) whether any salmon stock is endangered or threatened based on NMFS'
listing criteria. In addition, NMFS specifically solicited information
on the petitioned stocks. NMFS also requested information on areas that
may qualify as critical habitat for all stocks of pink, chum, sockeye,
and chinook salmon, and sea-run cutthroat trout in Washington, Oregon,
Idaho, and California. Status reviews for west coast coho salmon and
steelhead are nearing completion.
Biological Background
The NMFS' Northwest Fisheries Science Center Biological Review Team
(BRT) has reviewed the status of west coast pink salmon (Northwest
Fisheries Science Center BRT, 1995), the prominent results of which are
summarized below. A copy of the draft BRT report is available upon
request (see ADDRESSES).
Pink salmon occur in oceanic and freshwater areas around the
Pacific rim of Asia and North America. Spawning populations range from
Puget Sound, WA to Norton Sound, AK in North America and from North
Korea to the Anadyr Gulf, Russia in Asia (Heard, 1991; Mathisen, 1994).
In Washington, pink salmon regularly spawn as far south as southern
Puget Sound and on the Olympic Peninsula along the Strait of Juan de
Fuca (Williams et al., 1975, Washington Department of Fisheries (WDF)
et al., 1993), with about 70 percent of the spawning in north Puget
Sound (WDF et al., 1993).
Across its natural range, pink salmon spawn in both large and small
river systems in the late summer and fall. Spawning occurs in shallow
pools and riffles exposed to moderately fast currents. Water
temperatures during peak spawning activity range from about 5 deg.-
15 deg. C. Pink salmon mature at the smallest average size of any
species of Pacific salmon (1.0-2.5 kg) and show marked sexual
dimorphism (Davidson, 1935; Pritchard, 1937; Beacham and Murray, 1985).
Spawning populations throughout much of the range of pink salmon may be
extremely large, often exceeding hundreds of thousands of adults
(Heard, 1991; WDF et al., 1993).
Upon emerging from gravel, juvenile pink salmon migrate rapidly
downstream, generally in schools. After a few weeks to a few months in
estuaries and nearshore habitat, pink salmon migrate to sea where they
reside for 12-16 months (Heard, 1991).
In addition to their small size, extreme sexual dimorphism, and
short freshwater residence as juveniles, pink salmon differ from other
salmonids in that they lack a variable age structure. Almost all pink
salmon are 2 years of age at maturity (Gilbert, 1914; Bilton and
Ricker, 1965; Turner and Bilton, 1968). The most significant result of
this rigid age structure has been the development of two separate, and
often distinctive, broodlines of pink salmon. Fish in the broodline
that mature in even-numbered years are referred to as ``even-year''
pink salmon while those that mature in alternate, odd-numbered
[[Page 51929]]
years are referred to as ``odd-year'' pink salmon (Aspinwall, 1974;
Johnson, 1979; McGregor, 1982; Beacham et al., 1985).
The geographic distribution of the two pink salmon broodlines is
not random. At the southern extent of the pink salmon range in North
America, odd-year pink salmon are most abundant (Atkinson et al., 1967;
WDF et al., 1993). Pink salmon populations in British Columbia are
dominated by odd-year fish, whereas populations from the northern Queen
Charlotte Islands and western Alaska are dominated by even-year fish
(Neave, 1952; Aro and Shepard, 1967; Ricker and Manzer, 1974). In Asia
and North America, even-year pink salmon generally become more abundant
as latitude increases (Heard, 1991). The reasons for this variation in
broodline dominance are not well understood (Ricker, 1962; Heard,
1991).
Consideration as a ``Species'' Under the ESA
To qualify for listing as a threatened or endangered species, Elwha
River and lower Dungeness River pink salmon must constitute ``species''
under the ESA. The ESA defines a ``species'' to include any ``distinct
population segment of any species of vertebrate * * * which interbreeds
when mature.'' On November 20, 1991, NMFS published a policy (56 FR
58612) describing how it will apply the ESA definition of ``species''
to Pacific salmonid species. This policy provides that a salmonid
population will be considered distinct, and hence a species under the
ESA, if it represents an ESU of the biological species. The population
must satisfy two criteria to be considered an ESU: (1) It must be
reproductively isolated from other conspecific population units, and
(2) it must represent an important component in the evolutionary legacy
of the biological species. The first criterion, reproductive isolation,
need not be absolute, but must be strong enough to permit
evolutionarily important differences to accrue in different population
units. The second criterion would be met if the population contributed
substantially to the ecological/genetic diversity of the species as a
whole. Further guidance on the application of this policy is contained
in ``Pacific salmon (Oncorhynchus spp.) and the Definition of Species
under the ESA,'' which is available upon request (see ADDRESSES).
Reproductive Isolation
For this criterion, NMFS has considered available information
regarding geographic and life-history factors that may isolate pink
salmon, as well as genetic factors which indicate reproductive
isolation. The petitioners considered reproductive isolation with
respect to eleven groups of pink salmon which have previously been
identified in the State of Washington (WDF et al., 1993). In addition
to those identified by the petitioner, previously identified pink
salmon stocks include Snohomish River even-year pink salmon (the only
even-year population in Washington, Oregon, Idaho, or California) and
odd-year pink salmon populations in the following Washington rivers:
(1) Nooksack, (2) Skagit, (3) Stillaguamish, (4) Snohomish, (5)
Puyallup, (6) Nisqually, (7) Hamma Hamma, (8) Duckabush, (9)
Dosewallips, and (10) upper Dungeness.
With respect to the two criteria established by NMFS to define a
``species'' of Pacific salmon, the petitioner contended that the lower
Dungeness and Elwha River populations of pink salmon were both
reproductively isolated from other pink salmon populations.
Reproductive isolation was inferred primarily on the basis of distance
to nearest neighboring population. For lower Dungeness River pink
salmon, this distance is 10 km and for Elwha River pink salmon, this
distance is 25 km. Genetic data, in the form of allozyme variation,
support a hypothesis for at least partial reproductive isolation of the
lower Dungeness River population (Shaklee et al., 1991), but no genetic
data exist for the Elwha River population (WDF et al., 1993).
Considerable evidence exists that indicates that even- and odd-year
pink salmon are reproductively isolated. As discussed above under
Biological Background, pink salmon exhibit a rigid age structure that
results in two separate broodlines, even- and odd-year pink salmon.
Throughout much of the range of this species, many rivers which support
pink salmon populations produce both even- and odd-year broodlines
which have no opportunity for interbreeding. As a result, this life
history characteristic yields in each of these rivers two temporally
isolated populations with almost no prospect of genetic exchange.
Numerous genetic studies also support the belief that even- and
odd-year pink salmon populations are reproductively isolated. Studies
conducted by Okazaki (1984) and Reisenbichler (1992) found large
genetic differences between even- and odd-year pink salmon from the
same area, with the magnitude of the differences roughly comparable to
that found between coastal and inland steelhead. Strong allozyme
frequency differences between even- and odd-year broodlines spawning at
the same locality have been reported in Alaska (Aspinwall, 1974;
Johnson, 1979; McGregor, 1982), Canada (Beacham et al., 1985) and
Russia (Salmenkova et al., 1981; Altukohov et al., 1983; Kartavstev,
1991) for many polymorphic enzyme coding loci. In addition, Shaklee and
Varnavskaya (1994) reported a large genetic difference between even-
and odd-year Snohomish River pink salmon.
Ecological/Genetic Diversity
For this criterion, NMFS considered environmental, ecological, and
life history information in its assessment of potential pink salmon
ESUs. Further, historic accounts of artificial propagation were
considered to determine (1) How indigenous even- and odd-year west
coast pink salmon populations have been altered, and (2) the
relationship of historic populations to the presently defined ESUs.
Little information was provided by the petitioner regarding NMFS'
evolutionary significance criterion. The petitioner believed that
spatial and temporal isolation of the lower Dungeness River population
from the upper Dungeness River population, due to differences in run
timing and spawning location, contribute to the distinctiveness of the
lower river population. No quantitative data are available to support a
hypothesis for the distinctiveness of the Elwha River population.
Environmental, Ecological, and Life-History Information
Along the west coast of North America, climate varies primarily
with latitude. As such, coastal regions exhibit north to south
gradients of increasing average rainfall and decreasing average
temperature. Streamflows in this region tend to be lowest in August and
September, whereas water temperatures in northwestern Washington are
generally highest in July and August (Hydrosphere Data Products, Inc.,
1993). Run timing and spawn timing are sensitive to these factors. As a
result, streamflow patterns determine the temporal availability and
suitability of spawning and incubation habitat for pink salmon.
Pink salmon populations can vary considerably in run timing
(Sheridan, 1962) and spawn timing within a single river system. This
type of life-history variability can have consequences for a
populations' fitness (Taylor, 1980; Mortensen et al., 1991) and
therefore, is an important consideration when
[[Page 51930]]
attempting to identify distinct population units (Gharett and Smoker,
1993).
In its analysis of run timing, NMFS found the time period of peak
spawning for odd-year pink salmon populations to be highly variable
among river systems in northwestern Washington. Pink salmon populations
in the Strait of Juan de Fuca exhibit the earliest average date of peak
spawning, while peak spawning of Nisqually River populations typically
occurs an average of 1 month later. Timing of peak spawning of even-
year pink salmon in the Snohomish river is about 3 to 4 weeks earlier
than that of odd-year fish, even though these two groups use much of
the same habitat.
In addition to differences in run timing, considerable variation in
body size and shape is apparent among pink salmon populations.
Available data indicate significant variation in the length of odd-year
pink salmon among various drainages in Washington. In general, the
smallest fish appear in cold, turbid rivers in Puget Sound (Nooksack
and Nisqually Rivers), and along the Strait of Juan de Fuca (lower and
upper Dungeness River), while the largest fish tend to exist in Hood
Canal. Limited data regarding Snohomish River even-year pink salmon
suggest that this population contains the smallest pink salmon observed
in Washington.
Comparisons of pink salmon length data among British Columbia and
Washington indicate that, with the exception of Snohomish and Skagit
River populations, odd-year pink salmon populations in Washington
appear to be smaller than the average for odd-year British Columbia
populations (Beacham and Murray 1985). However, this comparison is
complicated by the fact that the Washington data were taken more
recently than the British Columbia data. Even-year Snohomish River
adult pink salmon are similar in size to pink salmon in even-year
populations from the central mainland and northern Vancouver Island,
but tend to be smaller than the even-year British Columbia average.
Again, however, the data may not be strictly comparable, because they
were taken in different years.
Some evidence exists for recent declines in body length of odd-year
pink salmon in Washington. This aspect raises concern regarding the
ability of natural populations of pink salmon to recover, since, in
general, decreases in body size equate to decreased fecundity and
decreased juvenile production (but see Ricker et al., 1978; Ricker,
1989). NMFS was unable to review any new data on body size in odd-year
British Columbia pink salmon to determine whether size has declined in
these stocks (Ricker et al., 1978; Ricker, 1989). However, the decline
in body length of odd-year Washington pink salmon is qualitatively
similar to a decline in length observed in pink salmon returning to
Auke Creek, AK, over the last 20 years. Further, data estimated from
catches of southeastern Alaska pink salmon suggest similarly declining
body length trends over an even longer period (Marshall and Quinn,
1988). Therefore, NMFS believes that this factor should be closely
monitored to ensure that natural populations remain viable in the
future.
Homing and straying are prominent features of Pacific salmon
biology that can have significant effects on population structure.
Consequently, these issues are relevant to ESU determinations for these
species. Pink salmon have a widespread reputation for straying at
higher rates than other species of Pacific salmon (Horrall, 1981). If
true, the result may be a less conspicuous population structure and,
potentially, reduced opportunity for local adaptations to be
maintained. Few technically sound studies have been conducted to
estimate straying rates of Pacific salmon and provide empirical
evidence supporting the hypothesis that pink salmon stray at relatively
higher rates than other species of Oncorhynchus is mixed (Quinn, 1993;
Altukhov and Salmenkova, 1994). However, the rapid colonization of
systems newly available to pink salmon indicates that this species has
an unusual ability to expand into suitable habitat when conditions are
favorable (Merrell, 1962; Kwain and Laurie, 1981; Heard, 1991).
It is difficult to say with any degree of certainty that pink
salmon stray more frequently relative to other species of Pacific
salmon. It is apparent that straying in pink salmon may be highly
dependent on spawning location and on conditions at time of spawning.
The consequences of straying on pink salmon populations are not clear,
but such consequences may contribute to less conspicuous population
structure and reduced local adaptations.
Artificial Propagation
It is commonly believed that even-year pink salmon were
historically either absent from Washington or were at an abundance too
low to sustain harvest (Rounsefell, 1938; Ellis and Noble, 1959).
Consequently, WDF made several attempts earlier in this century to
establish even-year pink salmon runs in northwestern Washington (WDF,
1916-1964; Neave, 1965; Roppel, 1982). More than 82 million pink salmon
eggs were transported from Alaska to various locations in Washington in
even-numbered years between 1910 and 1932. In addition, more than one
million odd-year Alaskan pink salmon eggs were brought into Washington
from southeastern Alaska in 1929. An estimated 85 million juveniles
released between 1911 and 1933 produced no recorded returns of even-
year pink salmon adults to Washington rivers, including the Snohomish
River (Ellis and Noble, 1959; Neave, 1965). Attempts to establish even-
year pink salmon in Washington were renewed between 1944 and 1956 with
the transport of nearly 4 million eggs from the Skeena River drainage
in British Columbia, Canada. Of the 1.3 million fry released, at least
several hundred are believed to have returned as adults. However, no
evidence exists that returns were sustained beyond one or two
generations (Ellis and Noble, 1959; Neave, 1965).
Even-year pink salmon in Washington are known only to occur in the
Snohomish River (WDF et al., 1993). The origin of this population is
uncertain; these fish may be endemic or may have resulted from one or
more transplants of even-year fish from Alaska or Canada. Regardless of
its origin, the Snohomish River even-year population has apparently
been naturally self-sustaining for at least the last 18 generations
(about 36 years).
In addition to stock transplants, relatively large numbers of pink
salmon were produced in Washington hatcheries around Puget Sound from
the early 1950's through the late 1980's. Transfers of fish among
hatcheries and drainages were common during this period; however, very
few pink salmon were transplanted to areas outside Puget Sound. Three
hatcheries have dominated pink salmon production in Washington: Hood
Canal Hatchery on Finch Creek in Hood Canal, Puyallup Hatchery on
Voight Creek in south Puget Sound, and Dungeness Hatchery on the
Dungeness River.
In recent years, only Hood Canal Hatchery has maintained an active
pink salmon propagation program. Most hatchery production of pink
salmon in Washington is composed of odd-year fish released from this
facility. Originally, in 1953, broodstock for this hatchery was derived
from adult pink salmon returning to the Dungeness and Dosewallips
Rivers. Presently, this hatchery uses native broodstock, which are
generally released into Finch Creek, the location of the hatchery. Over
the past decade releases from Hood Canal hatchery have averaged about 1
million fry released every other year into Finch
[[Page 51931]]
Creek. Therefore, although artificial propagation of pink salmon in the
past may have affected the population structure of odd-year pink salmon
in Puget Sound, recent hatchery production has probably had little
effect on this structure due in part to the use of native broodstocks.
ESU Determinations
Based on its evaluation of genetic, life-history, and ecological
information pertaining to pink salmon, NMFS has determined that two
ESUs exist for North American pink salmon in WA and southern British
Columbia, Canada. These two ESUs include: (1) even-year pink salmon
residing in the Snohomish River, Washington (and likely, even-year pink
salmon populations in southern British Columbia); and (2) odd-year pink
salmon occurring in Washington as far west as the Elwha River and in
southern British Columbia, Canada (including the Fraser River and
eastern Vancouver Island) as far north as Johnstone Strait. A summary
of the information that led to these conclusions is presented below.
Even-Year Pink Salmon ESU
A single population of even-year pink salmon occurs in the United
States south of Alaska--in the Snohomish River, WA. Genetically, this
population is much more similar to even-year pink salmon from British
Columbia and Alaska than it is to odd-year pink salmon from Washington.
In addition, a similar pattern is found in phenotypic and life-history
traits such as body size and run timing. This result is consistent with
numerous studies that have found large genetic differences between
even- and odd-year pink salmon from the same area (e.g., Aspinwall,
1974; Beacham et al., 1985; Kartavtsev 1991).
The Snohomish River even-year pink salmon population is
geographically isolated by several hundred kilometers from other even-
year pink salmon populations of appreciable size. However, life-history
features of the Snohomish River even-year population are similar to
those in other even-year populations from central British Columbia. For
example, time of peak spawning of even-year pink salmon in the
Snohomish River is comparable to that of even-year British Columbia
pink salmon and 3-4 weeks earlier than that of odd-year pink salmon in
the Snohomish River. Genetic analyses are highly dependent upon
standardization between laboratories, but available data indicate that
even-year Snohomish River pink salmon are among the most distinctive of
any pink salmon sample from the United States or southern British
Columbia.
At the present time, the Snohomish River even-year pink salmon
population is relatively small, on the order of a few thousand adults
per generation. In defining the term ``species'' as it applies to
Pacific salmon, NMFS has previously stated that a population should not
be considered an ESU if the historic size (or historic carrying
capacity) is too small for it to be plausible to assume the population
has remained isolated over an evolutionary important time period
(Waples, 1991). The fact that small spawning populations are regularly
observed may reflect the dynamic processes of extinction, straying, and
recolonization (Waples, 1991). Therefore, the small size of the current
Snohomish River even-year pink salmon population suggests that it may
be part of a larger geographic unit on evolutionary time scales
(hundreds or thousands of years). The odd-year Snohomish River pink
salmon population, which has the same spawning habitat available, is 1-
2 orders of magnitude larger; therefore, it is possible that the even-
year population was once much larger in the past. If that were the
case, long-term persistence of this population in isolation would be
easier to explain, since larger, isolated populations are likely to be
more resilient to extinction than a small population such as this one.
Odd-Year Pink Salmon ESU
Genetic information indicates that odd-year pink salmon from
southern British Columbia and Washington are clearly in a different
evolutionary lineage than nearby even-year populations and more
northerly odd-year populations. Within the southern British Columbia-
Washington pink salmon group, there is also evidence of geographic
population genetic structure, with detectable differences among groups
of populations from the Dungeness River, Hood Canal, Puget Sound, and
Fraser River, and southern and central British Columbia, Canada. In
some analyses, Nisqually and Nooksack River populations in Puget Sound,
WA are genetic outliers not similar to each other. Even so, none of the
genetic differences within the southern British Columbia-Washington
pink salmon group is very large in absolute magnitude.
Based on currently available information, NMFS concludes that the
northern boundary of the odd-year ESU corresponds to the Johnstone
Strait region of British Columbia, Canada. The ESU does not include
northern British Columbia, Alaskan, or Asian populations of pink
salmon. In Washington, westernmost populations in this ESU are found in
the Dungeness River, but the ESU presumably would also include the
Elwha River population, if a remnant still exists (see Status of West
Coast Pink Salmon ESUs). Some uncertainty exists whether populations in
the Dungeness River (and possibly the Elwha River in Washington and
southern Vancouver Island in British Columbia) belong in a separate
ESU. Further, given the uncertainty associated with the presence of
populations outside this range, NMFS believes that insufficient
information presently exists to determine whether other populations of
pink salmon on the Olympic Peninsula or locations further south should
be included in this ESU.
Status of West Coast Pink Salmon ESUs
In considering whether these ESUs are threatened or endangered
according to the ESA, NMFS evaluated both qualitative and quantitative
information. Qualitative evaluations considered recent, published
assessments by agencies or conservation groups of the status of pink
salmon within the geographic area. Quantitative assessments were based
on current and historical abundance information and time series data
compiled from a variety of Federal, state, and tribal agency records.
Nehlsen et al. (1991) considered salmon stocks throughout
Washington, Idaho, Oregon, and California and enumerated all stocks
that they found to be extinct or at risk of extinction. Pink salmon
stocks in the Klamath and Sacramento Rivers, located in California,
were considered extinct. Three stocks were considered to be at high
risk of extinction (Russian River, CA; Elwha River, WA; and Skokomish
River, WA) and one at moderate risk of extinction (Dungeness River,
WA). Pink salmon stocks that do not appear in their summary were either
not considered to be at risk of extinction or there was insufficient
information to classify them.
The WDF et al. (1993) categorized all salmon stocks in Washington
on the basis of stock origin, production type, and status (healthy,
depressed, critical, or unknown). Of the 15 pink salmon stocks
identified by WDF et al. (1993), nine were classified as healthy, two
as critical (lower Dungeness and Elwha Rivers), two as depressed (upper
Dungeness and Dosewallips Rivers), and two as unknown (North and Middle
Fork Nooksack, and South Fork Nooksack River). All runs were classified
as wild production and all,
[[Page 51932]]
except those in the North and Middle Forks of the Nooksack River, were
reported to be of native origin. In the planned 1995 revision of the
Washington State Salmon and Steelhead Inventory, the WDF intends to
recommend that Elwha River pink salmon be classified as extinct since
no adult fish have been observed since 1989 despite extensive annual
surveys (Northwest Fisheries Science Center BRT, 1995).
Based on available data, it is difficult to ascertain with any
degree of certainty the extent of the ESU that contains the Snohomish
River even-year pink salmon population. The small size of the current
Snohomish River even-year population suggests that it may be part of a
larger geographic unit over evolutionary time. The Snohomish River
even-year population is geographically isolated by several hundred
kilometers from other even-year populations of appreciable size;
however, similar life history characteristics, such as time of peak
spawning, are similar to that of even-year British Columbia pink
salmon. Results of genetic data are heavily dependent on whether an
adjustment is made for possible differences in methods for recording
data. Further, it is not clear which analyses should be preferred,
those with or without adjustment for possible bias.
Given the uncertainty associated with the extent of the even-year
ESU, NMFS considered the status of this ESU under two scenarios: (1)
The ESU is composed solely of the Snohomish River pink salmon
population, and (2) the ESU contains populations of even-year pink
salmon from British Columbia in addition to the Snohomish River
population. Under both scenarios, NMFS was unable to demonstrate that
this ESU is currently at risk of extinction or endangerment. Available
information indicates that the Snohomish River pink salmon population
is relatively small with, generally, an increasing trend in abundance
in recent years. Further, even-year pink salmon populations in British
Columbia are generally stable or increasing. Therefore, under both ESU
scenarios, NMFS has concluded that even-year pink salmon do not
presently warrant listing under the ESA.
Similar to the even-year ESU, uncertainty remains regarding the
extent of the odd-year pink salmon ESU. Environmental and ecological
characteristics generally show a strong north-south trend; however,
NMFS was unable to identify any substantial differences that
consistently differentiate Washington and British Columbia odd-year
pink salmon populations. Although odd-year pink salmon show
considerable variation in body size among populations in Washington,
the range of variation does not exceed that found in British Columbia.
Genetic information shows a clear distinction between nearby even-year
pink salmon and more northerly odd-year populations. Within the
southern British Columbia and Washington pink salmon group, evidence of
geographic population structure exists; however, none of the genetic
differences is very large in absolute magnitude. Even though genetic
differences among odd-year pink salmon are relatively small, the
consistent genetic differences among geographically isolated groups of
populations suggest that there has been some degree of reproductive
isolation among pink salmon populations in this region.
Most populations in the odd-year pink salmon ESU appear to be
healthy, and overall abundance appears to be close to historic levels.
The two most distinctive Puget Sound populations, the Nooksack and
Nisqually River populations, both show non-significant trends in recent
abundance. No other factors were identified by NMFS which would
threaten the near-term survival of these populations. However, the two
populations on the northern Olympic Peninsula (both of which occur in
the Dungeness River and one of which, in the lower river, was
petitioned for listing) appear to be at the greatest risk of extinction
in this ESU. Nevertheless, because (1) most of the populations in this
ESU are stable or increasing and (2) the two populations at greatest
risk are not consistently differentiated from other populations in the
ESU with regard to genetic or life history characters, NMFS concludes
that the odd-year pink salmon ESU is not presently at risk of
extinction or endangerment. Furthermore, NMFS concludes that the
geographic boundaries of the even- and odd-year pink salmon ESUs should
be regarded as provisional. As such, these geographic boundaries are
subject to revision should substantial new information become
available. The NMFS welcomes the submission of any new information that
may help resolve uncertainties regarding the extent of these pink
salmon ESUs.
Determination
After a thorough analysis of all available information, NMFS has
determined that neither Elwha River nor lower Dungeness River pink
salmon, as petitioned, constitute a ``species'' under the ESA. However,
Elwha River and lower Dungeness River pink salmon are part of a larger
ESU that includes all odd-year pink salmon stocks in Washington as far
west as the Elwha River and in southern British Columbia, Canada
(including the Fraser River and eastern Vancouver Island), as far north
as Johnstone Strait. Further, NMFS has identified a second ESU for pink
salmon which includes even-year pink salmon residing in the Snohomish
River, WA. NMFS has determined that, at the present time, neither ESU
warrants listing as a threatened or endangered species.
References
A list of references is available upon request (See ADDRESSES).
Dated: September 28, 1995.
Rolland A. Schmitten,
Assistant Administrator for Fisheries, National Marine Fisheries
Service.
[FR Doc. 95-24698 Filed 9-29-95; 4:08 pm]
BILLING CODE 3510-22-F
