Notice2021-17211
Listing Endangered and Threatened Wildlife; 12-Month Findings on Petitions To List Spring-Run Oregon Coast Chinook Salmon and Spring-Run Southern Oregon and Northern California Coastal Chinook Salmon as Threatened or Endangered Under the Endangered Species Act
Primary source
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Published
August 17, 2021
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
We, NMFS, announce 12-month findings on 2 petitions to list populations of spring-run Chinook salmon (Oncorhynchus tshawytscha) as threatened or endangered Evolutionarily Significant Units (ESUs) under the Endangered Species Act (ESA) and to designate critical habitat concurrently with the listings. We have completed a comprehensive analysis of Oregon Coast (OC) and Southern Oregon and Northern California Coastal (SONCC) spring-run Chinook salmon populations in response to the petitions. Based on the best scientific and commercial data available, including the ESU configuration report, we have determined that listing the OC and SONCC spring-run Chinook salmon populations as threatened or endangered ESUs is not warranted. We determined that the OC and SONCC spring-run Chinook salmon populations do not meet the ESU Policy criteria to be considered ESUs separate from the OC and SONCC fall-run Chinook salmon populations and, therefore, do not meet the statutory definition of a species under the ESA. We also announce the availability of an ESU configuration report we prepared to inform our determination.
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[Federal Register Volume 86, Number 156 (Tuesday, August 17, 2021)]
[Notices]
[Pages 45970-45974]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-17211]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[Docket No. 210806-0159]
RTID 0648-XW032 and 0648-XW013
Listing Endangered and Threatened Wildlife; 12-Month Findings on
Petitions To List Spring-Run Oregon Coast Chinook Salmon and Spring-Run
Southern Oregon and Northern California Coastal Chinook Salmon as
Threatened or Endangered Under the Endangered Species Act
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of 12-month petition findings.
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SUMMARY: We, NMFS, announce 12-month findings on 2 petitions to list
populations of spring-run Chinook salmon (Oncorhynchus tshawytscha) as
threatened or endangered Evolutionarily Significant Units (ESUs) under
the Endangered Species Act (ESA) and to designate critical habitat
concurrently with the listings. We have completed a comprehensive
analysis of Oregon Coast (OC) and Southern Oregon and Northern
California Coastal (SONCC) spring-run Chinook salmon populations in
response to the petitions. Based on the best scientific and commercial
data available, including the ESU configuration report, we have
determined that listing the OC and SONCC spring-run Chinook salmon
populations as threatened or endangered ESUs is not warranted. We
determined that the OC and SONCC spring-run Chinook salmon populations
do not meet the ESU Policy criteria to be considered ESUs separate from
the OC and SONCC fall-run Chinook salmon populations and, therefore, do
not meet the statutory definition of a species under the ESA. We also
announce the availability of an ESU configuration report we prepared to
inform our determination.
DATES: These findings were made on August 17, 2021.
ADDRESSES: The documents informing the 12-month findings, including the
ESU configuration report (Ford et al. 2021), are available by
submitting a request to the Assistant Regional Administrator, Protected
Resources Division, West Coast Regional Office, 501 W Ocean Blvd.,
Suite 4200, Long Beach, CA 90802, Attention: OC and SONCC spring-run
Chinook salmon 12-month Findings. The documents are also available
electronically at <a href="https://www.fisheries.noaa.gov/protected-resource-regulations?title=&field_species_vocab_target_id=Chinook+Salmon&sort_by=field_relevant_date_value">https://www.fisheries.noaa.gov/protected-resource-regulations?title=&field_species_vocab_target_id=Chinook+Salmon&sort_by=field_relevant_date_value</a>.
FOR FURTHER INFORMATION CONTACT: Gary Rule, NMFS West Coast Region at
<a href="/cdn-cgi/l/email-protection#375056454e1945425b52775958565619505841"><span class="__cf_email__" data-cfemail="20474152590e52554c45604e4f41410e474f56">[email protected]</span></a>, (503) 230-5424; or Heather Austin, NMFS Office of
Protected Resources at <a href="/cdn-cgi/l/email-protection#09616c687d616c7b27687c7a7d60674967666868276e667f"><span class="__cf_email__" data-cfemail="4c24292d3824293e622d393f3825220c22232d2d622b233a">[email protected]</span></a>, (301) 427-8422.
SUPPLEMENTARY INFORMATION:
Background
On September 24, 2019, the Secretary of Commerce received a
petition from the Native Fish Society, Center for Biological Diversity,
and Umpqua Watersheds (hereafter, the OC Petitioners) to list OC
spring-run Chinook salmon as a threatened or endangered ESU under the
ESA. Currently, OC spring-run Chinook salmon populations are part of
the OC Chinook salmon ESU that combines populations of spring- and
fall-run Chinook salmon and is not listed under the ESA. The OC
Petitioners request that OC spring-run Chinook salmon be considered as
a separate ESU and listed as threatened or endangered. The OC
Petitioners also request the designation of critical habitat for OC
spring-run Chinook salmon concurrent with ESA listing. On April 13,
2020, we published a positive 90-day finding (85 FR 20476) (RTID 0648-
XW013) announcing that the petition presented substantial scientific or
commercial information indicating that the petitioned action may be
warranted. In our 90-day finding, we also announced the initiation of a
status review to determine whether the spring-run populations of OC
Chinook salmon constitute an ESU, and, if so, whether that OC spring-
run Chinook salmon ESU is in danger of extinction or likely to become
so within the foreseeable future throughout all or a significant
portion of its range; and we requested information to inform our status
review.
On May 4, 2020, the Secretary of Commerce received a petition from
Richard K. Nawa (hereafter, the SONCC Petitioner, or Petitioners when
referring collectively to the OC Petitioners and the SONCC Petitioner)
to identify SONCC spring-run Chinook salmon as a separate ESU and list
the ESU as threatened or endangered under the ESA. Currently, SONCC
spring-run Chinook salmon populations are part of the SONCC Chinook
salmon ESU that combines populations of spring- and fall-run Chinook
salmon and is not listed under the ESA. The SONCC
[[Page 45971]]
Petitioner requests that SONCC spring-run Chinook salmon be considered
as a separate ESU and listed as threatened or endangered. The SONCC
Petitioner also requests the designation of critical habitat for SONCC
spring-run Chinook salmon concurrent with ESA listing. On March 16,
2021, we published a positive 90-day finding (86 FR 14407) (RTID 0648-
XW032) announcing that the petition presented substantial scientific or
commercial information indicating that the petitioned action may be
warranted. In our 90-day finding, we also announced the initiation of a
status review to determine whether the spring-run populations of SONCC
Chinook salmon constitute an ESU, and, if so, whether that SONCC
spring-run Chinook salmon ESU is in danger of extinction or likely to
become so within the foreseeable future throughout all or a significant
portion of its range; and we requested information to inform our status
review.
Listing Species Under the ESA
We are responsible for determining whether species under our
jurisdiction are threatened or endangered under the ESA (16 U.S.C. 1531
et seq.). To make this determination, we first consider whether a group
of organisms constitutes a ``species'' under section 3 of the ESA (16
U.S.C. 1532), and then, if so, consider whether the status of the
species qualifies it for listing as either threatened or endangered.
Section 3 of the ESA defines species to include any subspecies of fish
or wildlife or plants, and any distinct population segment (DPS) of any
species of vertebrate fish or wildlife which interbreeds when mature.
In 1991, we issued the Policy on Applying the Definition of Species
Under the Endangered Species Act to Pacific Salmon (``ESU Policy''; 56
FR 58612; November 20, 1991), which explains that a Pacific salmon
population unit will be considered a DPS, and hence a ``species'' under
the ESA, if it represents an ``evolutionarily significant unit'' of the
biological species. The two criteria for delineating an ESU are: (1) It
is substantially reproductively isolated from other conspecific
population units; and (2) it represents an important component in the
evolutionary legacy of the species. The ESU Policy is used exclusively
for delineating distinct population segments of Pacific salmon. A joint
NMFS-U.S. Fish and Wildlife Service (USFWS) (jointly, ``the Services'')
policy clarifies the Services' interpretation of the phrase ``distinct
population segment'' for the purposes of listing, delisting, and
reclassifying a species under the ESA (``DPS Policy''; 61 FR 4722;
February 7, 1996). In announcing this policy, the Services indicated
that the ESU Policy for Pacific salmon was consistent with the DPS
Policy and that NMFS would continue to use the ESU Policy for Pacific
salmon.
Section 3 of the ESA further defines an endangered species as any
species which is in danger of extinction throughout all or a
significant portion of its range and a threatened species as one which
is likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range. Thus, we
interpret an ``endangered species'' to be one that is presently in
danger of extinction. A ``threatened species,'' on the other hand, is
not presently in danger of extinction, but is likely to become so in
the foreseeable future. In other words, the primary statutory
difference between a threatened and endangered species is the timing of
when a species may be in danger of extinction, either presently
(endangered) or in the foreseeable future (threatened).
Section 4(a)(1) of the ESA also requires us to determine whether
any species is endangered or threatened as a result of any of the
following five factors: The present or threatened destruction,
modification, or curtailment of its habitat or range; overutilization
for commercial, recreational, scientific, or educational purposes;
disease or predation; the inadequacy of existing regulatory mechanisms;
or other natural or manmade factors affecting its continued existence
(16 U.S.C. 1533(a)(1)(A)-(E)). Section 4(b)(1)(A) of the ESA requires
us to make listing determinations 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 efforts being made by any
state or foreign nation or political subdivision thereof to protect the
species. In evaluating the efficacy of formalized domestic conservation
efforts that have yet to be implemented or demonstrate effectiveness,
we rely on the Services' joint Policy for Evaluation of Conservation
Efforts When Making Listing Decisions (PECE; 68 FR 15100; March 28,
2003).
Status Review
As part of our review of the Petitioners' requests to delineate the
OC and SONCC spring-run Chinook salmon ESUs and list them as threatened
or endangered under the ESA, we formed an expert panel (Panel)
consisting of scientists from NMFS Northwest Fisheries Science Center
and Southwest Fisheries Science Center. We asked the Panel to provide:
(1) An analysis and review of the Petitioners' claims that OC and SONCC
spring-run Chinook salmon populations should be considered ESUs; and,
if any new ESUs were identified, (2) a description of the demographic
risks (i.e., abundance, productivity, spatial distribution and
diversity) of the new ESUs. The first task was for the Panel to compile
the best available scientific and commercial information relevant to
re-evaluating the ESU structure of the OC and SONCC Chinook salmon
ESUs, including information provided by the Petitioners. Specifically,
the NMFS West Coast Region (WCR) requested the Panel use the criteria
in the ESU Policy (56 FR 58612; November 20, 1991) to evaluate whether
the OC and/or SONCC spring-run Chinook salmon populations should be
considered ESUs. If the Panel concluded that one or both of the spring-
run Chinook salmon populations should be considered a separate ESU, and
the WCR concurred, the Panel would complete the second task of
describing the demographic risks, and submit their report on both tasks
to the WCR. If the Panel concluded, and WCR concurred, that there
should not be a change in the current ESU structure for either ESU
(i.e., the spring-run Chinook salmon are part of the current ESU), the
Panel would finalize their ESU structure findings and submit a report
to the WCR. Under this second scenario, the Panel would not conduct a
demographic risk analysis of the OC or SONCC spring-run Chinook salmon.
In order to complete their ESU analysis, the Panel considered a
variety of scientific information from the literature, unpublished
documents, and direct communications with researchers working on the
genetics of Chinook salmon, as well as information submitted to NMFS in
response to the 90-day findings on the petitions. Information that was
not previously peer-reviewed was formally reviewed by the Panel. The
Panel evaluated the information provided by the Petitioners and
considered additional factors that may contribute to our understanding
of the evolutionary significance of run-timing in Chinook salmon.
The Panel's draft report was subjected to independent peer review
as required by the Office of Management and Budget (OMB) Final
Information Quality Bulletin for Peer Review (M-05-03; December 16,
2004). The draft report was peer reviewed by three independent
specialists selected from the academic and scientific community, with
expertise in the genetic diversity and biology of salmonids. The peer
[[Page 45972]]
reviewers were asked to evaluate the adequacy, appropriateness, and
application of data used in the report. Of the three peer reviewers,
two responded with written comments and the third responded informally
that they had no comments. All peer reviewer comments were addressed
prior to dissemination and finalization of the draft report and
publication of these 12-month findings.
We subsequently reviewed the report, its cited references, and peer
review comments, and believe the report, which informs our 12-month
findings, provides the best available scientific and commercial
information on the OC and SONCC Chinook salmon ESUs. Much of the
information discussed below is attributable to the report. However, in
making the 12-month findings determination, we have independently
applied the statutory provisions of the ESA, our regulations regarding
listing determinations (50 CFR part 424), and our ESU Policy.
Previous Federal Actions
On March 9, 1998, following completion of a comprehensive status
review of Chinook salmon (O. tshawytscha) populations in Washington,
Oregon, Idaho, and California, we published a proposed rule to list
seven Chinook salmon ESUs as threatened or endangered under the ESA (63
FR 11482). In this proposed rule, we identified the OC Chinook salmon
ESU as comprised of coastal populations of spring- and fall-run Chinook
salmon from the Elk River north to the mouth of the Columbia River (63
FR 11482, March 8, 1998). We did not propose to list the OC ESU of
Chinook salmon under the ESA, concluding that the ESU was neither in
danger of extinction nor likely to become endangered in the foreseeable
future.
On September 16, 1999, following an updated status review for four
Chinook salmon ESUs, we published a final rule to list two Chinook
salmon ESUs as threatened under the ESA (64 FR 50394). In this 1999
final rule, we identified the SONCC Chinook salmon ESU as composed of
coastal populations of spring- and fall-run Chinook salmon from Euchre
Creek, Oregon, through the Lower Klamath River, California (inclusive)
(64 FR 50394, September 16, 1999). After assessing information
concerning Chinook salmon abundance, distribution, population trends,
and risks, and after considering efforts being made to protect Chinook
salmon, we determined in this 1999 final rule that the SONCC ESU of
Chinook salmon did not warrant listing under the ESA.
Evolutionary Significant Unit Analysis
The Petitioners requested we delineate and list the OC and SONCC
spring-run Chinook salmon populations as ESUs. As described above, the
ESU Policy requires the consideration of two elements when deciding
whether a population unit is an ESU: (1) It is substantially
reproductively isolated from other conspecific population units; and
(2) it represents an important component in the evolutionary legacy of
the species. The first criterion, reproductive isolation, refers to
restricted interbreeding among populations. Such isolation does not
have to be absolute, but it must be strong enough to permit
evolutionarily important differences to accrue in different population
units. Information that can be useful in determining the degree of
reproductive isolation includes documentation of fish straying from one
population to another, recolonization rates of other populations, the
efficacy of natural barriers to migration, and measurements of genetic
differences between populations. Each of these types of information has
its limitations. Identification of physical barriers to genetic
exchange can help define the geographic extent of distinct populations
but reliance on physical features alone can be misleading in the
absence of supporting biological information. Documentation of straying
between populations can provide information about the movements of
individual fish but not the genetic consequences of migration.
Furthermore, measurements of current straying or recolonization rates
provide no direct information about the magnitude or consistency of
such rates in the past. In this respect, data from the analysis of
genetic variation between individuals or groups of fish can be very
useful because they reflect levels of gene flow that have occurred over
evolutionary time scales.
To be considered an ESU, the population must also represent an
important component in the evolutionary legacy of the species. The
evolutionary legacy of a species is the genetic variability that is a
product of past evolutionary events and which represents the reservoir
upon which future evolutionary potential depends. This second criterion
would be met if the population contributed substantially to the
ecological/genetic diversity of the species as a whole. In other words,
if the population became extinct, would this event represent a
significant loss to the ecological/genetic diversity of the entire
species? In making this determination, the following questions are
relevant:
1. Is the population genetically distinct from other conspecific
populations?
2. Does the population occupy unusual or distinctive habitat?
3. Does the population show evidence of unusual or distinctive
adaptation to its environment?
Several types of information are useful in addressing these
questions. Again, the strengths and limitations of the information will
be considered in making the determination. Phenotypic/life-history
traits, such as size, fecundity, and age and time of spawning may
reflect local adaptations of evolutionary importance, but
interpretation of these traits is complicated by their sensitivity to
environmental conditions. Data from DNA analysis provides valuable
insight into levels of overall genetic differentiation among
populations but in many cases does not contain direct information
regarding the extent of adaptive genetic differences. Habitat
differences suggest the possibility for local adaptations but do not
prove that such adaptations exist.
Methods for Analyzing Genetic Variation
Genetic variability within and between populations of Chinook
salmon generally falls into two categories: Neutral and adaptive
genetic variation. Most of the variation in a species' genome (the sum
total of an organism's DNA) has no influence on survival or
reproduction, and hence is considered to be selectively neutral.
Examining patterns of selectively neutral variation among individuals
in populations is very useful for understanding the relationships
between those individuals and the histories of the populations. For
example, neutral variation can be used to estimate the degree of gene
flow or interbreeding among different populations, or the familial
relationships among specific individuals. Adaptive genetic variation
refers to genes or regulatory regions of the genome that have an effect
on fitness (survival or reproduction). Adaptive genetic variation
occurs when certain DNA sequence variants in a population help some
members survive or reproduce better than others.
Reproductive Isolation Criterion
The 1998 and 1999 coastwide status reviews for Chinook salmon
focused on patterns of neutral genetic variation and did not consider
differences in run timing (adaptive genetic variation) alone to be
indicative of substantial
[[Page 45973]]
reproductive isolation. This conclusion was due in part to the observed
patterns of genetic variation, in which spring-run and fall-run fish
spawning in the same or nearby rivers were genetically similar to each
other and more similar to each other than to populations of either run
type spawning in geographically distant rivers (Myers et al. 1998;
Busby et al. 1999). The Panel reviewed subsequent genetic studies and
found that they clearly confirm the earlier findings that, as a group,
coastal spring-run Chinook salmon are not a distinct evolutionary
lineage within the species, but rather share their evolutionary history
and most of their genetic variation with the fall-run Chinook salmon
spawning in the same and nearby rivers. In other words, the patterns of
genetic variation coastwide indicate that spring-run Chinook salmon
spawning in different rivers are generally more differentiated from
each other than they are to co-occurring fall-run Chinook salmon.
Although this pattern is apparent when viewed on a coastwide scale,
it is important to note that most of the coastwide Chinook salmon
genetic studies conducted over the past two decades had few samples
from the OC and SONCC areas. The Oregon Department of Fish and Wildlife
identified up to nine rivers in the currently defined OC Chinook salmon
ESU as having either spring-run populations or a spring-run or summer-
run component to a population, but no genetics study has included more
than three spring-run or summer-run population samples, and spring-run
or summer-run samples have only been analyzed for a total of four OC
river systems: Nehalem, Trask, Siletz, and Umpqua rivers. Following a
review of the available information, the Panel found that some of the
samples from co-occurring spring-run and fall-run populations in the OC
areas do not necessarily seem to be closely genetically related. In
particular, Umpqua River spring-run (sampled from the Rock Creek
hatchery) tend to cluster with SONCC samples of both run types in a
number of studies rather than with Umpqua fall-run samples or other OC
fall-run samples (Myers et al. 1998; Waples et al. 2004; Seeb et al.
2007; Narum et al. 2008; Clemento et al. 2014; Hecht et al. 2015; note
that some studies used the same set of samples so these data are not
all independent). This pattern could indicate that Umpqua River spring-
run Chinook salmon are in fact historically more closely related to
SONCC Chinook salmon, or could be a result of past broodstock transfers
from the Rogue River (and elsewhere) into the Rock Creek Hatchery (as
summarized by Myers et al. 1998, Appendix D). In addition, fall-run
samples from the Trask River Hatchery were more closely related to
other OC fall-run samples than to Trask River Hatchery spring-run
samples (Beacham et al. 2006). A similar pattern was seen in wild fall-
run and spring-run Chinook salmon from the Siletz River (Davis et al.
2017). Extensive out-of-basin spring-run (and fall-run) Chinook salmon
hatchery releases in the Trask River may be an explanation for this
pattern. Similarly, although relatively few spring-run Chinook salmon
hatchery releases have occurred in the Siletz River, that basin did
receive more than 2 million Columbia River hatchery Chinook salmon
releases between 1934 and 1952 (Myers et al. 1998, Appendix D).
Additional sampling and genetic analysis of natural-origin fish across
the range of return timing in multiple OC and SONCC rivers would help
improve our understanding of the genetic relationships among OC and
SONCC Chinook salmon populations. However, the available data does not
indicate that spring-run Chinook salmon spawning in rivers on the
Oregon Coast, as a group, form a distinct lineage separate from OC
fall-run Chinook salmon.
The SONCC area is more thoroughly sampled, particularly with
respect to the Rogue River basin. Within the SONCC ESU, it is apparent
that the close genetic relationship between geographically proximate
spring-run and fall-run Chinook salmon continues to be true when viewed
at the within-ESU scale. In particular, in several studies, spring-run
and fall-run samples from the Rogue River are more genetically related
to each other than either are to samples from other rivers in the SONCC
ESU. In other words, within the currently delineated SONCC Chinook
salmon ESU, spring-run and fall-run fish spawning in the Rogue River
appear to reproduce more with each other than with fall-run fish
spawning in other rivers in the ESU. The Panel found that this pattern
is similar to what has been reported in the Upper Klamath and Trinity
Rivers (Anderson and Garza 2018), and is also apparent in the Puget
Sound and Lower Columbia Chinook ESUs.
In addition to neutral genetic variation, adaptive genetic
variation has been used to identify differences between individual fish
or groups of fish. An example is the gene-region that has been
associated with run-timing in Chinook salmon and steelhead, the GREB1L
gene (otherwise referred to as the GREB1L region of the genome). Hess
et al. (2016), Prince et al. (2017) and Thompson et al. (2019a)
characterized the GREB1L region as two alleles (different forms) and
three genotypes (different combinations of the two alleles):
Individuals with two early run-timing alleles (early run homozygotes),
individuals with two late run-timing alleles (late run homozygotes),
and individuals with one allele for the early and one for the late run-
timing (heterozygotes). There are five recent studies that have
examined run-time-associated variants in the GREB1L region in OC and
SONCC Chinook samples (Prince et al. 2017; Anderson & Garza 2018;
Thompson et al. 2019a; O'Malley et al. 2020a; O'Malley et al. 2020b).
These studies have found that heterozygotes are common, indicating that
interbreeding between fish homozygous for the spring-run and fall-run
variants is commonly occurring. This pattern has been extensively
studied in the Rogue River basin of the SONCC ESU (Thompson et al.
2019; O'Malley et al. 2020a; O'Malley et al. 2020b), where researchers
have obtained relatively large sample sizes of fish based on carcass
surveys and surveys of captured live fish conducted throughout the run.
For the OC, the only river that has been sampled using the GREB1L
markers is the Siletz River (Anderson and Garza 2018; Thompson et al.
2020). That study also found substantial proportions of heterozygotes,
particularly among fish that returned to the river early and were
identified as spring-run (29 percent). A similarly high proportion of
GREB1L region heterozygotes have been found in other coastal Chinook
salmon ESUs (Upper Klamath River, Anderson and Garza 2018; Rogue River,
Thompson et al. 2019a; Washington Coast, Thompson et al. 2019b).
The GREB1L region has been demonstrated to be highly associated
with run timing in multiple populations of coastal Chinook salmon
(i.e., coastal spring-run Chinook salmon are homozygous for the early
alleles, and fall-run Chinook are homozygous for the late alleles--
Anderson and Garza 2018, Thompson et al. 2019a,b, O'Malley et al. 2020,
Thompson et al. 2020). The finding of substantial proportions of
heterozygotes provides evidence of contemporary interbreeding between
alternative homozygotes at the GREB1L region. This, in turn, implies
that mating among spring-run and fall-run (and likely intermediate
timed) fish is common in multiple watersheds (reviewed by Ford et al.
2020). Analysis of recombination events (Anderson and Garza 2018,
Thompson et al. 2020) also indicates that at least in the Upper
[[Page 45974]]
Klamath River, such interbreeding must have also occurred historically
at some level, although the rate of interbreeding was not determined
and could be lower than is seen now.
In both the OC and the SONCC ESUs, there is therefore strong
evidence from GREB1L region markers that interbreeding between spring-
run and fall-run Chinook salmon is common, at least for the two
watersheds that have been studied to date (Rogue River, Siletz River).
However, the data do not indicate whether the current levels of
interbreeding occurred historically under more pristine conditions.
Patterns of random genomic variation (indicative of population history)
indicate that spring-run Chinook salmon in the OC and SONCC ESUs are,
as a group, not substantially reproductively isolated from fall-run
Chinook spawning in the OC and SONCC rivers. There is some indication
that spring-run Chinook salmon in the Umpqua River may have somewhat
reduced gene flow from other OC fall-run and spring-run Chinook salmon
populations, but past hatchery practices may have also influenced this
result. As a whole, however, the available data indicate that the
spring-run portions of the OC and SONCC ESUs are not substantially
reproductively isolated from the fall-run populations in the ESUs.
Additional genetic sampling of fish throughout the period of migration
in multiple populations, especially in the OC ESU, would be very
helpful for further evaluating this question.
Evolutionary Legacy Criterion
The early run-timing trait is an important component of diversity
within the Chinook salmon species. In particular, the trait allows
Chinook salmon to access upstream habitats that are inaccessible to
later returning fish in some years. Run time diversity as a whole is
also expected to increase viability by broadening the portfolio of
traits within a species or an ESU, which leads to increased resilience
to environmental variation (Quinn et al. 2016). Recent reviews of ESU/
DPS configurations of Chinook salmon (Anderson et al. 2018) and
steelhead (Pearse et al. 2019) support this point, as does a recent
expert workshop report (Ford et al. 2020) and the original coastwide
status review of Chinook salmon (Myers et al. 1998). Recovery plans for
Chinook salmon ESUs that contain populations with both spring-run and
fall-run fish also emphasize the importance of recovering populations
with both life-history strategies (Shared Strategy Development
Committee 2007; Dornbush 2013; Pearse et al. 2019).
While recognizing the importance of run-timing variation to species
and ESU viability, Myers et al. (1998) concluded that patterns of
genetic variation and patterns of variation for other life-history
traits indicated that coastal spring- and fall-run Chinook salmon
shared the same recent evolutionary history. Coastal ESUs were
identified based on concordant patterns of genetic, life-history, and
geographic variation, with run-timing variation considered to be an
important element of diversity within ESUs. Subsequent reports of Upper
Klamath Trinity River Chinook salmon and Northern California steelhead
have reached the same conclusion (Williams et al. 2013, Anderson et al.
2018, Pearse et al. 2019). Recent genetic studies have greatly
increased our knowledge of the genetic basis of run-timing variation,
but these studies do not change or invalidate the previous conclusion
that spring-run and fall-run Chinook salmon in the currently delineated
OC and SONCC Chinook salmon ESUs share a recent evolutionary legacy,
and they are, on the whole, more genetically similar to each other than
to populations in other ESUs. The two run types display similar
characteristics in other life-history traits, and are genetically
similar to each other due to a combination of recent common ancestry
and ongoing interbreeding. Identifying a spring-run-only Chinook salmon
ESU for either the OC or SONCC areas would therefore be inconsistent
with our ESU policy, both because of high levels of interbreeding
between spring-run and fall-run fish in these ESUs and because spring-
run fish, as a group, in these ESUs do not form a distinct evolutionary
lineage within the species.
Conclusions on the Evolutionarily Significant Unit Analysis
The Panel concluded, and the WCR concurred, that the best available
information indicates that OC and SONCC spring-run Chinook salmon
populations do not meet the reproductive isolation and genetic legacy
criteria of the ESU Policy. The spring-run phenotype and the spring-run
variant within the GREB1L chromosomal region are clearly an important
part of the diversity within the Chinook salmon species, but the
available data indicate that spring-run Chinook salmon in the OC and
SONCC ESUs regularly interbreed with and share a recent evolutionary
history throughout the vast majority of their genome with fall-run
Chinook salmon in the same rivers.
Final Determination
Section 4(b)(1) of the ESA requires that NMFS make listing
determinations based solely on the best scientific and commercial data
available after conducting a review of the status of the species and
taking into account those efforts, if any, being made by any state or
foreign nation, or political subdivisions thereof, to protect and
conserve the species. We have independently reviewed the best available
scientific and commercial information, including the information
provided in the petitions and public comments submitted on the 90-day
findings (85 FR 20476, April 13, 2020; 86 FR 14407, March 16, 2021),
the ESU configuration review report, and other published and
unpublished information, and have consulted with species experts and
individuals familiar with the OC and SONCC Chinook salmon ESUs.
Our determination set forth here is based on a synthesis and
integration of the foregoing information. Based on our consideration of
the best available scientific and commercial information, as summarized
here and in the ESU configuration report, we conclude that OC and SONCC
spring-run Chinook salmon populations do not constitute ESUs.
Accordingly, OC and SONCC spring-run Chinook salmon populations do not
meet the statutory definition of a species, and thus, OC and SONCC
spring-run Chinook salmon populations do not warrant listing under the
ESA.
This is a final action, and, therefore, we are not soliciting
public comments.
References
A complete list of all references cited herein is available upon
request (see FOR FURTHER INFORMATION CONTACT).
Authority
The authority for this action is the Endangered Species Act of
1973, as amended (16 U.S.C. 1531 et seq.).
Dated: August 6, 2021.
Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2021-17211 Filed 8-16-21; 8:45 am]
BILLING CODE 3510-22-P
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