Endangered and Threatened Species: Final Listing Determinations for 10 Distinct Population Segments of West Coast Steelhead, 834-862 [06-47]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 71, Number 3 (Thursday, January 5, 2006)]
[Rules and Regulations]
[Pages 834-862]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-47]



[[Page 833]]

-----------------------------------------------------------------------

Part IV





Department of Commerce





-----------------------------------------------------------------------



National Oceanic and Atmospheric Administration



-----------------------------------------------------------------------



50 CFR Parts 223 and 224



Endangered and Threatened Species: Final Listing Determinations for 10 
Distinct Population Segments of West Coast Steelhead; Final Rule

Federal Register / Vol. 71, No. 3 / Thursday, January 5, 2006 / Rules 
and Regulations

[[Page 834]]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Parts 223 and 224

[Docket No. 051216341-5341-01; I.D. No. 052104F]
RIN 0648-AR93


Endangered and Threatened Species: Final Listing Determinations 
for 10 Distinct Population Segments of West Coast Steelhead

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We, NOAA's National Marine Fisheries Service (NMFS), are 
issuing final determinations to list 10 Distinct Population Segments 
(DPSs) of West Coast steelhead (Oncorhynchus mykiss) under the 
Endangered Species Act (ESA) of 1973, as amended. We are listing one 
steelhead DPS in California as endangered (the Southern California 
steelhead DPS), and nine steelhead DPSs in California, Oregon, 
Washington, and Idaho as threatened (the South-Central California 
Coast, Central California Coast, California Central Valley, Northern 
California, Lower Columbia River, Upper Willamette River, Middle 
Columbia River, Upper Columbia River, and Snake River Basin steelhead 
DPSs). All 10 of these DPSs were previously listed as threatened or 
endangered species. The Upper Columbia River steelhead DPS, formerly 
listed as an endangered species, is now being listed as threatened.

DATES: The effective date of this rule is February 6, 2006.

ADDRESSES: NMFS, Protected Resources Division, 1201 NE Lloyd Boulevard, 
Suite 1100, Portland, Oregon 97232.

FOR FURTHER INFORMATION CONTACT: Craig Wingert, NMFS, Southwest Region, 
at (562) 980-4021, Dr. Scott Rumsey, NMFS, Northwest Region, Protected 
Resources Division, at (503) 872-2791, and Marta Nammack, NMFS, Office 
of Protected Resources, at (301) 713-1401. Reference materials 
regarding these determinations are available upon request or on the 
Internet at https://www.nwr.noaa.gov.

SUPPLEMENTARY INFORMATION:

Background

Policies for Delineating Species under the ESA

    Section 3 of the ESA defines ``species'' as including ``any 
subspecies of fish or wildlife or plants, and any distinct population 
segment of any species of vertebrate fish or wildlife which interbreeds 
when mature.'' The term ``distinct population segment'' is not 
recognized in the scientific literature. In 1991 we issued a policy for 
delineating distinct population segments of Pacific salmon (56 FR 
58612; November 20, 1991). Under this policy a group of Pacific salmon 
populations is considered an ``evolutionarily significant unit'' (ESU) 
if it is substantially reproductively isolated from other conspecific 
populations, and it represents an important component in the 
evolutionary legacy of the biological species. Further, an ESU is 
considered to be a ``distinct population segment'' (and thus a 
``species'') under the ESA. In 1996, we and FWS adopted a joint policy 
for recognizing DPSs under the ESA (DPS Policy; 61 FR 4722; February 7, 
1996). The DPS Policy adopts criteria similar to, but somewhat 
different from, those in the ESU Policy for determining when a group of 
vertebrates constitutes a DPS: The group must be discrete from other 
populations, and it must be significant to its taxon. A group of 
organisms is discrete if it is ``markedly separated from other 
populations of the same taxon as a consequence of physical, 
physiological, ecological, and behavioral factors.'' Significance is 
measured with respect to the taxon (species or subspecies) as opposed 
to the full species. Although the ESU Policy did not by its terms apply 
to steelhead, the DPS Policy states that NMFS will continue to 
implement the ESU Policy with respect to ``Pacific salmonids'' (which 
include O. mykiss). FWS, however, does not use our ESU policy in any of 
its ESA listing decisions. In a previous instance of shared 
jurisdiction over a species (Atlantic salmon), we and FWS used the DPS 
policy in our determination to list the Gulf of Maine DPS of Atlantic 
salmon as endangered (65 FR 69459; November 17, 2000). Given our shared 
jurisdiction over O. mykiss, and consistent with our approach for 
Atlantic salmon, we believe application of the joint DPS policy here is 
logical, reasonable, and appropriate for identifying DPSs of O. mykiss. 
Moreover, use of the ESU policy--originally intended for Pacific 
salmon--should not continue to be extended to O. mykiss, a type of 
salmonid with characteristics not typically exhibited by Pacific 
salmon. NMFS and FWS also intend to continue to evaluate application of 
the statutory term ``distinct population segment'' in a process outside 
the context of a species-specific listing.

Previous Federal ESA Actions Related to West Coast Steelhead

    In 1996, we completed a comprehensive status review of West Coast 
steelhead (Busby et al., 1996) that resulted in proposed listing 
determinations for 10 steelhead ESUs, five as endangered and five as 
threatened species (61 FR 41541; August 9, 1996). On August 18, 1997, 
we listed five of the ESUs, two as endangered (the Southern California 
and Upper Columbia River steelhead ESUs) and three as threatened (the 
South-Central California Coast, Central California Coast, and Snake 
River Basin steelhead ESUs) (62 FR 43937). On March 19, 1998, we listed 
the California Central Valley and Lower Columbia River steelhead ESUs 
as threatened. On March 25, 1999, we listed as threatened the Upper 
Willamette River and Middle Columbia River steelhead ESUs (64 FR 
14517). We listed the Northern California steelhead ESU as threatened 
on June 7, 2000 (65 FR 36074). As a result of these listing 
determinations, there are currently 10 listed steelhead ESUs, two 
endangered (Southern California and Upper Columbia River) and eight 
threatened (South-Central California, Central California Coast, 
California Central Valley, Northern California, Upper Willamette River, 
Lower Columbia River, Middle Columbia River, and Snake River Basin).
    In our August 18, 1997, steelhead listing determinations, we noted 
uncertainties about the relationship of resident and anadromous O. 
mykiss, yet concluded that the two forms are part of a single ESU where 
the resident and anadromous O. mykiss have the opportunity to 
interbreed (62 FR 43937, at 43941). FWS, the agency with ESA 
jurisdiction over resident O. mykiss, disagreed that resident fish 
should be included in the steelhead ESUs and advised that the resident 
fish not be listed (FWS, 1997; and 62 FR 43937, at 43941). Accordingly, 
we listed only the anadromous O. mykiss (steelhead) at that time (62 FR 
43937, at 43951). That decision was followed in each of the subsequent 
steelhead listings described in the preceding paragraph.
    In 2001, the U.S. District Court in Eugene, Oregon, set aside the 
1998 threatened listing of the Oregon Coast coho ESU (Alsea Valley 
Alliance v. Evans, 161 F. Supp. 2d 1154 (D. Or. 2001)) (Alsea). In the 
Oregon Coast coho listing (63 FR 42587; August 10, 1998), we did not 
include 10 hatchery stocks determined to be part of the Oregon Coast 
coho ESU. The court upheld our

[[Page 835]]

policy of considering an ESU to be a DPS, but ruled that once we had 
delineated a DPS, the ESA did not allow listing only a subset of that 
DPS. In response to the Alsea decision and several listing and 
delisting petitions, we announced we would conduct an updated status 
review of 27 West Coast salmonid ESUs, including the 10 listed 
steelhead ESUs (67 FR 6215, February 11, 2002; 67 FR 48601, July 25, 
2002; 67 FR 79898, December 31, 2002).
    On June 14, 2004, we proposed to continue applying our ESU Policy 
to the delineation of DPSs of O. mykiss, and to list the 10 O. mykiss 
ESUs including the resident fish that co-occur with the anadromous form 
(69 FR 33102). We proposed to list one ESU in California as endangered 
(Southern California), and nine ESUs in California, Oregon, Washington, 
and Idaho as threatened (South-Central California, Central California 
Coast, California Central Valley, Northern California, Upper Willamette 
River, Lower Columbia River, Middle Columbia River, Snake River Basin, 
and Upper Columbia). In the proposed rule, we noted that the Alsea 
decision required listing of an entire DPS (ESU), in contrast to our 
prior steelhead-only listings, and stated the scientific principles and 
working assumptions that we used to determine whether particular 
resident groups were part of an O. mykiss ESU that included anadromous 
steelhead (69 FR 33102, at 33113). We proposed that where resident 
(rainbow trout) and anadromous (steelhead) O. mykiss occur in the same 
stream, they are not ``substantially reproductively isolated'' from one 
another and are therefore part of the same ESU.
    Following an initial public comment period of 90 days, we twice 
extended the public comment period for an additional 36 and 22 days (69 
FR 53031, August 31, 2004; 69 FR 61348, October 18, 2004), 
respectively. During the comment period, we received numerous comments 
disagreeing with our proposal to include resident populations in the O. 
mykiss ESUs (in general and for specific resident populations) and 
criticizing how we considered resident O. mykiss in evaluating the risk 
to the continued existence of the whole ESU.
    On June 7, 2005, FWS wrote to NMFS (FWS, 2005), stating its 
concerns about the factual and legal bases for our proposed listing 
determinations for 10 O. mykiss ESUs, specifying issues of substantial 
disagreement regarding the relationship between anadromous and resident 
O. mykiss. On June 28, 2005, we published a notice in the Federal 
Register announcing a 6-month extension of the final listing 
determinations for the subject O. mykiss ESUs to resolve the 
substantial disagreement regarding the sufficiency or accuracy of the 
available data relevant to the determinations (70 FR 37219). As a 
result of the comments received, we re-opened the comment period on 
November 4, 2005, to receive comments on a proposed alternative 
approach to delineating ``species'' of West Coast O. mykiss (70 FR 
67130). We proposed to depart from our past practice of applying the 
ESU Policy to O. mykiss stocks, and instead proposed to apply the DPS 
Policy in determining ``species'' of O. mykiss for listing 
consideration. We noted that within a discrete group of O. mykiss 
populations, the resident and anadromous life forms of O. mykiss remain 
``markedly separated'' as a consequence of physical, physiological, 
ecological, and behavioral factors, and may therefore warrant 
delineation as separate DPSs. We solicited comment on whether our final 
listing determinations should delineate 10 steelhead-only DPSs, list 
one DPS in California as endangered (Southern California), and list the 
remaining nine DPSs in California, Oregon, Washington, and Idaho as 
threatened (South-Central California, Central California Coast, 
California Central Valley, Northern California, Upper Willamette River, 
Lower Columbia River, Middle Columbia River, Snake River Basin, and 
Upper Columbia). The public comment period on this proposed alternative 
approach closed on December 5, 2005.

Statutory Framework for ESA Listing Determinations

    The ESA defines an endangered species as one that is in danger of 
extinction throughout all or a significant portion of its range, and a 
threatened species as one that is likely to become endangered in the 
foreseeable future throughout all or a significant portion of its range 
(sections 3(6) and 3(20), respectively). The statute requires us to 
determine whether any species is endangered or threatened because 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 (Section 4(a)(1)(A)-(E)). We are to make this 
determination based solely on the best available scientific information 
after conducting a review of the status of the species and taking into 
account any efforts being made by states or foreign governments to 
protect the species. The focus of our evaluation of the five statutory 
factors is to evaluate whether and to what extent a given factor 
represents a threat to the future survival of the species. The focus of 
our consideration of protective efforts is to evaluate whether and to 
what extent they address the identified threats and so ameliorate a 
species' risk of extinction. In making our listing determination, we 
must consider all factors that may affect the future viability of the 
species, including whether regulatory and conservation programs are 
inadequate and allow threats to the species to persist or worsen, or 
whether these programs are likely to mitigate threats to the species 
and reduce its extinction risk. The steps we follow in implementing 
this statutory scheme are to: (1) Delineate the species under 
consideration; (2) review the status of the species; (3) identify 
threats facing the species; (4) assess whether certain protective 
efforts mitigate these threats; and (5) predict the species' future 
persistence.
    As noted above, as part of our listing determinations we must 
consider efforts being made to protect a species, and whether these 
efforts ameliorate the threats facing the species and reduce risks to 
its survival. Some protective efforts may be fully implemented, and 
empirical information may be available demonstrating their level of 
effectiveness in conserving the species. Other protective efforts are 
new, not yet implemented, or have not demonstrated effectiveness. We 
evaluate such unproven efforts using the criteria outlined in the 
Policy for Evaluating Conservation Efforts (``PECE'' 68 FR 15100; March 
28, 2003) to determine their certainties of implementation and 
effectiveness.

Summary of Comments Received

    We solicited public comment on the proposed listing determinations 
for West Coast O. mykiss for a total of 238 days (69 FR 33102, June 14, 
2004; 69 FR 53031, August 31, 2004; 69 FR 61348, October 18, 2004; 70 
FR 6840, February 9, 2005; 70 FR 37219, June 28, 2005; 70 FR 67130, 
November 4, 2005). In addition, we held eight public hearings in the 
Pacific Northwest, and six public hearings in California concerning the 
June 2004 West Coast salmon and steelhead proposed listing 
determinations (69 FR 53031, August 31, 2004; 69 FR 54647, September 9, 
2004; 69 FR 61348, October 18, 2004). We solicited public comment again 
for 30 days on our proposed alternative approach to delineating DPSs of 
O.

[[Page 836]]

mykiss (70 FR 67130; November 4, 2005).
    A joint NMFS/FWS policy requires us to solicit independent expert 
review from at least three qualified specialists, concurrent with the 
public comment period (59 FR 34270; July 1, 1994). We solicited 
technical review of the scientific information underlying the June 2004 
proposed listing determinations, including the proposed determinations 
for West Coast O. mykiss, from over 50 independent experts selected 
from the academic and scientific community, Native American tribal 
groups, Federal and state agencies, and the private sector.
    In December 2004 the Office of Management and Budget (OMB) issued a 
Final Information Quality Bulletin for Peer Review (Peer Review 
Bulletin) establishing minimum peer review standards, a transparent 
process for public disclosure, and opportunities for public input. The 
OMB Peer Review Bulletin, implemented under the Information Quality Act 
(Public Law 106-554), is intended to ensure the quality of agency 
information, analyses, and regulatory activities and provide for a more 
transparent peer review process. We consider the scientific information 
used by the agency in developing the subject listing determinations for 
West Coast steelhead to be ``influential scientific information'' in 
the context of the OMB Peer Review Bulletin.
    We believe the independent expert review under the joint NMFS/FWS 
peer review policy, and the comments received from several academic 
societies and expert advisory panels, collectively satisfy the Peer 
Review Bulletin's requirements for ``adequate [prior] peer review.'' We 
solicited technical review of the proposed hatchery listing policy and 
salmon and steelhead listing determinations from over 50 independent 
experts selected from the academic and scientific community, Native 
American tribal groups, Federal and state agencies, and the private 
sector. The individuals from whom we solicited review of the proposals 
and the underlying science were selected because of their demonstrated 
expertise in a variety of disciplines including: artificial 
propagation; salmonid biology, taxonomy, and ecology; genetic and 
molecular techniques and analyses; population demography; quantitative 
methods of assessing extinction risk; fisheries management; local and 
regional habitat conditions and processes; and conducting scientific 
analyses in support of ESA listing determinations. The individuals 
solicited represent a broad spectrum of perspectives and expertise and 
include those who have been critical of past agency actions in 
implementing the ESA for West Coast salmon and steelhead, as well as 
those who have been supportive of these actions. These individuals were 
not involved in producing the scientific information for our 
determinations and were not employed by the agency producing the 
documents. In addition to these solicited reviews, several independent 
scientific panels and academic societies provided technical review of 
the hatchery listing policy and proposed listing determinations, and 
the supporting documentation. Many of the members of these panels were 
individuals from whom we had solicited review. We thoroughly 
considered, and, as appropriate, incorporated the review comments into 
these final listing determinations.
    In response to the requests for information and comments on the 
June 2004 proposed listing determinations, we received over 28,250 
comments by fax, standard mail, and e-mail. The majority of the 
comments received were from interested individuals who submitted form 
letters or form e-mails and addressed general issues not specific to a 
particular ESU. Comments were also submitted by state and tribal 
natural resource agencies, fishing groups, environmental organizations, 
home builder associations, academic and professional societies, expert 
advisory panels, farming groups, irrigation groups, and individuals 
with expertise in Pacific salmonids. The majority of respondents 
focused on the consideration of hatchery-origin fish in ESA listing 
determinations, with only a few comments specifically addressing the O. 
mykiss ESUs under review. We also received comments from four of the 
independent experts from whom we had requested technical review of the 
scientific information underlying the June 2004 proposed listing 
determinations. The peer reviewers' comments did not specifically 
address the proposed determinations for the 10 O. mykiss ESUs. We 
received 14 comments in response to the 6-month extension of the final 
listing determinations for the 10 O. mykiss ESUs. The comments 
reflected a diversity of opinion and generally focused on whether 
resident populations should be included as part of O. mykiss ESUs, and 
the consideration of resident O. mykiss in assessing the extinction 
risk of ESUs including both resident and anadromous populations. We 
received 15 comments concerning our November 2005 proposed alternative 
approach to delineate and list 10 steelhead-only DPSs of West Coast O. 
mykiss. The majority of the comments were opposed to the proposed 
alternative approach, though others were supportive. Copies of the full 
text of comments received are available upon request (see ADDRESSES and 
FOR FURTHER INFORMATION CONTACT, above).
    Below we address the comments received that directly pertain to the 
listing determinations for West Coast O. mykiss. The reader is referred 
to our June 2005 final hatchery listing policy (70 FR 37204; June 28, 
2005) for a summary and discussion of general issues concerning: the 
inclusion and listing of hatchery programs as part of salmon and 
steelhead ESUs; and the consideration of artificial propagation in 
evaluating the extinction risk of salmon and steelhead ESUs. The reader 
is referred to our June 2005 final listing determinations for 16 salmon 
ESUs (70 FR 37160; June 28, 2005) for a summary and discussion of 
general issues related to: the interpretation and application of the 
hatchery listing policy in our review of the species' status under 
review; the consideration of efforts being made to protect the species; 
and amended protective regulations for threatened salmonids. The 
following summary of issues raised and our responses are organized into 
six general categories: (1) General comments on the consideration of 
resident O. mykiss in the determination of ``species;'' (2) general 
comments on the consideration of resident O. mykiss in assessing 
extinction risk; (3) comments regarding a specific ESU or DPS on the 
determination of species; (4) comments regarding a specific ESU or DPS 
on the assessment of extinction risk; (5) comments on the consideration 
of protective efforts; and (6) comments regarding public notice and 
opportunities for comment.

General Comments on the Consideration of Resident O. mykiss: 
Determination of Species

    Comment 1: Several commenters felt that we lack sufficient site-
specific information to justify our June 2004 proposed inclusion of 
resident rainbow trout as part of O. mykiss ESUs. These commenters felt 
that our proposal inappropriately extrapolated a few observations 
universally to all circumstances where resident and anadromous O. 
mykiss have overlapping distributions. Other commenters felt that 
rainbow trout and steelhead should be considered separate ESUs for 
biological reasons (differences in behavior, morphology, and ecology); 
or for policy or legal reasons (such as implementing the purposes of 
the ESA).

[[Page 837]]

    Response: Those commenters who noted the lack of site-specific 
information are correct--we relied on information about the 
reproductive exchange of some specific co-occurring rainbow trout and 
steelhead to conclude generally that where the two life forms co-occur, 
they are sufficiently reproductively related to satisfy our ESU policy. 
We continue to conclude that the best available scientific information 
suggests that co-occurring steelhead and rainbow trout are part of the 
same ESU, as we defined that concept in our ESU policy. Some of the 
concerns raised by these commenters have persuaded us to alter our 
approach to delineating DPSs of O. mykiss, and rely on the DPS policy 
rather than the ESU policy. Because we have decided to alter our 
approach, we do not address these comments in further detail.
    Comment 2: Several commenters felt we failed to provide a rationale 
for departing from our long-standing practice of applying the ESU 
policy. The commenters felt that the choice to use the DPS policy 
appeared to be based on an arbitrary jurisdictional division between 
NMFS and FWS, rather than new scientific information supporting an 
alternative approach. The commenters felt that it is not appropriate to 
base species delineations on arbitrary divisions between government 
agencies and the apparent desire to preserve jurisdictional 
authorities. These commenters stressed that such determinations must be 
made based on the best available scientific information.
    Other commenters supported the use of the DPS policy in delineating 
species of O. mykiss. They felt that consistency between NMFS and FWS 
would improve the public understanding of the listing process. They 
also felt that the DPS policy provides flexibility, affording a more 
practical consideration of resident populations, particularly above 
impassable dams, that do not warrant ESA protections.
    Response: In our previous status reviews for West Coast O. mykiss 
we applied our ESU policy and concluded that, where they co-occur and 
have the opportunity to interbreed, the resident and anadromous life-
history forms are part of a single ESU. FWS disagreed that resident O. 
mykiss should be included in the steelhead ESUs and recommended that 
only the anadromous fish be listed (FWS, 1997). Accordingly, we listed 
only the steelhead portion of the ESUs. The Alsea ruling informed us 
that this approach to implementing our jurisdiction over O. mykiss was 
invalid; once we have equated an ESU with a DPS, delineated an ESU, and 
determined that it warrants listing, we must include all components of 
the DPS (ESU) in the listing. In our June 2004 proposed listing 
determinations (69 FR 33102; June 14, 2004), we proposed to continue 
applying our ESU policy in delineating species of O. mykiss for listing 
consideration, consistent with our previous practice. Informed by the 
Alsea ruling, we proposed to list entire O. mykiss ESUs, including both 
the anadromous and resident components. FWS disagreed with our DPS 
delineations under the ESU policy, and questioned whether the proposed 
delineations are consistent with the DPS policy (FWS, 2005).
    The preamble to the joint DPS policy acknowledged that ``the NMFS 
[ESU] policy is a detailed extension of this joint policy. 
Consequently, NMFS will continue to exercise its policy with respect to 
Pacific salmonids'' (61 FR 4722; February 7, 1996). FWS, however, does 
not use our ESU policy in any of its ESA listing decisions. In a 
previous instance of shared jurisdiction over a species (Atlantic 
salmon), we and FWS used the DPS policy in our determination to list 
the Gulf of Maine DPS of Atlantic salmon as endangered (65 FR 69459; 
November 17, 2000). Given our shared jurisdiction over O. mykiss, and 
consistent with our approach for Atlantic salmon, we believe 
application of the joint DPS policy here is logical, reasonable, and 
appropriate for identifying DPSs of O. mykiss. Moreover, use of the ESU 
policy--originally intended for Pacific salmon--should not continue to 
be extended to O. mykiss, a type of salmonid with characteristics not 
typically exhibited by Pacific salmon.
    Comment 3: Two commenters argued that we are required to rely on 
the taxonomic distinctions established by the scientific community in 
making our species delineations. Commenters quoted NMFS' ESA 
implementing regulations stating that we ``shall rely on standard 
taxonomic distinctions and the biological expertise of the Department 
and the scientific community regarding the relevant taxonomic group'' 
(50 CFR 424.11(a)). The commenters noted that it is well established in 
the scientific literature that the resident and anadromous life forms 
of O. mykiss are members of the same taxonomic species, and where they 
co-occur they are genetically indistinguishable and represent a life-
history polymorphism within a single interbreeding population. Several 
commenters also noted that a group of independent scientific experts 
(Hey et al., 2005) recently empaneled by NMFS concluded: ``For * * * 
populations in which anadromous and resident fish appear to be 
exchanging genes and in which some parents produce progeny exhibiting 
both life history paths, the two life-history alternatives appear as a 
form of polymorphism. In these cases there is little justification for 
putting the resident and anadromous life-history types into different 
conservation units.''
    Response: The fact that anadromous steelhead and resident rainbow 
trout are both part of the biological species taxonomists recognize as 
O. mykiss does not end the inquiry. The statute clearly contemplates 
listing subunits of species, by defining species to include 
``subspecies * * * and any distinct population segment of any species * 
* *'' The ESA does not define the term ``distinct population segment,'' 
but it is clearly a subset of a taxonomic species. Nor does the ESA 
refer to conservation units. While we agree with the Hey et al. panel's 
conclusion that co-occurring resident and anadromous O. mykiss are part 
of a larger conservation unit (which we would consider an ESU), that 
also is not the end of the inquiry. The joint DPS policy takes a 
somewhat different approach from the ESU policy to identifying 
conservation units, which may result, in some cases, in the 
identification of different conservation units. There are also other 
potential approaches to delineating a DPS for purposes of the ESA (see 
Waples, 2005, in press). For reasons described in response to Comment 
2, we are applying the DPS policy (see also the response to Comment 4 
for additional discussion).
    Comment 4: Some commenters felt that applying the DPS policy to O. 
mykiss should lead to the same result as the ESU policy, with the co-
occurring rainbow trout and steelhead being considered part of the same 
DPS. The commenters felt that our application of the DPS policy 
overemphasizes inconsistent and qualitative phenotypic characteristics, 
and ignores scientific information regarding reproductive exchange and 
genetic similarity. These commenters cited several empirical studies 
documenting that resident and anadromous O. mykiss are similar 
genetically when they co-occur with no physical barriers to migration 
or interbreeding, and that individuals can occasionally produce progeny 
of the alternate life-history form. The commenters felt that the DPS 
policy clearly contemplates considering reproductive isolation as part 
of evaluating discreteness. The commenters noted that the DPS policy 
states as part of the discreteness criterion that quantitative measures 
of

[[Page 838]]

genetic discontinuity may provide evidence of discreteness.
    The commenters also stressed that the ESA's definition of 
``species'' focuses solely on reproductive exchange. (section 3(16) of 
the ESA defines the term species as including any ``distinct population 
segment of any species of vertebrate fish or wildlife which interbreeds 
when mature''; emphasis added). The commenters argued that the 
additional considerations provided in the DPS policy (including marked 
separation as a consequence of physical, physiological, ecological, and 
behavioral factors) are supplemental to the primary consideration of 
reproductive isolation required under the ESA.
    Response: The ESA requirement that a group of organisms must 
interbreed when mature to qualify as a DPS is a necessary but not 
exclusive condition. Under the definition, although all organisms that 
belong to a DPS must interbreed when mature (at least on some time 
scale), not all organisms that share some reproductive exchange with 
members of the DPS must be included in the DPS. The DPS policy outlines 
other relevant considerations for determining whether a particular 
group should be delineated as a DPS (i.e., ``marked separation'' as a 
consequence of physical, physiological, ecological or behavioral 
factors).
    Although the DPS and ESU policies are consistent, they will not 
necessarily result in the same delineation of DPSs under the ESA. The 
statutory term ``distinct population segment'' is not used in the 
scientific literature and does not have a commonly understood meaning. 
NMFS' ESU policy and the joint DPS policy apply somewhat different 
criteria, with the result that their application may lead to different 
outcomes in some cases. The ESU policy relies on ``substantial 
reproductive isolation'' to delineate a group of organisms, and 
emphasizes the consideration of genetic and other relevant information 
in evaluating the level of reproductive exchange among potential ESU 
components. The DPS policy does not rely on reproductive isolation to 
determine ``discreteness,'' but on the marked separation of population 
groups as a consequence of biological factors.
    Despite the apparent reproductive exchange between resident and 
anadromous O. mykiss, the two life forms remain markedly separated 
physically, physiologically, ecologically, and behaviorally. Steelhead 
differ from resident rainbow trout physically in adult size and 
fecundity, physiologically by undergoing smoltification, ecologically 
in their preferred prey and principal predators, and behaviorally in 
their migratory strategy. Where the two life forms co-occur, adult 
steelhead typically range in size from 40-72 cm in length and 2-5 kg 
body mass, while adult rainbow trout typically range in size from 25-46 
cm in length and 0.5-2 kg body mass (Shapovalov and Taft, 1954; Wydoski 
and Whitney, 1979; Jones, 1984). Steelhead females produce 
approximately 2,500 to 10,000 eggs, and rainbow trout fecundity ranges 
from 700 to 4,000 eggs per female (Shapovalov and Taft, 1954; Buckley, 
1967; Moyle, 1976; McGregor, 1986; Pauley et al., 1986), with steelhead 
eggs being approximately twice the diameter of rainbow trout eggs or 
larger (Scott and Crossman, 1973; Wang, 1986; Tyler et al., 1996). 
Steelhead undergo a complex physiological change that enables them to 
make the transition from freshwater to saltwater (smoltification), 
while rainbow trout reside in freshwater throughout their entire life 
cycle. While juvenile and adult steelhead prey on euphausiid 
crustaceans, squid, herring, and other small fishes available in the 
marine environment, the diet of adult rainbow trout is primarily 
aquatic and terrestrial insects and their larvae, mollusks, amphipod 
crustaceans, fish eggs, and minnows (LeBrasseur, 1966; Scott and 
Crossman, 1973; Wydoski and Whitney, 1979). These differences in diet 
are a function of migratory behavior and the prey communities available 
to resident and anadromous O. mykiss in their respective environments. 
Finally, steelhead migrate several to hundreds of miles from their 
natal streams to the ocean, and spend up to 3 years in the ocean 
migrating thousands of miles before returning to freshwater to spawn 
(Busby et al., 1996). Some fluvial populations of rainbow trout may 
exhibit seasonal migrations of tens of kilometers outside of their 
natal watersheds, but rainbow trout generally remain associated with 
their natal drainages (Meka et al., 1999). Given the marked separation 
between the anadromous and resident life-history forms in physical, 
physiological, ecological, and behavioral factors, we conclude that the 
anadromous steelhead populations are discrete from the resident rainbow 
trout populations within the ranges of the DPSs under consideration.
    Comment 5: Several commenters were critical of the evidence we 
provided that co-occurring resident and anadromous O. mykiss are 
markedly separate (``discrete''). Commenters felt that we exaggerated 
and oversimplified the differences between anadromous and resident O. 
mykiss, and that much of the evidence presented in support of their 
``marked separation'' is not illustrative of traits unique to a given 
life-history form. The commenters felt that the majority of the 
phenotypic differences cited are inconsistent, overlap considerably 
between the two life forms, and are predominantly caused by 
environmental factors.
    Several commenters were critical of the physical factors we cited 
as evidence of marked separation between the two life forms. The 
commenters documented overlap in the size and fecundity ranges of 
resident and anadromous O. mykiss in the same watersheds, and concluded 
that our assertion that steelhead are generally larger and more fecund 
than rainbow trout does not hold true. The commenters felt that fish 
size and fecundity are largely a function of food supply, rather than 
being a trait inherent to anadromy. The commenters cited examples 
where, provided sufficient food resources, rainbow trout achieve 
similar sizes and fecundity as steelhead.
    Commenters were critical of the ecological factors we cited. The 
commenters felt that it is inappropriate to distinguish between the two 
forms on the basis of diet, as it is a function of prey availability in 
different environments rather than reflecting intrinsic differences in 
prey preference. They noted that when steelhead and rainbow trout are 
in the same freshwater environment, individuals of similar size and 
life-history stage have similar prey preferences.
    Commenters were critical of the behavioral factors we cited. The 
commenters argued that the two life forms are not ``markedly 
separated'' in terms of migratory behavior. The commenters cited 
several scientific studies documenting migratory behavior in non-
anadromous O. mykiss including: movement within a river system 
(potadromy); movement from lakes into rivers for spawning (limnodromy); 
and movement to the estuary/lagoon for growth and maturation (partial 
anadromy). Although commenters generally acknowledge that only the 
anadromous form migrates to the open ocean, they contended that this 
does not represent a truly discrete difference. The commenters 
described the life history of the O. mykiss species as a continuum of 
migratory behaviors, with anadromous and resident fish representing 
points on this continuum.
    Commenters were also critical of the physiological factors we 
cited. Commenters argued that resident and

[[Page 839]]

anadromous fish are not discrete physiologically throughout the 
majority of their life cycle, and smoltification is not entirely unique 
to anadromy. Commenters noted that some resident individuals may 
exhibit anadromy later in their life cycle, and other non-anadromous 
fish exhibit partial anadromy by migrating into estuaries for growth 
and maturation. Commenters also noted that some resident fish are 
capable of exhibiting anadromy later in their life cycle, as well as 
producing anadromous progeny that undergo smoltification.
    Response: The fact that there is an overlap between co-occurring 
steelhead and rainbow trout in the physical, ecological, behavioral and 
physiological factors does not prevent them from satisfying the 
discreteness criterion under the DPS policy. While the commenters are 
correct that O. mykiss display a continuum of traits in these 
categories, at the end of that continuum steelhead are markedly 
separate in their extreme marine migration (leading to, or resulting 
from, marked separation in the other factors). As we stated in adopting 
the DPS policy, ``the standard adopted [for discreteness] does not 
require absolute separation of a DPS from other members of its species, 
because this can rarely be demonstrated in nature for any population of 
organisms. * * * [T]he standard adopted allows for some limited 
interchange among population segments considered to be discrete, so 
that loss of an interstitial population could well have consequences 
for gene flow and demographic stability of a species as a whole'' (61 
FR 4722, at 4724; February 7, 1996).
    Similarly, the ESU policy does not require absolute reproductive 
isolation, only sufficient isolation to allow evolutionarily important 
differences to accumulate (56 FR 58612, at 58618; November 20, 1991). 
In delineating ESUs, we have recognized that straying leads to some 
reproductive exchange among ESUs (particularly among populations at the 
geographic margins between ESUs), that biological entities do not 
divide along clear lines, and that professional judgment is required in 
drawing a line at the geographic edge of an ESU. Even among well-
recognized taxonomic groupings, such as subspecies, there may be 
overlapping characteristics, and some reproductive exchange.
    In developing the DPS policy we answered concerns that discreteness 
was an inappropriate criterion for delineating DPSs: ``With regard to 
the discreteness standard, the Services believe that logic demands a 
distinct population recognized under the Act be circumscribed in some 
way that distinguishes it from other representatives of its species. 
The standard established for discreteness is simply an attempt to allow 
an entity given DPS status under the Act to be adequately defined and 
described'' (61 FR 4721, at 4724; February 7, 1996). In the case of 
steelhead, there is a group of organisms that can be clearly 
distinguished by a variety of characteristics, particularly its marine 
migration.
    With respect to the comment that resident and anadromous O. mykiss 
are genetically indistinguishable, we explained in adopting the DPS 
policy why we did not adopt genetic distinctness as the test of 
discreteness: ``The Services understand the Act to support interrelated 
goals of conserving genetic resources and maintaining natural systems 
and biodiversity over a representative portion of their historic 
occurrence. The draft policy was intended to recognize both these 
intentions, but without focusing on either to the exclusion of the 
other. Thus, evidence of genetic distinctness or of the presence of 
genetically determined traits may be important in recognizing some 
DPS's, but the draft policy was not intended to always specifically 
require this kind of evidence in order for a DPS to be recognized'' (61 
FR 4721, at 4723; February 7, 1996).
    Comment 6: Several commenters noted that in the June 2004 proposed 
listing determinations, resident populations included in O. mykiss ESUs 
were determined to have minor contributions to the viability of the 
ESUs. (In the proposed listing determinations we concluded that, 
despite the reduced risk to abundance for certain O. mykiss ESUs due to 
speculatively abundant rainbow trout populations, the collective 
contribution of the resident life-history form to the viability of an 
ESU as a whole is unknown and may not substantially reduce an ESU's 
risk of extinction (NMFS, 2004a; 69 FR 33102, June 14, 2004)). The 
commenters questioned why resident O. mykiss populations should be 
included in an ESU given that they have little, if any, contribution to 
the viability of the ESU.
    Response: Although we have concluded that resident O. mykiss should 
not be included as part of the delineated steelhead DPSs (see response 
to Comment 4), we disagree with the commenters' basic argument that DPS 
delineations should depend upon the extent to which a potential 
component population contributes to the viability of the DPS. A 
population's contribution to DPS viability meets neither the 
reproductive isolation test of the ESU policy, nor the marked 
separation test of the DPS policy. Using such a test would lead to 
illogical results given the metapopulation structure of salmon and 
steelhead, where some components of an ESU or a DPS will (on average) 
contribute more to its viability, while other components will 
contribute less. The persistence of components with comparatively 
weaker contributions to viability may even depend upon their 
connectivity with other more productive components of the delineated 
species. These weaker components may nevertheless contribute in other 
important ways such as by increasing spatial distribution and reducing 
risks due to catastrophic events, or by exhibiting important traits to 
diversity of the species and conserving its ability to adapt to future 
environmental conditions.
    Comment 7: One commenter asserted that we cannot apply the ESU 
policy in determining that resident and anadromous populations of O. 
mykiss are part of the same ESU, because NMFS does not have the legal 
jurisdiction under the ESA to list resident O. mykiss populations. The 
commenter noted that pursuant to the 1974 Memorandum of Understanding 
(MOU) regarding ESA jurisdictional responsibilities between FWS and 
NMFS, FWS has exercised ESA jurisdiction over resident O. mykiss, while 
NMFS has exercised jurisdiction over the anadromous life form.
    Response: The commenter correctly highlights the issue of shared 
NMFS-FWS jurisdiction for O. mykiss ESUs including both resident and 
anadromous populations. In its 1997 letter responding to NMFS' proposal 
to include rainbow trout in O. mykiss ESUs, FWS objected to the NMFS' 
proposal and concluded rainbow trout and steelhead should not be 
considered part of the same DPS. In its June 7, 2005, letter 
recommending that the final listing determinations for the 10 O. mykiss 
ESUs under review be extended, FWS requested that we ensure that our 
delineation of O. mykiss ESUs complies with the DPS Policy. We agree, 
in this case, that it is appropriate that we depart from our past 
practice of applying the ESU Policy to O. mykiss stocks, and instead 
apply the joint DPS Policy in determining ``species'' where we share 
jurisdiction with FWS. This is consistent with our application of the 
DPS policy to delineate species of Atlantic salmon (Salmo salar) (65 FR 
69459; November 17, 2000).
    Comment 8: Commenters felt that our proposed approach was 
inconsistent

[[Page 840]]

with previous NMFS and FWS DPS determinations for non-salmonid fish 
species, which focused on migration rates between populations, evidence 
of reproductive exchange, and genetic differences (e.g., NMFS-FWS Gulf 
of Maine DPS for Atlantic salmon, 65 FR 69459, November 17, 2000; NMFS' 
recent DPS determination for the Cherry Point stock of Pacific Herring, 
70 FR 33116, June 7, 2005). The Department of Interior (DOI) similarly 
expressed concern that the proposed approach may be inconsistent with 
its previous applications of the DPS policy for fish species under its 
jurisdiction (e.g., bull trout, Salvelinus confluentus, and coastal 
cutthroat trout O. clarki clarki). DOI offered a comparison with its 
1999 listing determination for the Coastal-Puget Sound bull trout DPS 
(50 FR 58910) in which the resident, migratory, anadromous, 
amphidromous, fluvial, and adfluvial life-history forms, despite 
exhibiting distinct life-history strategies, were not found to be 
discrete because they interbreed. DOI noted that NMFS' previous 
determinations concluded that the two life forms interbreed, and where 
they co-occur are genetically more similar than they are to the same 
life form in another basin. DOI and other commenters felt that 
regardless of any ``marked separation'' in phenotypic traits, the 
documented reproductive exchange and genetic similarity between 
anadromous and resident fish requires that they be included as parts of 
the same DPS.
    Response: The reference to our DPS determination for the Cherry 
Point stock of Pacific herring is inapposite, as we found that stock 
was discrete, but not significant. None of the commenters suggested 
that steelhead are insignificant to the O. mykiss species. 
Additionally, we disagree with the commenters that our finding 
regarding the discreteness criterion was based on evidence of 
reproductive exchange and genetic similarity rather than marked 
separation in biological factors. We determined that the Cherry Point 
herring stock was discrete despite evidence of migration and 
reproductive exchange with other herring stocks. We determined that the 
Cherry Point stock is markedly separated from other Pacific herring 
populations as a consequence of physical, physiological, ecological, or 
behavioral factors due to: (1) Its locally unique late spawn timing; 
(2) the locally unusual location of its spawning habitat on an exposed 
section of coastline; (3) its consistently large size-at-age and 
continued growth after maturation relative to other local herring 
stocks; and (4) its differential accumulation of toxic compounds 
relative to other local herring stocks, indicative of different rearing 
or migratory conditions for Cherry Point herring (70 FR 33116; June 7, 
2005).
    With respect to the Atlantic salmon, bull trout, and coastal 
cutthroat trout determinations, we acknowledge that their expression of 
a range of life histories may raise some of the same issues we 
confronted in delineating an anadromous-only DPS of O. mkyiss. We 
conclude, however, that there are important differences between O. 
mykiss and these species that warrant different treatment. In addition 
to expressing anadromy (the life-history pattern in which fish spend a 
large portion of their life cycle in the ocean and return to freshwater 
to breed), bull trout and coastal cutthroat trout express amphidromy 
(migration between fresh and salt water that is for feeding and 
overwintering, as well as breeding). While the anadromous and resident 
forms of O. mykiss differ clearly in ocean-migratory behavior and 
associated biological factors (see response to Comment 4), ocean-going 
migratory behavior and associated physical, physiological, and 
ecological factors are comparatively more variable among the life-
history forms and life stages of bull trout and coastal cutthroat trout 
given their expression of amphidromy.
    Comment 9: One commenter questioned whether the alternative 
approach of delineating and listing steelhead-only DPSs was 
permissible, given that the Alsea ruling held that the ESA does not 
allow listing a subset of a DPS. The commenter observed that in the 
past we had equated an ESU with the statutory ``distinct population 
segment,'' and we included resident and anadromous O. mykiss within the 
same ESU. The commenter argued that our past practice of applying the 
ESU policy had established what constitutes a DPS of O. mykiss, and 
that our proposal to not include resident populations in the listings 
for steelhead-only DPSs would violate the ESA.
    Response: The commenter is correct that in our past listing 
determinations we made the policy choice to equate an ESU with the 
statutory term ``distinct population segment.'' The commenter is not 
correct, however, in asserting that an ESU (as that concept may be 
understood by conservation biologists) must necessarily be equated with 
the statutory term ``distinct population segment.'' We conclude that in 
the case of O. mykiss, an ESU may contain more than one DPS, because 
the different life history components display marked separation 
sufficient to justify delineating them separately for protection under 
the ESA.
    While both the ESU and DPS policies represent permissible 
interpretations of the statutory term, we have decided that the best 
approach for O. mykiss is to apply the joint DPS policy (see the 
response to Comment 2). We have concluded that the proposed steelhead-
only DPSs meet the criteria defined under our joint DPS policy (as 
outlined in the response to Comment 4) and are consistent with the ESA.
    Comment 10: Two commenters were critical of our consideration of 
hatchery stocks in delineating steelhead DPSs. The commenters 
questioned whether our review of hatchery programs under the ESU policy 
(NMFS, 2003, 2004b, 2004c) directly informs considerations of 
``discreteness'' and ``significance'' under the DPS policy. The 
commenters felt that we failed to explain how including hatchery stocks 
as part of the delineated species comports with our proposed 
application of the DPS policy. The commenters felt that under the 
proposed approach of determining discreteness based on marked 
separation in phenotypic traits, it seems reasonable that hatchery 
stocks would be considered discrete regardless of the life history and 
genetic similarities documented in our hatchery reviews.
    Response: We disagree with the suggestion that application of the 
DPS rather than the ESU policy should lead to the universal conclusion 
that hatchery fish are not part of the same DPS as naturally spawning 
fish. We recognize that hatchery stocks, under some circumstances, may 
exhibit differences in physical, behavioral, and ecological traits; 
however, conservation hatchery stocks under certain circumstances may 
exhibit few appreciable differences from the local natural 
population(s). We think it is inappropriate to make universal 
conclusions about all hatchery stocks, but think their ``discreteness'' 
relative to local natural populations needs to be evaluated on a case-
by-case basis.
    In the Final Species Determinations section below, we discuss more 
fully how our June 2004 proposed ESU delineations inform our DPS 
delineations, in terms of geographic boundaries and in terms of which 
hatchery populations are part of the DPS. We acknowledge that our 
review of hatchery programs (NMFS, 2003, 2004b, 2004c) was conducted in 
the context of the ESU policy; however, we disagree that our findings 
and the information we evaluated do not inform our considerations of 
discreteness under the DPS policy. In evaluating the ``reproductive 
isolation'' of individual

[[Page 841]]

hatchery stocks in the context of the ESU policy, we lacked program-
specific genetic data. As reasonable indicators of reproductive 
isolation and genetic similarity we relied on information including 
hatchery broodstock origin, hatchery management practices (e.g., the 
timing and location of release), and hatchery stock life-history 
characteristics (e.g., spawn timing, the size and age at maturity) 
relative to the local natural populations. We conclude that this 
information directly informs evaluations of marked separation as a 
consequence of physical, physiological, ecological, or behavioral 
factors.
    Comment 11: Several commenters were critical of the proposed DPS 
delineations, asserting that they fail to provide a clearly 
distinguishable species delineation for the purposes of effectively and 
efficiently enforcing the ESA. The commenters were concerned that 
steelhead-only DPSs would generate confusion and have undesirable 
regulatory implications. Commenters noted that it is difficult if not 
impossible to distinguish between the two life forms throughout much of 
their life cycle when they co-occur. The commenters cited our June 2004 
proposed rule in which we state that ``no suite of morphological or 
genetic characteristics has been found that consistently distinguishes 
between the two life-history forms'' (69 FR 33102, at 33113; June 14, 
2004). Given the difficulty in distinguishing the two forms, commenters 
felt that we would either treat all juvenile resident O. mykiss as if 
they are listed, or we would deny needed protections for listed 
steelhead during the critical early life-history stages when they are 
indistinguishable from resident fish. Commenters felt that it will be 
impossible for us to quantify take of listed steelhead versus non-
listed rainbow trout, and questioned how we could analyze the impact of 
actions on listed steelhead without considering the potential 
production of steelhead progeny by resident fish. Some commenters felt 
that the lack of a clearly enforceable standard further argues that 
resident and anadromous O. mykiss are not ``markedly separated.''
    Response: As we acknowledged in our steelhead listings prior to the 
Alsea ruling, juvenile steelhead can be difficult to distinguish from 
resident rainbow trout. This does not dictate, however, that they 
should be included in the same DPS. The ESA authorizes prohibiting the 
take of an unlisted species if its appearance closely resembles that of 
a listed species (Section 4(e)). This is the tool that the ESA provides 
to deal with such situations where an unlisted species is difficult to 
distinguish from a listed one. In lieu of ``similarity of appearance'' 
protective regulations concerning resident trout that co-occur with 
listed steelhead stocks, the commenter is correct that we have presumed 
that all juvenile O. mykiss in streams where listed steelhead occur are 
listed juvenile steelhead. In a decade of implementing steelhead-only 
listings, we have confronted this issue successfully, working closely 
with state managers of rainbow trout fisheries to ensure their 
management of rainbow trout does not jeopardize steelhead. Continuing a 
listing of steelhead-only DPSs should not change that successful 
regulatory landscape.

Comments Regarding a Specific ESU or DPS: Determination of Species

Northern California and Central California Coast Steelhead
    Comment 12: Several commenters expressed support for the proposed 
clarification of the Northern California and Central California Coast 
steelhead DPS boundaries. We received no comments opposed to the 
proposed changes.
    Response: We have included these DPS boundary clarifications in the 
final species determinations (see Final Species Determinations section, 
below).
    Comment 13: Several commenters disagreed with our proposal to 
include above-barrier resident O. mykiss populations from upper Alameda 
Creek in the Central California Coast O. mykiss ESU. Other commenters 
felt that resident O. mykiss populations in the Livermore-Amador Valley 
also should not be included in the ESU. The commenters were critical of 
the genetic data and analysis upon which we based our proposal, and 
felt that genetic similarity alone was insufficient to support the 
inclusion of these above-dam resident populations in the ESU.
    Response: Under our final approach of delineating steelhead-only 
DPSs of O. mykiss, the resident populations, including those in Upper 
Alameda Creek and the Livermore-Amador Valley, are not considered part 
of the listed DPSs.
California Central Valley Steelhead
    Comment 14: The California Department of Fish and Game (CDFG) 
disagreed with the defined spatial structure of the Central Valley O. 
mykiss ESU. It argued that the ESU should be split into two parts: one 
part north of the Sacramento-San Joaquin River Delta, and a second part 
that includes the Delta and the San Joaquin Basin. CDFG based its 
alternative ESU structure in large part on habitat conditions in the 
Delta, which it contends serve to reproductively isolate fish from the 
Sacramento and San Joaquin basins.
    Comments submitted during the 6-month extension by the California-
Nevada Chapter of the American Fisheries Society (AFS) disagreed with 
CDFG's recommended species determination. AFS scientists argued that 
the purported physical barrier to reproduction between the two basins 
(low dissolved oxygen levels in the lower San Joaquin River) is 
indicative of the severely degraded habitat conditions in the San 
Joaquin river system, but represents an ephemeral distributional 
barrier and not a substantial reproductive barrier. AFS scientists 
cited a recent genetic study that found no genetic differentiation 
between populations in the two basins, and concluded that there is no 
scientific basis for recognizing a distinction between the two river 
systems.
    Response: We disagree with CDFG and believe we have correctly 
defined the spatial extent of the California Central Valley steelhead 
DPS. Previous genetic analyses indicate that Central Valley steelhead 
are distinct from coastal populations (see Busby et al., 1996). More 
recent genetic data (Nielsen et al., 2003) suggest that significant 
genetic population structure remains for steelhead populations in the 
Central Valley, but that very little of the genetic variation can be 
attributed to differences between populations in the Sacramento and San 
Joaquin river drainages. Ecologically, the Central Valley is 
substantially different from ecoregions inhabited by coastal O. mykiss 
populations, and ecological conditions in the Central Valley are 
generally similar between the Sacramento and San Joaquin river basins. 
Low dissolved oxygen conditions in the Stockton Deep Water Ship Channel 
and along other reaches of the lower San Joaquin River are problematic, 
and may serve to limit anadromous fish migration under certain 
conditions and times. However, we do not believe this ephemeral barrier 
results in reproductive isolation between populations of O. mykiss in 
the Sacramento and San Joaquin river basins, as evidenced by the 
available genetic information. In our view, the available genetic and 
ecological information indicates that steelhead populations in the 
Sacramento and San Joaquin river basins are not discrete and 
collectively are significant to the O. mykiss species, and therefore 
constitute a single DPS.

[[Page 842]]

Snake River Basin Steelhead
    Comment 15: Several commenters in Idaho disagreed with including 
the population of rainbow trout above Dworshak Dam on the North Fork 
Clearwater River (Idaho) in the Snake River Basin O. mykiss ESU. The 
commenters felt that resident O. mykiss above Dworshak Dam likely 
represent a composite of past hatchery stocking programs, hybridization 
with cutthroat trout, and native O. mykiss, and as such there is 
insufficient information to justify including the entire population of 
resident O. mykiss above Dworshak Dam in the Snake River Basin O. 
mykiss ESU.
    Response: As noted in the response to Comment 13, resident 
populations, including above Dworshak Dam, are not part of the listed 
DPS.

General Comments on the Consideration of Resident O. mykiss: Assessment 
of Extinction Risk

    Comment 16: Several commenters noted that we did not address the 
ESU membership of, or consider the potential risks and benefits to the 
viability of an ESU from, rainbow trout hatchery programs in the 
proposed listing determinations for O. mykiss ESUs. The commenters 
asserted that the vast majority of rainbow trout hatchery programs 
propagate domesticated, non-native, and in some instances genetically 
modified rainbow trout. The commenters felt that in some O. mykiss 
ESUs, such as the Snake River Basin and Upper Columbia River O. mykiss 
ESUs, the negative impacts of hatchery rainbow trout on native O. 
mykiss populations may be profound.
    Response: We agree with the commenters that resident trout hatchery 
programs were not inventoried and assessed as part of the proposed 
listing determinations. In response, we conducted an inventory and 
assessment of hatchery programs that release rainbow trout in areas 
where steelhead or co-occurring native rainbow trout might be affected 
(NMFS, 2004b, 2005a). We have found that few hatchery rainbow trout 
stocks are released in the spawning and rearing areas for the O. mykiss 
ESUs under review. State and tribal managers have adopted wild salmonid 
policies that have largely eliminated releases of hatchery-produced 
rainbow trout in waters important to wild steelhead. Since the ESA 
listings of steelhead in 1997-2000, the vast majority of hatchery 
rainbow trout releases to support recreational fisheries are restricted 
to isolated ponds and lakes. Of the hatchery rainbow trout that are 
released, none are stocks that would be considered part of the O. 
mykiss ESUs reviewed. In the few instances where domesticated or 
genetically modified rainbow trout stocks are released into anadromous 
waters to support recreational fisheries, they likely do not have 
substantial adverse impacts on the local O. mykiss populations. The 
released stocks exhibit poor survival, are subject to high harvest 
rates in the recreational fisheries, and exhibit spawn timing isolating 
them reproductively from the local natural populations. In some 
instances, sterile ``triploid'' rainbow trout are released into 
anadromous waters, thereby eliminating the possibility for reproductive 
or genetic exchange with wild fish.
    Comment 17: Some commenters contended that the District Court in 
Alsea ruled that once an ESU is defined, risk determinations should not 
discriminate among its components. The commenters described the risk of 
extinction as the chance that there will be no living representative of 
the species, and that such a consideration must not be biased toward a 
specific behavioral or life-history component. A few commenters felt 
that populations of rainbow trout have persisted in isolation over long 
periods of time, demonstrating that resident representatives of an O. 
mykiss ESU would persist in the foreseeable future, even if the 
anadromous life-history form was extirpated.
    Response: We disagree that the Alsea ruling requires a particular 
approach to assessing extinction risk. The court ruled that if it is 
determined that a DPS warrants listing, all members of the defined 
species must be included in the listing. The court did not