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(iv) Location: 100-Yard Zone. All 40°51′07.9″ N, 073°48′16.8″ W, thence to ACTION: Notice of petition finding. waters of Jamaica Bay within 40°50′54.9″ N, 073°48′09.0″ W, thence to approximately 100 yards of John F. 40°50′49.7″ N, 073°48′03.6″ W, thence to SUMMARY: We, the Fish and Wildlife Kennedy Airport bound by the 40°50′50.1″ N, 073°47′57.9″ W, thence to Service (Service), announce our following points: Onshore east of Bergen 40°51′04.6″ N, 073°47′48.9″ W, thence to reconsidered 12-month finding for an Basin, Queens in approximate position 40°51′15.9″ N, 073°47′48.4″ W, thence to amended petition to list the westslope 40°38′49.0″ N, 073°49′09.1″ W, thence to 40°51′23.5″ N, 073°47′41.9″ W, (NAD cutthroat trout (WCT) (Oncorhynchus 40°38′45.1″ N, 073°49′11.6″ W, thence to 1983) thence southwesterly along the clarki lewisi) as a threatened species 40°38′02.0″ N, 073°47′31.8″ W, thence to shoreline to the point of origin. throughout its range in the United 40°37′52.3″ N, 073°47′55.0″ W, thence to (iii) Enforcement period. The zones States, pursuant to a Court order and the 40°37′50.3″ N, 073°47′53.5″ W, thence to described in paragraph (a)(9) of this Endangered Species Act (Act) of 1973, 40°38′00.8″ N, 073°47′29.4″ W, thence to section will be effective at all times. as amended. After a thorough review of 40°37′47.4″ N, 073°47′02.4″ W, thence to When port security conditions permit, all available scientific and commercial 40°37′19.9″ N, 073°47′25.0″ W, thence to the Captain of the Port will allow information, we find that listing the 40°37′10.0″ N, 073°47′03.7″ W, thence to vessels to operate within that portion of WCT as either threatened or endangered 40°37′37.7″ N, 073°46′41.2″ W, thence to the waters described in paragraph is not warranted at this time. Also 40°37′22.6″ N, 073°46′21.9″ W, thence to (a)(9)(i) that lies outside of the waters pursuant to the Court order, we assert 40°37′05.7″ N, 073°46′34.9″ W, thence to described in paragraph (a)(9)(ii). our scientifically-based conclusion 40°36′54.8″ N, 073°46′26.7″ W, thence to Authorization to enter the waters that about the extent to which it is 40°37′14.1″ N, 073°46′10.8″ W, thence to lie between the outer boundaries of the appropriate to include ‘‘hybrid’’ WCT 40°37′40.0″ N, 073°45′55.6″ W, thence to zones described in paragraphs (a)(9)(i) populations and populations of 40°38′02.8″ N, 073°44′57.5″ W, thence to and (a)(9)(ii) will be communicated by unknown genetic characteristics in the 40°38′05.1″ N, 073°45′00.3″ W, (NAD the Captain of the Port to the public by taxonomic group that we considered for 1983) thence along the shoreline to the marine broadcast, local notice to listing. point of origin. mariners, or notice posted at http:// DATES: The finding announced in this (v) Enforcement period. The zones www.harborops.com. document was made on August 1, 2003. (10) Port Newark/Port Elizabeth, described in paragraphs (a)(8) of this ADDRESSES: Data, information, section will be effective at all times. Newark Bay, NJ. All waters of Newark comments, or questions regarding this When port security conditions permit, Bay bound by the following points: ° ′ ″ ° ′ ″ document should be sent to the Chief, the Captain of the Port will allow 40 41 49.9 N, 074 07 32.2 W, thence to Branch of Native Fishes Management, 40°41′46.5″ N, 074°07′20.4″ W, thence to vessels to operate within that portion of U.S. Fish and Wildlife Service, Montana 40°41′10.7″ N, 074°07′45.9″ W, thence to the waters described in paragraph Fish and Wildlife Management 40°40′54.3″ N, 074°07′55.7″ W, thence to (a)(8)(iii) that lies outside of the waters Assistance Office, 4052 Bridger Canyon 40°40′36.2″ N, 074°08′03.8″ W, thence to described in paragraph (a)(8)(iv). Road, Bozeman, Montana 59715. The 40°40′29.1″ N, 074°08′06.3″ W, thence to Authorization to enter the waters that complete administrative file for this 40°40′21.9″ N, 074°08′10.0″ W, thence to lie between the outer boundaries of the finding is available for inspection, by 40°39′27.9″ N, 074°08′43.6″ W, thence to zones described in paragraphs (a)(8)(iii) appointment and during normal 40°39′21.5″ N, 074°08′50.1″ W, thence to and (a)(8)(iv) will be communicated by business hours, at the above address. the Captain of the Port to the public by 40°39′21.5″ N, 074°09′54.3″ W, (NAD The new petition finding, the status marine broadcast, local notice to 1983) thence northerly along the update report for WCT, the amended mariners, or notice posted at http:// shoreline to the point of origin. petition and its bibliography, our initial www.harborops.com. (11) Global Marine Terminal, Upper (9) NYPD Ammunition Depot, New York Bay. All waters of Upper New status review document and petition Rodman Neck, Eastchester Bay, NY. (i) York Bay between the Global Marine finding, related Federal Register Location: 150-Yard Zone. All waters of and Military Ocean Terminals, west of notices, the Court Order and Judgement Eastchester Bay within approximately the New Jersey Pierhead Channel. and Memorandum Opinion, and other pertinent information, may be obtained 150 yards of Rodman Neck bound by the * * * * * following points: Onshore in at our Internet Web site: http:// Dated: July 14, 2003. approximate position 40°51′30.4″ N, mountain-prairie.fws.gov/endspp/fish/ 073°48′14.9″ W, thence to 40°51′29.9″ N, C.E. Bone, wct/. 073°48′20.7″ W, thence to 40°51′16.9″ N, Captain, U.S. Coast Guard, Captain of the FOR FURTHER INFORMATION CONTACT: 073°48′22.5″ W, thence to 40°51′07.5″ N, Port, New York. Lynn R. Kaeding, by e-mail 073°48′18.7″ W, thence to 40°50′54.2″ N, [FR Doc. 03–20023 Filed 8–6–03; 8:45 am] ([email protected]) or telephone 073°48′11.1″ W, thence to 40°50′48.5″ N, BILLING CODE 4910–15–P (406–582–0717). 073°48′04.6″ W, thence to 40°50′49.2″ N, SUPPLEMENTARY INFORMATION: 073°47′56.5″ W, thence to 40°51′03.6″ N, Background 073°47′47.3″ W, thence to 40°51′15.7″ N, DEPARTMENT OF THE INTERIOR 073°47′46.8″ W, thence to 40°51′23.5″ N, Section 4(b)(3)(B) of the Endangered 073°47′41.9″ W, (NAD 1983) thence Fish and Wildlife Service Species Act of 1973 (Act), as amended southwesterly along the shoreline to the (16 U.S.C. 1531 et seq.), requires that point of origin. 50 CFR Part 17 within 90 days of receipt of the petition, (ii) Location: 100-Yard Zone. All Endangered and Threatened Wildlife to the maximum extent practicable, we waters of Eastchester Bay within and Plants: Reconsidered Finding for make a finding on whether a petition to approximately 100 yards of Rodman an Amended Petition To List the list, delist, or reclassify a species Neck bound by the following points: Westslope Cutthroat Trout as presents substantial scientific or Onshore in approximate position Threatened Throughout Its Range commercial information indicating that 40°51′30.4″ N, 073°48′14.9″ W, thence to the requested action may be warranted. 40°51′30.1″ N, 073°48′19.0″ W, thence to AGENCY: Fish and Wildlife Service, The term ‘‘species’’ includes any 40°51′16.8″ N, 073°48′20.5″ W, thence to Interior. subspecies of fish or wildlife or plants,

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and any Distinct Population Segment distribution of WCT also includes indicated that WCT then occurred in (DPS) of any species of vertebrate fish or disjunct areas draining the east slope of about 4,275 tributaries or stream reaches wildlife that interbreeds when mature. If the Cascade Mountains in Washington that collectively encompassed more the petition contains substantial (Methow River and Lake Chelan than 37,015 kilometers (km) (23,000 information, the Act requires that we drainages, and perhaps the Wenatchee miles [mi]) of stream habitat. Those initiate a status review for the species and Entiat River drainages), the John WCT were distributed among 12 major and publish a 12-month finding Day River drainage in northeastern drainages and 62 component watersheds indicating that the petitioned action is Oregon, and the headwaters of the in the Columbia, Missouri, and either: (a) Not warranted, (b) warranted, Kootenai River and several other Saskatchewan River basins. In addition, or (c) warranted but precluded from disjunct regions in British Columbia. WCT were determined to naturally immediate listing proposal by other East of the Continental Divide, the occur in 6 lakes totaling about 72,843 pending proposals of higher priority. A historic distribution of WCT is believed hectares (ha) (180,000 acres [ac]) in notice of such 12-month findings is to to include the headwaters of the South Idaho and Washington and in at least 20 be published promptly in the Federal Saskatchewan River drainage (United lakes totaling 2,164 ha (5,347 ac) in Register. States and Canada); the entire Missouri Glacier National Park in Montana. That On June 6, 1997, we received a River drainage upstream from Fort status review also revealed that most of petition to list the WCT (Oncorhynchus Benton, Montana, and extending into the habitat for extant WCT was on lands clarki lewisi) as threatened throughout northwest Wyoming; and the administered by Federal agencies, its range and designate critical habitat headwaters of the Judith, Milk, and particularly the U.S. Forest Service. for this subspecies of fish pursuant to Marias Rivers, which join the Missouri Moreover, most of the strongholds for the Act. The petitioners were American River downstream from Fort Benton. WCT were within roadless or Wildlands, Clearwater Biodiversity wilderness areas or national parks, all of Previous Federal Actions Project, Idaho Watersheds Project, which afforded considerable protection Montana Environmental Information On July 2, 1997, we notified the to WCT. Finally, the status review Center, the Pacific Rivers Council, Trout petitioners that our Final Listing indicated that there were numerous Unlimited’s Madison-Gallatin Chapter, Priority Guidance, published in the Federal and State regulatory and Mr. Bud Lilly. December 5, 1996, Federal Register (61 mechanisms that protected WCT and The WCT is 1 of 14 subspecies of FR 64425), designated the processing of their habitats throughout the subspecies’ cutthroat trout native to interior regions new listing petitions as being of lower range. of western North America (Behnke priority than were the completion of On April 14, 2000, we published a 1992, 2002). Cutthroat trout owe their emergency listings and processing of notice (65 FR 20120) of our finding that common name to the distinctive red or pending proposed listings. A backlog of the WCT is not likely to become either orange slash mark that occurs just below listing actions, as well as personnel and a threatened or an endangered species both sides of the lower jaw. Adult WCT budget restrictions in our Region 6 within the foreseeable future. We also typically exhibit bright yellow, orange, (Mountain-Prairie Region), which had found that, although the abundance of and red colors, especially among males been assigned primary responsibility for the WCT subspecies had been reduced during the spawning season. the WCT petition, prevented our staff from historic levels and its extant Characteristics of WCT that distinguish from working on a 90-day finding for populations faced threats in several this fish from the other subspecies of the petition. areas of the historic range, the cutthroat trout include a pattern of On January 25, 1998, the petitioners magnitude and imminence of those irregularly shaped spots on the body, submitted an amended petition to list threats were small when considered in with few spots below the lateral line the WCT as threatened throughout its the context of the overall status and except near the tail; a unique number of range and designate critical habitat for widespread distribution of the WCT chromosomes; and other genetic and the subspecies. The amended petition subspecies. Therefore, we concluded morphological traits that appear to contained additional new information that listing the WCT as either a reflect a distinct evolutionary lineage in support of the requested action. threatened or an endangered species (Behnke 1992). Consequently, we treated the amended under the Act was not warranted at that Although its extent is not precisely petition as a new petition. time. known, the historic (i.e., native) range of On June 10, 1998, we published a On October 23, 2000, plaintiffs filed, WCT is considered the most notice (63 FR 31691) of a 90-day finding in the U.S. District Court for the District geographically widespread among the that the amended WCT petition of Columbia, a suit alleging four claims. 14 subspecies of inland cutthroat trout provided substantial information They alleged that our consideration of (Behnke 1992). West of the Continental indicating that the requested action may existing regulatory mechanisms was Divide, the subspecies is believed to be be warranted and immediately began a arbitrary. Plaintiffs further claimed that native to several major drainages of the comprehensive status review for WCT. our consideration of hybridization as a Columbia River basin, including the In the notice, we asked for data, threat to WCT was arbitrary because, upper Kootenai River drainage from its information, technical critiques, while identifying hybridization as a headwaters in British Columbia, comments, and questions relevant to the threat to WCT, we relied on a draft through northwest Montana, and into amended petition. Intercross policy (61 FR 4710) to northern Idaho; the Clark Fork River In response to that notice, we received include hybridized WCT in the WCT drainage of Montana and Idaho information on WCT from State fish and subspecies that we considered for listing downstream to the falls on the Pend wildlife agencies, the U.S. Forest under the Act. Their third claim averred Oreille River near the Washington- Service, National Park Service, tribal that we arbitrarily considered the British Columbia border; the Spokane governments, and private corporations, threats to WCT posed by the geographic River above Spokane Falls and into as well as private citizens, isolation of some WCT populations and Idaho’s Coeur d’Alene and St. Joe River organizations, and other entities. That the loss of some WCT life-history forms. drainages; and the Salmon and information, subsequently compiled in a Finally, plaintiffs claimed that we failed Clearwater River drainages of Idaho’s comprehensive status review document to account for the threat of whirling Snake River basin. The historic (U.S. Fish and Wildlife Service 1999), disease and other important factors, and

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that our decision to not list the WCT as During the subsequent comment important evolutionary mechanism for threatened was arbitrary and capricious. period, we received written requests for the origin of new species of plants In the subsequent oral argument before an extension of that period from the fish (Rieseberg 1997). Conversely, natural the Court, plaintiffs conceded that their and wildlife agencies of the States of hybridization has only recently been strongest argument, and the one from Washington, Oregon, Idaho, and recognized as an important evolutionary which their other concerns stemmed, Montana, as well as the Kalispel Tribe mechanism for the origin of new species was that we included hybridized fish in of Indians and the Earthjustice Legal of animals (Dowling and Secor 1997). the WCT subspecies considered for Foundation. In their letters, those Natural hybridization is now listing under the Act, while also entities indicated that they were acknowledged as an important recognizing hybridization as a threat to assembling or awaiting important evolutionary mechanism that: (a) the subspecies. The hybridization threat information relevant to the status of Creates new genotypic diversity, (b) can to WCT is posed by certain nonnative WCT and that those entities wanted to lead to new, adaptive phenotypes, and fishes that management agencies and make such information available to us (c) can yield new species (Arnold 1997). other entities stocked into streams and for use in the new status review. Hybridization also can result in the lakes in many regions of the historic Accordingly, on December 18, 2002, we extinction of populations and species range of WCT, beginning more than 100 announced (67 FR 77466) that the (Rhymer and Simberloff 1996). Indeed, years ago. Subsequently, those comment period was reopened until hybridization resulting from nonnative fishes or their hybrid February 15, 2003. anthropogenic factors is considered a descendants became self-sustaining For the purposes of this listing threat to many species of fish (Campton populations and remain as such today. determination, ‘‘WCT subspecies’’ refers 1987; Verspoor and Hammar 1991; On March 31, 2002, the U.S. District explicitly to all populations of WCT Leary et al. 1995; Childs et al. 1996; Court for the District of Columbia found within the international boundaries of Echelle and Echelle 1997). In particular, that our listing determination for WCT the United States, although populations the extensive stocking of rainbow trout did not reflect a reasoned assessment of of WCT also occur in Canada. As part (O. mykiss) outside their native the Act’s statutory listing factors on the of this listing determination, the WCT geographic range has resulted in basis of the best available science. The subspecies many be found to consist of appreciable hybridization with other Court remanded the listing decision to DPSs, as described in a subsequent species of trout (Bartley and Gall 1991; us with the order that we reconsider section of this finding. Behnke 1992, 2002; Dowling and Childs whether to list the WCT as a threatened 1992; Carmichael et al. 1993). This The Value of Hybrid Westslope species, and that in so doing we interbreeding also has occurred for WCT Cutthroat Trout in Listing evaluate the threat of hybridization as it where natural hybridization with Determinations bears on the Act’s statutory listing introduced rainbow trout and factors. Specifically, the Court ordered As described in the preceding section, Yellowstone cutthroat trout (O. c. us to determine: (1) The current the U.S. District Court for the District of bouvieri; YCT) is considered a threat to distribution of WCT, taking into account Columbia ruled that the Service must the WCT subspecies (see subsequent the prevalence of hybridization; (2) provide a scientifically-based section, Hybridization with Nonnative whether the WCT population (i.e., conclusion about the extent to which it Fishes). subspecies, as used in the present is appropriate to include ‘‘hybrid WCT Hybridization also can result in the document) is an endangered or a stocks’’ and ‘‘stocks of unknown genetic genetic introgression of genes from one threatened species because of characteristics’’ in the WCT subspecies species into populations of another hybridization; and (3) whether existing considered for listing. We herewith species if F1 (i.e., the first filial regulatory mechanisms are adequate to respond to the Court. generation) and F2 hybrids are fertile address the threats posed by In the past, natural hybridization and can interbreed, or backcross, with hybridizing, nonnative fishes. between congeneric or closely-related individuals of a parental species. For The Court also pointed out that the species of fish was thought to be rare. example, first-generation hybrids draft Intercross policy (61 FR 4710; However, during the first half of the between WCT and rainbow trout appear February 7, 1996) in no way indicates 20th Century, Professor Carl Hubbs and to be fully fertile (Ferguson et al. 1985), what degree of hybridization would his associates demonstrated that natural and levels of genetic introgression or threaten WCT, or that the existing levels hybridization between morphologically ‘‘admixture’’ vary widely (<1 to >50 of hybridization do not presently distinct species, particularly for percent) among natural populations of threaten WCT. Furthermore, the Court temperate-zone freshwater fishes in WCT (e.g., Weigel et al. 2002). In this directed the Service to present a North America, was common in areas context, admixture refers to the scientifically-based conclusion about where the geographic ranges of those percentage of a population’s gene pool the extent to which it is appropriate to species overlap (Hubbs 1955). Such derived from rainbow trout genes (or include hybrid WCT stocks (i.e., natural hybridization may be especially alleles) versus WCT trout genes. In these populations, as used in the present common among centrarchid (basses and latter situations, the Service must document) and populations of unknown sunfishes) and cyprinid (minnows) determine which populations represent genetic characteristics in the WCT fishes in the central United States WCT, and the genetic resources of WCT, subspecies considered for listing. (Avise and Saunders 1984; Dowling and under the Act and which populations On September 3, 2002, we announced Secor 1997). threaten the continued existence of the (67 FR 56257) initiation of a new status Many investigators have subsequently WCT subspecies. review for the WCT and solicited demonstrated that several extant species The purpose of the Act is to conserve comments from all interested parties of fish most likely originated from the threatened and endangered ‘‘species’’ regarding the present-day status of this interbreeding of two or more ancestral and the ecosystems on which those fish. We were particularly interested in or extant species (Meagher and Dowling species depend. The definition of receiving data, information, technical 1991; DeMarais et al. 1992; Gerber et al. ‘‘species’’ under the Act includes any critiques, and relevant comments that 2001). Indeed, natural hybridization taxonomic species or subspecies, and would help us to address the issues that between taxonomically distinct species ‘‘distinct population segments’’ of had been raised by the Court. has long been recognized as an vertebrate species. The issue here for

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this status review is not the definition Campton and Utter (1985) used memorandum (Memorandum from of ‘‘species’’ under the Act, but rather, allozymes (proteins) to first document Assistant Solicitor for Fish and Wildlife, the scientific criteria used by the incidence of natural hybridization U.S. Department of the Interior, to professional zoologists and field between naturally sympatric Director, U.S. Fish and Wildlife Service, biologists to taxonomically classify populations of coastal cutthroat trout dated December 14, 1990): ‘‘New individuals, and populations of (O. c. clarki) and rainbow trout/ scientific information concerning interbreeding individuals, as members steelhead (O. mykiss), although earlier genetic introgression has convinced us of a particular species or subspecies. morphological descriptions had that the rigid standards set out in those The scientific criteria for describing suggested such interbreeding was previous opinions should be revisited. and formally recognizing taxonomic occurring (DeWitt 1954; Hartman and In our view, the issue of ‘‘hybrids’’ is species of fish are based almost entirely Gill 1968). The sensitivity of the more properly a biological issue than a on morphological characters (Behnke molecular genetic data simply provided legal one.’’ 1992; Bond 1996; Moyle and Cech compelling evidence that interbreeding Our increasing understanding of the 1996). Indeed, the scientific basis for was indeed occurring. wide range of possible outcomes distinguishing rainbow trout and In general, molecular genetic methods resulting from exchanges of genetic cutthroat trout (O. clarki) as distinct are capable of detecting extremely small material between taxonomically distinct species are well-established differences amounts of genetic introgression (e.g., species, and between entities within in the number of scales in the lateral- <1 percent) undetectable by other taxonomic species that also can be listed line series, spotting patterns on the methods (Weigel et al. 2002; see also under the Act (i.e., subspecies, DPSs), sides of the body, and the presence of: Fig. 2 of Kanda et al. 2002). For requires the Service to address these (a) Basibranchial teeth (i.e., teeth on a example, a large number of situations situations on a case-by-case basis. In series of bones behind the tongue and exist in the scientific literature where some cases, introgressive hybridization between the gills) and (b) a distinctive the mitochondrial DNA (mtDNA) from may be considered a natural red or orange slash mark that occurs just one species appears to have introgressed evolutionary process reflecting active below both sides of the lower jaw in via hybridization into the nuclear speciation or simple gene exchange cutthroat trout but not in rainbow trout genetic background of a closely related between naturally sympatric species. In (Miller 1950). Morphological species (e.g., Ferris et al. 1983; other cases, hybridization may be differences, particularly external Bernatchez et al. 1995; Glemet et al. threatening the continued existence of a spotting patterns, also distinguish 1998; Wilson and Bernatchez 1998; taxon due to anthropogenic factors or subspecies of cutthroat trout (Behnke Redenbach and Taylor 2002). This natural environmental events. In many 1992). These morphological differences ability to detect very low levels of cases, introgressed populations may among cutthroat trout subspecies are introgression raises fundamental contain unique or appreciable portions consistent with their distinct, questions regarding the criteria by of the genetic resources of an imperiled geographic distributions (e.g., which introgressed populations, and or listed species. For example, Yellowstone [River] vs. Lahontan [basin] individuals in those populations, populations with genes from another cutthroat trout [O. c. henshawi]). In should be included with, or excluded taxon at very low frequencies may still addition, the common names of the from, their parental or morphological express important behavioral, life- various species of trout clearly reflect species. In the mtDNA situations cited history, or ecological adaptations of the their distinctive morphological above, the scientific community appearances, e.g., rainbow trout, considers the ‘‘introgressed’’ individuals indigenous population or species within redband trout (O. m. gairdneri), to be legitimate members of their a particular geographic area. cutthroat trout, and golden trout (O. m. morphological species despite the Consequently, the Service plans to aguabonita) (Behnke 2002). presence of mtDNA from another carefully evaluate the long-term The advent of molecular genetic species. Similarly, individuals of a conservation implications for each techniques in the mid-1960s added an particular ‘‘species’’ may possess taxon separately on a case-by-case basis additional set of biological characters nuclear genes from another taxon where introgressive hybridization may that can be used to distinguish species detectable only by molecular genetic have occurred. The Service shall and subspecies of native trouts methods, yet those individuals may still perform these evaluations objectively (Oncorhynchus spp.) in the western conform morphologically, behaviorally, based on the best scientific and United States. In most cases, the new and ecologically to the scientific commercial information available molecular genetic data simply taxonomic description of the parental or consistent with the intent and purpose confirmed the evolutionary distinctness native species (e.g., Busack and Gall of the Act. of species and subspecies that had 1981; Weigel et al. 2002). For example, the Service may already been described taxonomically Previous Service positions regarding recognize that small amounts of genetic on the basis of morphology (Behnke hybridization, based upon introgression do not disqualify 1992). One notable exception was the interpretations in a series of opinions by individuals or populations from failure of molecular genetic techniques the U.S. Department of the Interior, ‘‘species membership’’ or the Act’s to distinguish fine-spotted Snake River Office of the Solicitor, generally protections if those individuals or cutthroat trout (O. c. subsp.) and YCT as precluded conservation efforts under populations conform to the scientific two evolutionarily distinct forms the authorities of the Act for progeny, or taxonomic description of that species. A (Loudenslager and Kitchen 1979). their descendants, produced by matings natural population of a particular Although molecular genetic data have between taxonomic species or species that possesses genes from had little impact on the taxonomic subspecies (O’Brien and Mayr 1991). another taxon at low frequency, yet recognition of rainbow trout, cutthroat However, advances in biological retains the distinguishing trout, and their respective subspecies, understanding of natural hybridization morphological, behavioral, and molecular genetic markers are very (e.g., Arnold 1997) prompted ecological characters of the native sensitive tools for detecting natural withdrawal of those opinions. The species, may remain very valuable to the hybridization and small amounts of reasons for that action were summarized overall conservation and survival of that genetic introgression. For example, in two sentences in the withdrawal species.

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The Service also recognizes special regardless of whether the cause is genetic introgression in natural cases where all individuals of a anthropogenic or ‘‘natural.’’ Both populations of WCT. In that study, ‘‘species’’ are considered hybrids. For natural evolutionary processes, Weigel et al. (2002) compared variation example, the Service recognizes that including catastrophic environmental in morphological characters to nuclear deliberate hybridization may be events (e.g., floods, earthquakes), and DNA genotypes at 16 dominant marker necessary in extreme cases to prevent anthropogenic factors can lead to loci (Spruell et al. 1999, 2001) in extinction of the genetic resources secondary contact and hybridization random samples of 20 trout from each associated with a highly endangered between species. Also, distinguishing of 100 sites in the Clearwater and species, as was the case for the Florida between anthropogenic and natural Lochsa River drainages in Idaho. In that panther (Felis concolor coryi) (Hedrick causes of hybridization, particularly for study, the presence of at least 1 rainbow 1995). Similarly, the Service continues species with naturally overlapping trout DNA marker among the 20 to protect red wolves (Canis rufus) geographic ranges, may be extremely individuals tested at a particular site under the Act despite ongoing difficult (e.g., Campton and Utter 1985; was accepted as evidence that genetic controversies regarding their possible Young et al. 2001; Baker et al. 2002). A introgression had occurred in the native hybrid origin (Nowak and Federoff complicating issue in these WCT population inhabiting that site. 1998). In both of those cases, extending determinations is the degree to which According to the authors, their DNA the Act’s jurisdictions and protections ‘‘natural’’ hybridization may have methods and sample sizes (n = 20) to ‘‘hybrids’’ may contribute to the compromised the identity of a distinct allowed them to achieve 95 percent conservation of the genetic resources of species prior to anthropogenic confidence (probability) of detecting those taxa, consistent with the intent influences (e.g., Weigel et al. 2002). The genetic introgression in WCT and purpose of the Act. principal issues here under the Act are populations with as little as 1 percent A potential dichotomy thus exists the threats and potential outcomes of rainbow (or redband) trout genes. under the Act between: (a) The need to hybridization, including other potential However, because those authors used protect the genetic resources of a species risks associated with the five statutory ‘‘dominant’’ genetic markers, they could in which introgression has occurred and listing factors (e.g., habitat loss, disease), not distinguish heterozygotes from (b) the need to minimize or eliminate and not necessarily the mechanistic homozygotes, thus precluding the threat of hybridization posed by causes (natural or anthropogenic) of calculations of allele frequencies and another taxon. Implementing actions those threats. In this context, the Act true estimation of admixture under the Act that distinguish between does not distinguish between natural proportions (i.e., percent rainbow trout these two alternatives is difficult when and ‘‘manmade’’ factors that may genes) in each sample or population imperiled species are involved because threaten the continued existence of a evaluated. a large number of populations may have species (section 4(a)(1)). experienced small amounts of genetic Several studies have demonstrated Despite those limitations, three main introgression from another taxon. These that natural populations, and individual results pertinent to this status review decisions are further complicated for fish, conforming morphologically to the can be gleaned from the paper by Weigel WCT because the native geographic scientific taxonomic description of WCT et al. (2002): (1) The percent of fish at ranges of WCT and rainbow (redband) may contain genes derived from each sample site with at least 1 rainbow trout overlap in portions of the rainbow trout or YCT as the result of a trout marker was bimodally distributed Columbia River drainage. For example, past hybridization event (Leary et al. among the 100 sample sites examined as noted by Howell and Spruell (2003), 1984; Marnell et al. 1987; Forbes and (see Figure 2 in Weigel et al. 2002); ‘‘It is apparent that WSCT [WCT] × RB Allendorf 1991a, b; Leary et al. 1996; approximately 62 percent of the sites [rainbow trout] hybridization can be Weigel al. 2002, 2003). For example, yielded population samples where zero extensive in areas, such as the John Day Leary et al. (1984) reported that an to 30 percent of the fish showed [River] subbasin, where both taxa are introgressed population of WCT, with evidence of introgression, while native and there have been little to no an estimated 20 percent of its nuclear approximately 36 percent of the sample introductions of hatchery RB.’’ genes derived from rainbow trout, was sites had 50 to 100 percent of the For the purpose of providing indistinguishable morphologically from individuals showing evidence of conservation guidelines, Allendorf et al. nonintrogressed WCT populations. A introgression. (2) Variation in the mean (2001) have suggested that hybridization subsequent study revealed a strong, values of four morphological characters be categorized as either anthropogenic positive correlation between percent among natural populations of WCT (i.e., or ‘‘natural.’’ They further suggest that rainbow trout genes in natural the presence or absence of red or orange ‘‘hybrid’’ populations or taxa resulting populations of WCT and the percent of slash marks, the number of from natural causes would be eligible individuals without basibranchial teeth basibranchial teeth, the shape of for conservation protection, whereas in those populations (Table 1 in Leary individual spots on the body, and the genetically introgressed individuals or et al. 1996). Indeed, based on this latter ratio of head length to total body length) populations resulting from study, the percent of individuals was correlated with the amount of anthropogenic causes would generally without basibranchial teeth appears to rainbow trout genetic introgression in not be protected unless ‘‘hybrids’’ were be a fairly accurate predictor of the those populations. (3) By employing a the last remaining genetic percent rainbow trout genes in natural dichotomous morphology key, field representatives of a hybridized species populations where WCT are native. observers attained 93 percent accuracy (their ‘‘Type 6’’ hybridization). Such However, this correlation collapses in in morphologically detecting genetic criteria may be useful for prioritizing nonintrogressed populations of WCT introgression in natural populations of management options for populations or where up to 18 percent of the WCT where 50 percent or more of the species that are not eligible for listing individuals may not have any fish in those populations had at least under the Act. However, the issue for basibranchial teeth (Leary et al. 1996). one rainbow trout DNA marker; species under potential jurisdiction of Weigel et al. (2002) recently however, those same observers were the Act is the extent to which conducted the most extensive study to unable to accurately distinguish WCT hybridization poses a threat to the date comparing variation in populations with no DNA evidence of continued existence of the ‘‘species’’ morphological characters to levels of introgression from populations with low

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levels of introgression where less than genetic purity’’ and the plaintiffs agreed include hybrid or genetically 50 percent of the individuals expressed with this proposition, noting that they introgressed WCT populations, and at least one rainbow trout DNA marker. were not insisting on genetic purity. The populations of unknown genetic Given the statistical power of the Court, in effect, concurred. ‘‘Genetic characteristics, in the WCT subspecies authors’ methods and their use of purity’’ is not a condition for including considered for listing. These criteria are dominant genetic markers, we conclude populations or individual fish with the specific to this listing determination for that rainbow trout genes constituted less WCT subspecies under the Act, but the WCT under the Act and may not be than 25 percent of the genes in those conditions for including potential applicable to other species or taxa. latter WCT populations where less than ‘‘hybrid stock’’ with WCT may not be To determine which natural 50 percent of the individuals expressed arbitrary and capricious. populations we should consider as WCT a rainbow trout DNA marker. In reconciling the dichotomy between under the Act, we used the best In a recent unpublished report to the hybridization as a threat and the scientific data available (as described Service, Allendorf et al. (2003) reviewed potential inclusion of ‘‘hybrid stock’’ previously) to establish three principal results from their laboratory regarding with WCT under the Act, one must criteria: (1) The population under the threshold levels of rainbow trout or make a clear distinction between the consideration must first exist within the YCT genetic introgression (i.e., action (hybridization) and the outcome recognized, native geographic range of threshold percent genetic admixture) of that action (hybrid stock). Therefore, WCT (Behnke 1992; Shepard et al. detectable by morphological criteria (see we must define these terms more 2003). The population must then satisfy also Leary et al. 1984; Marnell et al. precisely. Consequently, in response to one of the following two additional 1987; Leary et al. 1996). Allendorf et al. the Court order and for the purpose of criteria to be considered WCT under the (2003) presented data indicating that this new status review for WCT, we Act; (2) If all measured individuals in introgressed populations of WCT with define ‘‘hybridization’’ as the direct the population have morphological less than 20 percent of their genes interbreeding between two individuals characters that are all within the derived from another taxon are that conform morphologically to scientific, taxonomically-recognized morphologically indistinguishable from different species or subspecies, ranges of those characters for the WCT nonintrogressed populations with zero including the interbreeding between subspecies, then the population shall be percent genetic admixture. They also individuals conforming morphologically considered WCT; or (3) if not all of the presented data indicating that to WCT and individuals not conforming measured individuals have introgression exceeding 50 percent non- morphologically to WCT. We further morphological characters that are within WCT genes in natural populations of define ‘‘hybrid stock’’ (Court’s term), or the scientific, taxonomically-recognized WCT would most likely be detectable by introgressed population, as a group of ranges of those characters for the WCT morphological methods. potentially interbreeding individuals subspecies, then additional evidence of Therefore, based on the best scientific with a genetic ancestry derived from reproductive discreteness between and commercial data available, we two or more extant species or individuals that conform conclude that natural populations of subspecies. Under these definitions, morphologically to the WCT subspecies WCT may have a genetic ancestry ‘‘hybridization’’ may represent a and individuals that do not conform derived by as much as 20 percent from ‘‘natural or manmade factor affecting the morphologically to the subspecies will rainbow trout or YCT when fish in those continued existence’’ of the WCT be examined. If the two forms are populations express a range of subspecies. Similarly, introgressed considered reproductively discrete (e.g., morphological variation that conforms populations composed of individuals naturally sympatric populations of to the scientific taxonomic description not conforming morphologically to the native redband trout and WCT that may of WCT. In other words, a natural scientific taxonomic description of WCT only occasionally interbreed), then we population of WCT with less than 20 may be a potential hybridization threat shall consider the population under percent of its genes derived from to the continued existence of the WCT consideration to be WCT under the Act. rainbow trout or YCT is, most likely, subspecies. In making these latter determinations, morphologically indistinguishable from Conversely, in accordance with the we will consider the following nonintrogressed populations of WCT above definition of hybridization, we do additional information: (a) Whether with no hybrid ancestry. not consider populations or individual rainbow (redband) trout are native to the As noted previously, on March 31, fish conforming morphologically to the geographic area under consideration; (b) 2002, the U.S. District Court for the scientific taxonomic description of WCT the percent of measured individuals that District of Columbia found that our to be a hybridization threat to the WCT do not conform morphologically to the listing determination for WCT did not subspecies. Although such individuals taxonomic scientific description of reflect a reasoned assessment of the may have genes from another taxon at WCT, including their range of Act’s statutory listing factors on the low frequency, we are not aware of any morphological variation (e.g., a single basis of the best available science. The information to suggest that such anomalous individual reflecting a Court remanded the listing decision to individuals express behavioral, congenital abnormality would not us with specific instructions to evaluate ecological, or life-history characteristics disqualify the population from the threat of hybridization as it bears on differently than do WCT native to the inclusion); (c) the results of genetic tests the Act’s statutory listing factors and the particular geographic area. Without that would indicate reproductive status of the WCT subspecies. The Court such changes, we expect the frequency discreteness between the two forms; and also ruled that inclusion of introgressed of genes from the other taxon to remain (d) any other additional information that populations or ‘‘hybrid stock’’ (Court’s low in the population. Therefore, we do would assist with these determinations term) as part of the WCT subspecies in not consider such populations as (e.g., information on the locations and our status review, based on the visually contributing to the threat of timing of spawning for each of the two based, professional opinions of field hybridization to the WCT subspecies. forms). biologists familiar with the subspecies, Therefore, in accordance with the Hence, our principal criterion for ‘‘was arbitrary and capricious.’’ During Court’s order, we provide our including potentially introgressed the Court proceedings, we noted that the scientifically-based conclusion about populations, and populations of Act does not require ‘‘100 percent the extent to which it is appropriate to unknown genetic characteristics, with

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the WCT subspecies under the Act is morphologically to the scientific Act is to be inclusionary, not whether fish in those populations taxonomic description of the exclusionary. Consequently, any natural conform morphologically to the subspecies. population conforming to the scientific scientific taxonomic description of the These criteria are further justified for taxonomic description of WCT, as WCT subspecies. As noted previously, this subspecies because: (a) There are no conditioned by the criteria stated natural populations conforming generally applicable standards for the previously, will be considered WCT morphologically to the scientific extent of hybridization considered under the Act. The Service also has taxonomic description of WCT are acceptable under the Act; (b) decisions concluded that alternative approaches presumed to express the behavioral, regarding status of WCT under the Act would either be arbitrary and capricious ecological, and life-history must be made for the entire subspecies (e.g., ≥90 percent genetic ‘‘purity’’ characteristics of WCT native to the and its component populations (see required for inclusion) or inconsistent geographic areas where those Distinct Population Segments section); with the intent and purpose of the Act populations occur. (c) in most cases, the taxonomic (e.g., 100 percent genetic ‘‘purity’’ The Service acknowledges that classification of extant WCT has been required for inclusion). For example, the molecular genetic data also can be very based on the pattern of spots on the best scientific and commercial data useful for guiding these decisions fish’s body and the professional available indicate that WCT populations regarding inclusion or exclusion of evaluations and experiences of fishery with 1 percent to 20 percent of their particular populations from the WCT biologists who examined the fish in the genes derived from another taxon are subspecies under the Act. For example, field (see also Marnell et al. 1987); and indistinguishable morphologically from on the basis of data described (d) spotting pattern was chief among the nonintrogressed populations of WCT. previously in this section, our general morphological characteristics diagnostic Hence, establishing a threshold of ‘‘90 conclusion is that natural populations of the type specimens of WCT. percent genetic purity’’ would be conforming morphologically to the Our approach further acknowledges arbitrary and capricious because no scientific taxonomic description of WCT that a significant proportion of the scientific or commercial data exist to may have up to 20 percent of their genes genetic resources associated with WCT support that threshold based on the derived from rainbow trout or YCT. throughout its native geographic range morphological criteria by which species Consequently, for populations for which may be represented by populations with are described taxonomically. In contrast, molecular genetic data may be the only low-frequency genes from other taxa the ‘‘80 percent genetic threshold’’ data available, populations with less (e.g., rainbow trout) detectable only by described previously is based on the than 20 percent introgression will be molecular genetic methods. Such best scientific and commercial data considered WCT under the Act, whereas populations, if they conform available, although, as we have populations with more than 20 percent morphologically to the scientific described, that threshold is not the taxonomic description of WCT, are introgression will generally be excluded principal criterion by which considered part of the WCT subspecies from the WCT subspecies. However, populations are included or excluded under the Act. As noted previously, such decisions involving possible from the WCT subspecies. Similarly, as individual fish or populations inclusion or exclusion will need to noted previously, the Solicitor’s Office conforming to the scientific taxonomic consider other potentially important for Department of the Interior description of WCT shall not be characteristics of the populations, overturned (withdrew)—in December considered a threat to the continued including the ecological setting, 1990—the Service’s old ‘‘hybrid policy’’ geographic extent of the introgression existence of the subspecies. which precluded federal protections to across the population’s range, and Conversely, we will consider hybrid offspring or their descendants whether rainbow (or redband) trout are genetically introgressed populations not under the Act (O’Brien and Mayr 1991). naturally sympatric with WCT in the classified as WCT as potential Moreover, the court in the present WCT particular region under consideration. hybridization threats to the WCT The Service shall evaluate natural subspecies. By definition, these latter case ruled that ‘‘100 percent genetic populations for which no morphological populations do not conform purity’’ is not a condition for including or genetic data exist on a case-by-case morphologically to the scientific populations or individual fish with the basis considering their geographic taxonomic description of WCT, or—in WCT subspecies under the Act. relationship to natural populations for the absence of morphological data—we Our criteria for including potentially which such data do exist and any other would expect them to not conform introgressed populations of WCT with available information pertinent to those morphologically to WCT based on the the WCT subspecies considered for evaluations (e.g., ecological setting, level of introgression detected by a listing under the Act also are consistent degree of geographic isolation, and molecular genetic test or other available with a recent Position Paper developed historical stocking records of nonnative information. by the fish and wildlife agencies of the trout species). As a result, the Service must intermountain western States (Utah The species criteria described above determine which natural populations Division of Wildlife Resources 2000). are consistent with the best scientific represent potential hybridization That document identifies, for all and commercial data available because ‘‘threats’’ to the future existence of the subspecies of inland cutthroat trout, they are based on: (a) The criteria by WCT subspecies and which populations three tiers of natural populations for which taxonomic species of fish are represent potential genetic resources of prioritizing conservation and recognized scientifically, and (b) the the subspecies itself. The criteria we use management options under the States’ biological relationship between those to make such decisions must not only be fish and wildlife management taxonomic criteria and levels of genetic consistent with previous Service rulings authorities: (1) Core conservation introgression detected by molecular dealing with ‘‘hybrids’’ under the Act, populations composed of ≥99 percent genetic methods in natural populations but decisions resulting from those cutthroat trout genes; (2) conservation of WCT. Those criteria exclude from the criteria also must be consistent with the populations that generally ‘‘have less WCT subspecies considered for listing intent and purpose of the Act itself. The than 10 percent introgression, but [in genetically introgressed populations and Service has concluded that, in such which] introgression may extend to a individual fish that do not conform situations, the intent and purpose of the greater amount depending upon

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circumstances and the values and minimum of four or five codominantly- genes affecting those phenotypes) and attributes to be preserved’’; and (3) expressed, diagnostic loci are usually molecular genetic markers used to cutthroat trout sport fish populations required to attain sufficient statistical detect introgression in natural that, ‘‘at a minimum, meet the species power in evaluations of introgressive populations. In other words, molecular (e.g., WCT) phenotypic expression hybridization (Fig. 2 in Campton 1990; genetic markers (e.g., microsatellite defined by morphological and meristic Figure 1 in Epifanio and Phillip 1997; DNA alleles, DNA fingerprint patterns) characters of cutthroat trout.’’ Figure 2 in Kanda et al. 2002). Under provide very sensitive methods for Conservation populations of cutthroat these conditions, percent introgression evaluating ancestral or pedigree trout also include those believed to have (P) in a population can be calculated as relationships among populations, uncommon, or important, genetic, P = (NA/2LN) × 100, where L = the species, or individuals independent of behavioral, or ecological characteristics number of diagnostic, codominantly the genes affecting morphology and relative to other populations of the expressed loci that distinguish the two other species-specific characters. subspecies under consideration. Sport taxa or species, N = the number of We now perform our new status fish populations are those that conform individual fish in a random sample of review for WCT based on the described morphologically (and meristically) to individuals from the population, and NA criteria for including potentially the scientific taxonomic description of = the number of alleles from another introgressed populations and the subspecies under consideration but taxon observed at the diagnostic loci in populations of unknown genetic do not meet the additional criteria of the sample of individuals. This characteristics with the WCT subspecies ‘‘conservation’’ or ‘‘core’’ populations. estimator is equally applicable to considered for possible listing under the Consequently, the Service’s criteria for allozyme and microsatellite nDNA Act. including potentially introgressed markers and is identical to the statistic New Status Review populations of WCT with the WCT proposed by the State fish and wildlife subspecies considered for listing under agencies (Utah Division of Wildlife Background the Act include the first two tiers, as Resources 2000). Consequently, this In response to our September 3 and defined by the intermountain State fish estimator provides a standardized December 18, 2002, Federal Register and wildlife agencies, as well as those approach for evaluating genetic notices, we received comments and sport fish populations in the third tier introgression in natural populations. information on WCT from several State for which morphological or genetic data Evaluations of introgression based on fish and wildlife agencies, the U.S. are available. The implicit premise of dominant markers (Weigel et al. 2002) Forest Service, private citizens and the Position Paper is that populations should computationally convert the organizations, and other entities. Among must conform, ‘‘at a minimum,’’ to the observed data (e.g., percent of the materials that we received, the most morphological and meristic characters individuals with one or more rainbow important was a status update report for of a particular cutthroat trout subspecies trout alleles) into estimates of percent WCT, a comprehensive document in order for those populations to be introgression on the basis of explicitly (Shepard et al. 2003) prepared by the included in a State’s conservation and stated assumptions (e.g., that a single, fish and wildlife agencies of the States management plan for that subspecies. random-mating population was of Idaho, Montana, Oregon and Signatories to the Position Paper are the sampled). If one or more codominantly Washington, and the U.S. Forest Colorado Division of Wildlife, Idaho expressed loci are not diagnostic Service. Department of Fish and Game, Montana between species, then the statistical The WCT status update report Department of Fish, Wildlife and Parks, methods of least squares or maximum (Shepard et al. 2003) and the Nevada Division of Wildlife, New likelihood can be used to estimate comprehensive database that is the Mexico Game and Fish Department, admixture proportions in introgressed report’s basis, presented to us the best Utah Division of Wildlife Resources, populations (Campton 1987; Bertorelle scientific and commercial information and the Wyoming Game and Fish and Excoffier 1998). available that describes the present-day Department. Further support for the morphological rangewide status of WCT in the United Molecular genetic methods for and genetic criteria developed by the States. To compile that important estimating percent introgression, or Service and the State fish and wildlife information, 112 professional fishery genetic admixture proportions, in agencies for classifying natural biologists from 12 State, Federal, and natural populations of WCT need to be populations as WCT comes from field Tribal agencies and private firms met at consistent to help guide the observations of the effects of natural and 9 workshops held across the range of conservation decisions described here artificial selection in genetically WCT in fall 2002. Those fishery under the Act. The continual introgressed populations of other taxa. biologists had a combined 1,818 years of development of new types of molecular Gerber et al. (2001) note that natural professional experience, 63 percent of genetic markers for population-level selection may act to retain the which involved work with WCT or evaluations complicates estimation of morphological phenotypes of native other subspecies of cutthroat trout. At genetic admixture proportions in species despite introgressive the workshops, the biologists submitted introgressed populations (e.g., Weigel et hybridization resulting from secondary essential information on the WCT in al. 2002). The most accurate estimates contact of a colonizing, congeneric their particular geographic areas of are obtained with codominant genetic species. Busack and Gall (1981) note a professional responsibility or expertise, markers in which heterozygotes and similar outcome resulting from artificial according to standardized protocols. homozygotes at single loci can be selection (i.e., selective removal of Presentation of information directly distinguished. Allozymes and alleles at ‘‘hybrid-looking’’ individuals) for the applicable to addressing the issues microsatellite nuclear DNA (nDNA) loci Paiute cutthroat trout (O. c. seleniris) raised by the Court, as well as other meet this ‘‘codominance’’ criterion. phenotype within introgressed concerns that we consider when making ‘‘Amplified fragment-length populations of this latter subspecies. listing determinations under the Act, polymorphisms’’ (AFLPs) and ‘‘paired Those results suggest the lack of a was central to those protocols. interspersed nuclear elements’’ (PINES; genetic correlation between In conducting the new status review Weigel et al. 2002) do not. Also, a morphological phenotypes (i.e., the for WCT in the United States described

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in the present document, we considered measured genetic variation in the WCT WCT (and the probable human transport our initial review (U.S. Fish and genome is within WCT populations, 34 and stocking of native WCT into waters Wildlife Service 1999) to be the percent is among the populations outside the subspecies’ historic range) foundational compendium of themselves, and about 1 percent is during the 20th Century, WCT information on the present-day status of between the aggregates of populations in populations are more numerous and WCT. In turn, the more-recent WCT the Columbia and Missouri River basins. widely distributed in Washington today status update report (Shepard et al. Those authors also found that there can than prior to European settlement (U.S. 2003), as well as the other materials that be genetic differences among WCT Fish and Wildlife Service 1999). Those we received or otherwise obtained while populations that are separated by short populations now occur in over 493 conducting the new review, clarified geographic distances. In the context of streams and 311 lakes in Washington and improved our understanding of the DPS designation, those differences (Fuller 2002). Similarly, some WCT present-day status of WCT and also suggest reproductive isolation among populations have been intentionally helped us to address the important populations that may be indicative of established in Oregon’s John Day River issues that had been raised by the Court. ‘‘discreteness.’’ Nevertheless, because of drainage (Unterwegner 2002). However, While describing our findings in the the large amount of genetic variation in as was done during our initial status present document, we will often the WCT subspecies, the occurrence of review (U.S. Fish and Wildlife Service compare the recently received a WCT population with molecular 1999), our decision whether or not to information for WCT to that found genetic characteristics that differ recommend listing the WCT as a during our initial status review. statistically (with adequate sample threatened or an endangered species, as sizes) from those of other WCT described in the present document, will Findings of the New Status Review populations is often sufficient to meet be based entirely on WCT that presently Distinct Population Segments the discreteness criterion but not occur within the formally recognized sufficient to meet the significance historic range of the subspecies (Behnke The Service and the National Marine criterion indicative of unique 1992), as modified by Shepard et al. Fisheries Service have adopted criteria morphological, behavioral, (2003) in their status update report. (61 FR 4722; February 7, 1996) for physiological, or ecological attributes. Recent data from ongoing studies designation of DPSs for vertebrate Recently, the Northwest suggest that native WCT populations do organisms, such as WCT, under the Act. Environmental Defense Center (2002) occur in the Yakima, Entiat, and To constitute a DPS, a population or argued that the WCT populations in Wenatchee River drainages of group of populations must be: (1) Oregon’s John Day River drainage Washington (Trotter et al. 1999, 2001; Discrete (i.e., spatially, ecologically, or merited listing as a DPS; however, the Howell and Spruell 2003). In assessing behaviorally separated from other Northwest Environmental Defense the origins of the cutthroat trout they populations of the taxonomic group Center provided no supportive, collected from selected streams in those [i.e., taxon]); (2) significant (e.g., empirical evidence for that contention drainages, Trotter et al. (1999, 2001) ecologically unique for the taxon, and only speculated as to why those assumed that the absence of a written extirpation would produce a significant populations may be significant in the stocking record for WCT, particularly in gap in the taxon’s range, the only context of DPS designation. Congress the studied streams where those fish are surviving native population of the has made clear that DPSs should be now present, was evidence that WCT taxon, or substantial genetic divergence used ‘‘sparingly’’ in the context of the are native to those areas. However, as occurs between the population and Act (see Senate Report 151, 96th pointed out by Howell and Spruell other populations of the taxon); and (3) Congress, 1st Session). While (2003), who are presently conducting a the population segment’s conservation conducting the new status review for similar study of the WCT in those status must meet the Act’s standards for WCT, we found no compelling evidence drainages as well as in Oregon’s John listing. for recognizing DPSs of WCT. Instead, Day River drainage, the historic stocking In our initial status review, we found for purposes of the new status review, records of management agencies in no morphological, physiological, or we recognize WCT as a single taxon in Washington and Oregon are incomplete ecological data for WCT that indicated the contiguous United States. and have ‘‘large gaps.’’ Moreover, as unique adaptations of individual WCT Trotter et al. (2001) indicate, during the Disjunct Westslope Cutthroat Trout populations or groups of populations 20th century it was common for the Populations in Washington that inhabit discrete areas within the representatives of many Federal, State, subspecies’ historic range. Although the In addition to the historic range of and county agencies, and even private disjunct WCT populations in WCT previously described (see citizens, to stock hatchery-produced Washington and Oregon, as well as the Background), Behnke (1992) speculated fish. Those fish were often readily populations in Montana’s upper that the WCT is native to the Wenatchee obtained from nearby fish hatcheries, Missouri River basin, met the first and Entiat River drainages in whose managers took advantage of the criterion for DPS designation (i.e., Washington. Because Behnke’s willingness of citizens to haul hatchery discreteness), scientific evidence in conclusion was largely speculative, we fish to remote areas by whatever means. support of the second criterion did not consider those two drainages as Moreover, angler conservationists often (significance) was absent or insufficient being within the historic range of WCT moved fish from established to conclude that any of those in our initial status review (U.S. Fish populations to nearby ostensibly populations represented a DPS (U.S. and Wildlife Service 1999). Similarly, fishless streams. Fish and Wildlife Service 1999). those drainages were not included in Howell and Spruell (2003) concluded Extant WCT show a remarkably large the WCT status update report (Shepard that WCT in the Yakima, Wenatchee, amount of genetic variation at the et al. 2003) because the Washington Entiat, and Methow River drainages of molecular level, both within and among Department of Fish and Wildlife did not Washington are probably native WCT WCT populations across the subspecies’ consider those drainages to be within because populations from each of those historic range (Allendorf and Leary the historic range of WCT. drainages possessed some genetic 1988; Leary et al. 1997). Leary et al. Because of the extensive characteristics (i.e., allozyme alleles) (1997) found that 65 percent of the total introductions of hatchery-produced that were absent from those of the Twin

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Lakes WCT hatchery population information available prior to the WCT percent of the occupied habitat; WCT in maintained by the State of Washington. status update report, preceding the remaining 28 percent of occupied However, as those authors point out, the assessments (e.g., U.S. Fish and Wildlife habitat did not satisfy the criteria of Twin Lakes population is not the only Service 1999) had treated the streams in ‘‘conservation’’ populations and are population of hatchery WCT that was those drainages, except Hangman River, thus being managed as ‘‘sport fish’’ stocked in Washington during the past as historic WCT habitat. Today, WCT populations, as described previously century. Moreover, random genetic drift, occupy over 28,968 km (18,000 mi) of (Utah Division of Wildlife Resources which has a greater probability of stream in Idaho (95 percent of historic 2000). Individual conservation occurring in small, isolated populations, range in Idaho), about 20,922 km populations ranged in geographic extent could have resulted in genetic (13,000 mi) in Montana (39 percent of from small, nonintrogressed, isolated differences among populations of historic range in Montana), about 402 populations (i.e., isolets) to large introduced WCT, and perhaps in the km (250 mi) in Oregon (21 percent of metapopulations that included Twin Lakes hatchery population itself. historic range in Oregon), and about numerous populations and Howell and Spruell (2003) describe 3,219 km (2,000 mi) of stream in encompassed hundreds of stream miles. their study as a ‘‘work in progress.’’ We Washington (66 percent of historic range According to Shepard et al. (2003), 457 agree and suggest that their caveat in Washington). In our initial status (81.2 percent) of the 563 WCT should be applied to both the recent and review (U.S. Fish and Wildlife Service conservation populations were isolets ongoing investigations of WCT 1999), we reported that WCT occupied that were often restricted to headwater populations in Washington. Extensive about 37,015 km (23,000 mi) of stream areas and represented 11.5 percent of discussions of the available data and in the United States. the total occupied stream miles. Most of their interpretations among members of Information provided in the WCT the occupied stream miles (88.5 percent) the scientific community, as part of the status update report (Table 9 of Shepard were habitat for WCT in normal, peer-review process, will be et al. 2003) also indicated that metapopulations. required to determine whether any of laboratory-based genetic testing has Finally, the status update report the putative, native WCT populations been performed on samples of WCT (Shepard et al. 2003) revealed that 70 that Trotter et al. (1999, 2001) and collected from locations representative percent of the habitat occupied by Howell and Spruell (2003) have of about 6,100 (18 percent) of the extant WCT populations lies on lands identified in Washington are native to occupied stream miles and that managed by Federal agencies, including the streams from which the fish were nonintrogressed (i.e., showing no lands designated as national parks (2 collected. However since these evidence of introgressive hybridization) percent of occupied habitat), wilderness populations are putative, we did not WCT are known to inhabit about 3,500 areas (19 percent), or U.S. Forest Service include them as part of this listing of those stream miles (57 percent of roadless areas (40 percent). Although we decision. Rather in our assessment we tested stream miles; 10 percent of could not distinguish wilderness and relied on those populations that the best occupied miles). An additional 1,669 roadless areas from other Federal lands scientific data currently indicate are km (1,037 mi) of stream contained a in our initial status review (U.S. Fish native (as described by Behnke 1992 mixture of individual WCT that were and Wildlife Service 1999), we reported and Shepard et al. 2003). either nonintrogressed or introgressed. that most of the habitat for extant WCT Finally, based on the absence of populations was on lands administered Distribution of Westslope Cutthroat nonnative, potentially hybridizing fish by Federal agencies, particularly the Trout and the Prevalence of species, we conclude WCT inhabiting U.S. Forest Service. Hybridization an additional 14,645 km (9,100 mi) of Occurrence of Westslope Cutthroat New, definitive information on both stream, for which genetic testing of the Trout Life-History Forms the probable historic and present-day WCT therein has not yet been performed range-wide distributions of WCT was (Table 9 of Shepard et al. 2003), are Biologists commonly recognize three provided in the status update report most likely not introgressed (see WCT life-history forms: resident fish do (Shepard et al. 2003). That information preceding section on the Value of not move long distances and spend their indicated WCT historically occupied Hybrid Westslope Cutthroat Trout in lives entirely in their natal stream, about 90,928 km (56,500 mi) of stream Listing Determinations). Thus, where they themselves were produced; in the United States and now occupy nonintrogressed WCT are known to fluvial fish spawn in small tributaries about 33,500 (59 percent) of those inhabit 5,633 km (3,500 mi) of stream and their young migrate downstream to stream miles. About 33,000 (58 percent) and probably inhabit as many as 20,278 larger rivers, where they grow and of the historically occupied stream km (12,600 mi) of stream in which no mature; and adfluvial fish spawn in miles were in Montana, 19,000 (34 potentially hybridizing fishes occur. In streams and their young migrate percent) in Idaho, 1,000 (2 percent) in our initial status review (U.S. Fish and downstream (or upstream, in the case of Oregon, 3,000 (5 percent) in Wildlife Service 1999), we reported that: outlet-spawning populations) to mature Washington, and 161 km (100 mi) (<1 (1) WCT occupied about 37,015 km in lakes. All three life-history forms may percent) in Wyoming (i.e., Yellowstone (23,000 mi) of stream; (2) data on the occur in a single drainage and whether National Park). Shepard et al. (2003) genetic characteristics of WCT were they represent opportunistic behaviors, also concluded that several river limited and available mainly for heritable (i.e., genetically-based) traits, drainages, including the Milk Montana; and (3) nonintrogressed WCT or a combination of these factors is Headwaters, Upper Milk, Willow, were known to occupy 4,237 km (2,633 unknown. Bullwhacker-Dog, Box Elder, and the mi) of stream. In our initial status review (U.S. Fish Upper, Middle, and Lower Musselshell The WCT status update report and Wildlife Service 1999), we found in the Missouri River basin, the (Shepard et al. 2003) grouped most of that adfluvial WCT occur naturally in 6 Hangman River watershed in the the WCT in the occupied miles of lakes in Idaho and Washington that total Spokane River drainage, and the North stream into 563 separate ‘‘conservation’’ about 72,843 ha (180,000 ac) and at least John Day River drainage in Oregon, populations. Those conservation 20 lakes that total 2,164 ha (5,347 ac) in were outside the historic range of WCT. populations collectively occupied Glacier National Park in Montana. Most On the basis of the less definitive 39,349 km (24,450 mi) of stream or 72 of those populations receive the high

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level of protection afforded by Glacier Value of Hybrid Westslope Cutthroat Regulatory Mechanisms Involving Land National Park. We also reported that Trout in Listing Determinations). We Management). about 37,015 km (23,000 mi) of stream applied our analyses of threats to this The best scientific and commercial were occupied by WCT, most of which more restricted subset of WCT information available to us indicates were of either the resident or fluvial life- populations to take advantage of the that the WCT subspecies is not history form. More recently, the status States’ detailed database and to be threatened by the present or threatened update report (Shepard et al. 2003) conservative regarding the status and destruction, modification, or indicated that WCT populations that viability of extant WCT populations. curtailment of its habitat or range. include resident and fluvial fish, both of This approach also avoided (B) Overutilization for Commercial, which live entirely in streams, presently classification uncertainties associated Recreational, Scientific, or Educational occur in 53,913 km (33,500 mi) of with possible marginal populations Purposes stream habitat. In preparing that report, managed primarily as sport fisheries the lake habitats occupied by WCT were (i.e., populations that may not explicitly Our initial status review revealed that necessarily treated as stream habitat meet our stated criteria of WCT under each of the States and the National Park because of the limitations of the the Act but for which detailed Service greatly restricted the harvest of hydrologic database used in the morphological or genetic analyses have WCT and that in many regions only geographic information systems-based not been performed). Detailed catch-and-release angling was allowed analyses. Consequently, perhaps several geographic summaries of biological (U.S. Fish and Wildlife Service 1999). hundred of the stream miles that information pertinent to each of the However, catch-and-release-only Shepard et al. (2003) reported as drainages within the historic range of angling regulations are not essential to occupied by WCT were actually lake WCT were provided in our initial status protecting WCT from excessive harvest by anglers. Instead, the angling habitats. The WCT in those lakes have review (U.S. Fish and Wildlife Service regulations must not allow harvests that the adfluvial life history. In addition, 1999). Our evaluations of the five factors cause adverse population depletion and the extensive WCT conservation of potential threats to the thereby threaten population survival. populations that function as aforementioned subset of WCT Our initial status review also revealed metapopulations encompass hundreds populations are presented below. of stream miles and frequently exhibit that, where there was collection of WCT all three life-history forms. Nonetheless, (A) Present or Threatened Destruction, for educational or scientific purposes, WCT with the adfluvial life history Modification, or Curtailment of the such collection was highly regulated probably constitute the smallest Species’ Habitat or Range and had a negligible effect on the WCT proportion of the WCT subspecies subspecies. Our initial status review revealed that today, and this may have been true The additional information that we most of the habitat for extant WCT historically. received while conducting this new populations lies on lands administered status review confirmed our earlier Analysis of Extant Threats to Westslope by Federal agencies, particularly the conclusions. In Montana, recreational Cutthroat Trout U.S. Forest Service (U.S. Fish and fishing and scientific collecting are The Act identifies five factors of Wildlife Service 1999). Moreover, most highly regulated and have become potential threats to a species: (1) The of the strongholds for WCT populations increasingly restrictive. Enforcement of present or threatened destruction, occurred within roadless or wilderness regulations pertaining to native fishes is modification, or curtailment of the areas or national parks, all of which a priority, and regulations limit the species’ habitat or range; (2) afforded considerable protection to locations, dates, bag limits, and methods overutilization for commercial, WCT. More recently, the information of fishing. In many WCT waters in the recreational, scientific, or educational that we received during the two Columbia River basin, and in all waters purposes; (3) disease or predation; (4) comment periods, in particular the in the Missouri River basin in Montana, the inadequacy of existing regulatory information provided in the status fishing is restricted to catch-and-release mechanisms; and (5) other natural or update report (Shepard et al. 2003), (Hagener 2002; Shepard et al. 2003). In manmade factors affecting the species’ entirely supported our earlier Idaho, nearly all WCT populations are continued existence. conclusions and clearly indicated that managed with restrictive fishing We examined each of these factors in WCT populations are widespread across regulations (Moore 2002). In Oregon, the context of present-day WCT. We the subspecies’ historic range, abundant angling regulations in areas occupied by also used the database of Shepard et al. in several regions, and that many of WCT are designed to protect (2003) to more closely examine the those populations receive the Endangered Species Act-listed Mid- effects of several specific threats (i.e., appreciable protections afforded by Columbia steelhead and Columbia Basin whirling disease, nonnative predators, roadless and wilderness areas and bull trout (Salvelinus confluentus). competition from nonnative brook trout national parks (see also Hagener 2002). There is little angling pressure in the [Salvelinus fontinalis], and The status update report (Shepard et al. John Day River drainage, particularly in hybridization) to WCT in two categories 2003) indicated that 70 percent of the areas occupied by WCT (Unterwegner of extant populations: (1) habitat occupied by extant WCT 2002). In Washington, the sportfishing Nonintrogressed and suspected populations lies on lands managed by rules for 2003–2004 allow the daily nonintrogressed WCT populations and Federal agencies, including lands harvest of 2 trout longer than 20 (2) introgressed and suspected designated as national parks (2 percent centimeters (8 inches) from most introgressed WCT classified as of occupied habitat), wilderness (19 streams, and 5 trout of any size from ‘‘conservation’’ populations (Utah percent), or U.S. Forest Service roadless lakes, with the exception that all wild Division of Wildlife Resources 2000). areas (40 percent). In addition, the cutthroat trout caught from Lake Chelan Collectively, those two categories regulatory mechanisms in place to and its tributaries, as well as from the exclude introgressed ‘‘sport fish’’ prevent the destruction or adverse Methow River, must be released alive. populations and thus are a subset of the modification of WCT habitat on those The best scientific and commercial populations we defined previously as Federal lands and elsewhere are information available to us indicates WCT under the Act (see section on The extensive (see subsequent section, that the WCT subspecies is not

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threatened by overutilization for (2003) to assemble their database (Kerans and Zale 2002; MacConnell and commercial, recreational, scientific, or inevitably led to inflated estimates of Vincent 2002). Among the salmonid educational purposes. the proportions of stream miles in fishes that have been examined under which the WCT are at moderately high controlled conditions, rainbow trout has (C) Disease or Predation or high risk of disease. Moreover, as we been found to be the most susceptible to Threats from Disease—As part of both will describe, the available scientific whirling disease (Bartholomew and the initial and new status reviews, we information indicates whirling disease Wilson 2002). Studies conducted on considered the threat that diseases may is not a substantial threat to the majority various salmonids by Vincent (2002) pose to WCT. Perhaps the most of populations constituting the WCT revealed that WCT were moderately important of the contemporary diseases subspecies. Although the whirling susceptible to whirling disease and had is whirling disease, which is caused by disease parasite continues to spread in the lowest susceptibility of the three an exotic myxozoan parasite. That many waters of the western United cutthroat trout subspecies examined. microscopic parasite was introduced to States (Bartholomew and Reno 2002), We are unaware of any studies of the the eastern United States from Europe in few outbreaks of whirling disease in susceptibility of the hybrids of rainbow the 1950s and has since been found in resident fishes (mainly rainbow trout) trout and WCT to whirling disease. many western States. Two separate host have occurred. Studies summarized by In addition, although the parasite’s organisms are necessary for completion Downing et al. (2002) indicated that essential oligochaete host, Tubifex of the parasite’s life cycle, a salmonid presence of the whirling disease parasite tubifex, can be found in a wide variety (i.e., salmon, trout, and their close does not portend outbreaks of the of habitats and is considered ubiquitous relatives) fish and a specific aquatic disease in resident fishes. For example, across the diversity of freshwater oligochaete worm. Within the range of although 46 of 230 sites tested in habitats used by trout, T. tubifex has a WCT, whirling disease was first found Montana were positive for the parasite, much higher probability of occurring at in Idaho in 1987 and in Montana in disease outbreaks were known to have locations with abundant fine sediments 1994 (Bartholomew and Reno 2002). occurred at only 6 of those sites. in eutrophic (i.e., nutrient-rich) lakes The WCT status update report Downing et al. (2002) provided and streams (Granath and Gilbert 2002). (Shepard et al. 2003) concluded that the evidence that the frequent absence of The mountain streams that WCT often threats to extant WCT populations from manifest whirling disease in resident inhabit are cold and have low biological diseases in general were greater for the trout, despite presence of the parasite, is productivity, factors that make those extensive WCT metapopulations than due to complex interactions among the streams much less suited to both the for the smaller WCT populations that timing and spatial locations of whirling disease parasite and T. tubifex occur as isolets. The key assumption important host-fish life-history events (Bartholomew and Wilson 2002). made in reaching that conclusion was Extensive research is being conducted (e.g., spawning, fry emergence from that, because the ranges of individual to determine the distribution of whirling stream gravels, and early-life growth) metapopulations were naturally much disease, the susceptibility of WCT and and spatial and temporal variation in larger and encompassed habitats more other fishes to whirling disease, the occurrence of the parasite itself. diverse than those of isolets, the infection rates, and possible control Only under specific conditions, which probability that diseases may be measures (Bartholomew and Wilson evidently occur only in a small introduced and become established in 2002). Although no means have been proportion of the locations where the WCT populations was greater for found to eliminate the whirling disease parasite has been found, are those metapopulations than isolets. As noted parasite from streams and lakes, the interactions such that disease outbreaks previously, we examined the database of States have established statutes, Shepard et al. (2003) to assess the occur in resident fishes. The available policies, and protocols that prevent the disease risk to two groups of extant scientific information specific to human-caused spread of extant WCT: (1) Nonintrogressed or suspected whirling disease thus indicates pathogens and the introduction of new nonintrogressed populations and (2) considerable variation in the probable pathogens (e.g., Hagener 2002). Except introgressed or suspected introgressed disease threat among individual WCT for whirling disease, the fish pathogens fish classified as ‘‘conservation’’ populations and provides evidence that that occur in the natural habitats of populations. Results indicated that only the disease is not a significant threat to WCT are mainly benign in wild about 10 percent of the 1,944 stream the majority of populations constituting populations and cause death only when miles occupied by nonintrogressed and the WCT subspecies. The database the fish are stressed by severe suspected nonintrogressed WCT procedures used by Shepard et al. environmental conditions. populations occurring in isolets were at (2003) necessarily resulted in entire On the basis of the best scientific and moderately high or high risk of disease, WCT metapopulations being treated at commercial information available to us, whereas 69 percent of the 9,999 stream the same level of risk from disease, even we conclude that the WCT subspecies is miles occupied by nonintrogressed WCT though that risk applied only to specific not threatened by whirling disease, in the considerably more-extensive populations within those although some specific populations may metapopulations were considered to be metapopulations. Thus, we conclude be at higher risk. at similar risk. Similarly, introgressed or that the percent of stream miles in Threats From Predation—The suspected introgressed WCT which Shepard et al. (2003) reported instances when predation by other ‘‘conservation’’ populations occurring as that WCT are at moderately high or high fishes may negatively affect extant WCT isolets were at moderately high or high risk of disease is inflated to an extent populations are few and limited to a few risk of disease in about 20 percent of that cannot be quantified with the large rivers, lakes and reservoirs (U.S. their 751 occupied stream miles, available data. Fish and Wildlife Service 1999; Hagener whereas introgressed WCT in A broad suite of variables has been 2002). However, as reported in the metapopulations were considered at shown to influence the incidence and initial status review, predacious, similar risk in 88 percent of their 11,775 intensity of infections of salmonid nonnative fishes in Idaho’s Coeur occupied stream miles. fishes by the whirling disease parasite, d’Alene Lake, Montana’s Flathead Lake, However, we believe that the including host-fish species and age, and other lakes have negatively affected procedures used by Shepard et al. parasite dose, and water temperature resident WCT. In those instances,

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predation has reduced the abundance of and regulations that help to prevent the During our initial status review, we WCT that have the adfluvial life history. adverse effects of land-management found Federal regulations and We examined the database of Shepard activities on WCT. More recently, guidelines that protect WCT and their et al. (2003) to assess the extent that Hagener (2002) reiterated that Montana habitat in Oregon and Washington nonnative fishes, including recognized laws that benefit WCT include the included CWA, NEPA, FLPMA, INFISH, predacious species, co-occur (i.e., are Montana Stream Protection Act, the PACFISH, and National Forest sympatric) with extant WCT for: (1) Streamside Management Zone Law, the Management Plans (U.S. Fish and Nonintrogressed or suspected Montana Natural Streambed and Land Wildlife Service 1999). More recently, nonintrogressed populations and (2) Preservation Act, and the Montana information received from Oregon introgressed or suspected introgressed Pollutant Discharge Elimination System. (Unterwegner 2002) indicated that the ‘‘conservation’’ populations. Results Federal laws that protect WCT and their Oregon Plan for Salmon and Watersheds indicated that two predacious species, habitats in Montana and elsewhere (ORS 541.405) mandates restoration of brown trout (Salmo trutta) and lake include the CWA, Federal Land watersheds and the recovery of fish and trout (Salvelinus namaycush), each Management Protection Act (FLMPA), wildlife populations therein to occur in only small proportions of the and the National Environmental Policy productive and sustainable levels in a habitat occupied by WCT, mainly WCT Act (NEPA). Much of the habitat of manner that provides substantial that occur in metapopulations. extant WCT is managed by Federal environmental, cultural, and economic However, for reasons related to the agencies, including the U.S. Forest benefits; the Oregon Forest Practices Act database and described previously for Service and the Bureau of Land (ORS 527.610) mandates the protection, whirling disease, those small Management. Those Federal agencies maintenance, and, where appropriate, proportions are inflated to an extent that have adopted the Inland Native Fish improvement of functions and values of cannot be quantified using the available Strategy (INFISH) that includes streams, lakes, wetlands, and riparian data. Brown trout occur primarily in standards and guidelines that protect management areas; State fill and mainstem rivers and their major watersheds. Furthermore, because the removal laws (ORS 196.800–990) tributaries, whereas lake trout occur broad distribution of bull trout—listed require that a permit be obtained before almost exclusively in lakes. When one as a threatened species under the Act in materials are moved and mitigation or the other species occurred in the 1999—considerably overlaps the measures be implemented if stream range of a WCT metapopulation, the distribution of WCT, the WCT will habitats will be negatively affected; a procedures of Shepard et al. (2003) benefit from the Act’s section 7 water right must be obtained before any necessarily resulted in the entire WCT protective actions for bull trout in areas surface water is diverted from a stream metapopulation being treated as where the two species coexist. for beneficial use; and a Water Quality sympatric with the nonnative species, Management Plan is being written that In addition, the U.S. Forest Service although the actual region of species addresses nonpoint source water-quality recently reported (McAllister 2002) that overlap within that range may be small. issues in the mainstem John Day River, existing regulatory mechanisms that The best scientific and commercial identifies nonpoint source pollution, information available to us indicates protect WCT habitat include the and ensures that agricultural producers that the WCT subspecies is not Northwest Forest Plan; the Interim do not degrade water quality as threatened by predation from brown Strategies for managing Anadromous prescribed by the CWA. In Oregon, WCT trout, lake trout, or other predaceous, Fish-producing Watersheds in Eastern inhabit a number of protected areas, nonnative fishes. However, where such Oregon and Washington, Idaho, and including the Strawberry and North predation does occur, it is mainly on Portions of California (i.e., PACFISH); Fork John Day Wilderness Areas, and WCT that have either the fluvial or INFISH; the Wilderness Act; and the the Vinegar Hill-Indian Rock Scenic adfluvial life history. The remaining, Upper Missouri (River) Memorandum of Areas. nonnative fishes sympatric with WCT Understanding and Land Use Strategy In Washington, the Act’s section 7 will be discussed in subsequent sections (in draft). In Idaho (Moore 2002), protections accorded to bull trout and of this document. regulatory mechanisms that protect Pacific salmon also benefit WCT. The WCT habitat include the Stream same holds true for Oregon, where bull (D) Inadequacy of Existing Regulatory Channel Protection Act, the Lake trout and mid-Columbia River steelhead Mechanisms Protection Act, and the Forest Practices are listed fishes. The Act requires us to examine the Act. At the Federal level, protection is Hitt and Frissell (2001) used data adequacy of existing regulatory afforded by the CWA, the National from the Interior Columbia (River) Basin mechanisms with respect to those extant Forest Management Act, NEPA, Wild Ecosystem Management Project threats that place the species in danger and Scenic Rivers legislation, and the (ICBEMP) to assess the degree of spatial of becoming either threatened or Wilderness Act. The St. Joe and Lochsa overlap between populations of bull endangered. Our initial status review rivers are protected by ‘‘Wild and trout and populations of WCT that were (U.S. Fish and Wildlife Service 1999) Scenic’’ designation and nearly all of both considered ‘‘strong’’ by the revealed that there are numerous the Middle Fork Salmon and Selway ICBEMP. Those authors found that existing Federal and State regulatory rivers and their watersheds are about 75 percent of the WCT mechanisms whose purpose is to protect protected by Wilderness Act populations did not co-occur with bull WCT and their habitats throughout the designations. In addition, the range of trout. Accordingly, Hitt and Frissell subspecies’ range. Neither our initial WCT in Idaho is almost entirely (2001) concluded that the bull trout may nor our new status review revealed overlapped by that of one or more not be a good ‘‘umbrella’’ species, i.e., information to indicate that those federally listed fish species, namely, a species whose protections accorded by mechanisms were not working or will bull trout, Kootenai River white the Act’s section 7 also would serve to not work to protect the WCT subspecies. sturgeon (Acipenser transmontanus), protect WCT. However, our conclusion Regulatory Mechanisms Involving chinook salmon (O. tshawytscha), stated herein that the Act’s section 7 Land Management—During our initial sockeye salmon (O. nerka), or steelhead. protections accorded bull trout and status review (U.S. Fish and Wildlife Protective measures under the Act for other listed fish species also would Service 1999), we found numerous laws those listed fishes also benefit WCT. benefit WCT is not based on the

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assumption that all extant WCT contain native WCT populations. In represented only 11.5 percent of the populations co-occur with one or more areas where stocking occurs in total stream miles occupied by WCT. of those listed fishes. Rather, we believe mainstem river reaches (e.g., the Pend Thus, the small WCT populations in that in those instances of co-occurrence, Oreille River), only sterile (i.e., triploid) headwater areas were numerous but the WCT will derive protections from rainbow trout are stocked (Fuller 2002). they occupied a small proportion of the the section 7 protections that are In Oregon, the Department of Fish and total habitat occupied by WCT. Most of accorded the listed species. Wildlife exclusively manages all the occupied stream miles (88.5 percent) Regulatory Mechanisms That Address streams within the John Day River were habitat for WCT in Threats From Hybridizing, Nonnative drainage for wild fish production and metapopulations. Consequently, the best Fishes—Montana has a number of laws none of those streams has been stocked scientific and commercial information and regulatory mechanisms that address with hatchery fish since 1997 available to us indicates that the WCT threats posed by the unlawful stocking (Unterwegner 2002). subspecies is not threatened by the of potentially hybridizing, nonnative The best scientific and commercial fragmentation and isolation of small fishes (Hagener 2002). These include information available to us indicates WCT populations in headwater areas. statutes, rules, and policies that restrict that the WCT subspecies is not Competition From Introduced Brook the capture, possession, transportation, threatened by the inadequacy of existing Trout—Brook trout, a nonnative species and stocking of live fish, including regulatory mechanisms related to the that can adversely compete with WCT fishes that may hybridize with WCT, as stocking of potentially hybridizing, (e.g., Griffith 1988), have been stocked well as rigorous fish-health policies that nonnative fishes. However, as described in numerous areas throughout the range restrict the transport or stocking of live in a subsequent section (see of WCT. We examined the database of fish. The stocking of private ponds also Hybridization with Nonnative Fishes), Shepard et al. (2003) to assess the extent is closely regulated. Furthermore, hybridization with introduced, that brook trout co-occur (i.e., are although the stocking of rivers and nonnative fishes that have become sympatric) with extant WCT. Results streams with a variety of nonnative established as self-sustaining indicated that in the: (1) Combined fishes was routine early in the 20th populations does pose a threat to WCT. nonintrogressed and suspected Century, it no longer occurs in Montana. As discussed in that subsequent section, nonintrogressed WCT populations and In 1976, Montana adopted a policy that there are no regulatory mechanisms that (2) the introgressed or suspected prohibits the stocking of hatchery fish in would prevent hybridization from self- introgressed WCT conservation rivers and streams. Consequently, sustaining populations of an introduced populations, both of which occur as unless done for government-sponsored species. However, in some instances, either isolets or metapopulations, brook conservation purposes, no other trout or certain management actions may serve trout are sympatric with a substantial nonnative fish may be stocked in rivers as preventative actions and there also proportion of those populations (41 to and streams inhabited by WCT. may be natural factors that limit the 90 percent of the collective stream miles In Idaho, regulatory mechanisms that spread of hybridization in the WCT for each category). However, as was the protect extant WCT from hybridization subspecies. case for assessments of other threats are in place (Moore 2002, 2003). The made using this database, it was not (E) Other Natural or Manmade Factors Idaho Department of Fish and Game possible to determine the extent that Affecting the Species’ Continued helped develop and has adopted the brook trout are distributed throughout Existence interstate position paper on genetic the range of an individual WCT considerations associated with cutthroat Fragmentation and Isolation of Small population, nor was it possible to trout management (Utah Division of Westslope Cutthroat Trout Populations quantify the competitive effect of brook Wildlife Resources 2000). Department of in Headwater Areas—Our initial status trout on the abundance or viability of Fish and Game management direction, review (U.S. Fish and Wildlife Service WCT. Nonetheless, it is evident from as described in its Fisheries 1999) revealed that extant WCT their longstanding coexistence in some Management Plan (a publicly reviewed, populations are not necessarily small or streams that complete competitive Commission-adopted document), gives limited to headwater streams. Instead, exclusion of WCT by brook trout is not priority in management decisions to that review indicated that many river inevitable where the two fishes co- wild, native populations of fish. The drainages had numerous, occur. In addition, the database did not Department of Fish and Game has interconnected miles of stream habitat provide conspicuous insights into how redirected almost all of its hatchery occupied by WCT. Those areas included far upstream brook trout may eventually rainbow trout program to the production Montana’s Clark Fork River drainage move in the various drainages in which of sterile, triploid fish, and only triploid (8,314 stream km [5,166 stream mi]) and they now occur. Nonetheless, as we will rainbow trout are now stocked in waters Idaho’s Salmon River drainage (6,563 describe, the available scientific connected to or near WCT habitat. In stream km [4,078 stream mi]). information indicates brook trout are addition, the transport of live fish to, Furthermore, our initial review revealed not a substantial threat to the majority within, and from Idaho is regulated by no evidence that the isolation of some of extant populations constituting the the Department of Fish and Game and WCT populations had resulted in either WCT subspecies. the Idaho Department of Agriculture. deleterious inbreeding (see also Caro Adams et al. (2000) assessed the The Department of Fish and Game and Laurenson 1994) or stochastic ability of brook trout to move upstream regulates private ponds in the State and extirpations that threatened the WCT in four headwater streams in a applies the same criteria to private-pond subspecies. mountainous area of northern Idaho. stocking that it does to the stocking of Information provided in the WCT They concluded that the upstream public waters, i.e., stocking of status update report (Shepard et al. movement of brook trout was inhibited, potentially hybridizing fishes that may 2003) substantiated our earlier but not precluded, by stream gradients pose a hybridization threat to native conclusions and indicated that, up to 13 percent. That study did not cutthroat trout is prohibited. although 457 (81.2 percent) of the 563 involve the experimental introduction In Washington, the Department of WCT conservation populations were of brook trout into streams in which Fish and Wildlife no longer stocks isolets that were often restricted to they were absent; instead, brook trout resident rainbow trout in tributaries that headwater areas, those isolets were already established in the study

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streams. The study design involved aquatic environment: (1) Population among researchers regarding the mechanical removal of brook trout in productivity, (2) temporal variability, (3) applicability of those criteria. Despite certain stream reaches; the marking of isolation, and (4) population size. That those limitations, 21 of 23 YCT brook trout in neighboring reaches; and analysis suggested that about 76 percent populations met 2 of the 3 criteria, and the subsequent assessment of movement of the stream miles occupied by WCT the third criterion (i.e., a population size of marked brook trout into the stream conservation populations considered of at least 500 fish) was met by 7 of the reaches that had been mechanically isolets were at high risk from 23 populations. Nevertheless, the depopulated. Because they were already catastrophic events because WCT would authors speculated that isolated YCT inhabited by brook trout, the four not be available to naturally recolonize populations are vulnerable to chance streams examined by Adams et al. those habitats. In contrast, only a small extinctions, although they also pointed (2000) may have been among streams (∼2 percent) proportion of the stream out that ‘‘there has been little especially conducive to colonization by miles occupied by WCT conservation opportunity to observe the real effects of brook trout. Thus, it is not possible to populations considered small population size and isolation on extrapolate the results of Adams et al. metapopulations were at moderately native, extant Yellowstone cutthroat (2000) to the broad array of headwater high or high risk from catastrophic or trout populations.’’ We believe those streams in which WCT presently occur human events with respect to the four limitations of knowledge also apply to but brook trout do not, even though measures of population viability. WCT in isolated headwater streams brook trout occur in the downstream However, on the basis of empirical across the subspecies’ range. portions of those drainages. information, Rieman and Dunham Consequently, the best scientific and More recently, Adams et al. (2002) (2000) reported that none of the small commercial information available to us assessed historic changes in the WCT populations they studied in the indicates that the WCT subspecies is not upstream limits of distribution of brook Coeur d’Alene River drainage were threatened at the present time by risks trout in 17 streams accessible by the fish extirpated by a large winter flood that associated with catastrophic, natural in the upper South Fork Salmon River was considered a once-in-100-years events. drainage in central Idaho. Brook trout event and affected more than 50 Threats to Any of the Three Westslope already inhabited portions of 10 of the watersheds. Similarly, despite large Cutthroat Trout Life-History Forms— streams in 1971–1985. In 1996, their wildfires in 1996 and 2002 in Oregon’s The three WCT life-history forms occur upstream-distribution limit remained Indian Creek and Roberts Creek in numerous areas across the unchanged in 8 streams that historically drainages, respectively, WCT subspecies’ range. In our initial status contained brook trout and 5 of 6 streams populations in those streams have review, we found that WCT naturally that did not (i.e., one stream was exhibited no immediate negative effects occur in 6 lakes in Idaho and invaded by brook trout). In the of the fires (Unterwegner 2002). The Washington that total about 72,843 ha remaining 4 streams, the distribution of widespread geographic distribution of (180,000 ac) and in least 20 lakes that brook trout had moved upstream 1.9 to WCT across the subspecies’ range total 2,164 ha (5,347 ac) in Glacier 3.1 km (1.2 to 1.9 mi). There was no further mitigates potential negative National Park, Montana (U.S. Fish and detectable increase in the upstream effects resulting from local population Wildlife Service 1999). All of those distribution of brook trout in 10 streams extinctions following future WCT in lakes are adfluvial (i.e., that had no obvious physical barriers to catastrophic natural events, as no single migratory) populations and many of them receive the high level of protection such movement. The authors concluded event is likely to impact a significant that upstream colonization by brook afforded by Glacier National Park. percent of the overall number of isolated trout is not continuously progressing However, outside the park, protections populations. Moreover, given the throughout much of the drainage, and accorded WCT in most lakes are less widespread efforts for the conservation that the absence of brook trout in rigorous (U.S. Fish and Wildlife Service of these fish (see ‘‘Evaluation of streams with no apparent barriers to the 1999). Today, WCT with the adfluvial Ongoing Conservation Efforts,’’ below), upstream movement of fish indicated life history probably constitute the any such local extirpation is likely to be that other factors were limiting the smallest proportion of the WCT followed by reintroduction efforts if upstream expansion of brook trout. subspecies, and probably did so WCT were not available naturally to Consequently, the best scientific and historically. recolonize those habitats. commercial information available to us We also found (U.S. Fish and Wildlife indicates that the WCT subspecies is not Kruse et al. (2001) assessed the Service 1999) that resident (i.e., threatened by competition from possible demographic and genetic showing little movement) and fluvial introduced brook trout, although some consequences of purposely isolating the (i.e., migratory) WCT populations, populations may be at higher risk. populations of another cutthroat trout, which live entirely in streams, Risks Associated With Catastrophic, the YCT, in headwater streams in the constitute the most common WCT life- Natural Events—Our initial status Absaroka Mountains, Wyoming. Such history forms and occur in about 4,275 review found that the geographic isolation may actually result, for tributaries or stream reaches that isolation of some extant WCT example, from intentional placement of collectively encompass more than populations had not resulted in a movement barrier to prevent 37,015 km (23,000 linear mi) of stream stochastic extirpations of such nonnative fishes downstream from habitat. Those WCT populations are populations (due, for example, to floods, invading upstream reaches. Kruse et al. distributed among 12 major drainages landslides, or wildfires) to a degree that (2001) made estimates of population and 62 component watersheds in the threatened the WCT subspecies (U.S. size for YCT in each of 23 streams, then Columbia, Missouri, and Saskatchewan Fish and Wildlife Service 1999). compared those estimates to minimum River basins, within the international Information provided in the WCT criteria that the authors considered boundaries of the United States. As status update report (Shepard et al. necessary to prevent population described in the preceding section 2003) ranked each of four measures of extirpation. Kruse et al. (2001) Occurrence of Westslope Cutthroat population viability that could make acknowledged that their minimum- Trout Life-history Forms, the WCT vulnerable to catastrophic, natural viability criteria had not been confirmed information recently provided to us events or adverse human effects on the for YCT and that there was debate (Shepard et al. 2003) indicates even

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greater abundance of WCT across the characteristic of the metapopulation suspected nonintrogressed populations subspecies’ range than we had estimated itself, i.e., the ability of its member fish and (2) introgressed or suspected during the initial status review. The to move (and interbreed) among the introgressed ‘‘conservation’’ available data do not suggest the future various WCT populations that constitute populations. Rainbow trout or YCT loss of any of the three life-history forms the metapopulation. It is assumed that occur in 47 to 91 percent of the stream represented by WCT. Consequently, we potentially hybridizing fishes are miles occupied by WCT conclude that the WCT subspecies is not similarly unencumbered in their metapopulations but only 0 to 22 threatened by the loss of one or more of movements throughout the geographic percent of the stream miles occupied by its life-history forms throughout all or a area occupied by the metapopulation WCT isolets. significant portion of its historic range. and, accordingly, WCT metapopulations In most cases today, it is not Hybridization With Nonnative can inevitably become completely technologically possible to eliminate the Fishes—Hybridization with introduced, introgressed as a hybrid swarm. self-sustaining populations of nonnative fishes, particularly rainbow We examined the database of Shepard potentially hybridizing, nonnative trout and their hybrid descendants that et al. (2003) to assess the introgressive fishes from entire drainages or even have established self-sustaining hybridization risk to extant WCT that individual streams. Consequently, populations, is recognized as an consist of: (1) Nonintrogressed or perceived threats to extant WCT posed appreciable threat to the WCT suspected nonintrogressed populations by nonnative fishes in streams are subspecies. Hybridization requires that and (2) introgressed or suspected sometimes met by installing barriers to the nonnative species invade the WCT introgressed ‘‘conservation’’ the upstream movement of the habitat, the two species interbreed, and populations. Results indicated that nonnative fishes into stream reaches the resulting hybrids themselves survive nonintrogressed and suspected occupied by WCT. In a few cases, and reproduce. If the hybrids backcross nonintrogressed WCT populations usually involving small streams that with one or both of the parental species, occurring as isolets were at moderately provide the greatest opportunity for genetic introgression can occur. high or high risk of introgression in success, fish toxins may be used to Continual introgression can eventually about 16 percent of their 1,944 occupied completely remove all fishes upstream lead to the loss of genetic identity of one stream miles, whereas nonintrogressed from such barriers, after which WCT or both parent species, thus resulting in populations occurring in may be stocked (e.g., Hagener 2002). In a ‘‘hybrid swarm’’ consisting entirely of metapopulations were considered to be either case, because of technological, individual fish that each contain genetic at similar risk in 89 percent of their budgetary, and other limitations, such material from both of the parental 9,999 occupied stream miles. Similarly, actions are now being taken for only a species. WCT in introgressed or suspected small proportion of WCT populations The WCT is known to interbreed with introgressed conservation populations across the subspecies’ range. rainbow trout and YCT, both of which occurring as isolets were at moderately Because self-sustaining populations of were first stocked into many regions of high or high risk of introgression in nonnative fishes pose the greatest the historic range of WCT more than 100 about 38 percent of their 751 occupied hybridization threat to WCT and few of years ago. Nonetheless, the limited data stream miles, whereas introgressed those populations can be eliminated or available at the time of our initial status populations occurring in appreciably reduced, a key concern is review revealed that numerous, metapopulations were considered at for the extent that introgressive nonintrogressed WCT populations similar risk in 99 percent of their 11,775 hybridization may eventually pervade inhabited more than 4,184 km (2,600 occupied stream miles. The WCT in extant, nonintrogressed or suspected mi) of stream (U.S. Fish and Wildlife introgressed or suspected introgressed nonintrogressed WCT populations, Service 1999). Moreover, in the present populations inhabited a total 19,262 km particularly those that inhabit document, we have concluded that (11,943 mi) of stream, 1,060 km (657 mi) headwater streams in high-elevation nonintrogressed WCT are known to less than reported by Shepard et al. areas. Hitt (2002) reported that 55 inhabit 5,633 km (3,500 mi) of stream (2003). However, those authors also percent of 40 WCT populations and probably inhabit as many as 20,278 reported the 563 WCT ‘‘conservation’’ examined in the Flathead River drainage km (12,600 mi) of stream in which no populations collectively occupied in Montana showed evidence of potentially hybridizing fishes occur. 39,349 km (24,450 mi) of stream, nearly introgressive hybridization with Clearly, not all nonintrogressed WCT identical to the amount that we found rainbow trout, and that introgression populations have been equally (i.e., 39,466 km or 24,469 mi) when the had progressed upstream in several vulnerable to introgressive database was examined. The reason for tributaries during the past 2 decades. hybridization. In Idaho, WCT in many the small discrepancy (5.2 percent) in Additional evidence suggested that the populations are sympatric with the total amounts of habitat occupied by upstream introgression of rainbow trout potentially hybridizing, native redband WCT in introgressed or suspected genes would eventually be halted by trout but remain nonintrogressed introgressed populations is unknown diminished stream size, as evidenced by (Moore 2002). Thus, the occurrence of but may be due to differences in the the observation that rainbow trout potentially hybridizing fishes does not specific database queries. usually inhabit larger streams than portend their imminent hybridization The hybridization risk to WCT is cutthroat trout. However, Hitt (2002) with WCT. almost entirely from rainbow trout, further speculated that the stream The WCT status update report YCT, and the hybrid offspring and reaches upstream from those potentially (Shepard et al. 2003) concluded that the descendants of those fishes that have limiting locations would be too small to threats to extant WCT populations from established self-sustaining populations support viable WCT populations. introgressive hybridization were greater within the range of extant WCT In the Clearwater River drainage in for the extensive WCT metapopulations populations. We examined the database Idaho, Weigel et al. (2003) similarly than for the smaller WCT populations of Shepard et al. (2003) to assess the found that WCT at 64 percent of the 80 that occurred as isolets. As pointed out extent that rainbow trout and ‘‘other sample sites showed evidence of by Shepard et al. (2003), the cutthroat trout’’ (primarily YCT) co- introgression with rainbow trout or vulnerability to hybridization of WCT in occur (i.e., are sympatric) with extant native redband trout. The incidence and metapopulations stems from the key WCT in: (1) Nonintrogressed or intensity of that introgression was

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negatively associated with stream nonnative fishes, including potentially formalized coordination among the four elevation, which the authors believed hybridizing species and their hybrid State fish and wildlife agencies, the U.S. resulted from the interaction of low descendants. Thus, the eventual extent Forest Service, and the Service. water temperatures or other that rainbow trout, or YCT, genes move Beginning in June 2001, formal characteristics of the high-elevation upstream may be stream-specific and coordination meetings have been held hydrologic regimes and either the unpredictable. Nonetheless, as noted under the leadership of a representative physiological or habitat requirements of previously (see previous section, ‘‘The of the Idaho Department of Fish and rainbow trout and their hybrids with Value of Hybrid Westslope Cutthroat Game. A formal coordination agreement WCT. In a study conducted in the Trout in Listing Determinations’’), small is now being developed, consistent Kootenay (= Kootenai) River, British amounts of genetic introgression do not conservation goals and objectives for Columbia, Rubidge et al. (2001) found disqualify individual WCT or their WCT have been identified, and an that WCT introgressive hybridization populations from species membership emphasis on consistency and continuity with rainbow trout had become more under the Act. Finally, nonintrogressed in WCT conservation among the widespread in the drainage since the or suspected nonintrogressed agencies has emerged. An indication of mid-1980s, which the authors attributed populations of WCT inhabiting 2,454 the important level of coordination that to the ongoing stocking of rainbow trout km (1,525 mi) of stream are considered has been achieved is provided by the into Koocanusa Reservoir in British secure from genetic introgression recent WCT status update report Columbia. because those populations occur (Shepard et al. 2003), which was In addition, many extant WCT upstream from barriers to the upstream completed through a concerted effort populations occur upstream from movement of nonnative fishes or their among the parties to the coordination barriers that entirely prevent the hybrid descendants. Therefore, the best agreement. To complete that report, 112 upstream movements of nonnative scientific and commercial information biologists—working with 19 geographic fishes, including those that may available to us indicates that the WCT information systems and data-entry potentially hybridize with WCT. We subspecies is not threatened by specialists—completed the task of examined the database of Shepard et al. introgressive hybridization. updating the current information on (2003) to determine the extent that WCT in a timely and comprehensive Evaluation of Ongoing Conservation extant, nonintrogressed or suspected manner. nonintrogressed WCT populations occur Efforts In Idaho, hundreds of conservation upstream from such ‘‘complete’’ In the initial status review (U.S. Fish efforts have been undertaken in recent barriers. Results indicated that 48 and Wildlife Service 1999), we years to protect WCT and their habitats percent of the 1,944 stream miles identified numerous, ongoing (Moore 2003). Those efforts include inhabited by WCT in isolets are conservation efforts that benefitted WCT initiation of a study to determine protected by such barriers, whereas and their habitats. For example, the U.S. movement patterns of WCT in the about 6 percent of the 9,999 stream Forest Service, State fish and wildlife Middle Fork of the Salmon River basin miles inhabited by nonintrogressed agencies, and National Park Service (this study will be expanded into the WCT in metapopulations are similarly reported more than 700 ongoing projects upper Salmon River basin), accelerated protected. Thus, nonintrogressed or directed toward the protection and genetic sampling of fishes in central and suspected nonintrogressed WCT restoration of WCT and their habitats. northern Idaho streams, addition of a populations inhabiting 2,454 km (1,525 Recent information indicates that qualified geneticist to Department of mi) of stream are protected from these important conservation efforts are Fish and Game staff, and introgressive hybridization by barriers ongoing and increasing in number. At implementation of joint efforts with the to the upstream movement of nonnative the time of the initial status review, the U.S. Forest Service focused on fishes. four State fish and wildlife agencies, the protection and enhancement of WCT The available empirical evidence and U.S. Forest Service, and other entities habitat and populations. Montana Fish, speculations by many fishery scientists were implementing WCT conservation Wildlife and Parks continues to indicate that rainbow trout genes are actions in a minimally coordinated implement its conservation agreement expected to continue moving upstream manner. The State of Montana had and plan. In Montana, more than 200 into many stream reaches presently developed a formalized conservation projects that directly benefit WCT have inhabited by nonintrogressed WCT, program for WCT that included a State- now been completed, many of which although, as we have discussed, there wide conservation agreement, a were accomplished as part of a may be limits to that upstream dispersal conservation strategy with specific goals Memorandum of Understanding and set by low stream temperatures or other and objectives, a steering committee Conservation Agreement for Westslope factors. However, the observation that consisting of representatives from Cutthroat Trout in Montana, and numerous nonintrogressed WCT various key agencies and other numerous, additional projects are populations persist today despite both concerned entities, and a technical ongoing (Hagener 2002). Included in the the longstanding occurrence (i.e., more oversight group. At that time, Idaho, Montana Fish, Wildlife and Parks efforts than 100 years) of potentially Oregon, and Washington also were are removal of nonnative trout through hybridizing fishes in regions implementing WCT conservation both physical and chemical means, downstream and the absence of obvious actions as an integral part of their installation of fish-passage barriers, and intervening barriers to the upstream fisheries management programs. The coordinated efforts with U.S. Forest movement of those fish suggests that not U.S. Forest Service also was protecting Service and other management all nonintrogressed WCT populations WCT habitat as specified under INFISH authorities focused on WCT habitat have been and are equally vulnerable to and PACFISH, and had established a protection and enhancement. introgression. Behnke (1992, 2002) new professional position whose Oregon and Washington fishery provides evidence that phenotypically incumbent focused entirely on inland agencies are likewise planning and true, native cutthroat trout of several cutthroat trout conservation in the implementing WCT conservation subspecies persist in many essentially western United States. actions. In Oregon (Unterwegner 2002), undisturbed, natural habitats because More recently, the conservation the Department of Fish and Wildlife is they have fitness superior to that of efforts for WCT have been enhanced by developing a Native Fish Conservation

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Policy in response to a Governor’s species and the probability that the Although the WCT subspecies has Executive Order to review the existing species will persist in ‘‘the foreseeable been reduced from historic levels and Wild Fish Management Policy. The future.’’ The Act does not define the its extant populations face threats in Oregon Department of Fish and Wildlife term ‘‘foreseeable future.’’ However, the several areas of the historic range, we also has an active fish-screening WCT interagency conservation team, the find that the magnitude and imminence program for irrigation diversions in the group that produced the WCT status of those threats do not jeopardize the John Day River drainage and elsewhere. update report, considered the continued existence of the subspecies That program began in the 1950s and ‘‘foreseeable future’’ to be 20 to 30 years within the foreseeable future. Many more than 300 fish screens are now in (approximately 4 to 10 WCT former threats to WCT, such as those place and operated during the annual generations) beyond the present time posed by excessive harvest by anglers or irrigation season. The Oregon (Shepard et al. 2003), a measure that we the widespread stocking of nonnative Department of Fish and Wildlife also believe is both reasonable and fishes, are no longer factors that threaten has accomplished several habitat- appropriate for the present listing the continued existence of the WCT restoration projects throughout the determination. subspecies. The effects of other extant drainage, funded mainly by the In our initial status review, we threats are being effectively countered Bonneville Power Administration and provided evidence from the Missouri by the management actions of State and Oregon Watershed Enhancement Board. River basin that indicated a conspicuous Federal agencies, in conjunction with The U.S. Forest Service has a very decline in the WCT subspecies occurred existing regulatory mechanisms. active conservation program in place for early in the 20th Century (U.S. Fish and Nonetheless, hybridization with WCT. Between 1998 and 2002, the U.S. Wildlife Service 1999). We attributed nonnative rainbow trout or their hybrid Forest Service, in partnership with the that decline to rapid, abundant progeny and descendants, both of which States and others, implemented 324 colonization of mainstem rivers and have established self-sustaining projects that benefit WCT. The total their major tributaries by one or more populations in many areas in the range investment of funds for these projects introduced nonnative fish species (e.g., of WCT, remains the greatest threat to was approximately $9,665,000 brown trout, rainbow trout, and brook WCT. The available empirical evidence (McAllister 2002). During the 2002 trout) that had adverse effects on WCT. and speculations of many fishery Fiscal Year, the U.S. Forest Service Our analysis also showed that the rate scientists indicate that introgression of accomplished 54 on-the-ground of decline in the WCT subspecies is rainbow trout genes will continue to restoration projects, inventories, markedly lower today than it was early move upstream into many stream evaluations, and public outreach efforts in the 20th century. We believe that the reaches presently inhabited by WCT, at a cost of $1.6 million (Johnston 2003). evidence from the Missouri River basin although there may be limits to that The conservation efforts presently provided a model for the historic upstream spread set by environmental being accomplished as part of the decline of WCT that was applicable to factors and the superior fitness of extant routine management objectives of State WCT in many other regions of the WCT populations in their native and Federal agencies, and as part of subspecies’ historic range. habitats. The eventual extent that such formal interagency agreements and Conclusions hybridization moves upstream may be plans, provide substantial assurance stream-specific and impossible to that the WCT subspecies is being The information that we have predict. Nonetheless, the criteria that we conserved. The best information summarized in this document, provided for inclusion of individual available to us indicates that numerous, particularly that obtained from the fishes in the WCT subspecies, in ongoing conservation efforts for WCT status update report (Shepard et al. response to the Court’s order, allow for are being implemented across the 2003), indicates even greater abundance the limited presence in WCT of genetic subspecies’ range. These ongoing of WCT across the subspecies’ range material from other fish species, conservation efforts are commendable than we had estimated during the initial consistent with the intent and purpose and they contribute to the certainty that status review (U.S. Fish and Wildlife of the Act. WCT can be conserved and protected. Service 1999). Today, 563 extant WCT The WCT subspecies is widely ‘‘conservation’’ populations collectively distributed and there are numerous, Listing Determinations Made Under the occupy 39,349 km (24,450 mi) of stream Act robust WCT populations and aggregates in Idaho, Montana, Oregon, Washington, of populations throughout the In the context of the Act, the term and Wyoming. Those WCT populations subspecies’ historic range. Moreover, ‘‘threatened species’’ means any species are distributed among 12 major numerous nonintrogressed WCT (or subspecies or, for vertebrates, DPS) drainages and 62 component watersheds populations are distributed in secure that is likely to become an endangered in the Columbia, Missouri, and habitats throughout the subspecies’ species within the foreseeable future Saskatchewan River basins, within the historic range. In addition, despite the throughout all or a significant portion of international boundaries of the United frequent occurrence of introgressive its range. The term ‘‘endangered States. In our initial status review (U.S. hybridization, we find that numerous species’’ means any species that is in Fish and Wildlife Service 1999), we WCT populations are nonintrogressed or danger of extinction throughout all or a reported that WCT occupied about nearly so, and thus retain substantial significant portion of its range. The Act 37,015 km (23,000 mi) of stream in the portions of their genetic ancestry. We does not indicate threshold levels of United States. In addition, consider slightly introgressed WCT historic population size at which, as the nonintrogressed WCT are now known to populations, with low amounts of population of a species declines, listing inhabit 5,633 km (3,500 mi) of stream genetic introgression detectable only by as either ‘‘threatened’’ or ‘‘endangered’’ and probably inhabit as many as 20,278 molecular genetic methods, to be a becomes warranted. Instead, the km (12,600 mi) of stream in which no potentially important and valued principal considerations in the potentially hybridizing fishes occur. In component of the overall WCT determination of whether or not a our initial status review (U.S. Fish and subspecies. species warrants listing as a threatened Wildlife Service 1999), we reported that Finally, the numerous ongoing WCT or an endangered species under the Act nonintrogressed WCT were known to conservation efforts clearly demonstrate are the threats that now confront the occupy 4,237 km (2,633 mi) of stream. the broad interest in protecting WCT

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held by State, Federal, local, and mitochondrial DNA and allozyme management. CRC Press, Boca Raton, nongovernmental organizations and markers. Genetics 108:237–255. Florida. other entities. Nonetheless, those Baker, J., P. Bentzen, and P. Moran. Campton, D.E., and F.M. Utter. 1985. ongoing conservation efforts, while 2002. Molecular markers distinguish Natural hybridization between steelhead important, are not pivotal to our coastal cutthroat trout from coastal trout (Salmo gairdneri) and coastal decision whether or not to list the WCT rainbow trout/steelhead and their cutthroat trout (Salmo clarki clarki) in as either a threatened or an endangered hybrids. Transactions of the American two Puget Sound streams. Canadian species under the Act. That decision is Fisheries Society 131:404–417. Journal of Fisheries and Aquatic based mainly on the present-day status Bartholomew, J.L., and P.W. Reno. Sciences 42:110–119. of the WCT subspecies, and the 2002. Review: the history and Carmichael, G.J., J.N. Hanson, M.E. occurrence of the numerous extant laws dissemination of whirling disease. Pages Schmidt, and D.C. Morizot. 1993. and regulations that work to prevent the 3–24 in J.L. Bartholomew and J.C. Introgression among Apache, cutthroat, adverse effects of land-management and Wilson, editors. Whirling disease: and rainbow trout in Arizona. other activities on WCT, particularly on reviews and current topics. American Transactions of the American Fisheries those lands administered by Federal Fisheries Society, Symposium 29, Society 122:121–130. agencies. Bethesda, Maryland. Caro, T.M., and M.K. Laurenson. On the basis of the best available Bartholomew, J.L., and J.C. Wilson, 1994. Ecological and genetic factors in scientific and commercial information, editors. 2002. Whirling disease: reviews conservation: a cautionary tale. Science which has been broadly discussed in and current topics. American Fisheries 263:485–496. this notice and detailed in the Society, Symposium 29, Bethesda, Childs, M.R., A.A. Echelle, and T.E. documents contained in the Maryland. Dowling. 1996. Development of the Administrative Record for this decision, Bartley, D.M., and G.A.E. Gall. 1991. hybrid swarm between Pecos pupfish we conclude that the WCT is not likely Genetic identification of native (Cyprinodontidae: Cyprinodon to become either a threatened or an cutthroat trout (Oncorhynchus clarki) pecosensis) and sheepshead minnow endangered species within the and introgressive hybridization with (Cyprinodon variegatus): a perspective foreseeable future. Therefore, listing of introduced rainbow trout (O. mykiss) in from allozymes and mtDNA. Evolution the WCT as a threatened or an streams associated with the Alvord 50:2014–2022. endangered species under the Act is not Basin, Oregon and Nevada. Copeia DeMarais, B.D., T.E. Dowling, M.E. warranted at this time. 1991:854–859. Douglas, W.L. Minkley, and P.C. Marsh. Behnke, R.J. 1992. Native trout of 1992. Origin of Gila seminuda References Cited western North America. American (Teleostei: Cyprinidae) through Adams, S.B., C.A. Frissell, and B.E. Fisheries Society Monograph 6. introgressive hybridization: Rieman. 2000. Movements of nonnative Behnke, R.J. 2002. Trout and salmon implications for evolution and brook trout in relation to stream channel of North America. Simon and Schuster, conservation. Proceedings of the slope. Transactions of the American New York. 359p. National Academy of Science (USA) Fisheries Society 129:623–638. Bernatchez, L., H. Glemet, C.C. 89:2747–2751. Adams, S.B., C.A. Frissell, and B.E. Wilson, and R.G. Danzmann. 1995. DeWitt, J.W., Jr. 1954. A survey of the Rieman. 2002. Changes in distribution Introgression and fixation of Arctic char coastal cutthroat trout, Salmo clarki of nonnative brook trout in an Idaho (Salvelinus alpinus) mitochondrial clarki Richardson, in California. drainage over two decades. Transactions genome in an allopatric population of California Fish and Game 40: 329–335. of the American Fisheries Society brook trout (Salvelinus fontinalis). Dowling, T.E., and C.L. Secor. 1997. 131:561–568. Canadian Journal of Fisheries and The role of hybridization in the Allendorf, F.W., and R.F. Leary. 1988. Aquatic Sciences 52:179–185. evolutionary diversification of animals. Conservation and distribution of genetic Bertorelle, G., and L. Excoffier. 1998. Annual Reviews in Ecology and variation in a polytypic species, the Inferring admixture proportions from Systematics 28:593–619. cutthroat trout. Conservation Biology molecular data. Molecular Biology and Dowling, T.E., and M.R. Childs. 1992. 2:170–184. Evolution 15:1298–1311. Impact of hybridization on a threatened Allendorf, F.W., R.F. Leary, P. Bond, C.E. 1996. Biology of Fishes trout of the southwestern United States. Spruell, and J.K. Wenberg. 2001. The (2nd edition). Saunders College Conservation Biology 6:355–364. problems with hybrids: setting Publishing, Orlando, Florida. 750p. Downing, D.C., T.E. McMahon, B.L. conservation guidelines. Trends in Busack, C.A., and G.A.E. Gall. 1981. Kerans, and E.R. Vincent. 2002. Relation Ecology and Evolution 16:613–622. Introgressive hybridization in of spawning and rearing life history of Allendorf, F.W., R.F. Leary, N.P. Hitt, populations of Paiute cutthroat trout rainbow trout and susceptibility to K.L. Knudsen, L.L. Lundquist, and P. (Salmo clarki seleniris). Canadian Myxobolus cerebralis infection in the Spruell. 2003. Intercrosses and the U.S. Journal of Fisheries and Aquatic Madison River, Montana. Journal of Endangered Species Act: should Sciences 38:939–951. Aquatic Animal Health 14:191–203. hybridized populations be included as Campton, D.E. 1987. Natural Echelle, A.A., and A.F. Echelle. 1997. westslope cutthroat trout? Unpublished hybridization and introgression in Genetic introgression of endemic taxa manuscript, from the Division of fishes: methods of detection and genetic by non-natives: a case study with Leon Biological Sciences, University of interpretations. Pages 161–192 in N. Springs pupfish and sheepshead Montana, Missoula, submitted to the Ryman and F. Utter, editors. Population minnow. Conservation Biology 11:153– U.S. Fish and Wildlife Service, Genetics and Fishery Management. 161. Bozeman, Montana. 23p. University of Washington Press, Seattle. Epifanio, J.M., and D.P. Philipp. 1997. Arnold, M.L. 1997. Natural Campton, D.E. 1990. Application of Sources of misclassifying genealogical hybridization and evolution. Oxford biochemical and molecular genetic origins in mixed hybrid populations. University Press, New York. markers to analysis of hybridization. Journal of Heredity 88:62–65. Avise, J.C., and N.C. Saunders. 1984. Pages 241–263 in D.H. Whitmore, Ferguson, M.M., R.G. Danzmann, and Hybridization and introgression among editor. Electrophoretic and isoelectric F.W. Allendorf. 1985. Absence of species of sunfish (Lepomis): analysis by focusing techniques in fisheries developmental incompatibility in

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hybrids between rainbow trout and two rainbow trout (O. mykiss): distribution Loudenslager, E.J., and R. Kitchen. subspecies of cutthroat trout. and limiting factors. Master of Science 1979. Genetic similarity of two forms of Biochemical Genetics 23:557–570. thesis. University of Montana, Missoula. cutthroat trout, Salmo clarki, in Ferris, S.D., R.D. Sage, C.M. Huang, 80p. Wyoming. Copeia 1979:673–674. J.T. Nielsen, U. Ritte, and A.C. Wilson. Hitt, N.P., and C.A. Frissell. 2001. MacConnell, E., and E.R. Vincent. 1983. Flow of mitochondrial DNA Umbrella species in habitat 2002. The effects of Myxobolus across a species boundary. Proceedings conservation planning: a case study cerebralis on the salmonid host. Pages of the National Academy of Science from the interior Columbia basin. 95–107 in J.L. Bartholomew and J.C. (USA) 80:2290–2294. Unpublished manuscript. 17p. Wilson, editors. Whirling disease: Forbes, S.H., and F.W. Allendorf. Howell, P., and P. Spruell. 2003. reviews and current topics. American 1991a. Associations between Information regarding the origin and Fisheries Society, Symposium 29, mitochondrial and nuclear genotypes in genetic characteristics of westslope Bethesda, Maryland. cutthroat trout hybrid swarms. cutthroat trout in Oregon and central Marnell, L.F., R.J. Behnke, and F.W. Evolution 45: 1332–1349. Washington. Preliminary report. 18p. Allendorf. 1987. Genetic identification Forbes, S.H., and F.W. Allendorf. Hubbs, C. 1955. Hybridization of cutthroat trout, Salmo clarki, in 1991b. Mitochondrial genotypes have between fish species in nature. Glacier National Park. Canadian Journal no detectable effects on meristic traits in Systematic Zoology 4:1–20. of Fisheries and Aquatic Sciences 44: cutthroat trout hybrid swarms. Johnston, E.P. 2003. Letter dated 1830–1839. Evolution 45: 1350–1359. February 12, 2003 from Eric Johnston, McAllister, K.A. 2002. Letter dated Fuller, R. 2002. Letter dated U.S. Forest Service. 1p. (plus 1 November 1, 2002, from Kathleen November 4, 2002 from Ross Fuller, attachment). McAllister, Deputy Regional Forester, Chief, Fish Management Division, Kanda, N., R.F. Leary, P. Spruell, and U.S. Forest Service. 2p. (plus 11 Washington Department of Fish and F.W. Allendorf. 2002. Molecular genetic attachments). Wildlife. 7p. (plus 5 attachments). markers identifying hybridization Meagher, S., and T.E. Dowling. 1991. Gerber, A.S., C.A. Tibbets, and T.E. between the Colorado River—greenback Hybridization between the cyprinid Dowling. 2001. The role of introgressive cutthroat trout complex and fishes Luxilus albeolus, L. cornutus, and hybridization in the evolution of the Yellowstone cutthroat trout or rainbow L. cerasinus, with comments on the Gila robusta complex (Teleostei: trout. Transactions of the American hybrid origin of L. albeolus. Copeia Cyprinidae). Evolution 55:2028–2039. Fisheries Society 131:312–319. 1991:979–991. Glemet, H., P. Blier, and L. Kerans, B.L., and A.V. Zale. 2002. The Miller, R.R. 1950. Notes on the Bernatchez. 1998. Geographical extent ecology of Myxobolus cerebralis. Pages cutthroat and rainbow trouts with the of Arctic char (Salvelinus alpinus) 145–166 in J.L. Bartholomew and J.C. description of a new species from the mtDNA introgression in brook char Wilson, editors. Whirling disease: Gila River, New Mexico. Occasional populations (S. fontinalis) from eastern reviews and current topics. American Papers of the Museum of Zoology, Quebec, Canada. Molecular Ecology Fisheries Society, Symposium 29, University of Michigan, No. 429. 43p. 7:1655–1662. Moore, V. 2002. Letter dated October Bethesda, Maryland. Granath, W.O., and M.A. Gilbert. 31, 2002 from Virgil Moore, Chief, Kruse, C.G., W.A. Hubert, and F.J. 2002. The role of Tubifex tubifex Bureau of Fisheries, Idaho Fish and Rahel. 2001. An assessment of (Annelida: Oligochaeta: Tubificidae) in Game Department. 6p. (plus 15 headwater isolation as a conservation the transmission of Myxobolus attachments). cerebralis (Myxozoa: Myxosporea: strategy for cutthroat trout in the Moore, V. 2003. Letter dated February Myxobolidae). Pages 79–85 in J.L. Absaroka Mountain of Wyoming. 10, 2003 from Virgil Moore, Chief, Bartholomew and J.C. Wilson, editors. Northwest Science 75(1):1–11. Bureau of Fisheries, Idaho Fish and Whirling disease: reviews and current Leary, R.F., F.W. Allendorf, S.R. Game Department. 2p. (plus 3 topics. American Fisheries Society, Phelps, and K.L. Knudsen. 1984. attachments). Symposium 29, Bethesda, Maryland. Introgression between westslope Moyle, P.B., and J.J. Cech, Jr. 1996. Griffith, J.S. 1988. Review of cutthroat and rainbow trout in the Clark Fishes: an introduction to ichthyology competition between cutthroat trout and Fork River drainage, Montana. (3rd ed.). Prentice Hall, Upper Saddle other salmonids. American Fisheries Proceedings of the Montana Academy of River, New Jersey. 590p. Society Symposium 4. 4:134–140. Sciences 43:1–18. Northwest Environmental Defense Hagener, M.J. 2002. Letter dated Leary, R.F., F.W. Allendorf, and G.K. Center. 2002. Letter dated November 4, November 4, 2002 from M. Jeff Hagener, Sage. 1995. Hybridization and 2002 from the Northwest Environmental Director, Montana Fish, Wildlife and introgression between introduced and Defense Center, Portland, Oregon. 6p. Parks Department. 7p. (plus 74 native fish. American Fisheries Society (plus 5 attachments). attachments). Symposium 15:91–101. Nowak, R.M., and N.E. Federoff. 1998. Hartman, G.F., and C.A. Gill. 1968. Leary, R.F., W.R. Gould, and G.K. Validity of the red wolf: response to Roy Distributions of juvenile steelhead and Sage. 1996. Success of basibranchial et al. Conservation Biology 12:722–725. cutthroat trout (Salmo gairdneri and S. teeth in indicating pure populations of O’Brien, S.J., and E. Mayr. 1991. clarki clarki) within streams in rainbow trout and failure to indicate Bureaucratic mischief: recognizing southwestern British Columbia. Journal pure populations of westslope cutthroat endangered species and subspecies. of the Fisheries Research Board of trout. North American Journal of Science 251:1187–1188. Canada 25: 33–48. Fisheries Management 16:210–213. Redenbach, Z., and E.B. Taylor. 2002. Hedrick, P.W. 1995. Gene flow and Leary, R.F., F.W. Allendorf, and N. Evidence for historical introgression genetic restoration: the Florida panther Kanda. 1997. Lack of genetic divergence along a contact zone between two as a case study. Conservation Biology between westslope cutthroat trout from species of char (Pisces: Salmonidae) in 9:996–1007. the Columbia and Missouri River northwestern North America. Evolution Hitt, N.P. 2002. Hybridization drainages. Wild Trout and Salmon 56:1021–1035. between westslope cutthroat trout Genetics Laboratory Report 97/1. Rhymer, J.M., and D. Simberloff. (Oncorhynchus clarki lewisi) and University of Montana, Missoula. 25p. 1996. Extinction by hybridization and

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introgression. Annual Review of resident trout of the interior Columbia Fisheries Society, Symposium 29, Ecology and Systematics 27:83–109. River basin: FY 1998 report on Bethesda, Maryland. Rieman, B.E., and J.B. Dunham. 2000. populations of the upper Yakima basin. Weigel, D.E., J.T. Peterson, and P. Metapopulations and salmonids: a Annual Report to Bonneville Power Spruell. 2002. A model using synthesis of life history patterns and Administration, Portland, Oregon. 51p. phenotypic characteristics to detect empirical observations. Ecology of Trotter, P.C., B. McMillan, N. Gayeski, introgressive hybridization in wild Freshwater Fish 9:51–64. P. Spruell, and M.K. Cook. 2001. westslope cutthroat trout and rainbow Rieseberg, L.H. 1997. Hybrid origins Genetic and phenotypic catalog of trout. Transactions of the American of plant species. Annual Reviews in native resident trout of the interior Fisheries Society 131:389–403. Ecology and Systematics 28:359–389. Columbia River basin: FY 2001 report Rubidge, E., P. Corbett, and E.B. on populations in the Wenatchee, Weigel, D.E., J.T. Peterson, and P. Taylor. 2001. A molecular analysis of Entiat, Lake Chelan, and Methow River Spruell. 2003. Introgressive hybridization between native westslope drainages. Northwest Power Planning hybridization between native cutthroat cutthroat trout and introduced rainbow Council, Bonneville Power trout and introduced rainbow trout. trout in southeastern British Columbia, Administration. 48p. Ecological Applications 13(1):38–50. Canada. Journal of Fish Biology 59 Unterwegner, T. 2002. Letter dated Wilson, C., and L. Bernatchez. 1998. (Supplement A):42–54. November 1, 2002 from Tim The ghost of hybrids past: fixation of Shepard, B.B., B.E. May, and W. Urie. Unterwegner, District Fish Biologist, arctic charr (Salvelinus alpinus) 2003. Status of westslope cutthroat trout Oregon Department of Fish and mitochondrial DNA in an introgressed (Oncorhynchus clarki lewisi) in the Wildlife. 9p. population of lake trout (S. namaycush). United States: 2002. Report of the U.S. Fish and Wildlife Service. 1999. Molecular Ecology 7:127–132. westslope cutthroat interagency Status review for westslope cutthroat conservation team. 88p. Available at trout in the United States. Regions 1 and Young, W.P., C.O. Ostberg, P. Keim, http://www.fwp.state.mt.us/wildthings/ 6. Available at our web site http:// and G.H. Thorgaard. 2001. Genetic westslope/content.asp. In addition, the mountain-prairie.fws.gov/endspp/fish/ characterization of hybridization and data files analyzed as part of the wct/. introgression between anadromous preparation of this report may be Utah Division of Wildlife Resources. rainbow trout (Oncorhynchus mykiss obtained at http://www.streamnet.org/ 2000. Genetic considerations associated irideus) and coastal cutthroat trout (O. online-data/OutSideDataSets.html. with cutthroat trout management. A clarki clarki). Molecular Ecology Spruell, P., K.L. Pilgrim, B.A. Greene, position paper prepared by the fish and 10:921–930. C. Habicht, K.L. Knudsen, K.R. Lindner, wildlife agencies of seven western Authors J.B. Olsen, G.K. Sage, J.E. Seeb, and F.W. States. Utah Division of Wildlife Allendorf. 1999. Inheritance of nuclear Resources Publication Number 00–26. The primary author of this document DNA markers in gynogenetic haploid Salt Lake City. 9p. Available at http:// is Lynn R. Kaeding (see ADDRESSES pink salmon. Journal of Heredity wildlife.utah.gov/pdf/cuttpos.pdf. section). 90:289–296. Verspoor, E., and J. Hammar. 1991. Authority Spruell, P., M.L. Bartron, N. Kanda, Introgressive hybridization in fishes: the and F.W. Allendorf. 2001. Detection of biochemical evidence. Journal of Fish The authority for this action is the hybrids between bull trout (Salvelinus Biology 39 (Suppl. A):309–334. Endangered Species Act (16 U.S.C. 1531 confluentus) and brook trout (S. Vincent, E.R. 2002. Relative et seq.). fontinalis) using PCR primers susceptibility of various salmonids to Dated: August 1, 2003. complementary to interspersed nuclear whirling disease with emphasis on elements. Copeia 2001:1093–1099. rainbow and cutthroat trout. Pages 109– Steve Williams, Trotter, P.C., B. McMillan, N. Gayeski, 115 in J.L. Bartholomew and J.C. Director, Fish and Wildlife Service. P. Spruell, and R. Berkley. 1999. Genetic Wilson, editors. Whirling disease: [FR Doc. 03–20087 Filed 8–6–03; 8:45 am] and phenotypic catalog of native reviews and current topics. American BILLING CODE 4310–55–P

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