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Last modified
7/14/2009 5:02:32 PM
Creation date
5/20/2009 10:15:27 AM
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UCREFRP
UCREFRP Catalog Number
7994
Author
Duff, D. A., Tech. Ed.
Title
Conservation Assessment For Inland Cutthroat Trout, Distribution, Status and Habitat Management Implications.
USFW Year
1996.
USFW - Doc Type
\
Copyright Material
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<br />within 28 tributaries, while in the Entiat watershed, 17 sites within 11 different streams were sampled. <br />Westslope cutthroat trout were found in 19, 17, and 3 of these sites in the Methow, Wenatchee, and <br />Entiat watersheds, respectively. Among these 9, 10, and 1 of these sites for the Methow, Wenatchee, <br />and Entiat watersheds, respectively, contained "pure" (100% confidence in identification) or "essen- <br />tially pure" (near 100% confidence; one + morphometric feature may be questionable) westslope <br />cutthroat trout. In the remaining westslope cutthroat trout sites, specimens were questionable; <br />morphometric characters suggest historic gene flow with other cutthroat trout races or, perhaps, <br />rainbow trout. Populations in these drainages are mostly on National Forest System lands. <br /> <br />The status of populations generally remain unknown with the greatest threat being anglers in highly <br />accessible streams (Larry Brown, Washington Department of Wildlife, personal communication). <br />Other threats such as habitat loss, competition, and hybridization exist but remain unquantified. <br /> <br />Wvominq <br /> <br />The range of westslope cutthroat trout extends into the headwaters of the Madison and Gallatin rivers <br />within Yellowstone National Park. Colonization was precluded into the Gibbon and Firehole rivers due <br />to barrier falls. Biologists with the United States Fish and Wildlife Service working within the park <br />estimate that westslope cutthroat trout may have occupied between 12-15 streams in the headwaters <br />of these rivers. Currently, about 6 populations remain with each having some degree of hybridization <br />with Yellowstone cutthroat trout and/or rainbow trout. Only two tributary streams contain populations <br />with genetic purity greater than 98% based upon electrophoretic analysis (Personal Communication, <br />Dan Mahoney and Lynn Kaeding, United States Fish and Wildlife Service). Reasons for decline are <br />competition and hybridization with exotic species, particularly brown trout, rainbow trout, brook trout, <br />and Yellowstone trout. Yellowstone trout were also introduced into the Madison and Gallatin rivers <br />which are outside their native range in Yellowstone National Park. <br /> <br />TRENDS <br /> <br />As early as 1959, Hanzel (1959) documented in Montana that westslope cutthroat trout were restrict- <br />ed to headwater streams with pure populations being retained above barriers. Westslope cutthroat <br />trout were originally on the United States Fish and Wildlife Service's (USFWS) "Red Book" of threat- <br />ened and endangered species from 1966- 1972 but were dropped from the list with the passage of <br />the Endangered Species Act in 1973 due to questions concerning classification (Roscoe 1974). The <br />USFWS previously classified westslope cutthroat trout as a Category 2 species (listing is possibly <br />appropriate, but persuasive data on biological vulnerability and threat are not currently available to <br />support proposed rules) prior to the deletion of Category 2 species from the candidate list on <br />February 28, 1996 (61 FR 7596). <br /> <br />Reasons for decline were noted early. Hanzel (1959) listed: stream habitat changes, competition with <br />exotic species and hybridization with rainbow trout as major factors of decline. In the 1970 T,E, & S <br />supplement to the Forest Service Manual Region 1, the Forest Service identified habitat degradation <br />and increased fishing pressure as factors of decline. They cited "road construction as perhaps the <br />most serious source of damage from man's activities". Not only as a result of sediment but increased <br />temperatures, improper culvert installations, and increased angler access. Three decades later, <br />populations continue to decline from competition and hybridization with exotic species, habitat loss <br />and degradation. and continued fishing pressure. <br /> <br />Presently, Washington was the only state that indicated populations appear stable where known but <br />status of numerous populations remain unknown. As a whole, trend is declining throughout this <br /> <br />6 <br />
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