The Lahontan cutthroat trout was originally listed as endangered in 1970 but was downlisted to threatened in 1975. A recovery plan was published in 1995. There is no critical habitat designation.

Historical Status and Current Trends

Lahontan cutthroat trout historically occurred in most cold waters of the Lahontan Basin of Nevada and California, including the Humboldt, Truckee, Carson, Walker, and Summit Lake/Quinn River drainages. Large alkaline lakes, small mountain streams and lakes, small tributary streams, and major rivers were inhabited, resulting in the present highly variable subspecies. Only remnant populations remain in a few streams in the Truckee, Carson, and Walker basins out of an estimated 1,641.5 kilometers (1,020 miles) of historic habitat (Gerstung 1986). Although mechanisms of stream colonization outside of the Lahontan basin by this subspecies are uncertain, transport by humans is suspected. Subsequently, resident stream populations were used to stock Oregon streams during the 1970s and 1980s.

The Lahontan cutthroat trout occurs in the following streams in southeastern Oregon: Willow Creek, Whitehorse Creek, Little Whitehorse Creek, Doolitle Creek, Fifteen Mile Creek (from the Coyote Lake Basin) and Indian, Sage, and Line Canyon Creeks, tributaries of McDermitt Creek in the Quinn River basin (Nevada).

Description and Life History

Although coloration is variable, this species is generally heavily marked with large, rounded black spots, more or less evenly distributed over the sides, head, and abdomen. Spawning fish generally develop bright red coloration on the underside of the mandible and on the opercle. In spawning males, coloration is generally more intense than in females.

Lahontan cutthroat trout are obligate but opportunistic stream spawners. Typically, they spawn from April through July, depending on water temperature and flow characteristics. Autumn spawning runs have been reported from some populations. The fish may reproduce more than once, though post-spawning mortality is high (60 to 90 percent). Lake residents migrate into streams to spawn, typically in riffles on well washed gravels. The behavior of this subspecies is typical of stream spawning trout; adults court, pair, and deposit and fertilize eggs in a redd dug by the female. Although the Lahontan cutthroat in Oregon were originally classified as Willow-Whitehorse cutthroat trout, genetic and taxonomic investigations led to the re-classification in 1991 (Williams 1991).

Habitat

The Lahontan cutthroat trout is one subspecies of the wide-ranging cutthroat trout species (O. clarki) that includes at least 14 recognized forms in the western United States. Cutthroat trout have the most extensive range of any inland trout species of western North America, and occur in anadromous, non-anadromous, fluvial, and lacustrine populations (Behnke 1979). Many of the basins in which cutthroat trout occur contain remnants of much more extensive bodies of water which were present during the wetter period of the late Pleistocene epoch (Smith 1978).

These fish are unusually tolerant of both high temperatures (>27 C) and large daily fluctuations (up to 20 C). They are also quite tolerant of high alkalinity (>3000 mg/l) and dissolved solids (>10000 mg/l). They are apparently intolerant of competition or predation by non-native salmonids, and rarely coexist with them (Behnke 1992, LaRivers 1962).

Reasons for Decline

The severe decline in range and numbers of Lahontan cutthroat is attributed to a number of factors including hybridization and competition with introduced trout species, loss of spawning habitat due to pollution from logging, mining, and urbanization, blockage of streams due to dams, channelization, de-watering due to irrigation and urban demands, and watershed degradation due to overgrazing of domestic livestock (Gerstung 1986, Coffin 1988, Wydoski 1978). Declining Lahontan cutthroat populations in the Whitehorse and Trout Creek Mountains are a result of decades of season-long intensive livestock grazing, recreational over-fishing, and more recently drought conditions from 1985 to 1994.

Conservation Measures

Oregon Department of Fish and Wildlife (ODFW) surveys indicated that Lahontan cutthroat trout populations were reduced from 1985 to 1989 by: 62 percent on Willow Creek; 69 percent on Whitehorse Creek; 93 percent on Little Whitehorse Creek; and 42 percent on Doolittle Creek. No Lahontan cutthroat trout were found in either the 1985 or 1989 ODFW surveys on Fifteen Mile creek (USDI 1997). These declining numbers prompted ODFW to close area streams to fishing (by special order) in 1989. This closure remains in effect. Fish surveys of area streams were conducted again in October of 1994. Although methods vary among the conducted surveys (1985, 1989, and 1994), fish numbers have increased in general from approximately 8,000 fish in the mid-1980s to approximately 40,000 fish in 1994. However, in many areas, stream conditions remain less than favorable for the cutthroat.

References and Links

Behnke, R.J. 1979. Monograph of the native trouts of the genus Salmo of eastern North America. Unpub. Man. 215pp.

Behnke, R.J. 1992. Native trout of Western North America. Am. Fish. Soc. Monog. 6.

Coffin, P.D. 1988. Nevada's native salmonid program:status, distribution, and management. Nevada Dept. of Wildlife. Reno, NV. 17pp.

Gerstung, E.R. 1986. Draft fishery management plan for Lahontan cutthroat trout (Salmo clarki henshawi) in California and western Nevada waters. California Dept. of Fish and Game. Inland Fisheries Admin. Rept. No. 86. Fed Aid Proj. No. F33-R-11. 53pp.

LaRivers, I. 1962. Fish and Fisheries of Nevada. Nevada State Fish and Game Commission. Carson City.

Smith, G.R. 1978. Biogeography of intermountain fishes. Great Basin Nat. Mem. 2:17-42.

USDI. 1991. Biological opinion for the Jordan Meadows allotment grazing decision. Document No. 1-5-91-F-23. U.S. Fish and Wildlife Service. Reno, NV. 16pp.

USDI. 1997. 1996 Whitehorse Butte Allotment evaluation. U.S. Bureau of Land Management, Vale, OR. 45 pp.

USFWS. 1970. United States List of Endangered Native Fish and Wildlife. Federal Register 35:16047-16048.

USFWS. 1975. Threatened Status for Three Species of Trout (Lahontan cutthroat, Salmo clarki henshawi; Paiute cutthroat, Salmo clarki seleniris; Arizona trout, Salmo apache). FR 40:29863-29864.

USFWS. 1995. Lahontan cutthroat trout, Oncorhynchus clarki henshawi, Recovery Plan. Portland, OR. 147.

Williams, R.N. 1991. Genetic analysis and taxonomic status of cutthroat trout from Willow Creek and Whitehorse Creek in southeastern Oregon. BSU Evolutionary Genetics Lab Report 91-3. Boise, ID. 15pp.

Wydoski, R.S. 1978. Responses of trout populations to alterations in aquatic environments: a review. Pages 57-92 in J.R. Moring, ed. Proceedings of the wild trout-catchable trout symposium, Eugene, OR. Feb. 15-17, 1978.