Paiute Cutthroat Trout

Oncorhynchus clarki seleniris

Description

The Paiute cutthroat trout, Oncorhynchus clarki seleniris, is a subspecies of the cutthroat trout, growing 10-12 in (25-30 cm). Its body is elongated and compressed, its head is relatively long, and it has a bright red stripe, or "cutthroat" mark, under each side of the lower jaw. Distinguishing characteristics of the Paiute cutthroat are its purplish pink color and the absence (or near absence) of body spots. Before being reduced to subspecies status in 1947, it was classified as a full species (Oncorhynchus seleniris ).

Behavior

The Paiute cutthroat trout matures sexually at two years and spawns during the early summer in flowing waters above a clean gravel stream bed. The female excavates a nest and spawns with the dominant male. Eggs hatch in six to eight weeks when the water temperature is 42-52°F (6-11°C). The number of eggs produced is proportional to the female's length. An 8 in (20 cm) female will spawn 250-400 eggs. Fingerlings often move into tributary streams until large enough to survive in the main streams. The largest fish vigorously defend stream pools, driving smaller ones into runs and riffles in available unoccupied habitat.

The Paiute, like other trout, are opportunistic feeders of aquatic insects throughout the year and terrestrial insects during the summer. Although the Paiute cutthroat cannot successfully compete with other trout species for food, food is not a limiting factor for establishing a new environment as long as no other trout species are present.

Habitat

The Paiute cutthroat trout requires cool, well-oxygenated water during all its life stages and prefers streams with moderate current in meadow areas. It can survive in lakes, but must have access to flowing water for spawning. There are no unique cover or shelter requirements.

The Silver Creek habitat above Llewellyn Falls is a large mountain meadow at 8,000 ft (2,500 m) elevation. At the highest elevation of Silver Creek the dominant vegetation is pine and red fir. Stands of aspen trees occur throughout the watershed. The stream is mainly riffles with few large pools; the temperature ranges from 32°F (0°C) in winter to 65°F (18°C) in summer. North Fork Cottonwood Creek is smaller than Silver Creek and receives less precipitation but the habitat conditions are similar.

Distribution

This subspecies was first collected above Llewellyn Falls in Alpine County, California, and has an extremely limited range. Historically, it was found only in Silver King Creek in the East Fort Carson River watershed in the Toiyabe National Forest. Silver King Creek is a headwater tributary of the enclosed Lahontan basin of Nevada.

The Paiute cutthroat trout was eliminated from much of its range in the early twentieth century because of interbreeding with the introduced rainbow trout. Several small populations had previously been transplanted into the upper reaches of Silver King Creek above Llewellyn Falls, an impassable barrier for other trout. Some of these fish were transplanted into other California lakes and streams, and at least two populations survive outside the native drainage—Cottonwood Creek (Mono County), and Stairway Creek (Modero County). Recent estimates placed the number of Paiute cutthroat trout at about 2,550. Except for one small inholding in the Silver King basin, the major habitat streams are within the Toiyabe National Forest.

Threats

Probably the greatest threat to this subspecies, besides its limited distribution, is competition and interbreeding with other non-native trout. Where other trout have invaded its habitat, the Paiute cutthroat trout has been displaced or hybridized out of existence. Waters managed for the Paiute cutthroat trout must be protected from the natural or accidental introduction of other trout.

Conservation and Recovery

The extremely limited native range—approximately 9 mi (15 km) in three streams—has complicated recovery efforts. Recovery activities have focused on protecting existing habitat, rehabilitating new sections of streams by removing non-native fishes, and reintroducing the Paiute. State and federal personnel have cooperated to reduce sedimentation and promote the regrowth of native stream-bank vegetation in the watershed.

In 1988, the U.S. Fish and Wildlife Service (FWS), in cooperation with the Forest Service, completed the first phase of planned recovery activities for Paiute cutthroat trout populations in the Toiyabe National Forest. Several low, instream dams were constructed to improve spawning habitat; a barrier was built to prevent competing trout from intermingling with the Paiute on Fourmile Creek; sections of river bank were recontoured to decrease erosion and promote regrowth of natural vegetation; work was completed on the banks of a tributary to reduce sedimentation in Silver King Creek; and solar-powered electric fences were installed to exclude cattle and protect the growth of willow trees along streams. Volunteers donated more than 1,100 hours of labor to these projects.

Contact

U.S. Fish and Wildlife Service
Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Ave.
Portland, Oregon 97232
http://pacific.fws.gov/

References

Behnke, R. J. 1980. Monograph of the Native Trouts of the Genus Oncorhynchus of Western North America. U.S. Fish and Wildlife Service, Denver.

Diana, J. S., and E. D. Lane. 1978. "The Movement and Distribution of Paiute Cutthroat Trout in Cottonwood Creek, California." Transactions of the American Fisheries Society 107:444-448.

U. S. Fish and Wildlife Service. 1985. "Paiute Cutthroat Trout Recovery Plan." U. S. Fish and Wildlife Service, Portland.