Lost River Sucker

Deltistes luxatus

Description

The Lost River sucker, known locally as mullet, is one of the larger members of the sucker family, growing to 25 in (60 cm) in length and weighing as much as 10 lbs (4.5 kg). It has a short, terminal mouth, a hump on its snout, and triangular gill rakers (bony appendages that direct food into the gullet). Once classified in the genus Chasmistes, the species was moved into a separate genus, Deltistes, in 1896 based on the shape of its gill rakers.

Behavior

The Lost River sucker leaves its lake habitat in the spring and swims into smaller mountain streams to spawn. Sexual maturity for Lost River suckers sampled in Upper Klamath Lake occurs between the ages of 6-14 years with most maturing at age 9. Maximum life span is about 45 years. It is a bottom feeding species, adapted to siphoning sediments for plant matter and detritus.

Habitat

This lake-dwelling species spawns in the head-waters of small, flowing streams in spring.

Distribution

The Lost River sucker ranged in the lakes that fed the Lost and Klamath Rivers in the Klamath Basin of south-central Oregon and north-central California. Before the region was heavily farmed, beginning in the late 19th century, large numbers of spawning suckers were taken from Sheepy Creek, a tributary of Sheepy Lake. The Sheepy, Lower Klamath, and Tule Lakes were drained temporarily in 1924, eliminating Lost River suckers from these waters.

Once very plentiful in Klamath and Tule Lakes, the species' population has been reduced by as much as 95%. The present distribution of the Lost River sucker includes Upper Klamath Lake and its tributaries, Clear Lake Reservoir and its tributaries, Tule Lake and the Lost River up to Anderson-Rose Dam, the Klamath River downstream to Copco Reservoir and probably to Iron Gate Reservoir. In the Upper Klamath Lake watershed, Lost River sucker spawning runs are primarily limited to Sucker Springs in Upper Klamath Lake, and the Sprague and Williamson Rivers. Spawning runs also occur in the Wood River and in the Crooked Creek watershed. An additional run may occur in Sheepy Lake in the Lower Klamath Lake watershed, and spawning has been documented in the Clear Lake watershed.

In the 1980s, the numbers showed a decline severe enough to spark the Endangered listing in 1988. A 1984 survey estimated the number of spawning suckers moving out of Upper Klamath Lake to be 23,120. By 1985, the number had declined to 11,860. The species had been almost eliminated from the river's Copco Reservoir in Siskiyou County, California. Despite an intensive search, only one specimen was collected there in 1987.

Threats

Early surveys of the Klamath Basin found Lost River suckers in sufficient abundance to constitute a major food source for the Klamath Indians and early settlers. In the late 1890s a cannery was operated near Olene, Oregon, to commercially harvest the fish.

The Upper Klamath Basin once had over 350,000 acres (141,641 hectares) of wetlands, extensive riparian corridors, and functional floodplains that could intercept storm runoff, dampen sharp peaks in the hydrograph, reduce erosion forces, remove organic and inorganic nutrients, and improve water quality. The loss of these wetlands has had large scale detrimental effects to the quality and quantity of suitable sucker habitat. Currently, less than 75,000 acres (30,352 hectares) of wetlands remain in the Basin.

The entire Klamath River basin has been transformed by dam construction, water diversion, and dredging. Although the large artificial reservoirs technically provide new habitat for lake-dwelling fish, the dams block the fishes' spawning runs. The most significant event in the decline of the Lost River sucker was construction of the Sprague River Dam at Chiloquin, Oregon, in 1970, which cut off the species from more than 95% of its historical spawning habitat. Since this dam was built, significant numbers of young have not been added to the population. Most living fish are at least 19 years old.

In 1988, thousands of Lost River suckers in Upper Klamath Lake were killed because of blue-green algal blooms. These toxic algal blooms occur in particularly hot, dry years. Pollution of the lake and decreased summer inflows aggravate this problem. Such large-scale die-offs are clearly a contributor to this species' current status, though they don't occur every year.

Fish ladders, constructed to assist fish over the dams, have not aided the Lost River sucker, a fish that does not leap. Unless some way is found to lift this fish over the dams and into spawning waters, the species is doomed. The Oregon Fish and Wildlife Commission placed the Lost River sucker on the state's list of protected species in 1987, and California law recognizes it as Endangered.

Conservation and Recovery

In 1996, the FWS (National Wildlife Refuge System) released the Sucker Critical Habitat Proposal, with the goal of defining, preserving and restoring the habitat of the Klamath Basin, critical to both the Lost River and shortnose sucker—the latter of which shares the habitat and is also listed as Endangered.

Contact

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

References

Coots, M. 1965. "Occurrences of the Lost River Sucker, Deltistes luxatus (Cope), and Shortnose Sucker, Chasmistes brevirostris (Cope) in Northern California." California Fish and Game 51:68-73.

Moyle, P. B. 1978. Inland Fishes of California. University of California Press, Berkeley.

U.S. Fish and Wildlife Service. 1988. "Determination of Endangered Status for the Lost River Sucker and Shortnose Sucker." Federal Register 53(137): 27130-27133.

U. S. Fish and Wildlife Service. 1993. "Recovery Plan for the Lost River Sucker and Shortnose Sucker." U.S. Fish and Wildlife Service, Portland.