SPECIES CODE: E057 V01
Listed Threatened with Critical Habitat on September 27, 1985 (50 FR 39117 39123). Recovery Plan completed on April 27, 1998.
Note: All descriptions are abstracted and/or excerpted from the Federal Register (1985) and the Recovery Plan (1988).
The Warner sucker is a member of the Catostomidae
family. The species grows to a maximum
length of about 20 inches (510mm) (USFWS 1985). Suckers recovered from an ice induced kill
REPRODUCTION AND DEVELOPMENT:
The species, due to habitat modification, has evolved to adapt to available habitat, i.e. lake and/or stream. They are dubbed lake morphs and stream morphs. Individuals residing in the lake are larger, presumably longer-lived, and are capable of surviving through years of isolation from stream spawning habitats due to drought or other factors. The lake habitat represents a less stable but more productive environment that the metapopulations of Warner suckers use on an opportunistic basis. However, Warner suckers inhabiting streams can migrate into the lake habitat and become lake morphs.
Warner sucker typically ascends stream tributaries to lakes in the
RANGE AND POPULATION LEVEL:
Warner sucker is endemic to the streams and lakes of the
During times of high flow the species is able to inhabit all areas within its range. However, in times of low flow the lake habitat in inaccessible and the lake population declines. Generally, stream dwelling individuals inhabit stretches of slow flowing streams that can be characterized as long pools (50m (166.6ft) or longer) (USFWS 1998). Habitat use by lake resident suckers appears to be similar to that of stream resident suckers in that adult suckers are generally found in the deepest available water where food is plentiful.
The decline of the species is attributed to human induced habitat modification and degradation including irrigation diversion, watershed degradation, and competition and predation by introduced exotic species.
induced habitat modification and degradation has caused increased siltation,
erosion of banks and streambeds, straightening of streams leading to increased
water velocities, changes in timing and levels of peak and low flows, increased
water temperatures, and has caused eutrophication of ponds and lakes. Although natural processes can lead to
erosion of banks and siltation of streambeds, these processes are usually in
equilibrium with the natural recovery process.
Siltation covers spawning beds, decreasing suitable spawning habitat. These changes have also restricted spawning
migration, and peak flow changes have altered the timing of “natural” cues for
spawning migration. Water level
decreases have occurred to the point of complete dry-ups, as was the case with
the early 1970’s, Oregon Department of Fish and Wildlife stocked white crappie,
black crappie, and largemouth bass in Crump and Hart Lakes. Prior to this, brown bullhead and non-native
rainbow trout were introduced into the
Past threats still remain.
1991, 75 adults from
Coombs, C.I., C.E. Bond, and S.F. Drohan. 1979. Spawning and early life history of the Warner sucker (Catostomus warnerensis). Unpublished report to the U.S. Fish and Wildlife Service. 52 pp.
R.S., and R.R. Whitney. 1979. Inland Fishes of