Catostomus snyderi

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General Information
Common Name: 
Klamath largescale sucker

Conservation Status in California: Class 1, Endangered (Moyle et al. 2011).
Klamath largescale sucker are found in isolated, restricted populations throughout their range. It is possible that they may already be extirpated from California but data on the species is scarce.

Life History: 

Life History: Detailed information is scant on the biology and life history of this species. Mature suckers collected during a spawning migration were aged at 5-8 yrs (Andreasen 1975), but this is probably a major underestimate. Although growth rates have not been determined, they likely become mature at lengths of 20-30 cm FL at ages of 4-6 years (Moyle 2002). One male was aged as 7 years old at a FL of 31 cm (Buettner and Scoppetone 1991). In Upper Klamath Lake, spawning migrations occur from early March to May, peaking at the end of March when ripe individuals of both sexes move up river in large numbers. Males migrate before females (Andreasen 1975). Initiation of reproduction was attributed to temperature (range 5.5-19?C) and flow (Janney et al. 2007 in Ellsworth et al. 2009). In Oregon, spawning migration was initiated by water temperatures above 10°C and rising flows (Ellsworth et al. 2009). The fecundity of three females was estimated as 39,697 (353 mm SL), 64,477 (405 mm SL), and 63,905 eggs (421 mm SL). In the Sprague and Williamson Rivers (Oregon), larvae moved quickly from spawning to rearing areas (9-14.5 mm TL) as surface drift at night (Ellsworth et al. 2009). The uniformity of larval drift size suggested that drift only occurs during early swim-up phases.
Historically, adults likely occupied deep lake habitats while juveniles occupied streams or lake margins. A number of larger streams currently support reproducing populations (Scoppetone and Vinyard 1991). Adults have also been found during near-shore and offshore sampling of upper Klamath Lake, suggesting that they use habitats at different depths within the lake (Burdick et al. 2007). Like other large catostomids, largescale suckers are benthic grazers, preferring invertebrates and algae (Scoppetone and Vinyard 1991, Moyle 2002). Juveniles from upper Klamath Lake fed primarily on zooplankton (Scoppetone et al. 1995).

Dispersal Capability: Freshwater obligate; only capable of natural colonization via hydrologic stream connection.

Habitat Requirements: 

Habitat Requirements: Although the Klamath largescale sucker is known to inhabit both lentic and lotic habitats, it is primarily adapted to a riverine existence (Andreasen 1975). Little additional information on its ecology is available. They seem to require high water quality although they are able to withstand temperatures as high as 32?C, dissolved oxygen concentrations as low as 1 mg/L and pH levels higher than 10 for short periods of time (Falter and Cech 1991, Scoppetone and Vinyard 1991, Castleberry and Cech 1993). However, streams occupied by Klamath largescale suckers seldom reach water temperatures higher than 25?C (Moyle 2002).


Distribution: Klamath largescale suckers are native to the Lost River-Clear Lake and Klamath River systems in Oregon and California (Moyle 2002). Although they are found in the Klamath River below Klamath Falls, most are found in the river above the falls. Andreasen (1975) reported them from Upper Klamath Lake, the Clear Lake-Lost River system, the entire Sprague River, the lower 20 km of the Sycan River, and reaches of the lower and upper (above Klamath Marsh) Williamson River. In California, they are found mainly in the Lost River drainage, above Harpold Dam and in Wilson Reservoir (USFWS and NOAA 2004), and in the Klamath River upstream of Iron Gate Reservoir.

Abundance Trends: 

Trends in Abundance: Abundance estimates for Klamath largescale suckers were not found. However, it is likely that their abundance has declined to some degree like that of the Lost River and shortnose suckers with which they co-occur. Both Lost River and shortnose suckers were listed as endangered in 1988 (53 FR 27130) and have not recovered (69 FR 43554).


Description: The Klamath largescale sucker is similar to the Sacramento sucker (Catostomus occidentalis) in gross morphology. Andreasen (1975) described this species as being a generalized sucker, intermediate in most morphological characteristics, especially between the Lost River sucker (Deltistes luxatus) and the shortnose sucker (Chasmistes brevirostris) with which it co-occurs. The inferior mouth of this sucker is smaller than that of the Sacramento sucker. The lips are papillose with a medial incision resulting in only one row of papillae extending across the lower lip (Moyle 2002). The narrow upper lip has 4 or 5 complete rows of papillae. They also differ from the Sacramento sucker in having a shorter dorsal fin, with a basal length equal or shorter than the longest dorsal ray and an insertion closer to the snout than to the caudal fin. There are 11 dorsal fin rays (may range from 11 to 12) and 7 anal fin rays. Scales are large and there are 67-81 along the lateral line, with 11-14 scale rows above and 8-12 rows below. Gill rakers number 30-35, but usually 32, in adults and 25-28 in juveniles. Adults have gill rakers with well-formed processes (bony bumps). Adult body coloration is similar to the Sacramento sucker. Their dorsal surface is green-hued while their ventral surface is yellow-gold (Moyle 2002).