Record Details

A dwarfed population of Catostomus rimiculus (Catostomidae: Pisces) in Jenny Creek, Jackson County, Oregon

ScholarsArchive at Oregon State University

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Title A dwarfed population of Catostomus rimiculus (Catostomidae: Pisces) in Jenny Creek, Jackson County, Oregon
Names Hohler, David Berry (creator)
Bond, Carl E. (advisor)
Date Issued 1981-04-17 (iso8601)
Note Graduation date: 1981
Abstract The population of Catostomus rimiculus from Jenny Creek basin is identified as a dwarfed derivative of the normally much larger C. rimiculus from the Klamath and Rogue River systems. C. rimiculus in Jenny Creek basin are separated from those in the Klamath by a series of 3-10m waterfalls resulting from a Pleistocene lava flow. C. rimiculus in Jenny Creek basin can be distinguished from the Rogue River stock by number of scales above the lateral line, number of pectoral fin rays, number of caudal vertebrae, number of post-Weberian vertebrae and size of the lips. Stocks from Jenny Creek basin and the Klamath can be distinguished on the basis of number of caudal vertebrae. The suckers from Jenny Creek basin mature at approximately 130 mm SL at age II. Only one specimen was older than III. Growth rate appears to be similar in all three stocks of suckers despite the young age of maturity of Jenny Creek suckers. Age at maturity is IV or V for Klamath and Rogue River C. rimiculus. The largest sucker collected from the Jenny Creek basin
was 210 mm SL whereas many specimens 250-390 mm SL were collected in the Rogue and Klamath River systems. I hypothesize that fish colonized the Jenny Creek basin by headwater capture in the Skookum-Rocky Creek area. Jenny Creek suckers are opportunistic omnivores. Segregation of foods in the intestine indicate discriminative feeding. Jenny Creek suckers were found in most habitat types in the lower reaches of Jenny, Beaver, Corral, Keene and Johnson Creeks in summer 1979. Sampling throughout the year established a pattern of migration upstream to spawn in spring and movement downstream in fall.
Genre Thesis/Dissertation
Topic Catostomidae
Identifier http://hdl.handle.net/1957/22203

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