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. .. ~. .- .. , 61 UTAH ACADEMY PROCEEDINGS, VOL 51, PART 2,1974 cealed by an overhanging snout. Few papillae are present on the upper lip and not arranged in rows as in other sympatric suckers, such as the Utah sucker, Catostomus ardens (La Rivers, 1962). The Webug sucker appears to be a hybrid between the June and Utah suckers (Sigler and Miller, 1963). Its upper lip is intermediate in size between the June (thin) and Utah (thick) suckers, as is the amount and arrangement of papillae (La Rivers, 1962). Documentation: Both suckers are endemic to Utah Lake. Early descrip- tions (Jordan, 1878) suggest confusion between several suckers in Utah Lake. Suckers were very abundant in the lake, causing an early commercial fJSherman to call it the "greatest sucker~ond in the universe" (La Rivers, 1962). Tanner (1936) consideredtbe June sucker extinct; he also con- . sidered the Utah sucker and Webug suckers (Catostomus fecundus) to be the same species as the June sucker. Specimens of Ouwnistes-like fish are still collected in Utah Lake. R. R. MiDer(University of Michigan) considers these recent specimens as hybrids of Utah and June suckers. He says they do not appear similar to early Chasmistes from the lake and suggest that this hybrid population may be a self-sustaining, i.e., a reproducing popu- lation. Whether or not this recent hybrid resembles the original Webug sucker is unknown. Factors Influencing Decline: The tamnomic confusion concerning these species leaves little room for conclusiolls of any kind. Apparently Tanner's (1936) hypothesis of extinction for the June sucker was based on the severe drought of the early 1930s. Winter kill in 1934-35 killed most of the fish remaining in Utah Lake. flybridization due to low population levels may have occurred after 1935, aeating present conditions. Recent Studies: We are aware of no ecent studies on Utah Lake suckers. Recommendations: A thorough taxClDOmic study of Utah Lake suckers, especially the Ozasmistes-like specimms,. is needed to clarify the present confusion. Once this is done, a mOle realistic assessment of June sucker and Webug sucker population status cat be made. Disc_on All of the rare fishes listed in t1his report are adapted to specific environments. Many are endemic toa small geographic area or to a distinct portion of a larger drainage system. .Because they are highly specialized, they are less flexible and do not eaRly adapt to new conditions. Altera- tions of their environment cause population declines, sometimes to the point of extinction. Generalist speci~ especially introduced forms, often become abundant in disturbed envillDllffients where specialist species are declining, creating added competiti!llll to the further detriment of the highly specialized fishes. ~-1"'1""'1' . + , . ~