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<br />o <br />o <br />o <br />,\7) <br />CJl <br />C,J1 <br /> <br />Mr. Calvin Joyner <br /> <br />10 <br /> <br />along the Colorado River near Clifton, Colorado, observed several thousand <br />razorback suckers during spring runoff in the 1930's and early 1940's. In the <br />San Juan River drainage, Platania and Young (1989) relayed historical accounts <br />of razorback suckers ascending the Animas River to Durango, Colorado, around <br />the turn of the century, Platania and Young (1989) also reported the 1976 <br />capture of two adult razorback suckers by VTN Consolidated, Inc., from an <br />irrigation pond adjacent to the San Juan River near Bluff, Utah. <br /> <br />In August 1990, the New Mexico Department of Game and Fish (lief Ahlm, <br />Fisheries Specialist, pers. comm.) interviewed two anglers from Aztec, New <br />Mexico, who claimed to have "commonly" caught razorback suckers in the Animas <br />River near Cedar Hill bridge in the 1930's and 1940's. When the two men were <br />shown a battery of photographs, including roundtail chub (Gila robusta), <br />humpback chub (Gila ~), bony tail (Gila eleQans), bluehead sucker <br />(Pantosteus discobolus), flannelmouth sucker (Catostomus latipinis), razorback <br />sucker, and Colorado squawfish, they both immediately identified the razorback <br />sucker as the fish they had caught. However, prior to the 1976 capture by <br />VTN Consolidated, Inc., there were no scientifically verified reports of <br />razorback sucker captures in the San Juan River drainage. <br /> <br />The current distribution and abundance of razorback sucker has been <br />significantly reduced throughout the Colorado River system (McAda 1987; McAda <br />and Wydoski 1980; Holden and Stalnaker 1975; Minckley 1983; Marsh and Minckley <br />1989; Tyus 1987), The only substantial population of razorback suckers <br />remaining, made up entirely of old adults (McCarthy and Minckley 1987), is <br />found in Lake Mohave; however, they do not appear to be successfully <br />recruiting. While limited numbers of razorback sucker persist in other <br />locations in the lower Colorado River, they are considered rare or incidental <br />and may be continuing to decline. <br /> <br />In the Upper 8asin, above Glen Canyon Dam, razorback suckers are found in <br />limited numbers in both lentic and lotic environments. The largest population <br />of razorback suckers in the Upper Basin is found in the upper Green River and <br />lower Yampa River (Tyus 1987). Lanigan and Tyus (1989) estimated that from <br />758 to 1,138 razorback suckers inhabit the upper Green River. In the Colorado <br />River most razorback suckers occur in the Grand Valley area near Grand <br />Junction, Colorado; however, they are increasingly rare. Osmundson and <br />Kaeding (1991) report that the number of razorback sucker captures in the <br />Grand Junction area have declined dramatically since 1974. <br /> <br />In the San Juan River subbasin, small concentrations of razorback suckers have <br />been reported at the inflow area in the San Juan arm of Lake Powell, Utah <br />(Meyer and Moretti 1988), and at least one specimen was captured in the San <br />Juan River near Bluff, Utah, in 1988 (Platania 1990; Platania et al. 1991). <br />In Bestgen (1990) additional captures of small numbers of razorback suckers <br />also were reported from the Dirty Devil and Colorado River arms of lake <br />Powe 11 . <br /> <br />Beginning in May 1987 and continuing through October 1989, complementary <br />investigations of fishes in the San Juan River were conducted in Colorado, <br />New Mexico, and Utah (Platania 1990; Platania et al. 1991). In 1987, a <br />total of 18 adult razorbacks (6 recaptures) were collected on the south <br />