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. ~. . -- , .... .. ~ .... 51 UTAH ACADEMY PROCEEDINGS, VOL. 51, PART 2,1974 nia (Jordan, 1891; Jordan and Evermann, 1896). Apparently quite com- mon, this fish was used as food by Indians and early settlers. It was frequently caught by hook and line until the 1930s. This fish is presently extinct, or nearly so, below the Grand Canyon (Minckley and Deacon, 1968) and in Wyoming (Baxter and Simon, 1970). Populations in the upper basin appear much lower than earlier in the 20th century, and spawning populations are known from only a few sites (Holden, 1973). Presently Colorado squawfish are found in all the major channels of the Green and Colorado Rivers in Utah except the area below Flaming Gorge Dam to the Colorado state line. Areas of most consistent reproduction are on the Green River below Ouray, Utah, to its mouth, including Desolation Canyon and the Canyonlands National Park area. Little recent reproduc- tion has been noted above Ouray or in the Colorado River within Utah (Holden, 1973). Populations of squaw fish are also known from Colorado in the Green and Yampa Rivers of Dinosaur National Monument and the Colorado and Gunnison Rivers near Grand Junction, Colorado. Unfor- tunately, reproduction in these areas appears poor (Holden, 1973). Utah is presently the stronghold of this species. Factors Influencing Decline: Major reasons for decline of Colorado squawfish are reservoir construction, water diversion, and competition from introduced species. This river species apparently cannot adapt to large reservoirs (Minckley and Deacon, 1968; Holden, 1973). Also, loss of habitat through water diversion, as in the Gila drainage of Arizona, has decreased the habitable range of the species (Miller, 1961; Minckley and Deacon, 1968). Utah squaw fish populations have probably been in- fluenced by competition with introduced fishes, especially channel catfish. The squawfish is thought to be a migratory species (Holden, 1973); thus declines in other sections of the Colorado basin may have affected Utah's populations. Gila elegans-Bonytail Chub Status: Endangered species Description: Adult bony tail chubs are characterized by a very thin caudal peduncle, enlarged caudal and paired fins, and a smooth nuchal hump (Figure 2). Adults are commonly 10-12 inches instandard length with an extreme of 18 inches S.L. Dorsal and anal rays are usually 10-10, pharyn- geal teeth usually 2, 5-4, 2 but variable. They are silvery in appearance and light green dorsally. Orange-red coloration on lower sides and belly during spawning period (June-July) is most prominent in males, as are fine breeding tubercles. Juvenile bony tail :chubs have not been positively iden- tified, most likely because of appearance similar to that of young roundtail ....--..-1lI!'lIlI" - . + , ,