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<br />Total Humber u! slnm:'.ll'hs <br /> <br />20 <br /> <br />1 UlldiHef('lIliah~d into r011lHIlnil or hOllY tail forms. <br /> <br />VII) was taken on July 20. These fish were <br />found in pools, eddies, and slow runs over <br />boulder or rubble bolloms. Males in spawn-. <br />ing condition had many small breeding <br />tubercles on the head. Dotson (unpublished <br />data, Utah State Division of Fish and Game) <br />reported taking ripe male squawfish from <br />the Green River just below the Flaming Gorge <br />damsite on August 3, 1961. <br />The length-frequency analyses (Figure 4) <br />provided supporting evidence that spawning <br />had occurred during the periods when ripe <br />fish were taken. In all three years, postlarvae <br />12 to 20 mm long were collected 3 to 4 weeks <br />after Ihe ripe fish were found. Water tem- <br />perature and receding waleI' level appeared <br />to be importanl spawning slimuli, The 1966. <br />spawning period was about a month earlier.' <br /> <br />57 <br /> <br />115 <br /> <br />50 <br /> <br />30 <br /> <br />3,S <br /> <br />than' in.19P4" and 1965, and was probably <br />due _to the. e~~lier rise in water t~mperatures' <br />(Figure 2L and earlier recession' of water" <br />level. Inal] years, ripe squawfish were taken' <br />approximately one month after the wate~ <br />temperature had reached 65 F, <br />Squawfish spawned successfully in the <br />Green River in all 4 years since impound- <br />ment, but only below ils confluence with the <br />Yampa River. A poor year-class was pro- <br />duced in 1965. Relatively few young-of-lhe- <br />year (42) were collected that year, and only <br />one yearling was taken in 1966 (Table 8). <br />A weak year-class was also indicated for 1962, <br />Sex was determined for most fish age V <br />and older. The sex ratio was nearly 1: 1 for <br />fish of ages V and VI. After age VI, females <br />became relatively scarce, and 20 of the 24 <br />