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Tyus 1991), where warmer water promotes faster growth and better survival. <br />Furthermore, movements of marked age-0 Colorado squawfish suggest they seek warmer <br />water (Tyus 1991b). <br />If optimal embryo hatch and larval survival temperatures are indeed different, <br />then hatch and larval survival may not be independent at some temperatures due to the <br />experimental design used in this study. In the 30°C treatment, which is marginal for <br />hatch, survival of larvae may be confounded by the low number and poor condition of <br />embryos that hatched. Survival of larvae hatched in cooler temperatures and then <br />acclimated and reared at 30°C might have been higher than that of larvae hatched and <br />reared at 30°C. <br />Hatch was not significantly different in fluctuating and constant regimes. <br />Survival of larvae to d 7 was higher in fluctuating temperatures (11-31%), due largely to <br />high survival in the fluctuating regime and low survival in the constant regime in the <br />18°C treatment. <br />Abnormalities.--Abnormalities were apparent in all fish from the 30°C treatment, <br />but incidence was lower at 18-26°C and similar to that observed by Marsh (1985) at 20 <br />(11%) and 25°C (26 %). Abnormalities observed in all treatments in this study were <br />usually so severe (pronounced spinal deformity, ballooning of the abdominal cavity) that <br />these fish would not survive in the wild. <br />Developmental rates and growth.--Rates of development of Colorado squawfish <br />embryos and larvae varied directly with water temperature. Reasons for the markedly <br />longer hatching interval at constant than at fluctuating regimes at 18 and 22°C are <br />unknown. Fluctuating temperatures at 18 and 22°C may have also shortened the time to <br />17 <br />