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41 <br />Paulin et al. (1990) reported laboratory results indicating that • <br />downstream drift of Colorado squawfish is associated with high <br />velocities, and that dispersal of larvae to suitable nursery areas may, not <br />occur as well if flows are too low. <br />o No data are available regarding specific flows needed to insure dispersal <br />without being so high as to cause larval mortality. <br />o Excessively high flows in late summer-fall may decrease larval survival by <br />depressing growth rates due to decreased water temperatures. <br />Kaeding and Osmundson (1986, 1988b) reported the small size of age-0 <br />Colorado squawfish going to their first winter to be a potential factor in' <br />increased mortality. Suitability of temperatures explained 91% of the <br />variation in fish length exhibited between the Colorado and Green rivers. <br />The relatively larger number of young Colorado squawfish in the Green <br />River than in the Colorado River may be partially explained by more <br />suitable (higher) temperatures for larval growth thus resulting in larger <br />size and resultant lower mortality during the first winter. <br />Jones and Tyus (1985) reported 27 percent shorter total length Colorado <br />squawfish larvae in high flow years (1983 and 1984) than in low flow <br />years (1979 and 1980). <br />o Daily and shorter term flow fluctuations are detrimental to survival of Colorado <br />squawfish. <br />40