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37 <br />DISCUSSION <br />Temperature Preference <br />Juvenile Colorado squawfish acclimated to 14 C were the least <br />precise of the three groups of juveniles tested. The range of indivi- <br />dual modes was 17-27 C (Table 1), and the pooled data did not have a <br />strong mode (Figure 4). During testing, six 14 C -acclimated fish '~ <br />swam to the 30 C region and lost equilibrium within the first few mi- <br />nutes after introduction to the gradient; two subsequently died. No <br />other fish exhibited similar behavior except for one 20 C -acclimated .. <br />fish during preliminary testing which lost equilibrium at 35 C. <br />~~ <br />Norris (1963) noted that the reactions of cold-acclimated fish to i <br />thermal gradients appeared dulled. Several other investigators have <br />}`~ <br />found warmwater fish species acclimated to low temperatures to have an ~~ <br />..~ <br />:;E <br />inability to avoid stressful or lethal temperatures in a thermal gra- ~~' <br />z, <br /> t <br />dient (Meldrim and Gift 1971; Barans and Tubb 1973; Beitinger and Mag- ?! <br />~ <br /> a <br />nuson 1979). Meldrim and Gift termed this behavior "low thermal res- ~~'', <br /> <br />" r, ; <br />ponsiveness <br />. <br />-The majority of adult squawfish appeared to exhibit low thermal <br />----- ~~' <br />'' <br />responsiveness. Barans and Tubb (1973) suggested that confinement and , <br />limited direction of escape in the experimental apparatus might have <br />~ ~: <br />contributed to the initial exposure mortalities of underyearling white <br />. <br />bass, yellow perch, and adult smallmouth bass in their study. ~ <br />~' <br /> <br />