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. F <br />17 <br />(Coutant 1977). Acute cold stress caused increased predation on 45-mm-lonq <br />largemouth bass by unstressed largemouth bass (Coutant et al. 1974), <br />probably because of reduced swimming performance of shocked fish. Another <br />example demonstrating that cold shock can cause normally invulnerable fish <br />to become vulnerable to predation occurred when water temperatures near 6 C <br />allowed largemouth bass to prey on cold-stunned tilapia in an Arizona <br />reservoir (Wanjala and Tash 1983). Adult fish require up to 20 days to <br />recover physiologically from cold shock (Peterson and Anderson 1969, Brett <br />1970, Allen and Strawn 1971, Davies 1974), however, there is no data on <br />recovery of small fish because of the difficulty in obtaining blood <br />samples. <br />Other authors have reported on the effects of temperature chanqe to <br />wild fish caused by weather, stream flow, and reservoir releases. <br />Chittenden (1972) found that young American shad were not killed by <br />temperature decreases from 24, to 12 C in 1.25 hr, but speculated that <br />reservoir releases of cold water may have caused shad to abandon affected <br />nursery areas. Larimore and Duever (1968) found that temperature changes <br />from 28 to 12 C in Illinois streams were not lethal to smallmouth bass but <br />may have affected distribution by reducing the ability of the fish to <br />maintain position. Strength of northern pike year classes can be affected <br />when temprerature drops suddenly below 10 C during embryonic development <br />(Hasler 1970). <br />Results of aqe-0 squawfish sampling and water temperature records in <br />1983 are circumstantial evidence that cold water releases from Flaming <br />Gorge Dam contributed to the poor 1983 year class of squawfish. In 1979, <br />1980, and 1981 the temperature differences between the Yampa and Green <br />Rivers in August were 0 C, 1.5 C, and 1.5 C respectively (Archer et al.