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<br />2:0 <br />~ <br /> <br /> <br />I <br /> <br />~g <br />.~ <br />-3 <br />.0'. <br />~ <br />...!' <br /> <br />11 <br />g <br />1I <br />~\ <br />I <br />1 <br />-I <br />11 <br />t <br />'I <br />11 <br />II <br />I <br /> <br />system. The resulting larvae were held for 30 days and monitored for survival, growth, and <br /> <br />selenium residues. The egg and larval studies were conducted in clean reconstituted test water. <br /> <br />Survival and growth of adults were not affected by the combined dietary and waterborne <br /> <br /> <br />selenium exposures for 155 days. Adults of both sexes lost weight during the first 30 days of the <br /> <br /> <br />study and during the depuration period. The rate of weight loss was higher in females than in <br /> <br /> <br />males. Regardless of sex, none of the fish exhibited a significant weight gain during the study <br /> <br /> <br />compared to their weights at day O. Spawning success offemales was low and highly variable <br /> <br />among selenium treatments. Only 10 of35 females expressed eggs and spawning success was <br /> <br />limited to one female in three treatments, two females in two treatments and three females in one <br /> <br />treatment. All males expressed milt during the spawning trials, but 6 ofl9 males expressed less . <br /> <br /> <br />than 20 m!. None of the reproductive metrics (eggs released, hatchability, egg size, incidence of <br /> <br /> <br />deformities, and survival and growth oflarvae) were correlated with dietary or waterborne <br /> <br />selenium. exposure concentrations of the female parent. However, due to the lack of replicate <br /> <br />spawns for half of the treatments, we were not able to draw unequivocal conclusions concerning <br /> <br />the effects of these dietary and waterborne selenium exposures onreproduction of Colorado <br /> <br />pikeminnow. <br />Selenium concentrations in muscle plugs of adults were strongly correlated with dietary <br /> <br />selenium concentrations, but not with waterborne selenium, and concentrations seemed to reach <br /> <br />an equilibrium after 120 days of exposure. The reduction in muscle plug selenium residues after <br /> <br /> <br />90 days of depuration was minimal, which indicated that selenium accumulated in muscle was <br /> <br /> <br />slowly eliminated from the fish. Bioaccumulation factors for selenium in muscle tissue <br /> <br /> <br />(compared to the diet) were less then one (range, 0.17 to 0.60) and were inversely related to <br />dietary selenium concentrations. <br /> <br />x <br />