Laserfiche WebLink
<br /> I <br />.1 0 <br />~"I <br />< . ~ (-) <br /> l':t <br />- i .~. <br /> , t.;l <br />--I <br /> ., <br /> i <br /> 1 <br />, j <br /> ., <br />.. I <br />~~1 <br />u <br />',"" <br />.;": <br /> , <br />."..1 <br /> " <br />, <br />'. . <br /> <br />~. . ~ <br /> <br />- . <br /> <br />with endangered fishes of the Colorado River basin determined their sensitivity to lethal <br /> <br />waterborne concentrations of selenium and other inorganic elements found in irrigation <br /> <br />drainwater (Hamilton 1995, Buh] and Hamilton 1996, Hamilton and Buhl 1997). However, the <br /> <br />bioaccumulation and toxic effects of selenium in fish result primarily from the consumption of <br /> <br />selenium-laden food (Lemly and Smith 1987, W oock et al. 1987, Hamilton et al. 1990, Coyle et <br /> <br />aI. 1993, Maier and Knight 1994), Consequently, the hazard potential of selenium to these fish <br /> <br />should be based on selenium concentrations in their tissues and food, rather than on waterborne <br /> <br />concentrations (Lemly 1993). <br /> <br />Objective <br /> <br />The objective of this study was to determine the effects of combined dietary and <br /> <br />waterborne selenium exposures on adult Colorado pikeminnow in a water quality simulating that <br /> <br />in the San Juan River. We exposed the adults to selenium via diet and water in the laboratory for <br /> <br />155 days followed by a 90-day depuration period and monitored survival, growth, reproduction, <br /> <br />and selenium residues in muscle tissue. Hatching success of eggs and survival and growth of <br /> <br />larvae produced by these adults were evaluated. In addition, selenium residues in tlle eggs and <br /> <br />larvae were measured, <br /> <br />METHODS AND MA TERlALS <br /> <br />Test Fish <br /> <br />Fifty-eight adult Colorado pikeminnow (16 years old) were transported from Dexter <br /> <br />National Fish Hatchery (DNFH), Dexter, NM, to our laboratory in a distribution truck equipped <br /> <br />with two hauling tanks (1,230 and 1,419 L) supplied with pure oxygen. The fish were hatched in <br /> <br />1981 (DNFH Lot no. 81DXGRCR) and each fish was tagged with an internally implanted <br /> <br />passive integrated transponder (PIT) by personnel at DNFH before transport to our laboratory, <br /> <br />3 <br />