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Degraded water quality due to irrigation returns, industrial <br />pollution, and municipal waste may contribute to Colorado squawfish <br />scarcity (Holden and Wick 1982, Seethaler et al. 1976}. Heavy <br />metals, chemicals, and total dissolved solids (TDS) in the Colorado <br />and Green rivers probably were not directly affecting Colorado <br />. squawfish in 1979 to 1982; however, bio-accumulation of toxins in <br />individuals could affect their survival (Miller et al. 1982c). <br />Large amounts of TDS in the Dolores River may partly explain why no <br />Colorado squawfish were found there in 1980-1981. An oil shale <br />industry could affect water quality in Colorado Basin rivers <br />.(Woodward et al. 1985). Leachates from retorted shale probably <br />would not harm Colorado squawfish in areas where dilution factors <br />are high, but fish in backwaters may require protection from toxic <br />effects. <br />CONCLUSIONS AND RECOMME NDATIONS <br />The survival status of Colorado squawfish has not measurably <br />improved between 1981 and 19$5 (Tyus et al. 1985}. There is no <br />indication that species recruitment is adequate; -the species may <br />continue to decline if habitat conditions remain unchanged and if <br />management practices are not implemented. Notwithstanding this <br />precarious status, the USFWS's goal for species recovery is to <br />maintain natural populations in the Green, Yampa, White, and <br />Colorado Rivers (USFWS 1987}, <br />14 <br />