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<br />!}l)2355 <br /> <br />Biota Results <br /> <br />Analytical results for the biota samples are listed in ~ables 20 through <br />24 in the "Supplemental Data" section at the back of the report. Trace ele- <br />ments listed in the tables are expressed as dry-weight concentrations. To <br />express these data as wet-weight concentrations for comparison to toxico- <br />logical data, multiply the dry-weight concentration by the factor (1 minus the <br />percent moisture content of the sample expressed as a decimal). For example, <br />a dry-weight concentration of 25.2 ~g/g for a sample that has 64.3 percent <br />moisture is equivalent to a wet-weight concentration of about 9.0 ~g/g <br />[25.2 multiplied by (1-0.643)]. <br /> <br />Wildlife Observations <br /> <br />Onsite observations and collections of biota began in the first week of <br />May 1988 and concluded in July. Observations indicated that there were few <br />waterfowl nests along the Gunnison River at Escalante State Wildlife Area and <br />at Sweitzer Lake. Nesting along the Gunnison River was most successful for <br />Canada geese. Several mallard nests were found that did not produce young <br />because of predation. Only two active mallard nests were located at Escalante <br />State Wildlife Area during this study, and eggs were sampled from those nests. <br />Other birds such as killdeer, sandpipers, great blue herons, and blackbirds <br />seem to have good nesting success at the Escalante State Wildlife Area. The <br />heron rookery had young birds in early May; however, despite numerous visits <br />under the rookery, no abandoned young or prey remains were collected. Killdeer <br />and sandpipers were always present on the gravel bars of the Gunnison River. <br />Coots were not seen at the wildlife area. <br /> <br />A mixture of waterbirds, shorebirds, and other species were present <br />during each visit to Sweitzer Lake. In late May, more than 20 blackbird nests <br />containing eggs were located. Coots had suitable habitat at the lake for <br />nesting, but only a single coot nest that had eggs was located. Eggs judged <br />to be less than a week old were collected from the coot nest. Killdeer seemed <br />to be defending territories on the alkali flats along the shore, but only one <br />killdeer nest was found in late June. Although excellent habitat for bird <br />nesting is present at Sweitzer Lake, relatively few birds were observed <br />nesting at the lake during the study. There were four western grebes present <br />at Sweitzer Lake for more than two months. Two grebes were collected on July <br />19, and these two birds were assumed to be the grebes that had been present <br />since May. <br /> <br />Reasons for the lack of use of nesting habitat at the lake are not known. <br />The Escalante State Wildlife Area and Sweitzer Lake are used as a staging area <br />for migrating waterfowl in the spring and fall. Large numbers of ducks and <br />geese use the Gunnison River in the vicinity of the wildlife area and Sweitzer <br />Lake as a temporary stQPover, but most tend to migrate out of the study area <br />prior to nesting. <br /> <br />The largest diversity of fish species was in the Gunnison River at the <br />Escalante State Wildlife Area, where 12 species were observed (chemical <br />analysis were done for 8 species). The species most frequently observed were <br />suckers, carp, roundtail chub, and fathead minnows. There was a similar <br /> <br />49 <br />