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I I I I I I I I I I I I I I I I I I I water as the beaker, and examined using a dissecting scope to record the number of live and dead eggs, and the number and type of deformities. Egg viability also was measured on groups of about 100 eggs from each spawn maintained at 24-Road, including three spawns from brood stock. Egg diameter was measured on 25 eggs from each spawn, including three spawns from brood stock. A 30-day larval fish study was initiated with 5-day-old larvae and was conducted in a mobile laboratory housed in the garage at the CRFP office. For each of three spawns of adults from Horsethief, Adobe Creek, North Pond, and brood stock, eight groups of 10 larvae were placed in 2-L exposure beakers to assess survival, growth, abnormal development, and whole-body residues of selenium. The beakers were filled with 1.6 L of water, and fifty percent of the water was renewed daily. One set of larvae in two beakers from each source were exposed to one of four treatments: (1) reference food (brine shrimp) and reference water (24-Road), (2) reference food and site water where adults were held, (3) site food where adults were held [for Horsethief and brood stock, zooplankton were collected from Horsethief east wetland] and reference water, and (4) site food and site water. Zooplankton were collected using modified light traps, sieved to separate zooplankton <0.425 mm for feeding, and counted for feeding 40 organisms per fish in each exposure beaker. The number of live fish were counted daily, and the weight and total length of fish measured after 30 days of exposure. Larvae were collected for selenium residue analysis after about 1 week and after 30 days of exposure. Informal observations were made on a separate group of adult razorback suckers held in a hoop net at North Pond for 89 days. Muscle plugs from five fish were collected at 30-day intervals for selenium analysis. Various tissues from adults were sampled at the end of the exposure period for selenium analysis. Informal observations were made on razorback sucker -larvae (aged 31-134 days old) held at 24-Road. Measurements of weight and total length were made on three 20-fish subgroups of larvae from the four sources at 30-day intervals, and samples were collected at the end of the observation period for selenium residue analysis. During the adult study, selenium was elevated in water and food organisms at Adobe Creek, and in water, food organisms, and sediment at North Pond. Adults at the three sites lost weight during the first couple of months apparently while adapting to conditions at the holding sites, but gained weight during the latter portion of the study period. Although there were differences among the three sites in concentrations of inorganic elements in water, sediment, and biota, selenium was the only element elevated to concentrations of concern for adverse effects in fish. Adult razorback sucker at Adobe Creek and North Pond accumulated selenium in muscle plugs, various tissues, and eggs to concentrations reported to cause adverse effects on reproduction in studies with other fish species (Summary Table 1). Selenium concentrations in eggs from Adobe Creek adults (46 jlg/g) and North Pond adults (38 J,Lg/g) were 3-4 times higher than the proposed toxic threshold (10 J,Lg/g) for reproductive failure. The selenium concentrations in muscle plugs from adults at Adobe Creek and North Pond were lower than in 40% of wild adults collected from the Green River in Utah. During a depuration period when adults from Adobe Creek and North Pond were held at Horsethief, fish lost 1-2% of their selenium burden in 32 days and 14-19% in 66 days, which suggested a slow rate of elimination compared to that of other fish species given in the literature. Eggs from young adults held at the test sites had a smaller diameter and higher moisture content than those fromthe older brood stock. It was assumed, based on the literature, that brood stock larvae had a higher level of fitness than larvae produced by the young adults used in the XIV