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o c ~ _~ a 200 Further, elevated selenium concentrations in water at the mouth of Ashley Creek (i.e., 59-78 µg/L; Peltz and Waddell 1991) apparently would not prevent razorback suckers from using the area for prespawning activities because fish, such as fathead minnows, have failed to behaviorally avoid concentrations of selenium that would cause death in 24 h (Watenpaugh and Beitinger 1985). Because adult razorback suckers use the Stew- art Lake outfall and Ashley Creek confluences with the Green River prior to spawning (Tyus 1987) and post-spawning (un- published data, B. Waddell, C. Wiens, and B. Haines, FWS, 1991), selenium uptake from both diet and water and deposition in eggs is occurring. Larvae Effects °~~ The effects of pazental transfer of selenium to eggs and the ~o ~ resulting larvae are adverse, even though no effects have been reported to occur on fertilization or hatching success. Schultz ~~ wand Herirtanutz (1990) reported that ovaries of fathead min- ~ ~ Wows reared for 1 year in streams with 10 µg/L selenium (i.e., ~ ~ fish were exposed to selenium in water and the food chain) had ~ j ~, 24 µg/g selenium (reported as 5.89 µg/g wet weight) compazed ~ o to controls with 3.1 µg/g (reported as 0.77 µg/g wet weight); ~ ~ v the resulting embryos had l6 µg/g selenium compared to 1.2 ~ ~~ µg/g in control fish. The incidence of edema was 25% and lordosis was 23% in selenium-laden 4-day-old fry compared ~~ 3~ with 1% edema and 696 lordosis in controls. Likewise, Herma- ZC v nutz et al. (1992) reported that exposure of bluegills to 10 µg/L selenium for 258 days in streams before spawning resulted in ~ embryos with significantly lower hatch and larval survival, and c a v increased occurrence of edema. These effects occurred in ~p _p~ `~ spawns resulting from ovaries with 18 µg/g selenium. Many of `~'~ ~ the larvae with lordosis and hemorrhaging failed to survive c~ -~ more than 1 day, and those with edema failed to develop prop- erly. Gillespie and Baumann (1986) reported similar effects in progeny of bluegill with 28 µg/g selenium in ovaries. Pyron and Beitinger (1989) reported that nearly alt of the larvae pro- duced by fathead minnows exposed to 20 or 30 mg/L selenium for 24 h had gross morphological abnormalities, particularly edema, and none of the edematous larvae survived longer than 7 days post-hatch. in contrast to Hermanutz et al. (1992), Gillespie and Bau- mann (1986) reported that neither percent fertilization nor hatch were different among 18 artificial crosses of bluegills with high or low selenium body burdens. Ogle and Knight (1989) also reported no effect on percent hatch or survival of larvae from adult fathead minnows fed up to 30 µg/g selenium dry weight in the diet for 100+ days before spawning. Their results seem confusing because females had an unrealistically low 10.9 µg/g selenium in ovaries compared to 24 µg/g selenium (reported as 5.89 µg/g wet weight) in ovaries of fathead minnow reported by Schultz and Hermanutz (1990) and 18 µg/g selenium (re- ported as 4.4 µg/g wet weight) in ovaries of bluegill reported by Her-manutz et al. (1992). Ogle and Knight (1989) believed the low selenium residues were because their experimental diet contained 75% inorganic selenium (25% organic selenium), which they theorized was less readily taken up in the fish gut. The above-normal selenium concentrations in eggs of razor- back suckers from the Green River in the current study is probably having some adverse effect similar to those described above on the resulting fry. Because of the limited information S. 1. Hamilton and B. Waddell available, it is not possible to predict what those specific effects might be. Muscle Plugs A significant correlation was found between selenium concen- trations in eggs, milt, and muscle plugs collected from the same razorback suckers in this study. For females, the Pearson corre- lation coefficient was 0.99 (p=0.03; n=3) and for males it was 0.87 (p=0.05; n=5). Although the number of samples avail- able for the comparison was small because of a very limited number of razorback suckers in the wild, it does-neverthe- less-show that the selenium concentrations in muscle plugs seem to be directly related to the amount of selenium present in eggs and milt of adult razorback suckers. The concentration of selenium in muscle plugs was not sig- nificantly different from that in either eggs or milt (paired t-test), although the amount in muscle plugs was consistently higher than in eggs or milt. These results aze somewhat similar to those of Sager and Cofield (1984), who reported that the concentration of selenium in female gonads of bluegill from Hyco Reservoir, North Carolina, were not significantly differ- ent than in muscle tissue. However, they also reported male gonads of bluegill contained significantly less selenium than did muscle. In contrast, they found female gonads in white catfish (Ictalurus taros) and channel catfish (Ictalurus punctatus) had significantly more selenium than muscle. Cumbie and Van Horn (1978) also reported substantially higher selenium concen- trations in female gonads of bluegill and black bullhead in Belews Lake, North Carolina, than in muscle. Both Hyco Reservoir and Belews Lake Itad been studied extensively and shown to have selenium contaminant problems derived from long-term exposure to low waterborne selenium concentrations (_ =10 µg/L), but in- creasingly higher dietary concentrations at higher trophic levels. Conclusion Eggs, but not milt, of razorback suckers had concentrations of selenium that were above background concentrations in control fish from laboratory studies or reference fish from field studies. The concentrations, however, were below those reported in other species of selenium~xposed fish that had reproductive problems in laboratory studies or field investigations. Never- theless, selenium concentrations in eggs of reproductive razor- backsuckers in the Green River, in our opinion, are sufficiently elevated to suspect reproductive problems that contribute to the decline of this and possibly other endangered fish in the upper Colorado River basin. Acknowledgments. This study was funded in part by the U.S. Bureau of Reclamation and the U.S. Fish and Wildlife Service. S. Stephenson and B. Haines are thanked for collecting eggs and milt; B. Haines for information on the fertilized egg study; A. Bullard for the NFCR selenium analyses; and B. Jensen (Dexter NFH, NM) for supplying reference razorback sucker eggs. References Baumann PC, Gillespie RB (1986) Selenium bioaccumulation in go- nads of largemouth bass and bluegill from three power plant cool- ing reservoirs. Environ Toxicol Chem 5:695-701