Effect of selenium on early life-stage development of westslope cutthroat trout

As part of on-going efforts by the Elk Valley Selenium Task Force to characterize benchmarks for selenium that are protective of environmental quality, the effect of egg selenium burden on early life-stage development of westslope cutthroat trout was investigated for fish from the Elk Valley, BC. The investigation was designed to provide data to derive a Tissue Residue Guideline for selenium for this species and region, and to resolve apparent differences in results from prior studies. Eggs collected from adult fish from lentic and lotic habitats were reared to 28-days beyond swim-up to establish whether habitat type resulted in differences in expression of selenium-related effects, including larval survival, rates of deformities and growth. Speciation of selenium in eggs from lentic and lotic environments was measured, and effects on study results assessed. The study demonstrated that larval mortality was the primary adverse effect of elevated selenium, with deformities generally limited to surviving fry from egg batches that also elicited significant mortalities. A sharp dose-response curve was obtained, with no evidence of differing sensitivities for eggs obtained from fish from lentic and lotic habitats. The EC10, EC20 and EC50 values for larval survival were 19.0, 22.8 and 29.9 µg/g Se (egg, dry weight). Speciation of selenium was shown to be similar in eggs from lentic and lotic sites, although analytical complications prevented an assessment of the relative concentrations of individual seleno-amino acids present.Non UBCUnreviewedUnknow