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Abstract
The current study evaluated the effects of estrogens on fishes in the upper Conasauga River (UCR) and identified tributaries with the highest estrogen inputs. Estrogen concentrations were higher in sediment than surface water. However, vitellogenin, a biomarker of estrogen exposure, was higher in male fish exposed to UCR water than those exposed to UCR sediments, suggesting estrogens in the water were more bioavailable than those in the sediment. In a survey of wild adult fishes from the UCR, 13 (7.5%) of the 174 male fishes (27 species) collected had testicular oocytes. Additionally, gonopodia of Western Mosquitofish collected from a UCR farm drainage ditch were shorter compared to mosquitofish from other areas of the basin with different land uses. Larval fish exposed to sediment from Mill Creek and Sugar Creek had lower growth compared to controls. Results indicate estrogen compounds in the UCR may be linked to declines in fish populations.