Midwest Fish & Wildlife Conference 2018

AUTHORS. Anabela Maia, Eastern Illinois University; Neeta Parajulee-Karki, Eastern Illinois University; Robert Colombo, Eastern Illinois University; Karen Gaines, Embry-Riddle Aeronautical University

ABSTRACT. Fish natural habitats are increasingly contaminated with various estrogenic compounds, including 17ß estradiol (E2). E2 causes adverse effects on the reproductive system of male fish; however, not much is known about the effects of E2 on metabolism and morphology. The objective of this study is to evaluate the effects of E2 exposure on the basal and stressed metabolic rate and morphological changes in body shapes of sunfish species. Fish were held individually in ten gallon tanks under two treatments of 40 and 80 ng/L and one control treatment (no E2). The duration of E2 exposure was 21 days, with E2 being replenished every week based on its half-life. Basal and maximum aerobic scopes were measured using closed respirometry and a chase protocol before and after exposure. Lateral pictures of the fish were also taken at these two time points. We hypothesize that (1) fish subjected to E2 exposure would experience stress and thus increase oxygen consumption, (2) male dimorphic characters would become less noticeable in exposed fish. The results showed that in the control group the basal metabolic rate decreased after 21 days; whereas in the estradiol exposed groups, it did not. In terms of morphological changes, there was a reduction in operculum size and decrease in head size in exposed individuals but not in control fish. E2 exposure caused morphological changes in male related characters, eroding male dimorphic characters. This research highlights negative effects of estradiol that are more widespread than simple gonadal alterations which warrant for close monitoring of estradiol contamination in the natural water system.