Wild Male Bluegill Legacy Contaminant Profile: Associated Reproductive Effects and Implications

Endocrine disrupting chemicals in wild fishes could potentially disrupt reproduction by causing intersex.  Legacy contaminants, specifically polychlorinated biphenyls and organochlorine pesticides, have been shown to be estrogenic or anti-androgenic likely contributing to intersex in males.  These contaminants continue to persist in the environment despite being restricted from use in the United States.  Many lakes where fishing is an important source of recreation have elevated contaminant concentrations.  Bluegills Lepomis macrochirus play a crucial role in lake food webs as forage and sport fish and may be affected by legacy contaminants.  We quantified the concentration of legacy contaminants in male bluegills, paired these fish with females with below reporting limit concentrations of contaminants in research ponds to measure if there was an effect on reproductive output.  We also evaluated male bluegills (N=200) for intersex.  Lake specific bluegill tissue contaminant concentrations ranged widely from below reporting limit to 2 ppm (non-lipid normalized basis) and were significantly different (Tukey’s HSD, p<0.05), allowing for comparison.  No intersex fish were observed.  Young production per pond was reduced in a dose-dependent manner.  The highest male contaminant treatment produced the least young in the pond study, which suggested alterations to reproductive behavior and viability of offspring.