Undergraduate Research and Creativity

URECA

2008-2009

Sex ratios as evidence of endocrine disruption in winter flounder, Pseudopleuronectes americanus: Long Island and Hudson River studies

Brandilyn Peters and Anne McElroy
School of Marine and Atmospheric Sciences

The purpose of our study was to evaluate the extent of endocrine disruption in winter flounder (Pseudopleuronectes americanus) by determining their sex ratios in the waters surrounding Long Island and the Lower Hudson River, New York. Previous research in our lab has shown that young -of-the-year (YOY) winter flounder from the polluted Jamaica Bay have higher ratios of females to males, and elevated levels of vitellogenin, a protein associated with female reproduction, as compared to a reference population from Shinnecock Bay at the eastern end of Long Island. In the summer of 2007, YOY winter flounder were collected from 9 sites on Long Island. I helped develop a method to determine sex in these very young fish in fresh frozen and histologically preserved samples. In apparent contrast to date from previous years, sex ratios from fish collected in the 2007 study showed more males than females in western Long Island embayments, though sample sizes were too small for this to be statistically significant. The correlation between longitude, with higher longitudes close to New York City as proxy for urbanization, and female sex ratio was also not significant. In contrast, sex ratios of YOY flounder collected from 24 locations in the lower Hudson River showed uniformly more females than males in all the Hudson River, though these differences were not large and also not statistically significant. Further work needs to be done to determine whether or not these apparent differences are significant. This work was supported with funding from Undergraduate Research & Creative Activities.