Studies in fish
Exposure to endocrine disrupting compounds at an early life stage can cause sex change in fishes, but little is known about how this influences population size or the overall fecundity of a population. We recently published work in Environmental Science and Technology describing how masculinization or feminization of group spawners such as Menidia species impacts overall reproductive output. In summation, we found that masculinization can be more detrimental than feminization.
In ongoing work, silversides are being exposed to known EDCs to determine effects on gene expression, DNA methylation, fecundity, and sex ratio. All endpoints are being evaluated over three generations to examine the potential for trans-generational effects. This work is currently funded by the Environmental Protection Agency (EPA Science to Achieve Results).
Studies in invertebrates
We recently detected a byproduct of the insecticide fipronil in the eggs and ovaries of blue crab females (Callinectes sapidus) sampled from regional estuaries (Southeastern NC and Northeastern SC). In a follow-up study, naive juvenile crabs were exposed in the lab to fipronil and the detected byproduct, fipronil desulfinyl. Responses included altered growth and decreased expression of genes involved in growth and reproduction. This study was funded in part by North Carolina Sea Grant, a blog post about the research can be found here.
New collaborative work in oysters (Crassostrea virginica) will examine the potential effects (both positive and negative) of aquaculture in research reserves. This research is funded by the NOAA National Estuarine Research Reserve (NERR) program.