Identifying Endocrine Disrupters as an Emerging Issue: Smallmouth Bass in the Potomac River

Jeff Schaeffer | AFS Co-Chief Science Editor. E-mail: jschaeffer@usgs.gov

Photo credit: USFWS

Photo credit: USFWS

With this article, Vicky Blazer (U.S. Geological Survey, National Fish Health Research Laboratory) and her colleagues established clearly that endocrine disruptors were a potential issue for fish health, and not just in watersheds with high human population densities. They found a surprisingly high incidence of intersex condition in Smallmouth Bass Micropterus dolomieu collected from both densely and more sparsely developed watersheds within streams throughout both Virginia and West Virginia, with the surprising result that intersex conditions could be detected in areas that were considered more pristine. Their work was influential in that, although they were not the first group of researchers to examine the problem, their article made people realize that the effects of endocrine disruption were more widespread than thought previously and that it had potential effects on game species important to fishers. Additionally, they demonstrated that detection of intersex conditions was not simple and required adequate sample sizes, careful techniques, and consideration of seasonality when sampling. This widely read article (it is one of the most frequently cited in JAAH) led to the adoption of more thorough sampling techniques and broad discussion of endocrine disrupters as an important emerging issue. REFERENCE Blazer, V. S., L. R. Iwanowicz , D. D. Iwanowicz , D. R. Smith , J. A. Young ,J. D. Hedrick , S. W. Foster, and S. J. Reeser. 2007. Intersex (testicular oocytes) in Smallmouth Bass from the Potomac River and selected nearby drainages. Journal of Aquatic Animal Health 19:242-253. dx.doi. org/10.1577/H07-031.1