Cooperative Fish and Wildlife Research Units Program: West Virginia
Education, Research and Technical Assistance for Managing Our Natural Resources

In 2002-2003 reports of fish kills and a high incidence of external lesions of smallmouth bass and other species initiated fish health investigations by WV DNR and USGS. During these investigations it was determined that a high percentage, at some sites greater than 80%, of the smallmouth bass were intersex. Intersex is defined as the presence of both male and female characteristics in a normally gonochoristic animal. In the case of the bass, immature oocytes are observed within the testes of the male bass. This finding attracted much public and scientific interest, since intersex has been used as an indicator of exposure to estrogenic compounds. There are a number of ongoing projects of the USGS National Fish Health Research Laboratory in conjunction with numerous collaborators to 1) determine the extent of the problem throughout the Potomac and Shenandoah rivers; 2) document other potential effects on fish health such as reduced disease resistance, increased parasite or other pathogen loads; and 3) document the presence of potential causes. In addition the USGS's BEST (Biomonitoring of Environmental Status and Trends) program will conduct collections for their large rivers program in the MidAtlantic region in Fall 2006. Target species in this program are largemouth bass and carp which will provide information on the presence of intersex or other reproductive abnormalities in species other than smallmouth bass. Researchers propose to augment ongoing projects of USGS by: 1) During the spring collections in the Potomac and Shenandoah begin to assess sperm quantity and quality (graduate student project) 2) Assist in the development and testing of in vitro assays to detect estrogenic activity in extracts of water and sediment (technican/graduate student project) Study Tasks are: 1. Develop techniques to assess sperm quantity and quality. 2. Assist in field collections to obtain samples. 3. Work with researchers at the Leetown Science Center to evaluate gonad histopathology of normal and intersex males for which sperm quality has been assessed. 4. Test extracts of water and sediment using established mammalian cell lines and fish hepatocyte primary cell cultures to evaluate toxicity and estrogenicity