U.S. Fish & Wildlife Service

Intersex fish Endocrine disruption in smallmouth bass

Background Historic Samples Since 2003, scientists at the U.S. Geological Survey’s National Fish Watershed Health Research Laboratory Sample Locations (NFHRL) in Kearneysville, WV have 2005 been evaluating the reproductive 2006 Conococheague Creek 5PPERå#ONOCOCHEAGUE health of smallmouth bass in the upper ,OWERå#ONOCOCHEAGUE Potomac River and its tributaries, 5PPERå-ONOCACY including the . They ,OWERå-ONOCACY .&(2, noted the presence of immature female WV VA germ cells (oocytes) in the testes of West MD some of the male fish. This condition, South Branch Potomac R. VA a type of intersex, is evidence of a Shenandoah River DC "LUEå0LAINSå disturbance in the hormonal system North Fork

North Fork of the fish (i.e., endocrine disruption). South Fork

Chesapeake Bay Further evidence of endocrine South Fork disruption occurs when we detect the presence of vitellogenin in the blood of male fish. Vitellogenin is a protein Potomac River produced by female fish to form egg yolk and is normally absent in males. 0 25 50 100 Miles In addition to the effects on male fish, a substantial decrease of vitellogenin Map of sampling locations. in females also suggests endocrine The Team with collections and those from the disruption. To try to answer these questions, a University of Florida performed the collaborative partnership of scientists vitellogenin analyses. The U.S. Fish The Problem from many organizations was formed. and Wildlife Service and the U.S. Intersex and abnormal vitellogenin in Toxicologists from the U.S. Fish and Geological Survey funded the work smallmouth bass from portions of the Wildlife Service’s Environmental through a jointly prepared proposal Potomac watershed pose a threat to Contaminants Program at the submitted in 2004. fish resources. The USGS studies led Field Office identified to several research questions: the sampling sites, coordinated the The Survey field work, and gathered the land use In the fall of 2005, biologists collected • Is there a relationship between information. Biologists from the USGS male and female smallmouth bass intersex and abnormal vitellogenin NFHRL directed the field necropsies from two Potomac River tributaries and nearness to wastewater and performed the biological in Maryland, the Monocacy River treatment plant discharges? laboratory analyses. USGS chemists and Conococheague Creek. For each at the Columbia Environmental river, we identified one sampling • How widespread are these problems Research Center (Columbia, MO) location immediately downstream of a within the Potomac watershed? estimated water concentrations of wastewater treatment plant discharge organic contaminants at the collection and one about 10 miles upstream. We • What chemicals can be detected sites using long-term sampling devices. collected about 10 males and 10 females at fish sampling locations; Fisheries biologists from the Maryland from each location. We also collected which ones are considered to be Department of Natural Resources largemouth bass near the discharge endocrine disruptors; and do the provided local expertise on smallmouth of the Blue Plains Wastewater Plant concentrations relate to land use? bass populations and directed the in Washington, DC. Fish blood and collections. Biologists from the District tissue samples were taken for analysis. of Columbia’s Department of the Microscope slides were prepared of Environment provided additional help testes and ovaries. In the fall of 2005 and in the spring Ongoing Research For More Information of 2006, we installed passive water To gain a greater understanding of the Iwanowicz, L.R., V.S. Blazer, C.P. sampling devices at sampling sites reproductive health of bass and the Guy, A.E. Pinkney, J.E. Mullican, and for one to two months. These devices implications to the ecosystem in the D.A. Alvarez. 2009. Reproductive accumulate different types of organic Northeast U.S., sampling of fish from health of bass in the Potomac, USA contaminants, including both legacy rivers near National Wildlife Refuges drainage: Part 1. Exploring the effects and “emerging” compounds, allowing (from Virginia north to Maine) using a of proximity to wastewater treatment scientists to identify contaminants at similar upstream/downstream design is plant discharge. Environmental very low concentrations. ongoing. Further sampling is also being Toxicology and Chemistry 28:1072-1083. conducted in the mainstream upper The Results Potomac River and in the tidal area Alvarez, D.A., W.L. Cranor, S.D. We found female germ cells (oocytes) downriver of Washington, DC. Perkins, V. Schroeder, L.R. Iwanowicz, in the testes of 82% to 100% of the R.C. Clark, C.P. Guy, A.E. Pinkney, male smallmouth bass and in 23% of V.S. Blazer, and J.E. Mullican. 2009. the males from the single largemouth Reproductive health of bass in the bass collection near the Blue Plains Potomac, USA drainage: Part 2. Wastewater Plant in Washington, DC. Seasonal occurrence of persistent The baseline prevalence of testicular and emerging organic contaminants. oocytes in male smallmouth is uncertain Environmental Toxicology and but may be in the range of 14% to 22%; Chemistry 28:1084-1095. baseline for male largemouth may be closer to 0%. We found vitellogenin in Guy, C.P., A.E. Pinkney, V.S. Blazer, the blood of 33% to 90% of the male L.R. Iwanowicz, D.A. Alvarez, and smallmouth and 85% of the male J.E. Mullican. 2009. Assessment of largemouth. In Conococheague Creek, Smallmouth bass. Illustration by Timothy endocrine disruption in smallmouth there was more than a tenfold decrease Knepp, USFWS bass (Micropterus dolomieu) and in the concentration of vitellogenin in largemouth bass (Micropterus the females collected downstream from salmoides) in the Potomac River the treatment plant vs. those collected Watershed. CBFO-C09-03. U.S. Fish from the upstream location. and Wildlife Service, Chesapeake Bay Field Office, Annapolis, MD. Multiple environmental contaminants http://www.fws.gov/chesapeakebay/ were found in the sampling devices, envcont.html often with higher concentrations of wastewater chemicals (near the Contacts treatment plant outfalls). Pesticides [email protected] currently used in agriculture were [email protected] detected at all locations. Hormones [email protected] were not detected in the passive water [email protected] samplers. However, laboratory tests [email protected] (yeast screening assays) suggested [email protected] that estrogenic endocrine-disrupting chemicals were present at all locations. These tests do not identify single compounds, rather an overall response.

Based on the results of these samples, we cannot identify a single chemical or sources that may be causing the intersex and vitellogenin induction. Multiple chemical stressors that are Intersex (testicular oocytes). Most often observed not solely associated with agriculture as immature oocytes (arrows) within testes. or wastewater treatment plant effluent Suggested as a biological indicator of endocrine Monocacy River below wastewater treatment disruption. plant outfall. may be responsible.

U.S. Fish & Wildlife Service Chesapeake Bay Field Office 177 Admiral Cochrane Drive Annapolis, MD 21401 http://www.fws.gov/chesapeakebay/ Barge electroshocking for smallmouth bass in Conococheague Creek