Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects

Abstract

A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected over a 2-year period from three tributaries of the Potomac River: the Shenandoah River, the South Branch Potomac and Conococheague Creek, and an out-of-basin reference site on the Gauley River. The prevalence of TO varied seasonally with the lowest prevalence observed in July, post-spawn. Reproductive maturity and/or lack of spawning the previous spring, as well as land-use practices such as application of manure and pesticides, may influence the seasonal observations. Annual, seasonal, and site differences were also observed in the percentage of males with measurable concentrations of plasma vitellogenin, mean concentration of plasma vitellogenin in females, and plasma concentrations of 17β-estradiol and testosterone in both sexes. Bass collected in the South Branch Potomac (moderate to high prevalence of TO) had less sperm per testes mass with a lower percentage of those sperm being motile when compared to those from the Gauley River (low prevalence of TO). An inverse relationship was noted between TO severity and sperm motility. An association between TO severity and wastewater treatment plant flow, percent of agriculture, total number of animal feeding operations, the number of poultry houses, and animal density within the catchment was observed.

Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

“…The most commonly reported effects are those resulting from exposure to estrogenic/antiandrogenic chemicals. Feminization of male fishes as evidenced by testicular oocytes or intersex (Jobling et al, 1998;Kavanagh et al, 2004;Dietrich and Krieger, 2009;Blazer et al, 2012) and production of Vtg (Denslow et al, 1999;Jones et al, 2000;Dang et al, 2011;Vajda et al, 2011) has been observed in numerous fish species. In a few cases, population effects are reported (Kidd et al, 2007;An et al, 2009).…”

Comparative responses to endocrine disrupting compounds in early life stages of Atlantic salmon, Salmo salar

“…In particular, endocrine disrupting compounds (EDCs) are an increasing concern for wildlife, since population-level impacts of these compounds have been documented (Kidd et al, 2007;Lange et al, 2011;Blazer et al, 2012). Endocrine disrupting compounds are most often associated with municipal and industrial wastewater effluent, can feminize male fish in receiving waters (Sumpter, 2005;Desbrow et al, 1998;Blazer et al, 2007), and lead to local extinction (Kidd et al, 2007).…”

Introduction to Special Issue: Disruption of thyroid, sex steroid, and adrenal hormone systems and their crosstalk in aquatic wildlife

“…Strong interest in particular circumstances surrounding exposures of aquatic animals to EDCs has been driven, in part, by news and media accounts of reproductive abnormalities in fishes (e.g., Blazer et al, 2012) and amphibians (e.g., Skelly et al, 2010), and the mysterious loss of amphibian populations around the globe.…”