title: 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.
authors.affiliation: National Fish Health Research Laboratory, U.S. Geological Survey, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430, USA. vblazer@usgs.gov
authors.forename: Vicki S
authors.initials: VS
authors.lastname: Blazer
authors.forename: Luke R
authors.initials: LR
authors.lastname: Iwanowicz
authors.forename: Holly
authors.initials: H
authors.lastname: Henderson
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Mazik
authors.forename: Jill A
authors.initials: JA
authors.lastname: Jenkins
authors.forename: David A
authors.initials: DA
authors.lastname: Alvarez
authors.forename: John A
authors.initials: JA
authors.lastname: Young
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data; D000818:Animals; D001492:Bass / Q000502:physiology*; D015415:Biomarkers / Q000378:metabolism; D012734:Disorders of Sex Development / Q000139:chemically induced / Q000453:epidemiology / Q000378:metabolism / Q000662:veterinary*; D052244:Endocrine Disruptors / Q000032:analysis / Q000633:toxicity; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D005393:Fish Diseases / Q000139:chemically induced / Q000453:epidemiology* / Q000378:metabolism; D008297:Male; D010575:Pesticides / Q000032:analysis / Q000633:toxicity; D012098:Reproduction / Q000187:drug effects*; D045483:Rivers / Q000737:chemistry; D012621:Seasons; D013737:Testis / Q000187:drug effects / Q000473:pathology; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D015415:Biomarkers; D052244:Endocrine Disruptors; D010575:Pesticides; D014819:Vitellogenins; D014874:Water Pollutants, Chemical