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PW16 Ecological Risk Assessment (General)
(PW255) Rapid local adaptation of Atlantic tomcod in response to PCBs and dioxins in the Hudson River Estuary.
Wirgin, I1, Chambers, R2, Roy, N1, Witting, D2, 1 NYU School of Medicine, Tuxedo, NY, US2 Northeast Fisheries Science Center, NOAA, Highlands, NJ, US
ABSTRACT- Atlantic tomcod Microgadus tomcod a common forage fish of estuaries from the Hudson River, New York (HR) to Atlantic Canada, exhibits high tissue burdens of PCBs, dioxins. furans in various life stages. We used controlled exposure experiments to evaluate whether environmentally relevant congeners and concentrations of PCBs and TCDD could induce toxic responses in the offspring (F1s) and grand-offspring (F2s) of wild fish, and whether genetically based tolerance to these compounds exists in populations with a history of exposure. We exposed and compared toxic responses in early life-stages of HR tomcod to tomcod from two less-contaminated sources-Shinnecock Bay, New York (SB), and the Miramichi River, New Brunswick, Canada (MR). Eggs were exposed to a range of water-borne doses of PCBs (0.01 to 100-fold) that bracketed levels (x) measured previously in livers of adult HR tomcod. Morphometric, developmental, behavioral, viability, and molecular variables were measured in eggs and larvae. Significant dose effects were evident within the SB and MR groups for all classes of response variables. SB and MR fish exhibited lower viability, less activity, slower development, higher levels of abnormalities, greater CYP1A expression than HR fish at doses at and above 1 x. HR eggs and larvae were largely insensitive to PCBs across the entire range of doses in the F1 and F2 generations. Not only is the tolerance exhibited by HR tomcod believed to have arisen recently (within 100 yr), but the high levels of PCBs and TCDD in tomcod tissues are expected to bioaccumulate in an array of piscivorous fish species that consume tomcod in the Hudson River Estuary.
Key words: PCBs, resistance, Dioxins, Hudson River Estuary
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