| POPULATION DIFFERENCES IN EARLY LIFE-STAGE TOXICITY IN ATLANTIC TOMCOD, MICROGADUS TOMCOD, TO PCB CONGENERS |
| DAVIS, D.D., Chambers, R.C. (2), and Wirgin, I.I. (1), NOAA Fisheries Service, Northeast Fisheries Science Center, Highlands, New Jersey 07732 USA. dawn.davis@noaa.gov, (2) chris.chambers@noaa.gov, (1) New York University School of Medicine, Institute of Environmental Medicine, Tuxedo, New York 10987, USA, wirgin@env.med.nyu.edu |
| Atlantic tomcod (Microgadus tomcod), a common forage fish of estuaries from the Hudson River, New York to Atlantic Canada, exhibits high tissue burdens of contaminants in industrialized areas. We experimentally evaluated whether populations of tomcod from a contaminated site, the Hudson River (HR), differed from those from two less contaminated sources, Shinnecock Bay, New York (SB), and the Miramichi River, New Brunswick, Canada (MR), in their sensitivity to four PCBs congeners. These congeners (PCB 77, 81, 126, and 169) are common in the HR environment. Eggs were exposed to a range of water-borne concentrations of a 4-congener mixture of PCBs and to each congener separately at levels that bracketed those measured in livers of adult HR tomcod. Viability as well as developmental, behavioral, and morphometric variables were scored in eggs and yolk-sac larvae. SB and MR tomcod exhibited lower viability and activity, premature hatching, higher levels of morphological abnormalities, and slower escape responses than HR tomcod even when SB and MR tomcod were exposed at 0.01-fold lower doses than HR tomcod. The coplanar congener 126 was most toxic of the congeners to SB and MR tomcod. The tolerance exhibited by HR tomcod has likely arisen recently. The observed resistance to PCB congeners reported here is consistent with the high levels of PCBs reported for tissues of wild HR tomcod. These toxins can be expected to bioaccumulate in the diverse array of Hudson River fishes that regularly consume tomcod. |
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