Cytochrome P450 1A induction in sea ducks inhabiting nearshore areas of Prince William Sound, Alaska

Following the Exxon-Valdez oil spill, hepatic rates of EROD activity and thus, P450 1A expression, were significantly higher in harlequin ducks (Histrionicus histrionicus) and Barrow’s goldeneyes (Bucephala islandica) from oiled areas of Prince William Sound, Alaska when compared to birds from unoiled sites. Polychlorinated biphenyl exposure did not account for areal differences in P450 1A induction in harlequin ducks. Background hydrocarbon levels in Prince William Sound were negligible prior to the 1989 oil spill, but remnant Exxon-Valdez oil was still present in nearshore habitats of the spill zone coincident with our study. We conclude that P450 1A induction in sea ducks from areas oiled during the Exxon-Valdez oil spill was likely due to exposure to residual oil. We speculate that biochemical and physiological changes in individuals chronically exposed to oil may be constraining population recovery of some sea duck species affected by the spill.