Because of shorelines and coastal physiography, the nearshore ecosystem served as a repository for much of the oil spilled by the T/V Exxon Valdez (EVOS). Mortalities occurred across a suite of apex predators, as well as in benthic invertebrate populations, including mussels, clams, and crabs. The initial changes in composition and abundance of species which resulted from these acute mortalities and habitat disturbances likely continue to modify important structuring processes in the nearshore populations (i.e., competition, predation, and recruitment), thus constraining recovery.
Scientists with the Biological Resources Division-USGS, the Alaska Department of Fish & Game, National Oceanographic & Atmospheric Association, and US Fish & Wildlife Service, have implemented a 4-year study to determine the impact and recovery in the nearshore ecosystem of Prince William Sound, Alaska.
Four vertebrate predator species were selected for study because there was evidence for possible injury from EVOS and for lack of recovery, they are important members of the nearshore ecosystem in PWS and elsewhere in the spill affected area, they represent species with a varied prey base, and their trophic dependance on nearshore prey items can be effectively measured. These species are the invertebrate feeding sea otter (Enhydra lutris) and harlequin duck (Histrionicus histrionicus), and fish feeding pigeon guillemot (Cepphus columba) and river otter (Lutra canadensis). Read more on the natural history, evidence for injury from EVOS, and criteria for selection as an apex predator by clicking on the specific species.
Click here for an overview on the research study, "Mechanisms of Impact and Potential Recovery of Nearshore Vertebrate Predators".
Last Reviewed: March 26, 2003