Estimation and impacts of seabird mortality from chronic marine oil pollution off the coast of Newfoundland

摘要: The Grand Banks south off Newfoundland provide year-round feeding habitat for tens of millions seabirds numerous species, an abundance and diversity unparalleled in the North Atlantic. Dense ship traffic routes traverse this productive environment as vessels travel Great Circle Route between Europe America. Oiled have washed up on beaches many decades. Most oil their feathers has been identified heavy fuel mixed with lubricants, mixture found bilges large vessels. Beached bird surveys conducted 1984-1999 indicate that incidence chronic pollution along southeast coast is among highest world. More than 60% all dead birds over 16-year period had feathers; 74% during last five years. Auks, especially Thick-billed Murres (Uria lomvia), are most affected. -- In effort to estimate overall mortality winter due Atlantic Canada, I performed a series experiments determine fate oiled unoiled at sea beaches. First, determined carcasses persisted average only 3.3 ± 0.1 days southeastern Newfoundland, after which they were no longer detectable scavenging or burial beach substrate. addition, differences persistence rates birds. also deposition detection probabilities beaches, developed model number arriving periodic surveys. This performs well if survey intervals less 10 days. Second, designed drift block accurately mimics movements seabird carcass drifting sea. As blocks used past studies showed little resemblance actual because overly influenced by wind, more realistic was needed interpret Third, measured murre sinking float 8.2 5.2 before sinking, but important. Fourth, carried out extensive using new design proportion die reach shore, taking into account floating Recovery dropped different locations varied, best predictor lost distance from shore where dropped, combined cumulative wind direction vector first three following drops. Based patterns observed experiment, able specific recovery catchment areas Fifth, constructed general mathematical Seabird Mortality Model assess given coastline. applied based beached winters 1998/1999 through 2000/2001 parameters earlier. Several assumptions made extrapolate area sea, my robust average, 315,000 65,000 killed annually illegal discharges ships. over- 67 % kill. examined effects anthropogenic mortality, combination estimated murres traditional hunt Murre populations breed eastern Canadian Arctic, building stochastic (demographic environmental), age-structured, density independent, pre-breeding, Lefkovitch population projection matrix. suggested reduced potential annual growth 2.5 %. further 2 reduction caused hunting, these sustained causes particularly vulnerable environmental changes (e.g. global warming, ocean regime shifts). A actions outlined help reduce including increased enforcement, imposition minimum fines higher imposed fines, establishment convenient disposal facilities land, education awareness programs.