Petroluem Discharger no longer a major mortality factor for Magellanic Penguins along Chubut coast.

DEE BOERSMA, ESTEBAN FRERE & PATRICIA GANDINI

Tasmania, Australia

Congreso; 6th International Penguin Conference; 2007

University of Tasmania

We counted carcasses of Magellanic Penguins by walking one to two kilometre segments of the coast of Chubut, Argentina at 8 to 17 sites in March between 1982 and 2007 (n=13 years). We found an average of 44.9 % of the penguins were oiled between 1982 and 1990 (sd = 15.4 , n= 8 years, 3115 penguins). The majority of deads adults (67 % sd = 12.7, 888 penguins) between 1986 and 1990 had petroleum on the 10 % or more of their body. Of the dead fledglings, 38 % were oiled (sd = 24.1, 611 penguins). Petroleum pollution was more important in adult deaths, while starvation and predation was more important in fledling deaths. The number of dead oiled adults dropped to 20 % and fledglings to 8 % in 1990. The number of dead penguins found dropped from 49/km in 1982 to 5/km in 2003 to 1/km in 2005. The decline in dead penguins reflects both their lower population size and a change in mortality from petroleum pollution in Magellanic Penguins. Tanker lanes were moved 30 km farther offshore in 1997 but prior to this illegal  dumping appeared to decline.