Pigeon guillemots as a sentinel species: A dose-response experiment with weathered oil in the field

Nests of pigeon guillemots (Cepphus columba) were located along the south shore of Kachemak Bay, Alaska, and monitored during the breeding seasons of 1994 and 1995. Rates of nestling growth were measured and blood samples were collected for measurements of serum biomarkers. Haptoglobin, total protein, alanine aminotransferase, aspartate aminotransferase, and sodium in sera were measured as potential biomarkers of oil ingestion. Differences in mean levels of biomarkers were observed between years, and between nestlings and adults, as well as among locations within Kachemak Bay. During summer 1995, a controlled dose-response experiment was conducted with weathered Prudhoe Bay Crude Oil. Fifty-one nestlings were divided into three groups: controls, nestlings fed 0.05 ml of oil, and nesdings fed 0.20 ml of oil. Each experimental nestling was fed the dose of weathered oil twice: once at approximately day 20, and again 5 days later at approximately day 25 post-hatching. Blood samples were collected immediately before dosing on days 20, 25, and again on day 30 post-hatching. Site-specific differences in some blood variables were observed among treatments. These results suggest that the doses of weathered oil administered to guillemot nestlings were not sufficient to induce a persistent inflammatory response.