Indirect effects of an oil spill: reproductive failure in a population of South Polar skuas following the 'Bahia Paraiso' oil spill in Antarctica

Abstract

We report a complete reproductive failure in a population of seabirds as an indirect result of the Bahia Paraiso' oil spill near Palmer Station in Antarctica. Mortality among nestling South Polar skuas was highly compressed in time and was coincident with the spill. Adults were observed to forage in oil slicks and became fouled, but there was no transfer of oil to eggs or chicks. Young showed no evidence of toxicity (low growth rates or hemorrhagic gastroenteritis) and adult mortality was minimal. Instances of parental neglect increased 10-fold after the spill and undefended chicks were attacked by neighboring skuas. \\re suggest that exposure to oil caused a short-term disruption of normal parental attendance behavior which exposed young to fatal intraspecific aggression. This example emphasizes that behavior and ecological interactions play major roles in determining the effects of oil on species. While these factors may be understood post hoc, correctly predicting the effects of environmental perturbations on species is a formidable task.