Effect of sea-ice extent on adult survival of an Antarctic top predator: the snow petrel Pagodroma nivea

The snow petrel Pagodroma nivea is an obligate associate of sea-ice and one of the most abundant seabird species of the Southern Ocean. Time- and sex- specific annual variation in adult survival was estimated using capture-mar k-recapture of petrels nesting at Petrels Island, Terre Adelie, 1981-1997. On the basis of a regression analysis, 44% of the variation was linked inve rsely to the latitudinal extent of sea-ice during winter (June) in the regi on offshore of the study colony, where this population is likely to spend t he non-breeding season. Monthly sea-surface temperature anomalies tended to influence adult survival but the relationship was not statistically signif icant. Why sea-ice extent should have such a critical effect on this specie s is yet to be explained, but the relationship, in the context of environme ntal warming and the consequent potential loss of Antarctic sea-ice, is an important one for this species.