Variation in breeding success and survival of little penguins Eudyptula minor in response to environmental variation

Climate change is likely to result in continued warming of the oceans and an increase in the frequency and intensity of storms. To gain some insight into how such changes might affect little penguins, we studied how variation in sea surface temperature, chlorophyll a concentrations and the occurrence of severe storms affected little penguin Eudyptula minor breeding and survival at Oamaru, New Zealand. We examined the impact of prolonged, extreme storms using the 99th percentile of significant wave heights. Long durations of such wave heights at Oamaru were associated with a reduction in the number of penguins arriving ashore each evening and a reduction in adult survival. Ocean productivity positively influenced the penguins: increases in chlorophyll a were reflected by increases in survival of breeders, and by earlier onset of egg laying that generated increases in breeding success. Global climate change is highly likely to have negative impacts on the population of little penguins at Oamaru through impacts from storms. It is unclear, however, how climate change will influence chlorophyll a concentrations, and so we cannot predict what impact this will have on little penguins. Potential increases in chlorophyll a via increased nutrient input from the land may have positive effects on the penguins.