Population decline of chinstrap penguins (Pygoscelis antarctica) on Deception Island, South Shetlands, Antarctica

Population changes of top predators can provide key indications of environmental quality. In the Antarctic ecosystem, population dynamics of top predators like penguins may yield important information about how the environment is changing. From 1991–1992 to 2008–2009 censuses of the chinstrap penguin (Pygoscelis antarctica), breeding population of Vapour Col in Deception Island (South Shetlands Islands) were carried out. Censuses were conducted on 19 sub-colonies, mainly in December around the time of peak hatching. Nest counts were taken from photographs that were recorded from a standard location. Some censuses were also made in mid-January in 1999, 2006, 2007 and 2008. Our results reveal that the population has declined by 36 % when comparing data from 1991 with those from 2008. The strongest decline occurred since 2000. No temporal trends were detected in reproductive success. Declines of Chinstrap penguin populations constitute a general pattern in the South Shetlands, and it has been suggested to be related to climate change through effects of reduction in sea-ice extent during winter and a consequent decline in the abundance of krill.