Using habitat models for chinstrap penguins, Pygoscelis antarctica, to inform marine spatial management around the South Sandwich Islands during the penguin breeding season

If not carefully managed, harvesting of Antarctic krill risks disturbing the ecological balance of many Antarctic and sub-Antarctic sites where krill-dependent predators feed. One of the least disturbed sites anywhere within the Southern Ocean and one where krill fishing has so far been virtually non-existent is the South Sandwich Islands volcanic archipelago. Some of the main krill predators breeding at the South Sandwich Islands are penguins, with five species breeding on the islands, the dominant species of which is the chinstrap penguin. In this paper we report on the results of ARGOS PTT deployments during the chinstrap penguin chick-rearing period, using the recorded foraging trips to develop habitat models. Foraging habitats used by chinstrap penguins during this period were best characterised by distance from the colony and sea surface temperature and, using these two covariates, we predicted the chick-rearing foraging habitat use around all islands. We show that the provisions of the South Georgia and South Sandwich Islands Marine Protected Area ensure that chinstrap penguins, and other krill-dependent predators with similar foraging ranges, likely have robust protection during the summer. During the winter, when krill predators are likely to forage further offshore, seasonal sea ice provides a physical barrier to exclude the fishery, again ensuring the islands??? unique biodiversity receives strong protection. However, to the north of the marginal sea ice zone, competition between krill predators and the fishery could exist if the fishery were ever to explore new locations for resource extraction. We make a number of conclusions, including the need for winter tracking data to inform future management options.

Automated summary

This study developed habitat models for chinstrap penguins based on their foraging behavior during the chick-rearing period and predicted their foraging habitat use around the South Sandwich Islands. The results show that the provisions of the marine protected area ensure robust protection for chinstrap penguins and other krill-dependent predators during the summer, while seasonal sea ice acts as a physical barrier to exclude the fishery during the winter. However, competition between krill predators and the fishery could exist in new resource extraction locations.