A Review of the Impacts of Climate Change and Fishing on Penguins in the Western Antarctic Peninsula and Scotia Sea Region

Nicole C Bransome, The Pew Charitable Trusts, Protecting Antarctica's Southern Ocean, Washington, DC, United States, Cassandra M. Brooks, University of Colorado at Boulder, Boulder, United States and Annika Cobb, University of Colorado at Boulder, United States
Penguins are key mesopredators in the Antarctic marine ecosystem. Yet, some populations of penguins (Adélie, Pygoscelis adeliae; chinstrap; Pygoscelis antarctica) in the Western Antarctic Peninsula (WAP) region are in decline. The WAP is one of the most rapidly changing environments on Earth, with changing precipitation patterns and a reduction in sea ice extent and duration. Scientists have linked these environmental changes to shifts in the WAP ecosystem, including potential declines in krill, shifts in algal communities and potential declines in Adélie and chinstrap penguin populations. Declines in penguin populations are often due to alterations in availability of quality prey, nesting habitat, and juvenile fitness and recruitment. While climate change threats are widely acknowledged, there is less agreement on precisely which factors drive penguin population trends nor the best way to ameliorate these changes.

While penguins strive to adapt to environmental changes, the fishery for Antarctic krill (Euphausia superba) has been expanding in recent years, concentrating in coastal areas off the WAP. Managers, scientists and the conservation community are all concerned that this additional localized draw on krill may negatively impact already-fragile penguin populations. Here, we present a review of how climate change is impacting krill and krill-dependent penguin species, as well as an analysis of the cumulative impacts of krill fishing and climate effects on the regions penguins. Finally, we close with an examination of management measures that may provide for precautionary management of the WAP and Scotia Sea region, including ecosystem-based fisheries management, fishery buffer zones and marine protected areas.