Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels
William J. Sydeman, David S. Schoeman, Sarah Thompson, Brian A. Hoover, Marisol García‐Reyes, Francis Daunt, Philippa Agnew, Tycho Anker‐Nilssen, Christophe Barbraud, Robert T. Barrett, Peter Becker, Elizabeth Bell, P. Dee Boersma, Sandra Bouwhuis, Belinda Cannell, Robert J. M. Crawford, Peter Dann, Karine Delord, G. Elliott, Kjell Einar Erikstad, Elizabeth Flint, Robert W. Furness, M. P. Harris, SA Hatch, K. Hilwig, Jefferson T. Hinke, Jaime Jahncke, James A. Mills, Tone Kristin Reiertsen, Heather M. Renner, Richard B. Sherley, C. Surman, Graeme A. Taylor, Julie A. Thayer, Philip N. Trathan, Enriqueta Velarde, K. Walker, Sarah Wanless, Pete Warzybok, Yutaka Watanuki
Abstract
Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.