Trophic structure and community stability in an overfished ecosystem

Utne-Palm, Anne Christine; Salvanes, Anne Gro Vea; Currie, Bronwen; Kaartvedt, Stein; Nilsson, Göran E.; Braithwaite, Victoria A.; Stecyk, Jonathan A W; Hundt, Matthias; Van Der Bank, Megan G.; Flynn, Bradley A.; Sandvik, Guro Katrine; Klevjer, Thor Aleksander; Sweetman, Andrew K.; Brüchert, Volker; Pittman, Karin A.; Peard, Kathleen R.; Lunde, Ida Gjervold; Strandaba, R. A U; Gibbons, Mark J.

Abstract

Since the collapse of the pelagic fisheries off southwest Africa in the late 1960s, jellyfish biomass has increased and the structure of the Benguelan fish community has shifted, making the bearded goby (Sufflogobius bibarbatus) the new predominant prey species. Despite increased prédation pressure and a harsh environment, the gobies are thriving. Here we show that physiological adaptations and antipredator and foraging behaviors underpin the success of these fish. In particular, body-tissue isotope signatures reveal that gobies consume jellyfish and sulphidic diatomaceous mud, transferring "dead-end" resources back into the food chain.

Sponsors

We thank the crew of the G. O. Sars; F. Midtoy for assistance; and P. Ellitson, M. Hordnes, R. Jones, R. Amundsen and the rest of the scientific crew. We thank the National Research Foundation of South Africa, the Research Council of Norway, and our home institutions for funding and support. We thank BENEFIT (Benguela Environment Fisheries Interaction and Training), S. Sundby, D. C. Boyer, J. Otto Krakstad, and the crew of the research vessel Dr. Fridtjof Nansen for support with earlier goby cruises, laying the basis for the present study. We thank K. Helge Jensen for statistical support. We appreciate the comments on this manuscript by J. Giske, C. Jorgensen, M. P. Heino, and the anonymous reviewers. Care and handling of experimental animals were performed in accordance with institutional guidelines. J. A. W. S. was a postdoctoral researcher funded by the Natural Sciences and Engineering Reserach Council of Canada at the time when the research was conducted.

Publisher

American Association for the Advancement of Science (AAAS)

Journal

Science

ISSN

00368075