Predator-Prey Interactions in the Krill-centric Southern Ocean Marine Ecosystem

Noaa National Marine Fisheries Service, La Jolla CA

Investigators

Abstract

Variability in ecosystems is hypothesized to be a major constraint in the evolution of life history tactics of organisms. Marine polar ecosystems exhibit pronounced seasonal and interannual variability; these fluctuations are known to affect all levels of the trophic web, especially top predators. Few long-term studies recording reproduction and survival of individually marked animals exist, however, and studies that monitor several species simultaneously are even rarer. The proposed research will examine how reproductive, foraging and demography parameters of Pygoscelis penguins are affected by environmental variability. Adélie, chinstrap, and gentoo penguins (Pygoscelis adeliae, P. antarctica and P. papua) have been studied at Admiralty Bay, in the Antarctic Peninsula region, since 1976. These three species exhibited different population trends over the last 3 decades: Adélie and chinstrap penguin populations declined by over 70% in numbers while gentoo penguin populations remained stable. This study will continue to collect long-term life history data on these penguin species and will expand recent work on the distribution and trophic interactions among the three species during the critical winter period. A combination of multivariate statistical techniques and population dynamics models will be used to evaluate hypotheses relating environmental variation to changes in breeding biology and foraging ecology and to examine how variations in these parameters affect populations. Further, this research will assist in the validation of models for fisheries management that are ecosystem based, incorporating predator data with krill and climate data, and that take into account long-term temporal variability in these parameters. As members of a working group to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) the PIs for this project have direct scientific input regarding recommendations on fisheries policy in the Southern Ocean. This research will be used to parameterize and test models that will be used in management decisions regarding the krill fishery around the Antarctic Peninsula. The study will also provide professional training to young researchers and will support a PhD candidate at Scripps Institute of Oceanography.