Intellectual Merit: The krill surplus hypothesis argues that the near-extirpation of baleen whales from Antarctic waters during much the twentieth century led to significant changes in the availability of krill for other predators. Over the past decade, however, overall krill abundance has decreased by over an order of magnitude around the Antarctic Peninsula, in part due to physical forces, including the duration and extent of winter sea ice cover. Krill predators are vulnerable to variability in prey and have been shown to alter their demography in response to changes in prey availability This research will use novel tagging technology combined with traditional fisheries acoustics methods to quantify the prey consumed by a poorly understood yet ecologically integral and recovering krill predator in the Antarctic, the humpback whale (Megaptera novaeangliae). It also will use a combination of advanced non-invasive tag technology to study whale behavior concurrent with hydro-acoustic techniques to map krill aggregations. The project will (1) provide direct and quantitative estimates of krill consumption rates by humpback whales and incorporate these into models for the management of krill stocks and the conservation of the Antarctic marine ecosystem; (2) provide information integral to understanding predator-prey ecology and trophic dynamics, i.e., if/how baleen whales affect the distribution and behavior of krill and/or other krill predators; (3) add significantly to the knowledge of the diving behavior and foraging ecology of baleen whales in the Antarctic; and (4) develop new geospatial tools for the construction of multi-trophic level models that account for physical as well as biological data.
Broader Impacts: Whales are assumed to be a major predator on Antarctic krill, yet there is little understanding of how whales utilize this resource. This knowledge is critical to addressing both bottom-up and top-down questions, e.g., how climate change may affect whales or how whales may affect falling krill abundances. This program will integrate research and education by providing opportunities for undergraduate and graduate students as well as postdoctoral researchers at Duke University, the Florida State University and the University of Massachusetts at Boston. This project will also seek to integrate interactive learning through real time, seasonal and curriculum development in collaboration with the National Geographic Society as well as at the participating universities and local schools in those communities.
