Identifying core foraging areas of humpback whales in the Antarctic peninsula

Did you know that humpback whales feed in areas and times outside of previously studied krill predators around the Antarctic Peninsula?

-We hope that our findings represent a first step in establishing a long-term monitoring program of baleen whales around that Antarctic Peninsula that can yield dynamic and inter-annual information on the needs of baleen whales as they relate to prey distribution and abundance.  This information is critical to the management and conservation of baleen whales, krill predators, and the functioning of the Antarctic marine ecosystem, says Ari Friedlaender of the University of Santa Cruz who has completed this AWR supported study.

 In order to effectively and appropriately manage how human activity impacts the Antarctic marine ecosystem we need to understand both the behavior of humans and the animals that are potentially impacted.  Around the Antarctic Peninsula, a growing commercial krill fishery is focusing its effort on smaller areas and periods later in the Antarctic summer than it has traditionally operated.  While there is considerable information on the foraging ranges of land-based krill predators (including fur seals and penguins), a lack of information exists for the largest krill predators in the region, humpback whales.  Based on previous work, we have learned that the distribution of humpback whales largely reflects that of krill across broad spatial and temporal scales.  

With support from the AWR, the study has leveraged a large existing data set of long-term satellite tag data from humpback whales that we previously collected and developed a suite of analytical techniques to 1) better determine how the movement patterns and behavior of whales changes throughout the Antarctic foraging season, and 2) determine the amount of overlap between the commercial krill fishery and humpback whale foraging areas.  The latter was also assessed to better understand how this overlap changes throughout the feeding season.

 The study finds that the core foraging areas for humpback whales change dramatically throughout the feeding season and clear overlap between these areas and where the commercial krill fishery currently operates.The amount of overlap appears to increase from beginning to end of summer, with the later parts of the season containing the highest potential for overlap.This occurs in large part in areas and times that are outside of feeding ranges of previously studied krill predators.