Feeding ecology of the Greenland shark under different ice conditions

The Greenland shark is the largest fish (up to 7 m) and one of only two shark species that regularly inhabit the arctic seas. Virtually every marine organism has been found in the stomach of these large sharks, including ringed seals. This sharks can be very numerous in the Arctic (> 40,000 sharks/year have been harvested in Baffin Bay), and thus their impact on ringed seal populations could be very significant. The continued health of marine mammal populations is critical to aboriginal people of the Arctic. Unfortunately, we know little about the role of the Greenland shark in arctic ecosystems or how this might vary with changing climatic or ice conditions. The major goal of this project is to determine the feeding ecology of the Greenland shark in Cumberland Sound, Baffin Island, Nunavut, Canada under different ice conditions (open water versus full ice cover), with a particular focus on assessing the importance of marine mammal predation. Additionally, we hoped to understand the environmental mechanisms driving catch rates in the Inuit turbot fishery of Cumberland Sound. We use a combination of chemical tracers and stomach contents to investigate Greenland shark feeding ecology, and hierarchical modeling to assess catch rates of the fishery through time. Greenland sharks are also satellite tagged to better understand their movement and habitat use. Finally, this project has integrated local/traditional Inuit knowledge on the Greenland shark and its ecosystem (Cumberland Sound).