BOWHEAD WHALE AND ZOOPLANKTON RESEARCH
Bowhead whales live in a rapidly changing environment and are likely to experience further alterations in the quality and quantity of their prey. To understand how bowheads use their Arctic habitat under current environmental conditions, we worked with researchers from Woods Hole Oceanographic Institution (Dr. Mark Baumgartner), Fisheries and Oceans Canada (Dr. Steven Ferguson) and Inuit fishers and hunters (Ricky and Peter Kilabuk) from Pangnirtung, NU to determine when and where whales fed, and what they ate. Using aerial video of animals to observe behaviour through collaboration with William Koski (LGL Limited and Thomas Seitz), and satellite-linked transmitting tags to determine locations and diving depths, we found that bowhead whales feed year-round—especially during summer and fall. Cumberland Sound, Nunavut is a particularly important habitat for bowhead whales that contains energy rich zooplankton, as well as large boulders to rub off loose skin while molting. Our findings provide new insight into the diet, movements, seasonal moult, habitat-use, and year-round foraging behaviour of bowhead whales in the eastern Canadian Arctic.
Between 2013 and 2016, we collected high resolution information about the vertical distribution and abundance of zooplankton while deploying an oceanographic cage. The cage was outfitted with several instruments, to provide information about the temperature and salinity (CTD), size and number of zooplankton particles (OPC and multi-frequency echosounder) in the water column. Collecting this data allowed us to determine at what depth the greatest abundance and biomass of zooplankton was found. Overall, we determined that bowheads target lipid-rich species and life-stages of Calanus spp. and that they alternate between shallow and deep prey layers.
As part of a new DFO funded project, we're evaluating the ecosystem level impacts of climate change and energetic consequences for bowhead whales in the Eastern Canadian Arctic. We're collecting detailed information about whale behaviour using short-term, high-resolution biologgers (CATs) and longer-term information about whale dive behaviour from satellite-telemetry tags with time-depth recorders (Wildlife Computers). To understand ecosystem conditions, we're using eDNA sampling (Dartmouth Ocean Technologies), DNA metabarcoding (Hakai Institute), multi-frequency echosounders (University of St. Andrews), net and Underwater Vision Profilers (Ocean Frontier Institute). To understand whether climate induced shifts in zooplankton assemblages and whale behaviour are already underway, we'll examine spatio-temporal shifts in bowhead foraging effort and zooplankton species composition and abundance.
