Foraging Ecology and Habitat Selection of Bowhead Whales (Balaena mysticetus) in the Canadian High Arctic

The Eastern Canada–Western Greenland bowhead whale (Balaena mysticetus) population was severely depleted by commercial whaling during the 19th and 20th centuries, which led to their designation as ''Special concern'' by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in April 2009. Although Inuit knowledge supported by scientific research indicate that the number of whales in the region has been increasing in recent years, bowhead whales are still at risk of becoming threatened or endangered because of a combination of biological characteristics (e.g. extremely low natural growth rate) and identified threats (e.g. predation, human presence). Moreover, it remains unclear how bowheads will react and adapt to climate change and its effects on their habitat. In this context, we initiated a study that relates foraging ecology and habitat requirements of the bowhead whale by using stable isotopes of carbon, nitrogen and sulfur. Skin biopsies from live and dead bowhead whales were collected at various locations in the Eastern Canadian High Arctic from 1987 to 2008. Results indicate inter-regional variations in stable isotopes of carbon and sulfur but not in nitrogen. Gender was determined using genetic markers and there is no significant difference between males and females in carbon, nitrogen or sulfur isotope ratios. Differences in foraging as suggested by isotopic signatures are discussed in the perspective of the longevity, low fecundity and narrow-niche foraging of the species, which may make the bowhead whales more vulnerable to changes in sea ice coverage with continued global warming. We also looked at bowhead whales platform transmitter terminals (PTTs) in the eastern Arctic during the summers of 2002 through 2006. Bowheads' movements were estimated using a Bayesian state-space model and the telemetry data were used in conjunction with remotely-sensed net primary production (NPP) data to assess habitat selection. Overall there were no clear patterns with bowhead habitat selection and ocean net primary productivity.