The Arctic Research Consortium of the U.S. (ARCUS) invites registration for the next Arctic Research Seminar featuring Emily Choy, postdoctoral fellow in the Department of Natu ral Resource Sciences at McGill University and Environment and Climate Chan ge Canada. Emily’s presentation, titled Marine Predators as Sentine ls of Environmental Change in Arctic Ecosystems, will be held via Zoom on Friday, 23 April 2021 at 9:00 a.m. AKDT (1:00 p.m. EDT).
Seminar Abstract:
Arctic ecosystems are undergoing rapid change, and long-lived top predators are considered sentinels of the impac ts of climate change on marine ecosystems. Beaufort Sea beluga whales (Delp hinapterus leucas) and thick-billed murres (Uria lomvia) in northern Hudson Bay have experienced long-term shifts in prey species and declines in infe rred growth rates, believed to be the result of environmental changes. In p artnership with Inuvialuit communities, we examined inter-annual variation and environmental factors affecting prey, body condition, and physiology of Beaufort Sea beluga whales. The estimated proportional contributions of Ar ctic cod (Boreogadus saida) to beluga diet decreased from 2011 to 2014, coi nciding with an increase in capelin (Mallotus villosus). Belugas consumed t he highest proportions of capelin and the lowest proportions of cod in 2014 . Body condition of whales was positively correlated with myoglobin, hemogl obin concentrations, and % hematocrit, resulting in lower total body oxygen stores in whales with lower body condition. The relationship between body condition and oxygen storage capacity may represent a positive feedback mec hanism, in which environmental changes resulting in decreased body conditio n impair foraging ability. To examine the impacts of climate-induced prey s hifts on the energetics of seabirds, heart rate was examined as a proxy for O2 consumption in murres and black-legged kittiwakes (Rissa tridactyla), a nd were calibrated with GPS-accelerometers to classify behaviours and activ ity rate. Finally, we examined the effects of Arctic warming on murre physi ology. In response to increasing temperatures, murres exhibited limited hea t tolerance and low ability to dissipate heat, with one of the lowest evapo rative cooling efficiencies recorded in birds. These results highlight the various impacts of climate change on marine predators and their broader imp lications on Arctic ecosystems.
Registra tion is required for this event. Instructions for accessing the webinar wil l be sent to registrants prior to the event.
To register for the event, go to:
ARCUS Arctic Resear
ch Seminar Series webpage