[MARMAM] New paper: Drivers and consequences of polar bear diet in the Canadian Beaufort Sea

Katie Florko katieflorko at gmail.com
Thu Sep 10 09:20:59 PDT 2020


Dear MARMAM,



My co-authors and I are pleased to announce the publication of our paper in
Oecologia:



Florko, K.R.N, Thiemann, G.W., Bromaghin, J.F. Drivers and consequences of
an apex predator diet composition in the Canadian Beaufort Sea. *Oecologia*,
doi: 10.1007/s00442-020-04747-0



https://link.springer.com/article/10.1007/s00442-020-04747-0



Abstract:

Polar bears (*Ursus maritimus*) rely on annual sea ice as their primary
habitat for hunting marine mammal prey. Given their long lifespan, wide
geographic distribution, and position at the top of the Arctic marine food
web, the diet composition of polar bears can provide insights into temporal
and spatial ecosystem dynamics related to climate-mediated sea ice loss.
Polar bears with the greatest ecological constraints on diet composition
may be most vulnerable to climate-related changes in ice conditions and
prey availability. We used quantitative fatty acid signature analysis
(QFASA) to estimate the diets of polar bears (*n *= 419) in two western
Canadian Arctic subpopulations (Northern Beaufort Sea and Southern Beaufort
Sea) from 1999 to 2015. Polar bear diets were dominated by ringed seal (*Pusa
hispida*), with interannual, seasonal, age- and sex-specific variation.
Foraging area and sea ice conditions also affected polar bear diet
composition. Most variation in bear diet was explained by longitude,
reflecting spatial variation in prey availability. Sea ice conditions
(extent, thickness, and seasonal duration) declined throughout the study
period, and date of sea ice break-up in the preceding spring was positively
correlated with female body condition and consumption of beluga whale
(*Delphinapterus
leucas*), suggesting that bears foraged on beluga whales during entrapment
events. Female body condition was positively correlated with ringed seal
consumption, and negatively correlated with bearded seal consumption. This
study provides insights into the complex relationships between declining
sea ice habitat and the diet composition and foraging success of a
wide-ranging apex predator.


Keywords: Foraging ecology, Fatty acids, Sea ice, Climate change, Polar
bear


Best regards,

Katie Florko

--

Katie R.N. Florko, PhD Candidate

Statistical Ecology Research Group

Institute for the Oceans and Fisheries

University of British Columbia



Twitter: @kflorko

Email: katieflorko at gmail.com
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