[pccgrads] Hauser Ph.D. Defense -"Beluga whale distribution, migration, and behavior in a changing Pacific Arctic" Today, May 25 at 10 AM (NOW!)

UW PCC uwpcc at uw.edu
Wed May 25 09:22:34 PDT 2016


Beluga whale distribution, migration, and behavior in a changing Pacific

Donna DW Hauser
School of Aquatic & Fishery Sciences
University of Washington
PhD Defense
Chair: Kristin Laidre
25 May 2016
FSH 102 (School of Aquatic and Fishery Sciences), 10 AM


Sea ice is disappearing at unprecedented rates in the Pacific Arctic with
potential impacts to ice-associated marine predators that migrate to this
seasonally accessible and productive ecosystem. In this dissertation I used
satellite telemetry data spanning 1993-2012 collected from two migratory
populations of beluga whales (Delphinapterus leucas) in the Pacific Arctic
(i.e., Eastern Chukchi Sea and Eastern Beaufort Sea populations) to
investigate how loss of sea ice and changes in other environmental factors
affect distribution, movement, and behavior. I quantified fidelity to summer
areas, sexual segregation, and migration timing as well as variations in
diving behavior among regions. These analyses illustrate that
population-scale patterns of philopatry, migration, and foraging are
mediated by the combined effects of seasonal sea ice and oceanographic
fluctuations, prey distribution, and social interactions. I also addressed
the question of whether belugas would adjust their distribution, migration,
and behavior to shifting sea ice conditions and to what extent
matrilineally-learned behavior might supersede environmental forcing through
the development of resource selection functions. Results indicate that sea
ice is a contributing factor but not sole determinant of beluga habitat
preferences. One population (Eastern Chukchi Sea) exhibits delayed fall
migration in response to later sea ice freeze-up. Changing environmental
conditions also seem to favor deeper, longer dives for this population.
There were few overall differences in preferred habitat selection during
1990-2014, and summer distribution appears to be governed by philopatry
rather than ice conditions. These results correspond to a conclusion that
Eastern Chukchi Sea belugas are responding to a changing Pacific Arctic
environment through behavioral plasticity in migration timing and foraging
behavior. In contrast, there were few examples where migration timing or sea
ice associations of Eastern Beaufort Sea belugas changed between the 1990s
and 2000s. Taken as a whole, these results suggest population-specific
responses by belugas in the face of fluctuating sea ice conditions. Across
the circumpolar Arctic, some beluga populations may be more likely than
others to adapt and persist in a changing climate.

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