[MARMAM] Publication: Fjord habitat use strategies of fin and humpback whales

Eric Keen ericmkeen at gmail.com
Fri Sep 21 08:22:45 PDT 2018


On behalf of my co-authors, I would like to bring the following publication
in *Marine Environmental Research* to your attention:

*Distinct habitat use strategies of sympatric rorqual whales within a fjord
system*
EM Keen, J Wray, J Pilkington, KL Thompson, CR Picard

Link to article <https://authors.elsevier.com/a/1XmAyW5UJ5uGw>

*Abstract:*
We used ecosystem sampling during systematic surveys and opportunistic
focal follows, comparison tests, and random forest models to evaluate fin
whale (Balaenoptera physalus) and humpback whale (Megaptera novaeangliae)
habitat associations within an inland feeding ground (Kitimat Fjord System,
British Columbia, Canada). Though these species are sympatric and share a
common prey source, they were attuned to different aspects of the local
habitat. The fin whales were associated with habitat properties reminiscent
of the open ocean. Humpback whales, in contrast, were associated with
features more commonly associated with the inland waters of fjords. Fixed
habitat features, such as seafloor depth and distance from the fjord mouth,
were the most important predictors of fin whale presence, but fixed and
dynamic variables, such as surface properties, predicted humpback whale
presence with equal (moderate) success. With the exception of strong
salinity gradients for humpback whales, habitat conditions were poor
predictors of feeding state. Fin whales practiced a spatially confined,
seasonally stable, and thus more predictable use of certain channels within
the fjord system. These findings are compatible with site loyal behavior,
which is interesting in light of the species' historical, unique use of
this fjord system. The relatively lackluster performance of
humpback-habitat models, coupled with the importance of oceanographic
properties, makes the humpback's habitat use strategy more uncertain. The
fact that two sympatric species sharing a common prey source exhibited
different habitat use strategies suggests that at least one species was
informed by something in addition to prey. Given that the two species are
attuned to different aspects of the fjord habitat, their responses to
habitat changes, including anthropogenic impacts, would likely be different
in both nature and degree. Our findings highlight the value of comparative
studies and the complexity of rorqual habitat use, which must be understood
in order for critical habitat to be identified and protected.


--
Eric M Keen

PhD, Scripps Institution of Oceanography
Visiting Professor, Sewanee: The University of the South
Science Director, North Coast Cetacean Society
Biologist, Marine Ecology & Telemetry Research
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