[MARMAM] New Article: Repeated Vessel Interactions and Climate- or Fishery-Driven Changes in Prey Density Limit Energy Acquisition by Foraging Blue Whales

Marie Guilpin marieguilpin at gmail.com
Mon Aug 3 16:34:34 PDT 2020


My co-authors and I are pleased to announce the publication of our new
paper in Frontiers in M

Guilpin M, Lesage V, McQuinn I, Brosset P, Doniol-Valcroze T,
Jeanniard-du-Dot T and Winkler G (2020) Repeated Vessel Interactions and
Climate- or Fishery-Driven Changes in Prey Density Limit Energy Acquisition
by Foraging Blue Whales. Front. Mar. Sci. 7:626.

ABSTRACT: Blue whale survival and fitness are highly contingent on
successful food intake during an intense feeding season. Factors affecting
time spent at the surface or at depth in a prey patch are likely to alter
foraging effort, net energy gain, and fitness. We specifically examined the
energetic consequences of a demonstrated reduction in dive duration caused
by vessel proximity, and of krill density reductions potentially resulting
from krill exploitation or climate change. We estimated net energy gain
over a simulated 10-h foraging bout under baseline conditions, and three
scenarios, reflecting krill density reductions, vessel interactions of
different amplitudes, and their combined effects. Generally, the magnitude
of the effects increased with that of krill density reductions and duration
of vessel proximity. They were also smaller when peak densities were more
accessible, i.e., nearer to the surface. Effect size from a reduction in
krill density on net energy gain were deemed small to moderate at 5% krill
reduction, moderate to large at 10% reduction, and large at 25 and 50%
reductions. Vessels reduced cumulated net energy gain by as much as 25%
when in proximity for 3 of a 10-h daylight foraging period, and by up to
47–85% when continuously present for 10 h. The impacts of vessel proximity
on net energy gain increased with their duration. They were more important
when whales were precluded from reaching the most beneficial peak
densities, and when these densities were located at deeper depths. When
krill densities were decreased by 5% or more, disturbing foraging blue
whales for 3 h could reduce their net energy gain by ≥30%. For this
endangered western North Atlantic blue whale population, a decrease in net
energy gain through an altered krill preyscape or repeated vessel
interactions is of particular concern, as this species relies on a
relatively short feeding season to accumulate energy reserves and to fuel
reproduction. This study highlights the importance of distance limits
during whale-watching operations to ensure efficient feeding, as well as
the vulnerability of this specialist to fluctuations in krill densities.

The paper is open access and available here:

Best regards,
Marie Guilpin

Marie Guilpin, PhD Candidate in Oceanography
Université du Québec à Rimouski - Institut des Sciences de la Mer de
300, allée des Ursulines Rimouski, Qc, G5L 3A1, Canada
Phone: (418) 723-1986 poste #1252 O.202
marieguilpin at gmail.com
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