Feeding costs limit dive time in large whales

From: Pita Admininstrator (pita@whale.wheelock.edu)
Date: Wed Jun 05 2002 - 06:33:28 EDT


The following article was published recently. Please direct reprint
requests to aacevedo@calacademy.org.

Acevedo-Gutierrez A, Croll D, Tershy B (2002) Feeding costs limit dive
time in large whales. The Journal of Experimental Biology 205: 1747-1753.

Large body size usually extends dive duration in air-breathing
vertebrates. However, the two largest predators on earth, the blue whale
(Balaenoptera musculus) and the fin whale (B. physalus), perform short
dives for their size. Here, we test the hypothesis that the foraging
behavior of these two species (lunge feeding) is energetically expensive
and limits their dive duration. We estimated the cost of lunge feeding in
both species through an approach that combined attaching time-depth
recorders to seven blue whales and eight fin whales and comparing the
collected dive information to predictions made by optimality models of
dive behavior. We show that the rate at which whales recovered from a
foraging dive was twice that of a non-foraging dive and that the cost of
foraging relative to the cost of travel to and from the prey patch was
3.15 in blue whales (95% CI= 2.58 - 3.72) and 3.60 in fin whales (95% CI=
2.35 - 4.85). Whales foraged in small areas (<1 km2) and foraging bouts
lasted more than one dive, indicating that prey did not disperse and thus
could not account for the limited dive durations of the whales. Despite
the enormous size of blue whales and fin whales the high energetic costs
of lunge feeding confine them to short durations of submergence and to
areas with dense prey aggregations. As a corollary, due to their limited
foraging time underwater these whales may be particularly vulnerable to
perturbations in prey abundance.

====================================================================
Alejandro Acevedo

Division of Education
California Aacdemy of Sciences
Golden Gate Park
San Francisco, CA 94118
USA

(415) 750 7360 phone
(415) 750 7367 fax
aacevedo@calacademy.org

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