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International Journal of Ecology
Volume 2012 (2012), Article ID 208913, 13 pages
http://dx.doi.org/10.1155/2012/208913
Research Article

Hydrodynamic and Sensory Factors Governing Response of Copepods to Simulated Predation by Balaenid Whales

Department of Biology, Hampden-Sydney College, Hampden-Sydney, VA 23943-0162, USA

Received 29 July 2011; Accepted 3 February 2012

Academic Editor: Bruce Leopold

Copyright © 2012 Alexander J. Werth. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Predator/prey interactions between copepods and balaenid (bowhead and right) whales were studied with controlled lab experiments using moving baleen in still water and motionless baleen in flowing water to simulate zooplankton passage toward, into, and through the balaenid oral cavity. Copepods showed a lesser escape response to baleen and to a model head simulating balaenid oral hydrodynamics than to other objects. Copepod escape response increased as water flow and body size increased and was greatest at distances ≥10 cm from baleen and at copepod density = 10,000 m−3. Data from light/dark experiments suggest that escape is based on mechanoreception, not vision. The model head captured 88% of copepods. Results support previous research showing hydrodynamic effects within a whale’s oral cavity create slight suction pressures to draw in prey or at least preclude formation of an anterior compressive bow wave that could scatter or alert prey to the presence of the approaching whale.