Right whales feed on zooplankton, primarily copepods, tiny drifting animals approximately the size of a small grain of rice. Because of this specialized diet, right whales must locate feeding areas where copepods are concentrated into high-density patches. URI oceanographer Robert D. Kenney is studying how right whales find their feeding grounds and, once there, how they locate dense zooplankton patches. He conducted his study with Charles A. Stormy Mayo of the Center for Coastal Studies in Provincetown, Massachusetts, and the late Howard Winn of the URI Graduate School of Oceanography.
Kenney has estimated that zooplankton patches where right whales feed must reach concentrations on the order of tens to hundreds of thousands per cubic meter in order for the whales to obtain a net energy benefit from feeding. As reported in a recent special issue of the Journal of Cetacean Research and Management devoted entirely to right whales, copepod densities of that magnitude have rarely been measured in the North Atlantic. Although the actual extent of such high-density zooplankton patches in the western North Atlantic is very poorly known, some of the highest densities have been measured near feeding right whales.
It is clearly of interest to determine how right whales locate the dense zooplankton patches within their feeding grounds, said Kenney. It may provide insight into how and why right whales become entangled in fishing gear and how they may cope with potential changes in prey distribution caused by climate change.
Right whales use a number of strategies to locate feeding grounds and prey concentrations. Some have to do with long-distance seasonal migrations over weeks and months, and others depend on minute-by-minute selection of the optimal prey patches within a particular feeding area. Kenney has compiled and presented a variety of hypotheses resulting in a conceptual model of the mechanisms and strategies that may be involved in the a
Contact: Lisa Cugini
University of Rhode Island