Zooplankton filtering efficiency of the baleen of a North Atlantic right whale, Eubalaena glacialis

Abstract

In order to define the trophic requirements of the North Atlantic right whale, a series of experiments were designed to examine the foodcapture characteristics of the species. The food filtering efficiency of the baleen of an immature right whale was tested in a flume usinggraded samples of zooplankton, primarily calanoid copepods, collected in the path of surface-feeding whales. The filtering capacitydecreased with decreasing prey organism size, so that greater than 95% of the available caloric content of the zooplankton samples wascaptured in size fractions collected on 333m mesh nets. The experiments demonstrate that the filtering efficiency of the baleen narrowlyfocuses the right whale’s feeding on an energy-rich, yet spatially and temporally variable, portion of the mid-water food resource