Effect of food acclimation on assimilation efficiency of <i>Calanus pacificus</i>1

Abstract

A technique, based on quantitative conversion of chlorophyll a to pheophorbide during digestion, is described for determination of assimilation efficiencies of particle‐feeding zooplankton. Calanus pacificus had assimilation efficiencies ranging from 68.5 to 85.4% for carbon and 73.9 to 92.5% for nitrogen. Assimilation efficiencies for copepods first acclimated to different food concentrations of Thalassiosira weissflogii and then fed at the same food level varied systematically, with animals acclimated to low food having higher efficiencies than animals acclimated to high food.