Two cruises to the Peru upwelling in 1976 and 1977 provided the opportunity to examine the feeding response of Centropages brachiatus, Calanus chilensis, and Eucalanus inermis. The shipboard experiments with naturally occurring particulate matter were designed to test two hypotheses: 1) that food size selectivity by a copepod is a function of overall food concentration, and 2) that a copepod varies the range of food sizes ingested as a function of food concentration and available food size....