Resumen de Diel feeding rhythm of copepod size-fractions from Coliumo Bay, Central Chile

Danilo Calliari, Tarsicio Antezana

• The feeding behaviour of the size fractionated copepod assemblage was studied over a diel cycle in Coliumo Bay. In this shallow environment the photic layer reached the bottom and salinity, temperature, and food availability were fairly homogeneous throughout the water column. All four size-fractions (250-500 mm, 500-1000 mm, 1000-2000 mm, >2000 mm) showed a period of high feeding activity during the night and low feeding activity during the day. The persistence of nocturnal feeding in the presence of high food concentration over the 24-h cycle is interpreted as a predator avoidance strategy: empty guts by day make copepods less conspicuous to their visual daytime predators.