Comparison between five coexisting species of marine copepods feeding on naturally occurring particulate matter

Grazing by five species of copepods on naturally occurring particles has been investigated over a 1‐yr period. The consumption of particles by each species was associated with changes in both total concentration and composition of suspended particulate material. All the copepods reacted similarly and simultaneously to the changes of the particle size spectrum by shifting their grazing pressure from one size range to another. They all behaved as opportunistic particle feeders, seeking and keeping track of the most abundant particles. No species seemed to behave as a selective grazer with respect to particle sizes. There were quantitative differences between the ingestion rates per body dry weight of the copepods, and the ingestion per body dry weight was inversely proportional to the body dry weight. The feeding behaviors of the species should lead to rather severe interspecific competition. The apparently sustained coexistence of the five sympatric species is attributable to several physical and biological mechanisms working simultaneously.