Predator‐Prey Relationships in an Estuarine Littoral Copepod Community

Seasonal divergences of planktonic copepod communities in a marine eelgrass bed and adjacent unvegetated channel habitats were associated with increases in predator abundance in the littoral habitat. During midsummer, when planktivorous silversides, Menidia menidia, were abundant in the eelgrass bed, pelagic copepod densities were significantly reduced in the eelgrass bed, relative to channel abundances. Differences declined overnight, when fish were not feeding, and were reestablished after dawn. In late winter, coincident with the arrival of large numbers of postlarval fish in the eelgrass bed, there was selective reduction of juvenile Centropages spp. in the eelgrass bed, relative to channel abundances. Field and laboratory experiments indicate that these differences were due to intense predation by planktivorous fish. However, the littoral copepod Pseudodiaptomus coronatus appeared unaffected by the intense predation in the eelgrass bed. Laboratory experiments demonstrated that its epibenthic habit and cryptic coloration allow P. coronatus to utilize refuges in the littoral habitat, and that prey selection by two fish species differed due to differences in foraging behavior.