Feeding Ecology of Eelgrass Fish Communities

Abstract

The principal components in the diets of fishes utilizing eelgrass (Zostera marina) beds in the shallow water estuaries near Beaufort, North Carolina, were detritus, planktonic copepods, and epifaunal crustaceans. Food produced within the eelgrass beds such as eelgrass, crustaceans, gastropods, and detritus, could have accounted for approximately 56% by weight of the diet of the eelgrass fish community. Pinfish (Lagodon rhombiodes) under 35 mm feed primarily on planktonic copepods, thereafter detritus gradually replaced copepods. When pinfish reached a length of about 70 mm they became more omnivorous consuming a greater proportion of plant material and polychaetes. Changes in feeding habits may have been responsible for significant differences in the weight-specific caloric contents observed between three size groups of both pigfish and pinfish. All species except one did not feed in the beds at night even though biomass of all fish was twice as high at night than during the day. The eelgrass fish community does not appear to be food-limited because the total annual food production in the beds is greater than the total annual food consumption by the eelgrass macrofauna.