The fanbellied leatherjacket, M. chinensis, ingested fresh seagrass as a major part of its diet. Other important food items were gammarid amphipods, carid shrimps and several species of epiphytic algae [Microdictyon umbilicatum, Gracilaria edulis, Champia sp., Laurencia obtusa and Ceramium sp.]. All food items were of seagrass bed origin. Microscopic examination of gut contents suggested that seagrass and algae did not appear to be digested by the fish, but 14C-labeling of the plants showed that significant amounts of the labile C compounds were removed and assimilated during digestion. The fanbellied leatherjacket fed in the seagrass beds during the day, probably relying on eyesight for detecting food. Variations in tide height did not seem to affect their feeding pattern. The amounts of seagrass, algae, amphipods and shrimps removed by M. chinensis in Quibray Bay were calculated and compared with the availability of each of these foods. Grazing by M. chinensis had little effect on seagrass and algae production rates and standing crops, but probably had a significant influence on carid shrimp and amphipod populations. [In recent years there has been a growing interest in seagrass ecosystems, especially in their importance as a habitat and nursery ground for fish.].
