The food hnbits of most marine fishes arc roughly grouped into the following three major trophic categories: herbivores, carnivores, and omnivores. Some investigators working with coral reef fishes have subdivided these categories based on their various specialized feeding mechanisms. Randall (1967), for example, classified 212 species of reef fishes in the West Indies into seven categories baaed on their food habits: plant and detritus feeders, zooplankton feedera, "shelled"-invertebrate feeders, gcneralizied carnivores, ectoparasite feeders, and fish feeders.Such distinctions arc indispensable for structural analyses of the highly diverse reef fish communities (Randall, 1963; Gold- man and Talbot, 1976; Brock et al., 1979; Gladfelter et al,, 1980; Sano ct al., 1984), as well as examinations of trophic relationships among the reef fishes (e.g., Hiatt and Straaburg, 1960).

On the other hand, one cannot be sure that a certain reef fish will have the same food habits from one locality to another. Geographical differences and the physical and biological features of reefa may well affect the food habits of reef fishes, even though they arc genetically determined. Therefore, it is necessary to examine in detail the diets of reef fishes at each "separate locality," and then to determine their food habits carefully and precisely.

Despite the importance of food-habit analysis, however, there have been only a few comprehensive studies of the trophic relationships that include a broad selection of the fishes in an area. Studies of particular significance are those of Hiatt and Straaburg (1960) in the Marshall Islands, Randall (1967) in the West Indies, and Hobson (1974) in Hawaii. In the present study, we analyze in detail the gut contents of various fishca collected during the day from coral reefs and their adjacent areas at Minatogawa, Okinawa Island, and strictly classify them into several trophic categories.