Monthly variation in the composition of diet: Among the identifiable food items, the seaweeds were dominant in the gut of S. canaliculatus during most part of the year (Fig. 3). During 2005-06, the percentage contribution of benthic algae was higher than 50% to the total volume of food items during April-May and February. Seagrass was found in moderate percentages during May-June and July and its contribution ranged from 0 to 35.3%. The benthic invertebrates occurred only during January 2006 with 47.1%. The contribution of semidigested matter ranged between 10.4% and 95.5% during 2005-06. During 2006-07, the seaweeds were dominant in the gut during all the months.