Diet and trophic ecology of silver pomfret, Pampus argenteus (Euphrasen, 1788) exploited from the Southeast Arabian Sea

Abstract

Stomach content analysis of the silver pomfret, Parnpus argenteus using the Index of Relative Importance (IRI) revealed that crustaceans (IRI= 48.2%) and semi-digested pulp (IRI= 47.6%) formed the important diet. Copepods formed the largest propartion among crustaceans. Proportion of empty stomachs was higher in large fishes and the diet changed with body size as well as with season. Fishes in smaller length group (<I40 mm) had semi-digested pulp as the dominant component, whereas fishes above 140 mm had copepods and fish. The relationship between the mean weight of semi-digested pulp and mean number-of copepods with that of predator length suggested probable diet shift from omnivory to carnivorous feeding habits. The mean weight of semi-digested pulp gradually decreased with increasing length of the fish. The highest similarity in diet was observed between the monsoon and post-monsoon seasons, and by length groups, between the fishes of 191-240 and 241-290 mm. Diet breadth is narrow as revealed by Levin's index. The trophic level was estimated as 2.4 + 0.1. The Amundsen plot showed that P. argenteus is a specialized feeder on semidigested pulp and copepods.