Diet composition and trophic niche similarities of engraulid fishes in Pabean bay, Indramayu, Indonesia

Abstract

A study on the trophic ecology of fishes is one of the approaches to acquire a better understanding of fish feeding strategies, prey inclinations, niche competition and increase knowledge on the working of marine biological system. The present work aims to determine diet composition and trophic niche overlap among species of engraulid fishes in the coastal area of Pabean. Sampling was performed monthly from April 2016 to March 2017 and fishes were captured using gill nets and guiding barriers. During research period, seven species of engraulid were collected, namely Thryssa hamiltonii (with total length ranged from 47-186 mm), Thryssa mystax (53-151 mm), Thryssa kammalensis (66-112 mm), Thryssa setirostris (106-132 mm), Stolephorus indicus (54-133 mm), Stolephorus dubiosus (56-75 mm) and Stolephorus tri (66-91 mm). Prey of fishes were classified into four taxonomic groups i.e., Bacillariophyceae, Polychaeta, Crustacea and Pisces. Crustacea was the most consumed category (IRI>90%), recorded for all species of engraulid fishes, followed by Bacillariophyceae (<10%), polychaeta and fish juveniles (<5%). This finding indicates that all engraulid fishes in Pabean waters are crustasivore. Inter-specific feeding overlap was high, indicates that feeding competition among engraulid fishes tends to be high when food resources is decreased.