Feeding habits and trophic relationships of fishes utilizing an impacted coastal habitat, Singapore

Analysis of the feeding habits and trophic interrelationships between nine important fish species including Ambassis interruptus, Liza vaigiensis, Escualosa thoracata, Leiognathus decorus, Stolephorus indicus, Gerres oyena, Arius sagor, Sillago sihama and Ambassis kopsii utilizing an impacted coastal habitat revealed that the diets of most species underwent marked changes with ontogeny. Most of them had moderate food intake with fullness value ranging from 2.50-4.88. Variations of diet breadth and vacuity index were observed between species and size. New settlers of most species fed mainly on microcrustaceans especially calanoid copepods, before shifting to other food items. A multivariate analysis demonstrated that diet composition of the nine fish species differed from each other. However, significant overlaps between some fish species, including A. kopsii with G. oyena, E. thoracata with L. decorus, A. sagor with S. sihama and G. oyena with L. decorus, were detected by a Morisita-Horn index. This indicates that food partitioning with a slight competition among species occurs in this heavily impacted ecosystem.