Diet and food partitioning between juvenile of Epinephelus coioides (Perciformes: Epinephelidae) and other co-existing juvenile fishes in shallow waters of Thailand and Malaysia

This work examined diet composition of the juvenile orange-spotted grouper, Epinephelus coioides, and its trophic association with other juvenile fish species in tropical estuarine habitats during recruitment. From December 2015 to March 2016, juveniles were collected, their stomachs excised, preserved and analyzed. Small shrimps and amphipods, especially Grandidierella sp. and Elasmopus sp., were the most common food resources sharing among the most species. Epinephelus coioides predominantly ingested small shrimp, Grandidierella sp., Elasmopus sp. and fish larvae and had the greatest trophic overlap with Palatrus scapulopunctatus. Fish size, location and month significantly affected fullness indices and food items diversity in E. coioides. It is clear that the larger the size of E. coioides and its mouth opening, the larger the size of items ingested. This study confirms the ontogenetic dietary shift of juvenile E. coioides during recruitment season by starting as amphipod and small shrimp feeder and shifting to shrimp and fish larvae predator as they grow. This finding is fundamental to understanding how juvenile E. coioides cope with different conditions and its association with other co-existing species during the recruitment period.