Abstract:
The dietary habits and food resources partitioning of H. quadrimaculatus and S. crumenophthalmus
caught by stilt fishing in southern Sri Lanka were studied. Food particles found in the gut contents of 112
specimens of H. quadrimaculatus and 166 specimens of S. crumenophthalmus were identified. Different
food categories were sorted by taxonomic groups to calculate food electivity, overlap, trophic niche
breadth and food preference of each fish species. H. quadrimaculatus fed on both phytoplankton and
zooplankton while S. crumenophthalmus solely fed on zooplankton. Gut content of H. quadrimaculatus
consisted of 46 food items and it preferred diatoms, dinoflagellates and calanoid copepods. S.
crumenophthalmus preferred calanoid copepods, cyclopoid copepods and crustacean larvae (protozoea
and nauplii) and it consumed 41 food items. Two fish species had low dietary overlap (16%) and their
niche breadth was significantly different (p< 0.05). Therefore, these two fish species can aggregate with
minimum competition for food and that may be one of the reasons for their seasonal congregation on
shallow reef areas in the Southern coast of Sri Lanka.