Abstract:Pseudosciaena polyactis and Setipinna taty are two kinds of important commercial fish species in the northern East China Sea and the Bohai Sea, and they play an important role in the marine ecosystems. In our study, the dietary overlap and food competition between these two juvenile fish species at their common length of 35~69 mm were examined by applying the multivariate statistical technique, the Schoener’s similarity index, and the Pianka index, based on the total of 547 samples collected from seasonal bottom trawl surveys in the Haizhou Bay of the Yellow Sea during July~August, 2008. The results indicated that these two juvenile fish species had the same trophic level of 3.33. Both the Schoener’s similarity index (0.06~0.20) and dietary overlap coefficient (0.03~0.38) between juveniles of the two fish species were lower than 0.6. In contrast, their intra-specific values of food composition similarity and dietary overlap coefficient were relatively high. At the species level, crustaceans including Labidocera euchaeta and Acanthomysis longirostris were the common preys in the developing prophase of the two fish species. Then different changes in diet appeared as the two juvenile fish grew. We conclude that there is low inter-specific competition between juveniles of these two fish species and high intra-specific competition within each species.
