Dietary Composition and Trophic Niche Partitioning of Spotty‐bellied Greenlings Hexagrammos agrammus, Fat Greenlings H. otakii, Korean Rockfish Sebastes schlegelii, and Japanese Seaperch Lateolabrax japonicus in the Yellow Sea Revealed by Stomach Content Analysis and Stable Isotope Analysis

Abstract

AbstractStable nitrogen and carbon isotope ratios of fish tissues, in combination with stomach content analysis, provide insights into how energy flows through marine food webs. Using these techniques, we investigated the diets and trophic niches of four important fish species of the Yellow Sea: the Spotty‐bellied Greenling Hexagrammos agrammus, Fat Greenling H. otakii, Korean Rockfish Sebastes schlegelii, and Japanese Seaperch Lateolabrax japonicus. The stomach content analysis revealed that Spotty‐bellied Greenlings mainly fed on crabs and fish; Fat Greenlings mainly preyed on fish, crabs, and shrimps; Korean Rockfish primarily consumed fish and shrimps; and Japanese Seaperch mainly fed on fish. Korean Rockfish had the highest dietary breadth index among the four fish species. Dietary composition of the four species did not overlap significantly, as indicated by Schoener's index. Prey category composition varied across fish species and differed between species pairs (except Korean Rockfish and Japanese Seaperch), as suggested by permutational ANOVA tests. The stable isotope analysis suggested that Japanese Seaperch had significantly higher δ13C and δ15N and had a significantly different centroid position, both of which indicated a higher trophic position. The corrected standard ellipse area on the δ15N–δ13C (‰) biplot varied in size among species and significantly overlapped in the three rockfishes, with the largest overlap area observed between Fat Greenlings and Korean Rockfish. The results, in general, suggested that the three rockfish species, especially Korean Rockfish and Fat Greenlings, had similar trophic niches, but they were partitioned by prey resources according to the stomach content composition. Our study provides novel insights into the dietary niches and trophic dynamics of these four exploited species, which could help to improve ecosystem‐based fisheries management in the Yellow Sea.