Comparison of Stomach Contents of the Blotched Eelpout, Zoarces gillii, in the South Sea and Yellow Sea of Korea

초록

This study investigated the dietary composition of the blotched eelpout (Zoarces gillii) in the South Sea and Yellow Sea of Korea based on stomach content analysis. A total of 919 individuals from the South Sea and 561 from the Yellow Sea were collected using bottom trawl nets in 2021-2024. The total length ranged from 8.2 to 54.6 cm and from 4.6 to 58.4 cm, respectively. Prey items were identified and quantified using the relative importance index (%RI), which incorporates frequency of occurrence and wet weight. In the South Sea, Amphipoda were the dominant prey group, comprising 83.7%RI, whereas in the Yellow Sea, Bivalvia were the most important prey category, accounting for 45.2%RI. Diet composition varied with fish size, with larger individuals in the Yellow Sea feeding predominantly on bivalves, indicating ontogenetic dietary shifts. The trophic level of Z. gillii was estimated at 3.27 in the South Sea and 3.26 in the Yellow Sea, suggesting a consistent mid-level predatory role. The observed regional differences in diet reflect habitat-specific prey availability and ecological conditions. These results demonstrate that Z. gillii exhibits opportunistic feeding behavior and ecological plasticity, which are crucial for understanding spatial food web structures and informing ecosystem-based fisheries management strategies.

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