Feeding Habits and the Trophic Level of the Fat Greenling Hexagrammos otakii (Hexagrammidae) off the Gangneung Coast of Korea

Abstract

This study aimed to understand the feeding habits and trophic level of the fat greenling Hexagrammos otakii off the Gangneung coast of Korea. In total, 421 individuals were collected using gillnets between September and December 2023 and between March and August 2024. The total length of the specimens ranged from 20.0 to 47.8 cm. The most important prey of H. otakii was fish, with Ammodytes personatus being the most frequently consumed species. The mean estimated trophic level of H. otakii was 4.20 +/- 0.73, ranging from 3.46 +/- 0.52 to 4.34 +/- 0.75. H. otakii predominantly fed on fish across all seasons and exhibited an ontogenetic dietary shift in which the proportions of brachyuran crabs and polychaets in the diet decreased, while the proportion of fish increased with growth. The stomach fullness index of H. otakii was the highest in spring and showed an increasing trend with growth. Permutational multivariate analysis of variance analysis revealed significant differences in diet composition according to season and size class. However, no notable interaction was detected between these two factors.