Trophic ecology of largehead hairtail Trichiurus japonicus in the South Sea of Korea revealed by stable isotope and stomach content analyses

Largehead hairtail ( Trichiurus japonicus ) is one of the most commercially important fishes in western North Pacific. To identify dietary changes across ontogeny and seasons, we investigated its stomach contents stable isotope signatures (? 13 C ? 15 N) South Sea Korea. The index relative importance revealed that composition largehead consisted mainly Pisces (1.6%–84.8%) Euphausiacea (3.0%–93.0%). However, proportions items differed by season anal length (ALs), suggesting a trophic adaptability response to seasonal food availability size-related variation, respectively. Our isotopic results showed placed intermediately between pelagic benthic was more N-depleted than other carnivorous fishes, high consumption species. Similarly, variations were observed N values hairtails (PERMANOVA, p= 0.001). Interestingly, their spring decreased significantly with ALs r 2 = 0.594, p < 0.001), an ontogenetic change due increased proportion nutrition individuals during this specific season. Based on combination signatures, overall provide new insights into feeding characteristics hairtail, which improves our understanding ecology depending body size.