Ecological Characteristics of Large-Bodied Sharks in the East Sea of Korea

Large-bodied sharks are key apex predators in marine ecosystems; however, ecological data from Korean waters are limited. From February to November 2024, 44 individuals from six species were collected. Of these, 24 individuals were analyzed for ecological characteristics: shortfin mako (<i>Isurus oxyrinchus</i>, <i>n</i> = 6), salmon shark (<i>Lamna ditropis</i>, <i>n</i> = 11), blue shark (<i>Prionace glauca</i>, <i>n</i> = 6), and great white shark (<i>Carcharodon carcharias</i>, <i>n</i> = 1). Age and growth parameters were estimated from vertebral band counts using the von Bertalanffy growth model. Diet was assessed via stomach content and DNA metabarcoding, and trophic relationships were examined using stable isotopes. The monthly occurrence peaked in July, with shortfin mako, salmon shark, and blue shark being the most frequently observed species. Estimated ages ranged 8-16, 4-13, and 1-11 years, respectively. The diets were predominantly fish-based, with species-specific prey preferences. Stable isotope data revealed trophic differentiation, suggesting niche partitioning among species. The eastern coastal waters of Korea appear to serve as foraging grounds and potential nursery habitats for large shark species. This is the first comprehensive ecological baseline for these species in Korean waters, which supports future assessments, conservation, and management strategies.