Diel feeding patterns, prey selectivity, and predatory impact of the box jellyfish Carybdea brevipedalia (Cnidaria: Cubozoa)

Box jellyfish (Cubozoa) are key predators that prey upon zooplankton and fish, yet their feeding habits and ecological roles remain insufficiently understood. This study examines in situ diel feeding patterns, prey selectivity, and predatory impact of Carybdea brevipedalia in Korean coastal waters, based on analyses of its gut contents and ambient prey availability. C. brevipedalia exhibited a distinctly nocturnal feeding pattern, with both gut fullness and medusa density markedly higher at night, with diel differences in prey composition across the ambient water and gut contents. Ontogenic differences were not statistically significant, although larger medusae tended to consume proportionally larger prey, including fish larvae. Mysids were consistently the most selected prey across all size classes and showed the highest daily predation impact, with values that could amount to the equivalent of up to 13.4% of the ambient population being consumed over a 24-hour period. These results indicate that C. brevipedalia tends to target larger prey items, highlighting its potential influence on coastal food-web dynamics.