OCEAN ACIDIFICATION AND WARMING ON KEY ENZYMES IN THE SENSORY, MOTOR, AND DIGESTIVE SYSTEMS AND PREDATORY BEHAVIOR OF THE VEINED RAPA WHELK (RAPANA VENOSA)

This study investigated the effects of four experimental conditions-control (pH 8.1, 23℃), warming (pH 8.1, 25℃), acidification (pH 7.7, 23℃), and combined acidification–warming (pH 7.7, 25℃)-on the sensory and motor functions, key digestive enzyme activities, and subsequent predation behavior of the veined rapa whelk (Rapana venosa) toward the Manila clam (Ruditapes philippinarum). The results revealed that under individual acidification, key enzyme activities associated with sensory perception remained unaffected, whereas those related to motor function decreased and digestive enzyme activities increased. Under individual warming, sensory enzymes showed no significant change, but both motor and digestive enzymes were elevated. Acidification and warming exhibit a negative synergistic effect when combined, showing an inhibitory impact on the activities of three key system enzymes. Changes in enzymatic activities further led to modifications in the sensory, motor, and digestive functions of R. venosa, which consequently influenced its foraging performance: under acidification, the encounter rate with prey did not differ significantly, yet the predation rate declined; under warming, the encounter rate increased without a significant change in predation rate; under combined acidification–warming, both encounter and predation rates decreased markedly. These results indicate that ocean acidification and warming may affect the predatory behavior of R. venosa by modulating the activity of key enzymes in its sensory, locomotor, and digestive systems. This study provides a scientific basis for predicting population dynamics and the stability of the benthic “whelk–clam” food web, and offers theoretical support for optimizing gastropod aquaculture, enhancing shellfish resource restoration, and promoting sustainable utilization.