Scope for growth of the thick shell mussel Mytilus coruscus under combined stress of Vibrio alginolyticus and Charybdis japonica

Vibrio species is currently recognized as a major contributor to shellfish diseases and mortality in marine habitats. In the natural environment, predator-induced stress also triggers defensive responses in mussels. The purpose of this experiment was to evaluate the combined stress effects of Vibrio alginolyticus and predator crab (Charybdis japonica) on the energy expenditure of the thick shell mussel Mytilus coruscus. Based on our results, when crabs were co-cultured with mussels, there were no significant alterations observed in the clearance rate (CR), respiration rate (RR), or ammonia excretion rate (ER) of mussels. However, significant decreases were noted in the oxygen‑nitrogen ratio (O: N ratio), absorption efficiency (AE), and scope for growth (SFG) of the mussels. Subsequent exposure to V. alginolyticus led to significant reductions in CR, RR, O: N ratio, and SFG of mussels, while ER and AE were significant increased. Additionally, interactive effects of the presence of crabs and Vibrio were observed in CR, RR, ER, O: N ratios, AE and SFG. The results underscore that simultaneous exposure to V. alginolyticus and crabs can diminish the growth energy of mussels. This study provides a basis for better understanding the effects of multi-factorial stress on energy utilization and health of mussels, and lays the foundation for conducting ecotoxicological research on Vibrio and its predators in aquatic environments.