Effect of water temperature on diel feeding, locomotion behaviour and digestive physiology in the sea cucumber Apostichopus japonicus

ABSTRACT This study used controlled laboratory conditions to directly assess the role of water temperature in controlling diel feeding and locomotion behaviours, and digestive physiology, in the sea cucumber Apostichopus japonicus . The results revealed that both the proportion of feeding individuals and ingestion rate were highest at 16°C. Regardless of water temperature, sea cucumbers appeared to be nocturnal and their peak feeding activity occurred at 00:00 h to 04:00 h. Tentacle insertion rate was not significantly correlated with water temperature ( A. japonicus showed more active feeding and moving activities, and higher digestive enzyme activities, at night than during the day. These results demonstrated that diel feeding and locomotion behaviours, at least in the short term, were not controlled by light or low water temperature ( A. japonicus had the ability to optimize the digestive function for the coming feeding peak. These findings should provide valuable information for the development of the aquaculture of this species.