The characteristics of sheltering behavior in the sea cucumber Apostichopus japonicus

Based on the sheltering behavior, shelters are widely applied to enhance the aquaculture efficiency of sea cucumbers. However, the characteristics of sheltering behavior are still poorly understood in sea cucumbers. This study investigated the characteristics of the sheltering behavior of the sea cucumber Apostichopus japonicus under individual, group, and interspecific levels. In the individual experiment, the research findings showed that, regardless of whether it was day or night, there were no significant differences in the movement randomness, first-arrival time, and movement speed of sea cucumbers. Regardless of whether it was day or night, the residence time of sea cucumbers in the group with shelters was significantly longer than that in the group without shelters. This indicates that sea cucumbers are random into shelters rather than random leaving the shelter, no matter in the day or at night. In the group experiment and inter-species experiment, no significant differences existed in the residence time, the first-arrival time and the movement speed. This suggests that the basic characteristics of sheltering behavior of sea cucumbers is not affected by the interaction at the present densities. The present study clarified the characteristics of sheltering behavior of sea cucumbers under individual, group, and inter-species interactions. This research uncovered the characteristics of the sheltering behavior of A. japonicus and offered crucial information for enhancing the aquaculture efficiency of sea cucumbers in shelter. • We clarified the sheltering behavior of sea cucumbers in individual, group, and inter-species level. • Sea cucumbers are random into shelters rather than random leaving the shelter. • This study provides new ideas for understanding the mechanism of sheltering behavior in eyeless animals.