The Effect of Food Deprivation on Foraging Behavior and Digestive and Metabolic Capacities of the Chinese Mitten Crab, <i>Eriocheir sinensis</i>

Food deprivation is a common stress in crustaceans that can affect their behavior and physiology. In this study, a video recording analysis system was used to compare the predation rate and behavior of the Chinese mitten crab, <i>Eriocheir sinensis</i>, foraging on the freshwater snail, <i>Bellamya quadrata</i>, under different degrees of food deprivation. The activities of lactate dehydrogenase, α-amylase, pepsin, and lipase in the hepatopancreas of crabs were determined after food deprivation for 0, 3, 9, and 15 days. The results showed that the predation and encounter rates of <i>E. sinensis</i> increased and then decreased with an increase in food deprivation time. The proportion of stationary time of <i>E. sinensis</i> initially decreased and then increased, whereas the proportion of searching and handling time increased initially and then decreased. There was a significant difference in the probability of capture upon encountering; however, food deprivation did not significantly affect the probability of consumption upon capture. Under food deprivation, the proportion of <i>E. sinensis</i> crushing tactics after nine-day food deprivation was significantly lower than that in the first nine days. Lactate dehydrogenase activity in the <i>E. sinensis</i> hepatopancreas after food deprivation was significantly higher than that in those not subjected to food deprivation, and the activities of α-amylase and pepsin in the hepatopancreas were consistent with the predation rate trend, showing an initial increase followed by a decrease. In conclusion, different degrees of food deprivation significantly affected the predation cycle of <i>E. sinensis</i> on <i>B. quadrata</i>. These results lay a solid foundation for further studies on the foraging behavioral ecology of <i>E. sinensis</i> and provide important information for improving <i>E. sinensis</i> production.