MOLTING AND MORTALITY IN Macrobrachium rosenbergii

Mortality estimates for M. rosenbergii, grown from postlarvae to adult, range from 20 to nearly 50%. My observations indicated that certain types of mortality, previously reported as cannibalism by some authors, followed a characteristic pattern and were related to molt state. In order to explore the relationship between mortality and molt state, a method of fragmenting M. rosenbergii's molt cycle was used, in a 4 by 3 factorial experiment where the relationship of molt state and relative size to injury and mortality was tested. The results indicated that prawns of equal size were susceptible to behaviorally related deaths at 2 points in the molt cycle, late premolt and early postmolt. The importance of this finding to aquaculture and behavioral research on crustaceans is discussed.