GROWTH AND BEHAVIOR OF POST JUVENILE Macrobrachium rosenbergii (de MAN) IN CLOSE CONFINEMENT

ABSTRACT Macrobrachium rosenbergii is under examination in various parts of the world as a potential culture animal. Unfortunately, M. rosenbergii does not aggregate and has been reported to be aggressive and cannibalistic. The suitability of the animal for intensive culture in closed systems has not been established. In this study experiments have been carried out on growth rate, molting frequency, and incidence of cannibalism among equal age grouped and isolated M. rosenbergii of different sex and size with and without shelters and with and without removal of the second periopods. In groups, more aggressive males and females grow faster than less aggressive males and females. In isolation, males, on the average, grow faster for a longer period and thus get bigger. Molting frequency does not appear to be directly related to growth rate, but rather growth rate is related to food consumption, regardless of the molting frequency. Comparing equal age animals of different size, small animals molt more frequently than large animals but grow more slowly. The incidence of cannibalism is high. Cannibalism invariably follows attacks made on animals undergoing molt. The larger an animal the greater the chance of a kill, but small animals will attack larger animals and two or more animals may attack a single animal. Shelters which can be defended can reduce the incidence of cannibalism.