Characterization of Size Distribution Development in the Freshwater Prawn Macrobrachium Rosenbergii (De Man) Juvenile Populations

The development of the size distribution curve in Macrobrachium rosenbergii postlarval (PL) populations, reared under various stocking densities was examined. It was found that newly metamorphosed PL demonstrate a log-normal size distribution which with time becomes positively skewed. Individuals within the “leading tail” - jumpers, exhibit a higher growth rate than the bulk of the population. The appearance of the leading tail is enhanced under low initial stocking densities, as demonstrated by the negative correlation between the average weight and skewness on one hand, and the initial stocking density on the other. It is suggested that the appearance of jumpers is not a result of competition alone, but also of intrinsic factors associated with the population development, such as genetic or social in nature.