Fecundity and Embryonic Development in Three Macrobrachium Species

Fecundity of three Macrobrachium species (M. rosenbergii, M. malcolmsonii and M. lamarrei) was estimated through random sampling followed by egg counting where highest fecundity was observed in M. rosenbergii (1408±709) and lowest in M. malcolmsonii (32±7). Fecundity per individual, per unit body length and per unit body weight was higher in summer (in M. rosenbergii). In all three species, length vs. fecundity relationship was found to be significant but weight vs. fecundity was insignificant in case of M. malcolmsonii and M. lamarrei. Relative fecundity (/cm) vs. total length relationship of M.rosenbergii was insignificant in winter but significant in summer, insignificant for M. malcolmsonii and significant for M. lamarrei. Whereas, relative fecundity (/gm) vs. total weight relationship was insignificant in all the species. Comparatively larger eggs were found in M. lamarei (0.55mm) and smaller in M. rosenbergii (0.39mm). In the same time, a microscopic study was conducted to observe the embryonic development of selected species where successive stages of embryonic development was visualized from developing eggs of same individual indicated the asynchronous fertilization.