Molting, Movement, and Dispersion in the Freshwater Prawn Macrobrachium rosenbergii

Movement and dispersion patterns of the giant freshwater prawn Macrobrachium rosenbergii were assessed through sonic tagging and a novel quadrate sampling technique. Females moved greater distances at night than males, and females exhibited a weaker tendency than males to return to a home site. Reproductive condition and proximity to ecdysis were related to the distance females moved at night. Environmental heterogeneity, productivity, and habitat utilization differed between two ponds. In the more heterogeneous environment, late premolt and early postmolt prawns were apparently avoiding hard intermolt and early premolt prawns by occupying a less preferred habitat of deep, soft mud. Key words: Dispersion, habitat utilization, home range, Macrobrachium rosenbergii