Effects of Size and Age of Juvenile Freshwater Prawns Macrobrachium rosenbergii at Stocking on Population Structure and Production in Polyculture Ponds

Effects of size and age of juvenile freshwater prawns on their growth in polyculture ponds were investigated. Post‐larvae were nursed at two commercial nurseries, during either 66 or 129 days, to final mean weights of about 0.25 and 0.5 g, for each age group. Nursed prawns were stocked in ponds at a density of 2/m2 and polycultured with carps and tilapias for 148 days. No significant effect of age or size, or their interaction, was detected in mean harvest weight and gross income, although small age effect was noted in survival and total yield.