Compensatory growth of Malaysian prawns reared at high densities during the nursery phase

摘要

The objective of this work was to verify the occurrence of compensatory growth in Malaysian prawn (Macrobrachium rosenbergii) reared in pens, after being stocked in cages under high densities during nursery phase. The experiment was carried out in 0.5 m2 cages and 2-m2 pens set in natural bottom pond with 2,400 m2. Prawn post-larvae (PL) with an average weight of 0.026 ± 0.012 g (nursery phase) were initially stocked in 16 cages at the densities of 50, 400, 800 and 1,200 PL m-2. Sixty days later, prawns were transferred to 16 growing pens, at the density of 12 prawns m-2. Initial average weight of the prawn in this phase was the final average weight registered in the nursery phase, as follows: 50 PL m-2 = 2.3 ± 0.3 g; 400 PL m-2 = 0.5 ± 0.03 g; 800 PL m-2 = 0.3 ± 0.05 g and 1,200 PL m-2 = 0.1 ± 0.01 g. Commercial rations for prawns (35% crude protein) were given once a day, in the afternoon. After 244 days, survival, average weight and biomass did not differ significantly among prawns with different initial average weight. Relative growth rate was significantly greater in prawns previously stocked at 1,200 PL m-2 and feed conversion efficiency was significantly better for those previously stocked at 400 and 1,200 PL m-2. These results suggest the existence of partial compensatory growth in M. rosenbergii, what can successfully carry on stocking of prawns of this species at high densities in the nursery phase.