etude comparative de deux systemes de grossissement de la crevette penaeus monodon : ensemencement direct et elevage avec pre-grossissement

Abstract

In industrial shrimp farming, since the first concern of the stockbreeder is the
durability of the production system, it is always the primary importance to choose the more
adapted system of breeding leading to a better output. The comparative study of two
growthout systems of Penaeus monodon shrimp (direct sowing and breeding with pregrowthout) to the Aquamen E.F farm contributes to this objective.
After the follow-ups carried out, the variations of physicochemical parameters did not
really assign the growth of the livestock since the values obtained are not far away from the
range required by the species Penaeus monodon. Concerning the growth of shrimps, the
breeding with direct sowing spends less time to reach the objective weight but its ponds of
breeding worsen because the livestock remains in the same basins all along the breeding.
Indeed, the system with pre-growthout takes over after the transfer of youthful towards the
growthout ponds. The analysis of the variations of the survival rates shows that the rate
decreases more abruptly at the system with pre-growthout because of the high density
applied during the phase of pre-growthout. It gives final outputs of 2,89T/ha for direct
sowing against 1,76T/ha for the breeding with pre-growthout.
In deduction, if we limit the duration 33 weeks of breeding, the system with direct
sowing is more interesting. On the other hand, if the farm count to produce shrimps of mean
weight higher than 20g, it would be more profitable to adopt the system with pre-growthout.
But in this case, the transfer of youthful to the growthout ponds should be carried out
earlier in order to avoid the too significant increase in death rate in the basins of pregrowthout.
Key word: Direct sowing, pre-growthout, Penaeus monodon, growth, survival, output