Influence of initial stock-pile density in laboratory development of Macrobrachium rosenbergii (De man, 1879) and Macrobrachium amazonicum (Heller, 1862) (Decapoda, palaemonidae)

Abstract

This work aim was to analyze the effect of initial stock density in M. rosenbergii and M. amazonicum development under laboratory condictions. To the first species were used densities of A=5, B=10, C=15, D=20 animals/m² and to the second, G=10, H=30, I=50, J=70 animals/m². The experiments were realized in asbestos-concrete tanks with 1,000 liters of capacity and 1.5 m²of area, biological filtration and continue aeration. The temperature was constant, about 28°C±0.01 and pH = 8±0.5. Daily feeds were supplied in the proportion of 10% of biomass weight. The average weight and length in the densities A, B, C, D, were statistically similar on the 2^nd month of culture, while G and H densities were more statistically efficient than I and J. The results obtained in the 4^th and 5^th months of culture showed that A, G and H densities were more significatively efficient at 5% leveI. To conclude, the most efficient treatments to obtain animaIs with higher weight and length were those with low initial stock densities: 5 animals/m² to M. rosenbergii and 10 and 30 animals/m² to M. amazonicum.