Saturday, January 23, 2010

EFFECT OF THE HETEROGENEITY OF SIZES IN THE OPTIMAL MANAGEMENT OF INTENSIVE CULTIVATION OF P. vannamei IN FRESHWATER


Marcelo E. Araneda*, Juan M. Herny Eucario Gasca-Leyva
UNEXMAR, Universidad Marista de MPerifnorte tablaje catastral 13941
Carretera M- Progreso. C.P. 97300 MYucatM
maraneda@marista.edy.mx
A bioeconomic model was implemented using information from six experimental stocking densities (90 to 330 shrimp m-2). The objective was to analyze the effect of the heterogeneity of sizes in the optimal management of the intensive cultivation of P. vanamei in freshwater. The heterogeneity was described through a size structured model, which deals with the effect of stocking densities on the growth of shrimp. The optimal condition through the decision to harvest indicated that the density of 90 shrimp m-2 is the strategy of higher returns.

In each density there was a proper validation of the model for size since 1.5 g. The results of optimization at the end of the cicle crop, showed smaller size of organisms and high variability of sizes by increasing the density (Figure 1.)

Considering with and without variability in sizes, the optimum time of harvest was higher as the density decreased. However, at lower density of 230 shrimp m-2, the optimal harvesting times were found above the homogeneous case, but not in higher densities of 280 shrimp m-2. The profitability differences by ignoring the variability in sizes range from 7.7% to 21.5% (Table 1).

These results show the importance of the stocking density and the effect of the heterogeneity of sizes in short-term decisions, as optimal harvesting time, in the intensive culture of white shrimp in freshwater.

No comments:

Post a Comment