NOTES ON THE POPULATION DYNAMICS OF SWIMMING CRABS CALLINECTES SAPIDUS AND C. BOCOURTI FROM THE CIENEGA GRANDE DE SANTA MARTA, CARIBBEAN REGION OF COLOMBIA

Abstract

33 samplings were accomplished between february 1993 and january 1994, in different sites of the CGSM; in these a total of 428 individuals of C. bocourti and 762 of C. sapidus were captured. In each site, water samples were taken to obtain salinity and temperature parameters. In addition 29 visits to the "Comercializadora de Pueblo Viejo" were made in order to get additional information and samples, a total of 743 individuals of C. bocourti and 1117 of C. sapidus were measured. For each animal total width were recorder, based on width parameters of captured individuals, size-clases frequencies were obtained for both species. This data were processed with the FiSAT Program (Fish Stock Assesment tools- FAO, ICLARM). Sizefrequencies data of each species were compiled in ELEFAN O routine, growth parameters (L∞ and K) were obtained by ELEFAN I routine. The mortality rate were estimated with ELEFAN 11 routine using the catch curve option. Total mortality rate (Z) was 6.26 for C. sapidus and 5.78 for C. bocourti; the fish mortality rate (F) was 3.89 and 3.09. The exploitation rates (E= F/Z) was 0.62 for C. sapidus and 0.53 for C. bocourti. According to Beverton and Holt's maximum sustainable yield-per-recruit model, the values of the exploitation rates (E) obtained are under the optimum exploitation rate (Eopt) wich the resource can tolerate at the present time (0.86 for C. bocourti and 0.84 for C. sapidus), these results suggest that nowadays both species are being underexploited in the CGSM.