Evaluation of the fishery of the brown shrimp Penaeus aztecus of the mexican littoral of the northwest Gulf of Mexico

Abstract

Stock assessment of the brown shrimp (Penaeus azteca) from the northwest Gulf of Mexico is developed using monthly data from commercial catches from 1974 to 1982. Growth parameters from the von Bertalanffy equation were as follows: K_min = 0.142 m^–1 to K_max = 0.1812 m^–1; L_∞min = 214 mm to L_∞max = 236 mm. Mortality rates were obtained directly from the identified cohorts through the catch curve and the weighted average of the amount of fishing applied on each cohort; results were as follows: total mortality, Z_min(1981) = 0.8494 to Z_max(1974) = 1.240; fishing mortality, F_{min( 1981)} = 0.3786 to F_max(1974) = 0.646; and natural mortality, M_min(1978) = 0.415 to M_max(1974) = 0.594. Catchability estimations mere: q_min(1975) = 0.0012 to q_max(1978) = 0.0021. Exploitation rate indicates a reduction of 30% of the fishing intensity, for the last two years, compared with the previous ones. From these years (1981 and 1982), fishery was acting under the maximum sustainable yield level.