Mortality and stock assessment of the brown shrimp Penaeus aztecus (Crustacea: Penaeidae), in tile nortilwest Gulf of Mexico

Fishing mortality of the brown shrimp (Penaeus aztecus) was estimated off Tamaulipas (northwest Gulf of Mexico). Monthly age structure and fishing effort data for the 1974-1980 period, and cohort analysis by the virtual population analysis (VPA) technique were used. Catchability estimates indieate higher values for the first matnrity age (six months old), fishing mortality inereases with age, with an asymptotic tendeney after 8-9 rnoths oId, F=O.5 (l/year). Variance of F also inereases with age. Population size has strong interannual variations because of recruitment, though the seasonal recruitment pattern was similar during the periodo The rnonthly cohort tendency suggests a stable situation for the stock during this periodoFishing mortality of the brown shrimp (Penaeus aztecus) was estimated off Tamaulipas (northwest Gulf of Mexico). Monthly age structure and fishing effort data for the 1974-1980 period, and cohort analysis by the virtual population analysis (VPA) technique were used. Catchability estimates indieate higher values for the first matnrity age (six months old), fishing mortality inereases with age, with an asymptotic tendeney after 8-9 rnoths oId, F=O.5 (l/year). Variance of F also inereases with age. Population size has strong interannual variations because of recruitment, though the seasonal recruitment pattern was similar during the periodo The rnonthly cohort tendency suggests a stable situation for the stock during this period