Bio-economic assessment of a green crab fishery in Baja California South, Mexico

Optimum bio-economic harvesting strategies of the green crab Callinectes bellicosus (Stimpson) fishery of Magdalena Bay Mexico, were evaluated. The short life span implies high variability of the catch. The stock and its exploitation scenarios were evaluated with a simulation model. The stock biomass displays a slight decreasing trend over the second half of the 13 years of analysis, with a maximum of nearly 6,000 t. The fishing mortality and exploitation rate suggest that the stock was underexploited through all the period of analysis, except for two years (2009 and 2012). The profits have been over USD $200,000 for each of the last four years, whilst before then they were lower, and the efficiency of the fishery indicated by the benefit/cost ratio has been between 2 and 3. Three exploitation scenarios were evaluated, and compared to the current condition of the fishery, the maximum sustainable yield (MSY), the maximum economic yield (MEY), and the maximum economic benefit per fisher (MEBF). In order to do that, it was necessary to impose some constrains, like setting a maximum number of boats, to maintain the same number of fishers when the income per fisher was maximized, and setting a maximum age of first catch. The results with the scenarios MSY and MEY are the same with almost twice the current yield and profits. Those of the current scenario and that of MEBF also provided the same output values, meaning that the current condition almost provides the maximum benefit per fisher.