A multispecies stock assessment of a pelagic coastal fishery of the south-west Gulf of Mexico

Abstract. Multispecies stock assessment based upon Schaefer's theory was applied to a coastal pelagic fishery (Spanish mackerel, Scomberomorus maculatus (Mitchill); king mackerel, S. cavalla (Cuvier) and the blue runner, Caranx fusus (Geoffroy-St Hilaire)), from the west central Gulf of Mexico. Linear and non-linear systems of equations were estimated by using a multiple stepwise regression technique. The values of interaction parameters show a clear competition between mackerels, and technological interdependences between the blue runner and mackerels, The maximum yield estimation was from 4000 to 5000 tonnes, obtained with 23 and 34 beach seines respectively, depending on the applied model. Two stages were observed from the statistical records; in the first the Spanish mackerel is the most important species while in the second the abundance of this species declines and the others remain at the same level. Significant interactions were found from the first data group.