A univariate and multivariate study of reef fisheries off northeastern Brazil

This work was part of a programme to assess the potential living resources within the Exclusive Economic Zone (EEZ) of Brazil that collected information on the catch composition and biology of the main species within the zone (REVIZEE). It aimed to identify and, using statistical tools, to assess the factors that influence the dynamics of the demersal fishery, targeting the rocky, coral reef and associated sandy seabeds of the continental shelf. Within the reef fishery of northeastern Brazil, snappers (family Lutjanidae), in particular Lutjanus chrysurus, L. synagris, L. analis, L. jocu, and, to a lesser extent, L. vivanus, are the main artisanal catch and contribute most to the similarity between groups. Among the factors considered, the spatial effect (geopolitical state as a factor) appeared to be the strongest attribute in isolating groups. Of the technological factors, trip duration better discriminated the catch composition than fleet category. However, given some exceptions mainly linked to favourable strong wind, trip duration categories were usually related to fleet dynamics, because motorized boats generally undertake longer trips. Such characteristics are important for management decisions, because fleets are likely to exploit different stages of the life cycle of a fish as well as different species while operating in different geographical areas. The catch analysis was characterized by a “lutjanid community” typical of rock, coral, and coral-sand habitats, and it is clear that this community is dominant in Brazil as well as in the more usually quoted regions such as the Bahamas, Antilles and along the coast from Yucatan to Panama.