Impactos sócios-ambientais de Marambaias para a pesca de lagosta: o caso de Ponta Grossa, Icapuí-Ce

Abstract

The indiscriminate lobster fisheries has been causing stock reduction, minimizing the effectiveness of artesian fisheries and reducing the income of fishing communities, stimulating even more the overfisheries and the capture of undersized lobsters. As an alternative, the community has been implanting artificial reefs, which are structures where microorganisms settle forming a feeding chain, therefore serving as an attractor for commercial species. At Ponta Grossa community, Icapuí – CE, the use of artificial reefs exclusively for lobster fishing was an initiative taken by some of the local fishermen in 2002. With the successful result of the first fisheries at the artificial reefs, a fast increase on the number of artificial occurred, what made the control of their use very difficult. So far, there a very few information about the effects of artificial reefs on the lobster fishery at Ceará State. In order to provide information to organize the use of these structures there is an urgent need to determine the real effectiveness of the initiative in terms of increasing fisheries and to evaluate social, economic and environmental impacts. The artificial reefs for lobster are build of wood measuring 30 cm in height and 6 m2 of área. The launching of the structures was carried through by the fishing in depths between 3 and 13 m. A total of 36 fishermen took part in this study. Data from 484 fishing activities were analyzed during the years of 2003 (year I) to 2005 (year III), being 280 of them in shallow waters (less than 5 m of depth) and 204 in waters deeper than 5m. These depths intervals were chosen arbitrarily. The data were used to determine the amount of lobster captured in relation to the fishery effort (CPUE), the average lobster’s size and the percentage of lobsters above the legal commercial size. The socio-economic analysis was performed using the profit earned by each fishing activity. The environmental impact was performed by G.U.T. method. The results showed that the average size of captured lobsters (Panulirus argus) was below legal minimum size (13 cm). The amount of lobster captured in relation to the fishery effort was above the historical average of Ceará State, showing the efficiency of these structures to increase productivity, however the values for the average profit per fisherman decreased significantly during the second and third years of the study, suggesting that in the first year occurred just a concentration of lobster stock in the same area. In the first year the most significant negative impacts were the over exploitation of the stocks and the occurrence of juvenile lobster on the catches. The most significant positive impacts were the increase of local fishery, the formation of new habitats, the development of new technologies and the possibility to develop scientific research. In Year III the most significant negative impacts were the presence of juvenile lobsters in the catches, the reduction of fisheries biomass, the over exploitation and the reduction on the amount of local fishery. In relation to positive impacts, the reduction of the fisheries using gill nets and the possibility for scientific research were the most evident. In conclusion, the artificial reefs have not played a sustainable role because the main result was just the concentration of stocks in the same area. The use of artificial reefs should follow a management plan and respect the law restriction on capturing juvenile lobsters.