Uso de sistemas de informação geográfica na seleção de áreas propícias para a piscicultura marinha no litoral de Pernambuco

Abstract

his study evaluated the physical, chemical and biological weapons, together with the conditions of infrastructure and legal aspects, to identify of suitable sites for offshore marine fish-cage farming in the coast of Pernambuco. The factors were divided into three criteria (quality of water, security and infrastructure) and a restriction on the legislation, areas for fishing, boating and diving. The environmental data (dissolved oxygen, temperature, pH, salinity, transparency and concentration of nutrients) were obtained under the JOP's program, developed by the Department of Oceanography, Universidade Federal de Pernambuco - UFPE. Data on the Security Council concerning the composition of the sediment were obtained from the Geological Survey of Brazil - CPRM, under the Project Granulados Marinhos da Plataforma Rasa do Brasil. The geographic location of ports and industrial network of the State of Pernambuco were obtained from the Laboratory for Georeferencing of the Instituto de Tecnologia de Pernambuco - ITEP. The bathymetry data were collected through the use of digital nautical charts, the scale of 1:100,000, available from the Diretoria de Hidrografia e Navegação – DHN, Navy of Brazil and, finally, the material on the height of waves and currents were obtained developed through studies in undergraduate programs and graduate of the Departments of Oceanography and Fisheries, UFPE and Aquaculture of the Universidade Federal Rural de Pernambuco - UFRPE, respectively. The data were processed using ArcView version 9.2 and analyzed through a comparison of parity between the factors and criteria chosen to identify of suitable sites for offshore marine fish-cage, a process of hierarchical analysis. Two researchers and a representative of the environmental agency, at the state level, a questionnaire on which importance weights assigned to each factor or criterion in a percentage scale, which was used for the preparation of maps, involving a statistical analysis. We conducted a literature review to define the minimum and maximum limits, relating each factor to the culture of Cobia (Rachycentron canadum). Using the Boolean method, were restricted in coastal areas pertaining to conservation areas (APA), areas of navigation, local shipwrecks and traditional fishing. Among the protected areas are the Federal (APA Costa dos Corais), located between the states of Pernambuco and Alagoas, and State of (APA Guadalupe), located in Pernambuco coast between the towns of Serinhaém and Barreiros, forest south of the state, and (APA Santa Cruz) on the northern coast of the state. From there, it was observed that the criteria relating to water quality and safety were presented at a level classified as very suitable for growing Cobia and therefore did not contribute decisively the definition of suitable sites. We only considered sites with depth between 15 and 40 meters, for meeting both the legal and economic feasibility for the activity. Thus, the factors related to the criterion Infrastructure contributed differently to selection of the suitable sites for offshore marine fish-cage in the coast of Pernambuco. The study area covers 5,094 km2, of which 29% were considered very suitable, 49,2% moderately suitable and were not identified areas that are unsuitable for the installation of new developments for offshore marine fish-cage in the coast of Pernambuco. Still, we considered 21,8% of the area being restricted, set by the Units of conservation, fisheries, navigation and wreck. Upon completion of the project, believed to be of paramount importance to update the data considered essential to the zoning of the sites most suitable for offshore marine fish-cage in the coast of Pernambuco.