A pesca comercial dos tucunarés Cichla Spp. (Peciformes, Cichlidae) no Reservatório da UHE-Tucuruí, Rio Tocantins, PA

Abstract

This study describes the freshwater fishery based on peacock bass ("tucunaré") Cichla spp. in the lower Tocantins River, Pará state, northern Brazil, in the area influenced by the Tucuruí hydroelectric dam, with emphasis on the reservoir. The study was divided in two parts: Chapter I describes the commercial peacock bass fishery with relation to fishing gear, fishing strategies, utilized environments, seasonality, and local fishing management according to the fishermen’s perception. The fishermen’s local knowledge was studies, including their ethnobiological classification of peacock bass types, and the social, ecological, and economical aspects involved. Interviews with fishermen and participation observation were conducted in situ. The Tucurui reservoir peacock bass fishery is of great importance in the social and economic life of these fishermen and is their main income source. This fishery occurs in specific places in the lake and uses rudimentary methods and equipment. According to the fisherman, production is influenced by environmental variables and by the use of guild nets, that the fishermen say drives away peacock bass from the fishing environments. The use of environments for fishing is the main source of conflict among fisherman. Social relations among fishermen in a system of partnership and the presence of middlemen diminish the the fisherman’s income. Fishermen possess consistent knowledge on the ecology and behavior of peacock bass. Their system of fish classification recognizes three ethnospecies, two of which constitute a single scientific species. Chapter II treats peacock bass yields at landing points in the lake, from 1997 to 2003, according to data furnished by ELETRONORTE, and a measure of fishing effort was considered that was most adequate for these data. The data were analyzed according to port, fishing gear, type of boat, fishing grounds, and river flood cycle. The data demonstrated that different cities possess fishing fleets with their own characteristics and that these utilize nearby fishing grounds. The greatest yields were during periods of flooding and subsidence of water levels, with hook and line fishery being responsible for most of the catch. Canoes were the most used boats. The yield data at landing points indicate that this fishery is more important in cities and areas located on the lake. Fish yield for unit of effort only shows adequate statistical behavior when analyzed for fishing grounds and the adjusted units of effort are number of fisherman per days of fishing, after logarithmic transformation.