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.
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