Variação espaço-temporal em parâmetros populacionais de Prochilodus nigricans (Teleostei: Prochilodontidae) na Amazônia Central

Abstract

In the Amazon, the artisanal fisheries explore a high diversity of fish resources, with a predominance of Characiformes and Siluriformes migratory species. The curimatã (Prochilodus nigricans) is a migratory species of Characiformes of big important in fisheries production in the region. Nevertheless, there is little information about the actual situation this resource about of the exploitation. An accurate diagnosis of tolerable levels of exploitation by curimatã should consider the distribution of the specie in the Amazon basin. This is because the heterogeneity of environments in the region and the influence of abiotic factors may promote the existence of differents stocks, implying different tolerances to fishing pressure. Thus, it became important to identify differents stocks of the curimatã in sub-basins of the Central Amazon, considering the influence of spatial and temporal variability on the parameters that characterize a particular stock. For this, we used information from fishing landings of the species from a database of the integrated program of water resources and floodplain / PYRA of the Federal University of Amazonas. To form this bank were conducted interviews with the fish landings of Panair and Adolpho Lisboa, in Manaus from 1994 to 2004. Only records from the curimatãs subbasins Solimões, Purus and Madeira were considered in this work. The results indicated the existence of separate stocks of P. nigricans well as the type of environment within the same sub-basin, and between different sub-basins. Moreover, it was certified that the occurrence of droughts caused by sharp climatic events have a strong influence on the growth of the species, causing changes in growth parameters and compromising the natural replenishment of populations. These results call attention to the need to consider more deeply the kind of environment in which one species is inserted, as well as to the importance of continuous monitoring of the values of population parameters, since the fishing pressure must be adjusted to changes these parameters.