Estrutura de assembléias ictíicas em sistema lacustre manejado da Amazônia Central

Abstract

The Amazonian lacustrine systems of floodplain represent one of the main ecosystems of transition that support the biodiversity of the Amazon and its exploration sustain the Amazonian riparian population. A new proposal for the conservation of these fishing resources in the Amazon is Sustainable Open Sustainable (SAS). The Cururu system lacustrine, located in the right edge of the Solimões river in the state of the Amazon as a SAS, which plan of management was implanted in 2000. The SAS Cururu is a dendritic lake with four arms with average extension of 5,0 km. Two of the arms is managed, including restrictions of access for fishery (arms: Terra Preta and Cordeiros) and two not managed: without restrictions (arms: Lago and Divino). The present study it had as objective to evaluate the effect of access restrictions to the exploration of fishery resources by local Amazonian populations about fish assemblages of the system. It was analyzed the specific composition, richness, diversity and relative abundance of the fishes and investigated if the patterns of the assemblages were ruled by the environmental variables or for the forms of use of the resource. 2757 fishes were captured, distributed in 7 orders, 22 families and 79 species during rising and receding periods of 2006. The species richness for Terra Preta and Cordeiros (managed arms) was S=20 and S=19 in the rising period and in the receding period S=37 and S=35, respectively. In the not managed arms the richness was Lago S=43 and Divino S=29 in the rising in the receding S=45 and S=40, respectively. Therefore, the opposite to expected diversity of species resulted high in the arms not managed. Multivariate techniques revealed that the species composition varied among the periods of the hydrologic cycle and were influenced mainly by environmental factors. The differences between the periods can be attributed by high vulnerability of the individuals for the retraction of the aquatic environment. On the other hand, if it does not evidence influence of the access restrictions about fish assemblages which can be being more influenced by the entrance in the system of the white water originating from of the Solimões river, that in the case affects directly the arms of the Lago and Divino where the richness was higher.