FISH COMMUNITIES OF THE LAGO-DO-REI, A FL OODPLAIN LAKE IN THE CENTRAL AMAZON - A GENERAL DESCRIPTION

In an attempt to understand better the ecological basis of the high pr oduction generally observed in the floodplains, a detailed and global study was conducted on the fish community of a floodplain lake in the Amazon plain near Manaus. Community parameters were followed on a bimo nthly basis, during a 27 month period (February 1986 - May 1988). The community is characterized by high values of specific richness and div ersity and by a remarkable regularity in the distribution of the speci fic abundances. These parameters, and also the density and biomass of fish, vary on a seasonal and an interannual basis in relation with the hydrology of the system. In addition, the community is distributed am ong the different habitats in a heterogeneous way. Factorial analysis of correspondences show that the main source of variability is interan nual and concern mainly the most marginal habitats. The seasonal varia bility has been related to the water level in the system. The results suggest that, in spite of this variability, the community is persisten t and stable.