Associations of fishes in the coastal region of Itaipu, Niteroi

The coastal region of Itaipu, Rio de Janeiro forms a partially sheltered sound, protected by three islands, but still maintaining full communication with the open sea. The sound also receives fresh water input from the Itaipu-Piratininga lagoon system, constituting an area of intense artisanal fisheries. Using data from monthly monitoring of the artisanal fisheries (beach seining, gill netting and hand lining), experimental surf zone beach seine surveys, underwater visual census (Menina, Mae, and Pai islands), and a multisampling experiment at Itaipu Lagoon, we elaborated a list of fish species occurring in the region, observing their connectivity with different local habitats, including the sound, rocky reefs, the surf zone and Itaipu Lagoon. We identified 183 species including 26 Elasmobranchii, grouped in 13 families, and 157 Actinopterygii grouped in 63 families. The artisanal beach seining caught the greatest number of species (112), followed by the gill netting (94) and hand lining (35). The surf zone beach seining (picare) yielded 49 species (8 exclusive) represented mostly by juvenile fish and species of little economic importance. Visual censuses resulted in 41 species identified, with 21 exclusive and most of them cryptic. Within the Itaipu lagoon, 46 species were recorded, 18 exclusive and of occasional occurrence. Cluster analysis including 106 non exclusive species resulted in the formation of eight different groups. Groups A and B were composed by species captured exclusively by the artisanal fisheries within the sound, and included species of commercial interest. Group C included species occur-ring in the fisheries whose juveniles are found in the surf zone. Group D classified species of common occurrence in the fisheries and the islands. Group E was represented by species shared by the fisheries and Itaipu lagoon (mullets, mojarras, herrings). Species from group F were absent in the islands, those from group G in the lagoon, and those from group H were common to all areas considered. Compared with other coastal areas in southeastern Brazil, Itaipu represents an important concentration area for fish biological diversity and biomass, yielding species associations and connectivity between the different local habitats.