Do the shallow‐water habitats of a hypersaline tropical estuary act as nursery grounds for fishes?

Abstract: Fish assemblages were studied in a hypersaline tropical estuary in Northeastern Brazil. A total of 104 species were collected by beach seine during the dry and rainy seasons of 2012. Two families, Atherinopsidae and Gerreidae, were numerically dominant in all zones of the estuary; juveniles of <italic>Atherinella brasiliensis</italic>,<italic> Eucinostomus argenteus</italic>,<italic> Lile piquitinga</italic>,<italic> Ulaema lefroyi</italic>,<italic> Lutjanus analis</italic> and <italic>Sphoeroides greeleyi</italic> contributed 77% of the total catch. The factors that best explained the fish abundance pattern were salinity and depth, which were related to spatial segregation. Species richness was lowest in the upper zone, an area with high salinity and shallow depth. The distinct roles of structurally different habitats (submerged macrophyte beds and mangrove prop‐roots) and the influence of physicochemical conditions in the middle zone of the estuary may influence taxonomic diversity. The middle zone of the estuary is the one most attractive to juveniles of reef species (Lutjanidae and Serranidae). The fish assemblages are clearly dominated by marine estuarine dependent species, highlighting the importance of the ecosystem as a nursery ground for marine species of the Brazilian coast. [ABSTRACT FROM AUTHOR]