Regional patterns in species richness and taxonomic diversity of the nearshore fish community in the Brazilian coast

The nearshore fish assemblage structures and their seasonal changes were compared between two habitats (estuarine and surf zones) in three climatic regions (Tropical, 7°S; Transition, 23°S; and Warm Temperate, 32°S) encompassing ∼3200 km in the Brazilian coast. Regional patterns of species richness and taxonomic distinctiveness of the fish community were also described. We expected the highest richness and lowest seasonal variation in the assemblage's structure in the Tropical region and the opposite pattern in the Warm Temperate region. The assemblage structures differed significantly among regions and habitats. In the estuarine habitats, species richness and taxonomic distinctiveness (AvTD) were highest in the Tropical (84 species, AvTD = 92.3) and lowest in the Temperate (31 species, AvTD = 73.9) region. However, in the surf zone the highest species richness and taxonomic distinctiveness were found in the Transition region (49 species, AvTD = 78.5) and the lowest in the Warm Temperate region (19 species, AvTD = 51.9). The two habitats (estuarine and surf zone) differed consistently in the three regions. No seasonal change was found in the structure for the fish assemblage in the Tropical and Transition regions. However, the assemblage structure differed significantly between the spring and summer and between the spring and autumn in the Warm Temperate region. The most significant predictors of the fish community structure were salinity for the Tropical region, temperature and salinity for the Transition region, and transparency and temperature for the Warm Temperate region. The marine fish communities presented low levels of species redundancy in the Warm Temperate region with few species fulfilling key functional roles. The data provided here are references against which to detect future ecological changes at the regional-scale patterns for the Brazilian nearshore fish community and it is important to better inform fisheries management and coastal conservation planning.