Taxonomic composition and spatio-temporal distribution of ichthyoplankton in São Marcos Bay, Maranhão, Brazil

This study aims to verify the taxonomic composition and ecological diversity of ichthyoplankton in São Marcos Bay (SMB), a region on the Brazilian Amazon coast with vast ecological and socioeconomic importance. Samples of fish larvae were collected in four biannual campaigns at different points throughout the bay, during the rainy and dry seasons. In the field, physicochemical parameters (water temperature, salinity, pH, dissolved oxygen and turbidity) and meteorological conditions were recorded. The biological samples were morphologically identified according to the identification keys. A total of 8,231 fish larvae were identified belonging to 15 orders, 22 families, 25 genera and 31 species, with greater abundance of species during the dry season. The results obtained reveal that the ichthyoplankton present in São Marcos Bay is mainly composed of species from the families Engraulidae, Clupeidae and Sciaenidae, with greater occurrence during the dry season. It also shows that the structure and composition of aquatic biota is mainly determined by the variation in salinity and rainfall.