Fish assemblages along a morphodynamic continuum on three tropical beaches

A comparative study involving three mesotidal beaches from reflective to estuarine states was conducted between October 2010 and September 2011 in the estuary of Mamanguape River, northeastern Brazil. The aim was to test for differences in fish assemblages along a morphodynamic continuum, particularly the effects of wave action. In total, 3,732 fish from 71 species were examined; Rhinosardinia bahiensis and Atherinella brasiliensis dominated the estuarine beach, whereas Trachinotus carolinus dominated the reflective beach. Fish assemblages were structured by spatial differences among the sites, and overall abundance, richness and biomass demonstrated a clear increasing trend from the reflective to the estuarine beaches, indicating a primary influence of wave exposure in the measured parameters. The Mamanguape River estuary plays a crucial ecological role as a nursery for several species that depend on its resources and have adapted to the high variability of its physical and chemical factors and the diversity of its habitats.

Community descriptors; Juveniles; Nursery; Spatial patterns; Wave action