Composição, estrutura e recrutamento interanual das comunidades de peixes ao longo de um continuum morfodinâmico costeiro

Abstract

The fish communities of three beaches distributed along a morphodinamic continuum in the Mamanguape River estuary region (Paraíba Brazil), differentiated according to the wave exposure, substrate and salinity, were analyzed in the years 2011 and 2012, in order to evaluate possible differences in the spatiotemporal patterns of composition and structure and abiotic factors which influenced these patterns. Throughout the study, 13482 individuals were captured totaling 37236.68g fish, whereas 5982 individuals and 22282.50g were sampled in 2011 and 7500 and 14954.18g individuals were sampled in 2012. It was observed a constant pattern of community composition and structure through the years, with a decrease of the abundance, richness, diversity and biomass from the dissipative beach (located inside the estuary) to the reflective beach (higher marine influence), mainly due to wave action, which represents an energy barrier to many species. Temporally, rainfall was shown as the main structuring factor, influencing abiotic factors like salinity and processes like primary production. Salinity levels in the dissipative beach became close to sea levels, causing an increase in overall abundance, represented by Mullets, which might have taken advantage of the uniform levels of salinity in the dissipative beach and entered the estuarine zone to use available resources and microhabitats. Furthermore, the drop in rainfall rates may have may have influenced the Clupeiformes. Thus, it is highlighted the importance of long term assessments of fish communities due to changes that have, and factors related to abiotic and biotic processes.