Composição, estrutura e dieta das assembleias de peixes associadas a áreas vegetadas e não vegetadas do estuário do Rio Mamanguape, Paraíba – Brasil

Abstract

Seagrass beds are essential habitats for the high biodiversity in coastal environments. They provide nursery, feeding and shelter areas for many organisms. Despite its importance, the seagrass beds are among the most threatened coastal ecosystems on the planet and its influence on fish populations has been little studied in Brazil. The understanding of its influence on the dynamics of fish assemblages associated with these environments and the study of the feeding habits of the species that use them supports the development of new conservation policies of these habitats. Thus, the aim of this study was to compare the composition, structure and feeding ecology of fish assemblages found in vegetated and unvegetated areas on the estuary of the Mamanguape River, Paraiba - Brazil, observing the variations in hydrological conditions between the dry and rainy periods. The values of abundance and biomass were higher in non-vegetated areas, although there was no significant difference in species diversity between study areas. Thus, the environmental stability of unvegetated areas proved to be an important factor in determining the biomass and richness patterns. In addition, it was observed that these areas are used by the species at different stages of their ontogenetic development according to the ratio of optimal foraging and the possibility of refuge from predation. Among the species captured in vegetated and unvegetated áreas on the estuary, the four most representative were selected for analysis of stomach contentes, according to their abundance. Of these, three were considered generalists and showed a high degree of individual specialization, supporting the hypothesis of niche variation proposed by Van Valen. Also, we observed the importance of intraspecific competition and the availability of food items in the intraindividual variation in the diet of the species.