Estrutura e Composição da Macrofauna bêntica Associada a Bancos de Anomalocardia brasiliana Gmelin, 1791 (Veneridae Bivalvia) no litoral Sul Brasileiro

Abstract

This study investigated the structure and composition of benthic macrofauna associated with Anomalocardia brasiliana beds exploited commercially located in the Santa Catarina coast, southern coast of Brazil. Samplings conducted on four tidal flats, (Cubatão, Massiambu, Tapera and Taperinha) totalizing 80 stations. The macrofauna samples were taken with the assistance of a 15 centimeter diameter core cylinder buried 15 centimeters in the sediment. The fauna samples were washed in 0.5 mm mesh size sieves and fixed with 4% formalin. Sorting organisms were transferred to a 70% alcohol solution. Additional samples were collected in all stations for a sedimentological characterization. The four tidal flats had sandy sediments with a contribution of gravel and fines (silt and clay). A total of the 2209 specimen were collected, distributed in 50 species, being Polychaeta, Crustacea and Bivalvia the dominant classes. Numerically, Laeonereis acuta and Capitella capitata were the most abundant Polychaeta. Massiambu had the lowest numerical abundance and Tapera had the hightest numerical abundance. Tapera had the lower species richness between the tidal flats. Cubatao has the lowest equitability among the shoals, with one species dominating numerically. Massiambu has the most equitable, with no species dominating numerically. The curve Tapera showed greater tendency to asymptote. Species Laeonereis acuta and Anomalocardia brasiliana were found in higher concentrations near the mouth of the rivers that feed in the shallows. Species richness was lower in points with high concentrations of organic matter. The species C. capitata showed high densities along the high values of biomass of A. brasiliana.