Benthic macrofauna of sandy intertidal zone at Santos estuarine system, São Paulo, Brazil

Abstract

Species composition, faunal density, species diversity and zonation patterns of benthic macrofauna, as well as its relation to sediment characteristics were examined and compared in three sandy beaches on the polyhaline area at Santos estuarine system in the State of São Paulo. Samples were collected quarterly during one year (July/1977 - May/1978). Low, mean and high intertidal levels were sampled. Polyehaetes dominated the fauna, both in terms of numbers of species and numbers of individuals. The community structure of Ponta da Praia beach was characterized by high density, low diversity (H') and evenness (J'), due to the dominance of the spionid Scolelepis squamata. At Vicente de Carvalho the fauna was characterized by the dominance of the polyehaetes Laeonereis acuta and Capitella capitata and presented low density, high diversity and evenness. At Bertioga Channel, intermediate values were observed and the fauna was dominated by Scololepis squamata andLaeonereis acuta. The sediment texture was responsible for those figures, although some differences in diversity may be explained by differences in wave energy. The low number of crustaceans and molluscs suggests the effect of the estuarine pollution upon the fauna. The zonation pattern of both species distribution and community structure differed at the studied sites; it was not correlated with sediment characteristics which were relatively uniform down shore; however, the lowest diversity was observed at the high level in all sites.