Biodiversity in Saco da Fazenda, Itajaí-SC estuary

Abstract

Estuaries are characterized by presenting a high biological productivity working as important feeding, breeding, nursery and recruitmentareas for a large diversity of organisms. However, the increasing of human occupation associated to an intensive economic exploration, has led to agradual increase of habitat degradation of such areas. Saco da Fazenda (Itajai, Santa Catarina state, Brazil) suffers intense anthropic impact, receivingdomestic sewage discharge, solid residues and dredging activities. The aim of this work was to analyze the quail-quantitative composition of thecrustaceans, fishes and birds, and the probable impacts of dredging activities of its species. The ichthyofauna assemblage was composed by 51 species,42 genera and 23 families, with the white mullet, Mugil curema being the most abundant species in 2001-2002 and 2003-2005, while the atlanticsabretooth Anchovy Lycengraulis grossidens and the Caitipa mojarra Diapteurs rhombeus dominated in 2000-2001 and 2002-2003 respectively. Truecrabs and shrimps are distributed among five families and ten species, where Callinectes danae was the most abundant. Crabs were represented byfive species and two families, being Uca uruguayensis the most abundant species. The avifauna was characterized by 50 species where seven wereclassified as shorebirds, 39 were limnic waterbirds and four species were border inhabitants or visitors coming from the Atlantic Forest. The familiesArdeidae, Scolopacidae, Laridae and Charadriidae contributed with 64,0% of the species, being Phalacrocorax brasilianus (Gmelin, 1789) and Larusdominicanus Lichtenstein, 1823 the predominant ones. Despite the benthonic habitat degradation and the mortality of Ariidae, Paralichthydae andPortunidae specimens during the period of dredging activities, it was observed an increment in species abundance and richness after the accomplishmentof these activities, probably associated with depth increase, which improved local water circulation patterns, therefore favoring the entranceof fishes and crustaceans in the ecosystem.