CARACTERIZAÇÃO FÍSICA E QUÍMICA DA ENSEADA DE FORTALEZA, UBATUBA, SP

Abstract

The present study deals with the physical environment of Fortaleza Bay, Ubatuba (SP), as a subsidy for studies of Brachyura crustaceans composition and distribution which live on non-consolidated sublittoral bottom from this area. In a 4.5 sq mi area, seven stations one mile apart were chosen. Depth bottom and surface temperature, salinity, dissolved oxygen, organic content and bulkgranulometry were measured monthly from November, 1988 to October, 1989. The bay presents an average depth of 9 m and characterizes by following annual values for the hydrologic factors: temperature of 23.5°C, salinity of 34.4%0 and dissolved oxygen of 5.46 mg/1. The organic material annual mean of the bay was 4.07 o /oo and the most of the stations presented granulornetric composition dominated by pellitic sediments. It was verified that the Brachyura's abundance is closely related to the nature of the substrate. With reference to the abiotic factors analysed and the quantity of crabs registered, the stations II and IV were constituted in the more contrasting places from the bay, when compared with the others. The importance of this study is demonstrating the close relationship between the Brachyura fauna distribution and the nature of the substrates.