Performance of juvenile culture of the mangrove oyster Crassostrea sp. in suspended lanterns in subtidal zone of the Cananéia estuary and Itaguá bay, Ubatuba (São Paulo state, Brazil)

Abstract

 The purpose of this study was to evaluate the rearing of mangrove oyster (Crassostrea sp.) from juvenile stage, in suspended lanterns installed in subtidal zone. The growing was monitored in Cananéia and Ubatuba regions at different densities, from December 2002 to December 2003. The seeds were collected by artificial collectors and distributed, in a first stage, in lanterns with 8 mm internodes, in densities of 150, 300 and 450 seeds bed^-1 in Cananéia, and 300 seeds bed^-1 in Ubatuba. After three months, the oysters presented an average height of 28.1; 29.1 and 28.3 mm and survival rate of 19.7; 27.7 and 22.5%, respectively, for the three densities, in Cananéia. In Ubatuba, the oysters reached average height of 27.4 mm and survival rate of 74.8%. In a second stage, in Ubatuba, the oysters were distributed in lanterns of 15 mm internodes in the density of 120 oyster bed^-1 and reached about 35.0 mm after 3 months in the density of 120 oyster bed^-1, with survival rate of 48.0%. These data show that the rearing in lanterns, in these initial phases, is faster than the method of cultivation on bed frame in intertidal zone, in which it is needed about eight months for the oyster to reach 25 mm. The results of the present study indicate that it is possible to obtain after 6 months, in lanterns system, selected oysters with 35 mm. By the reduction of the cultivation time in subtidal zone, this activity may be stimulated, so that the overexploitation of the oyster could be avoided.