Santa Catarina State, is brasilian’s first producer of cultured marine mollusks, with an estimated annual production in 1998 over 7,500 tones. The main cultured species are the mussel Perna perna, and the japanese oyster Crassostea gigas. In the fauna associated with these cultures, the snails Thais (Stramonita) haemastoma and Cymatium parthenopeum parthenopeum, were identified as the main predators. The former species has been used as food by coastal fishing communities and its commercial value is potentially high. In Santa Catarina, T. (S). haematoma meat has been princommercialized at around 7.00 US$ a kilogram, and 2.00 US$ when the snail is sold with the shell. The acceptance of this snails as a seafood product and its high value indicate that their commercial exploitation could be profitable. This perspective, however, requires a previous understanding of their basic biological parameters, such as growth and survival in experimental culture environment. The results obtained in experiments conducted during six months in Itapocoroy Bay (26o 47´S - 48O 37´W, Penha , Santa Catarina), have shown, on average, a 3.0 cm shell increase and a 30.0 g increase in weight. A similar growth rate was shown by C. p. parthenopeum, not commonly commercialized in Santa Catarina.