(Attack on Crassostrea brasiliana (Lamarck, 1819) by Thais haematoma (Linné, 1767), in laboratory.)

Abstract

The ability of Thais haemastoma to prey on the oyster Crassostrea brasiliana was analyzed on an experiment carried out at laboratory from August 15^th to November 18^th, 1986. Individuals of Thais haemastoma with 44 to 75 mm of length and oysters of 6, 12 and 24 months old were utilized. Three ways of depredation were observed: by drilling or breaking the oyster, valves and by introducing the proboscide through the intervalvar aperture. T. haemastoma wirh medium size (about 60 mm) were more voracious; even oysters of 83 mm were drilled and among them, the most was of 6 and 12 months old. This predator was able to attack and eate a whole oyster in 1.10 hour. Canibalism was observed in T. haemastoma. This species must be recognized as a serious predator which can damage the natural as well the cultivated oysters, destroying about 19.3% of an annual production in an oyster farming.