Growth of Pacific oysters, Crassostrea gigas Thunberg, cultivated in Tasmania. II. Subtidal culture

Abstract

Pacific oysters cultured subtidally grew faster than intertidal oysters, both in the catching zone of the River Tamar and at the growing lease. Three months after settlement in the Tamar River, mean length of subtidal oysters was 24.4 mm and mean width was 18.6 mm.

Oyster spat transferred to a growing lease at Dover increased in mean length from 21.7 to 109.0 mm in 14 months while mean width increased from 13.5 to 76.1 mm. Seasonal differences in growth were not as marked as for intertidal oysters and were similar for both length and width. Significant differences in lengths were noted for position on the longline, with largest individuals on rens closest to the middle of the stream (north). To a lesser extent mean lengths also varied with depth: oysters growing at 3-6 m were significantly larger than other groups.

Live weights of oysters at 12 and 17 months were 69.5 and 106.7 g and drained flesh weights were 18.3 and 25.5 g respectively.