Laboratory Rearing of Larval Ostrea Angasi in Tasmania, Australia

Summary

Larval Ostrea angasi released from parents in the summer 1974/75 were about 190–200 μm in shell length. The darkly pigmented larvae formed rounded umbones during growth and the relationship between shell length (1) and width (w) was described by the G.M. regression: w = 0.820 1 + 13.010. Eye-spots were common in those 270 μm long and spat began setting at about 300 μm when 12–20 days old at 17°C. Few pelagic larvae larger than 320 μm were observed. The provinicular structure was simple and similar to other Ostrea species.

Larval development differs from that in the closely related New Zealand mud oyster and provides further evidence to separate these species. Success rates varied between the 6 batches held in 901 culture containers but one batch yielded a significant spat catch on scallop shells which were kept in a recycling system before transfer to the sea. Circulation of the cultures with a vertical, central airlift appeared to enhance success.