Pediveliger larvae of the commercial tropical oyster Crassostrea belcheri were allowed to settle under different conditions. Two types of seawater were used for the experiments: aged seawater (1 month) and aged seawater conditioned by the presence of adult oysters for 24 hours. Two groups of five different substrates were used, each group soaked in one of the two water types. More larvae settled in conditioned aged seawater than in aged unconditioned seawater and on soaked substrates contrary to unsoaked substrates. The larvae preferred substrates of their own species for settling rather than from other species within the same genus or from a different genus. Settling frequency was increased by the presence of living oysters together with soaked spatfall collectors in commercial aquaculture. The fact that larvae are induced to settle by pheromones released from the adults is an important mechanism that favours the gregariousness of the oysters in nature. Settling behaviour of oyster larvae was observed and the behaviour of the three main stages was described: free swimming searching stage, crawling stage and cementing stage.
Thailand Natural History Museum Journal, 2012, Vol 6, Issue 2, p. 75-87