1Fisheries and Marine Technology Center, Hiroshima Prefectural Technology Research Institute, 6-21-1 Hatami, Ondo, Kure, Hiroshima 737-1207, 2Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan
The presoaking of spat collectors in seawater containing adult Pacific oysters Crassostrea gigas is known to induce their larval settlement. In this study, we examined the effect of the size and feeding condition of larvae on the ratio of their settlement. Although the presoaking of collectors increased their settlement ratios in larger larvae with a mean shell height of 344 μm, the treatment of collectors did not increase the ratios in smaller larvae with a mean shell height of 295 μm. There were no significant differences in the ratios of larval settlement among the larvae fed with a cultured diatom at a variety of concentrations (0.0∼10.0×104 cells/mL) during the 24-hour periods of the experiments.