Effects of Benthic Diatoms on Settlement and Metamorphosis of Abalone Larvae

Abstract

The settlement and metamorphosis of veliger larvae of abalone, Haliotis discus hannai, were observed in chambers covered with monocultured benthic diatoms on the bottom surface. The monocultured benthic diatoms used for this experiment were 22 strains belonging to 18 species.
In general, the settlement rate of larvae 6 hours after the beginning increased as the diatom density increased in case of same diatom strains. The settlement rate of the larvae in chambers without diatoms were very low, and no larva metamorphosed in those chambers.
The high settlement and metamorphosis rates of larvae were observed mostly on diatom strains forming flat community. On the other hand, a large number of larvae settled on three-dimensional diatom communities died before metamorphosis.