Preferential settlement of abalone larvae: diatom films vs. non-geniculate coralline red algae

In this study, we demonstrate a difference in the settlement response of two temperate commercial abalone species, Haliotis rubra and H. laevigata. H. rubra did not respond to films of any diatom species tested, but settled on the natural settlement surface, a non-geniculate coralline red alga (NCA), Phymatolithon repandum (Corallinales, Rhodophyta). H. laevigata, however, settled particularly well on films of Navicula ramosissima and the NCA Sporolithon durum. Settlement of abalone larvae in response to diatom films depends on the abalone species, the diatom species tested, and the density of the diatoms on the plates. Settlement preferences of H. laevigata were reflected in subsequent growth and survival during the early days of post-larval life. Post-larvae survived and grew well only on the NCA, S. durum and the diatom films of N. ramosissima. (C) 1999 Elsevier Science B.V. All rights reserved.