Larval settlement of haliotis tuberculata coccinea in response to different inductive cues and the effect of larval density on settlement, early growth, and survival

Abstract

Settlement and metamorphosis of Haliotis tuberculata coccínea larvae were examined in the presence of different settlement cues reported effective in larval settlement of other abalone species (crustose coralline algae, Ulvella lens, conspecific mucus, γ-aminobutyric acid, and 4 benthic diatom species). In addition, larval density effect was tested on crustose coralline algae substrate. Larval settlement was highest on crustose coralline algae followed by U. lens. Settlement was very low on conspecific mucus and γ-aminobutyric acid, varying between 1% and 2%. U. lens inoculated with the diatom Navicula incerta induced a reduced settlement of 9% compared with the 22% obtained on films of U. lens alone. The settlement induction efficiency of all the benthic diatoms tested (Amphora sp., N. incerta, Proschkinia sp. and Nitzschia sp.) was very low and not significantly different among diatom species. Larval settlement at 48 h after addition and survival after 1 mo were higher for the lower larval density, whereas postlarval growth rates were not influenced by larval density.