Response of the tropical abalone, Haliotis asinina, larvae on combinations of attachment cues

The effects of different diatom species and types of substrates in combination with 0.45 mu M GABA on the metamorphosis of Haliotis asinina larvae were tested. Diatom slurry elicited the best metamorphic response followed by Amphora sp., Amphora + Nitzschia and Nitzschia cf. frustulum in that order. With regards to substrate types, roughened plexiglass seemed to be the most preferred while fibrocement the least preferred surface. Overall, diatom slurry grown on plexiglass surface promoted the greatest number of metamorphosed H. asinina postlarvae. For economic considerations and practical reasons, chemical inducers like gamma-aminobutyric acid (GABA), should be used singly or separately from other settlement-inducing cues, such as the "substrate-diatom" complex.