Settlement-competent larvae need several cues to initiate
settlement and metamorphosis. One of the most important
and intensively studied cues is the biofilm on the substrate.
While crustose coralline algae (CCA) and associated bacteria usually induce settlement, cyanobacteria and turf algae
may prevent settlement (Harrison & Wallace 1990). For
aquaculture purposes, it is important to incubate settlement tiles for 1–2 months prior to larvae settlement. Culture conditions for tile incubation need to favour ‘clean
surfaces’ with CCA’s and low cover of other algae or cyanobacteria; any sediment should be avoided because it may