Field and laboratory experiments were undertaken during the spawning period of Acanthaster planci (November to January) to examine substratum preferences of larvae; and the effect of extracts from crustose coralline algae (CCA), the role of bacteria from the coralline algae Lithothamnium pseudosorum, and certain known chemicals on settlement rates.
These experiments were conducted at Lizard Island and in the laboratory at the Australian Institute of Marine Science (with samples obtained from Davies Reef).
Lizard Island experiment variables
Substratum selection (no choice, choice of substrata offered) - L. pseudosorum (Lp); scratched (Lps); undamaged (Lpn); Neogoniolithon foslei (Nf); Peyssonellia sp. (Pe); Porolithon onkodes PO); coral rubble (RU); ceramic tile (Ti).
Bioassays with CCA and extracts of Lithothamnium pseudosorum - settlement on CCA shards variously treated and on coral blocks perfused with extracts of CCA (use of mesh barriers, boiled shards, dialysis tubing etc.)
Bioassays with coral blocks fouled for 9 d, and on coral blocks perfused with extracts from coral rubble.
Chemical induction using 5 concentrations of GABA (¿-amino butyric acid) and 4 of K+ [potassium].
AIMS experiment variables:
Bioassays with CCA and extracts of Lithothamnium pseudosorum - settlement on scratched and unscratched L. pseudosorum, within-plant variation, microhabitat selection.
Bacterial induction, the effects of antibiotics - the inductive ability of untreated and antibiotic-treated L pseudosorum, and of L. pseudosorum shards.
Bioassays with epiphytic bacteria isolated from L. pseudosorum.
