Larval dispersal of the ascidian, Lissoclinum patella at Davies Reef, Great Barrier Reef

Eight 30 m transects were made at Davies Reef and 139 Lissoclinum patella colonies from the intertidal to 25 m depth were recorded. Depth (5, 10, 15, 20 m), total swimming time (s), and the fate (eaten by fish; captured by coral polyps or zoanthids, settled, lost) of observed larvae (n=133) were recorded.Two experiments were conducted on the reef. To examine the maximum potential swimming time, a clear plastic box was placed on the bottom and examined every 10 mins: if a larvae was moving and had not everted its adhesive papillae it was deemed as 'swimming' (3 replicates of 10 larvae). Secondly, to examine the phototactic response (phototaxis), a 0.5 m long black chamber with a clear window at one end was placed on the bottom and larvae injected into it through a port (clear or dark): settlement distance was measured (cm) after 2 h (3 replicates of 20 larvae).
To describe the vertical distribution of Lissoclinum patella and investigate limitations by predators and photactic behaviour on larval dispersal.
Fish predators: Pomacentrus popei (=P. moluccensis), Glyphidodontops rollandi, G. talboti, P. lepidogenys, Abudefduf valgiensis, a black damselfish and a yellow wrasse (the only nonpomacentrid fish observed).