Polychaete recruitment onto dead coral substrates at Lizard Island, Great Barrier Reef, Australia

Polychaete recruitment onto defaunated blocks of dead coral substrate was investigated at two sites at Lizard Island, Great Barrier Reef, over a 2-year period. The sites differed in exposure to SE trades and depth. One hundred and forty four species of polychaetes representing 29 families were recruited, the majority to both sites at some stage during the study period. Most of the species were relatively rare. Five species contributed over 40% of the total number of individuals recruited. Substrates released at the same time of year and exposed for the same length of time at the two sites differed in species composition and abundance. Within a site, recruitment varied throughout the year with a distinct spring and summer peak. Recruitment varied over the 2-year study period with recruitment being higher in 1977 than in 1976. I suggest that the species composition of coral substrate is largely determined by the time of year at which the substrate becomes available, chance, and the availability of suitable space in the substrate for settlement.