Echinoderms (sea stars, sea urchins, sea cucumbers and their allies) typically have a pelagobenthic life cycle that includes a microscopic larval stage. Echinoderm larvae are found in small numbers in the waters surrounding Heron Island Reef throughout the year, although large synchronised spawnings of particular species can result in dramatic localised increases in larval density. Echinoderm larvae settle and typically metamorphose into benthic juveniles, which grow into macroscopic adults with a range of life styles. Adults can be conspicuous (e.g. sea cucumbers) or cyrptic (e.g. brittle stars), and found in a range of habitats including the beach rock, inner and outer reef zones, rubble crest, the seaward platform, reef slope and the deeper inter-reefal zone.
reef zones of the southwest end of Heron Island Reef
(Image provided by Digital Globe Inc and Biophysical Remote Sensing Group, The University of Queensland)