Asexual reproduction by fission was monitored in populations of Holothuria atra, Holothuria edulis and Stichopus chloronotus on 3 nearshore fringing reefs (Brook Island, Fantome Island and Great Palm Island) and one midshelf reef (Rib Reef) on the Great Barrier Reef between March 1995 and August 1996.
Holothuria atra was monitored at Brook Island, Fantome Island, one site at Great Palm Island and Rib Reef at depths of 0.5-3 m. Stichopus chloronotus was monitored at 3 sites on Great Palm Island and at Rib Reef at depths of 0.5-3 m. Holothuria edulis, occurring at depths of 12-15 m, was monitored at one site on Great Palm Island. Monitoring of the shallow nearshore reef sites occurred every 4 to 8 weeks, while the deeper Holothuria edulis population and the populations at Rib Reef were monitored less frequently.
Between 100 and 400 Holothuria atra and Stichopus chloronotus and a minimum of 60 Holothuria edulis were examined for external signs of asexual reproduction on each occasion. The number of intact individuals and recently divided specimens (with a fresh wound or with a healed wound and no regenerated anus or mouth) were recorded. Population density was estimated on one occasion at each site using belt transects between May and August 1995.
In February 1995, 30 Holothuria atra, 20 Holothuria edulis and 45 Stichopus chloronotus were collected and maintained in outdoor aquaria and fission and spawning in these individuals was monitored throughout 1995.
