1. Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences; James Cook University; Townsville Qld 4811 Australia
2. School of Marine and Tropical Biology; James Cook University and ARC Centre of Excellence for Coral Reef Studies; Townsville Qld 4811 Australia
3. Oceanic Fisheries Programme; Secretariat of the Pacific Community; BP D5, 98848 Noumea New Caledonia
4. CSIRO Marine and Atmospheric Research; P. O. Box 1538 Hobart Tas 7001 Australia