The Great Barrier Reef (GBR) has great economic importance as well as immense aesthetic value, contributing an estimated $5.8 billion to the Australian economy, principally through tourism, and commercial and recreational fisheries. Inscription on the World Heritage List recognises the area's global significance and entails regular reporting on its status. Coral reefs are always changing through natural processes such as recruitment, growth, mortality and disturbance by storms. Information about natural variability of populations is essential for informed management.