More warnings about the plight of the Great Barrier Reef

Scientists estimate this year's mass bleaching has killed around 35 per cent of coral on the northern and central Great Barrier Reef. Image: Coral bleaching affects captured by monitoring group Coralwatch. (Supplied)

The A-R-C Centre for Excellence for Coral Reef Studies, which conducted aerial and underwater surveys of 84 reefs in the World Heritage area, says the full impact of the environmental phenomenon is still unfolding.