UPDATE-2:  Looks like the Ningaloo reefs are likely to escape major mortality given they have remained just outside the main hot spot.  These reefs are likely to lose about 10% of their corals. Things still remain serious in this analysis for the Houtman Abrolhos Islands (well inside the hotspot – see map and Tyler’s comments).  We will have to wait for the results of the surveys to be completed and analysed.

UPDATE:   Tyler Christensen of NOAA‘s Coral Reef Watch commented:

“A small correction… the “hottest” color code for that DHW image really means “16 or more”. The DHWs off Western Australia got much higher than just 16. Our virtual station at the Houtman Abrolhos Islands got to a staggering 30.7 degree-weeks! Ningaloo maxed out at a comparatively cool 9.05 degree-weeks.”

Posted by Ove Hoegh-Guldberg, May 6 2011

On 12 April, we put up a report from Dr Tyrone Ridgway on West Australia’s reefs that were bleaching for the first time as result of high temperatures.  Unfortunately, the accumulated heat stress has got worse and appears to be hitting all-time records, with the latest degree-heating-week data from NOAA (May 5, 2011) reaching 16 along the West Australian coast as shown.

This amount of heat stress is not only driving record coral bleaching (as has already been seen in the region), but will also cause the mass mortality of corals and other organisms.

NOTE – to understand the novelty of the thermal stress seen across West Australian coral reefs, have a look at the NOAA ‘Hotspots’ time series data.  It looks like the problem relates to the exceptional warming that began around October-November last year.

PREDICTION: We will see large-scale mortality of reef-building corals (30% or more) and many other organisms on reefs along parts of the West Australian coastline.  This will occur over the next 1-3 months.  Reefs in this region will take more than 10 years to recover. Coral reefs around the Houtman Abrolhos Islands look particularly vulnerable.