| Hi Jeff
Recent evidence that I have read (that I cannot find a link to now) suggests that different coral zooxanthellae will depart at different temperatures so some coral is more resilient to higher temperatures than others.
29-30 degrees does not necessarily seem too high in any case - my 3 months of diving in Central America was all done at 29-31 degree range. Bleaching had occured during el nino but am not aware that it was a continual problem at 29 degrees in this part of the world.
If you google it I am sure you can find more information. Alternatively Dr Stevil will be along soon to correct all my errors and misinformation........
Regards
Roy |