WIO bleaching in 2016 – what to expect?

2015 has already been marked as the hottest year on record, and this is after 2014 having been a near-record year and the last five years being the hottest ever. These are in contrast to 1998, which was the year when Indian Ocean corals bleached and suffered mass mortality. Associated with the high temperatures in 2015 is the “3rd Global Coral Bleaching Event” with mass bleaching being reported across the Pacific, and in the Caribbean.

So what might the bleaching season of January – May 2016 be like for the Western Indian Ocean?


The WIO is starting the 2016 bleaching season HOT (map at left) … across the whole region, sea surface temperatures are over 1oC warmer than ‘normal’ for this time of year.

This compares with 2015, when the WIO started the season unusually COLD – with temperatures up to 3oC below ‘normal’ (map at right) in the north in early January, and this persisted into the southern part of the WIO even into February.

ENSO3.4-8Dec15-JAMSTECConditions in 2015-16 are exacerbated by a record El Niño that even topped the maximum values recorded in 1997-98 (figure at right, from UNESCO).


Bleaching in January-May 2015 in the WIO was minor, except for some bleaching in the Seychelles granitic islands, and after our bleaching season ended, the Chagos Archipelago showed high levels bleaching starting in May 2015, reported in the media.