Scientists in New Caledonia say an unprecedented episode of coral bleaching could be related to the intense heat from this year's El Niño.
The research agency, IRD, said until recently, only small episodes of bleaching had been found in the territory's lagoon, a UNESCO-listed World Heritage Area.
But a director, Claude Payri, said in recent weeks IRD scientists had found bleaching on a magnitude unprecedented for the territory, especially near the coast.
Ms Payri said months of abnormal weather conditions are likely to have contributed to the bleaching, a dieback phenomenon that results in discoloration and possible reproduction issues in coral.
She said greater monitoring sites had been set up around the lagoon to conduct further studies of the bleaching.