Australia sees second year of Barrier Reef bleaching

Australia's Great Barrier Reef is experiencing an unprecedented second straight year of mass coral bleaching, scientists said Friday, warning many species would struggle to fully recover.

The 2,300-kilometre reef suffered its most severe bleaching on record last year due to warming sea temperatures during March and April.

Bleaching is once again occurring, the government's Great Barrier Reef Marine Park Authority said after an aerial survey off Australia's eastern coast on Thursday.

"Regrettably, the temperatures have been high on the Great Barrier Reef this summer as well and unfortunately (we) are here to confirm... a mass coral bleaching event for the second consecutive year," the Authority's reef recovery director David Wachenfeld said in a Facebook video.

"And importantly, this is the first time we've ever seen the Great Barrier Reef bleached two years in sequence. We've seen heat stress build since December."

The agency said more bleaching was being observed in the central part of the reef, which last year escaped widespread severe bleaching.

The 2016 bleaching was more severe in the northern areas of the bio-diverse site.

The back-to-back occurrence of widespread bleaching also meant there was insufficient time for corals to fully recover, Neal Cantin from the Australian Institute of Marine Science said.

"We are seeing a decrease in the stress tolerance of these corals," Cantin added in a statement.