Severe coral bleaching along the Great Barrier Reef has prompted Australian wildlife officials to raise its response to Level 3 - the highest response level.

World Wildlife Fund (WWF) Australia recently released alarming video and photos of huge swathes of bleached coral near Lizard Island, located in the northern part of the reef.

The Great Barrier Reef is the world's largest coral reef system. As of three weeks ago, Lizard Island was suffering the worst bleaching in 15 years. Unfortunately, it has continued to deteriorate since then, largely due to climate change and increasing temperatures.

"The new video and stills are very concerning and show large sections of coral drained of all color and fighting for survival," said Richard Leck, WWF spokesperson. "This is the worst coral bleaching event ever to hit this most pristine part of the Great Barrier Reef."

After researchers working on the island reported the worst level of bleaching in 15 years, Australia's Environment Minister Greg Hunt flew over parts of Lizard Island to survey the bleaching event firsthand.

"It is not as severe at this stage as 1998 or 2002, which were both El Nino-related events, it is however, in the northern parts a cause for concern," Hunt said. "The reef is 2,300 kilometers long and the bottom three-quarters is in strong condition, but as we head north, it becomes increasingly prone to bleaching. Essentially what you could see was patches of coral bleaching as you approached Lizard Island."

A Level 3 response allows the Great Barrier Reef Marine Park Authority to increase surveying efforts to better understand what was happening. The Federal Government plans to fund another round of surveys at the same 40 sites of the reef area in September this year. The goal, they say, is to assess the health of corals and potential recovery options.

"The new project that the Minister is announcing today is really high technology and will speed up the rate of which we can get a full snapshot of the reef, using imaging recognition software, very much faster than the diver underwater days," said Russell Reichelt, chairman of the Great Barrier Reef Marine Park Authority.

The minister added that this information is vital to preserving the Great Barrier Reef, as the "frequency of coral bleaching events and the severity of tropical cyclones are predicted to increase in the future."

Coral bleaching, a process by which corals turn white or fade, threatens a valuable source of biodiversity, tourism and fishing. It occurs when reef symbiosis - the mutually beneficial relationship between two coral reef organisms - is disrupted by a rise in ocean warming driven by the release of greenhouse gases. 

The Great Barrier Reef, which also struggles with farming run-off, development and the coral-eating crown-of-thorns starfish, missed being put on the United Nations' "in danger" list by hair last year. Researchers working on the Reef 2050 protection plan hope to improve the reef's health by banning the dumping of dredge spoil at sea, limiting port development and focusing on cleaning up water running onto the reef.