This is special. The Great Barrier Reef is home to almost 6000 species. Thanks to GoPro, here’s what the journey through it looks like for one of them: a turtle’s eye view of the Reef.

THEY are arguably the Great Barrier Reef’s least welcome inhabitants.

For four decades the reef has suffered plagues of the dreaded crown-of-thorns starfish, a prickly, venomous invertebrate that feeds on hard coral and annihilates marine communities.

So severe has the impact of these starfish been, the Australian Institute of Marine Science regards them as one of the two biggest threats posed to coral on the Great Barrier Reef, along with tropical cyclones.

Now researchers say they’ve found the simple ingredient that could wipe them out for good: vinegar.

A small injection has proved a deadly poison for the pest, wiping them out in just 48 hours.

Vinega has been used before, but scientists from Queensland’s James Cook University have refined the process to result in a 100 per cent kill rate, according to a new research paper.

And it’s a much cheaper alternative to ox bile, the current poison used by divers, lead author Lisa Bostrom-Einarsson said.

“(Ox bile) is expensive, requires permits and has to be mixed to the right concentration,” she said.

“We used 20 millilitres of vinegar, which is half the price and can be bought off the shelf at any local supermarket.”

The revelation came days after experts handed down a damning new report card on the state of the Great Barrier Reef.

While lab trials found no bad effect, Ms Bostrom-Einarsson said the next step was a large-scale sea trial to ensure the killing process wouldn’t harm other marine life.

“There’s no reason to think it won’t work or it’ll be dangerous, but we have to be sure,” she said.

Ms Bostrom-Einarsson said killing off one starfish at a time wasn’t an effective way to save coral reefs by itself but was the only method available.

She said divers managed to wipe out about 350,000 crown-of-thorns starfish on the Great Barrier Reef last year with two fulltime boat crews, but there were estimated to be about four to 12 million of them on the reef, with each female able to produce about 65 million eggs in a single breeding season.

“While it would take an insane effort to cull them all that way, we know that sustained efforts can save individual reefs,” Ms Bostrom-Einarsson said.

The sea trial is expected to begin by the end of the year.

As well as crown-of-thorns starfish outbreaks, pollution, overfishing and climate change have been flagged as the biggest threats to reef health.

Reef health earns a C-

The Great Barrier Reef earned a C-minus in a bleak new report card highlighting the poor condition of the inshore marine environment and the need for farmers to reduce pollutants flowing into the reef.

It vindicated the United Nations Educational, Scientific and Cultural Organisation (UNESCO)’s ongoing concern about the health of the natural wonder, Queensland Environment Minister Steven Miles said.

“I’d say that if one of my kids came home with a report card like this, I’d be a bit disappointed,” he said at a RiverSymposium event in Brisbane on Monday.

“There’s more bad news here than good news.”

The report card monitored the reef from 2009 to 2014. There were some positive notes: sediment in the reef has reduced by 12 per cent, nutrients by 17 per cent and pesticide loads by 30 per cent.

But the report found that the progress had been sluggish and well behind the Queensland government’s water quality targets.

Only 25 per cent of farmers had adopted best management practice for reducing run-off, which includes pulling back on fertilisers. Graziers were exceeding their targets but sugar cane farmers were falling behind.

Dr Miles blamed the previous Newman government, noting all progress towards targets flatlined in 2013 and 2014.

“It does show that progress on meeting our targets had stalled,” he said.

But Deputy Opposition Leader John-Paul Langbroek defended the Liberal-National Party’s record, saying it had done more for the reef than any previous government.

“We commenced the work and it’s now important for everyone to work together,” he said.

Agriculturalists also defended their role, with Matt Kealley from peak lobby group Canegrowers arguing the target to reduce nitrogen run-off by 80 per cent by 2025 was a challenging one.

“I think targets are very ambitious” he told ABC News. “I’m not sure if we’ll meet them, but obviously the industry is there to play its part and do its part to try and get to improve water quality for the reef.

“I don’t agree with most of the nutrients coming from the sugar cane industry — we play our part, and we’re improving our practice all the time.”

The Queensland Government is spending $100 million over five years on reaching the targets.

World Wildlife Fund spokesman Sean Hoobin said the report constituted “a clear fail” for previous programs.

The world is watching

Earlier this year UNESCO spared Australia considerable embarrassment by leaving the Great Barrier Reef off its “in danger” list of shame, despite ongoing threats, opting instead to closely monitor it.

But it wants Australia to give an update on its Reef 2050 plan to the World Heritage Centre by December next year.

Last year Hollywood star Leonardo DiCaprio set off a cringe felt Australia-wide when he criticised the state of the reef.

“Since my very first dive in the Great Barrier Reef in Australia 20 years ago, to the dive I got to do in the very same location just two years ago, I’ve witnessed environmental devastation first-hand,” the actor and environmental activist said at an Ocean Conference in June last year.

“What once had looked like an endless underwater utopia is now riddled with bleached coral reefs and massive dead zones.”

DiCaprio went on the warn: “Unfortunately today, there’s no proper law enforcement capacity and little accountability for violating the law. It’s the Wild West on the high seas.”

In June actor Mark Ruffalo threw his weight in, tweeting a link to the Greenpeace website takeanotherlook.gp, which states the reef is “under threat from the coal industry”.

The Avengers star tweeted: “Coal & coral don’t mix. Join the movement to save the Great Barrier Reef”, alongside a photograph of himself smiling and holding up a sign that read “#savethereef”.

Before the UNESCO decision, billionaire businessman Richard Branson came under fire for saying the reef was being turned into an “industrial dumping ground”.

Sir Richard backed away from his comments after being accused of “trashing” the reef’s reputation, admitting he did not realise the Queensland Government had set targets in an effort to protect the reef.

“This is a very shabby intervention by a very rich businessman who makes a lot of money out of the Queensland economy and then has turned on the Queensland economy and set us up for a very bad outcome from the World Heritage Committee,” Queensland Resources Council chief Michael Roche fired back.

The reef still has its many big-name fans, including singer-songwriter Ed Sheeran, who told Sunrise host David Koch this month diving in the Great Barrier Reef was on his bucket list.

In response, Tourism Tropical North Queensland invited the star, who is touring Australia in November and December, to fly to the region for a VIP trip.

“We would love Ed Sheeran to be an ambassador for Cairns and the Great Barrier Reef and would happily pay for his flight and accommodation in return,” TTNQ chief Alex de Waal said.