These are the shocking images of the long term damage last year's BP oil spill has done to the Gulf coastline. Coming a day after scientists said Gulf of Mexico surface water was 'almost back to normal', these shots paint a very different picture of how wild life and fauna in the affected zones have fared a year on from the Deep Water Horizon accident.

Only yesterday, more than three dozen scientists graded the Gulf's health a 68 on average, using a 1-to-100 scale. This is just below the 71 grade the same researchers last summer said they would give the ecosystem before the spill. But despite the optimistic analysis for marine life, the shore line has suffered far more long lasting damage from the cloying oil. [ DM ]

On April 20 last year BP's Deepwater Horizon oil rig exploded, killing 11 workers, spewing 172 million gallons of oil into the surrounding sea.

The resulting fire could not be extinguished and, on 22 April 2010, Deepwater Horizon sank, leaving the well gushing at the sea floor and causing the largest offshore oil spill in United States history.

While scientists from a number of organisations were cautiously optimistic about the water surrounding last year's spill site, there were warnings that below the surface the marine wildlife was still suffering untold damage.

Deep below the surface, in hard-to-get-to marshes and in the slow-moving food web it is till feared some of the effects may not be seen for years.

'When considering the entire Gulf of Mexico, I think the natural restoration of the Gulf is back to close to where it was before the spill,' said Wes Tunnell at Texas A&M University, who wrote a scientific advisory report for the federal arbitrator who is awarding money to residents and businesses because of the oil spill.

Tunnell's grades are typical. He says the Gulf's overall health before the spill was a 70; he gives it a 69 now.

If that pre-spill grade isn't impressive, it's because the Gulf has long been an environmental victim - oil from drilling and natural seepage, overfishing, hurricanes and a huge oxygen-depleted dead zone caused by absorbing 40 per cent of America's farm and urban runoff from the Mississippi River.

Today, a dozen scientists give the Gulf as good a grade as they did before the spill. One of those is Louisiana State University professor Ed Overton, a veteran of oil spills.

Dolphins initially seemed to be OK, but as more carcasses than usual kept washing up - almost 300 since the spill - the grade fell to 66, compared to a pre-spill 75.

Oysters, always under siege, dropped 10 points, crabs dropped six points. And the overall food web slid from 70 before the spill to 64 now.

Despite the optimistic picture on the surface, Dana Wetzel at the Mote Marine Laboratory in Florida, said: 'Anyone who says the Gulf is fine is being precipitous. It's out-of-sight, out-of-mind, but in my humble opinion this is not over.'

While BP money has flowed for immediate cleanup and compensation, the bigger bill for environmental damage and federal penalties is still being calculated.

The federal government is collecting data on that, but much is kept from outside scientists. So some of the most important details are being held closely like cards in a high-stakes poker game, outside researchers say.

Barren: Brown pelican nests as well at terns, gulls and roseate spoonbills, are seen here on May 22, 2010, left. The second photo, taken April 8, 2011 in the same location, shows dead mangrove stumps sticking out of the water

Contrast: The, left, May 2010 photo shows birds nesting just after the spill hits the shore line. The second photo taken on April 8, 2011 near the same location, shows the shoreline heavily eroded

Ironically, one of the rig's operators, Transocean, has given staff big payouts for achieving the 'best year in safety performance in our company's history.'

Transocean gave it most senior managers, two thirds of the total possible safety bonus, according to papers filed to the Securities and Exchange Commission.

It noted 'the tragic loss of life' in the Gulf, but said the company still had an 'exemplary' safety record because it met or exceeded certain internal safety targets.

William Reilly, co-chairman of the White House commission that investigated the oil spill, said that Transocean's comments were ‘embarrassing’.

‘It's been said with respect to the disaster that some companies just don't get it - I think Transocean just doesn't get it,’ Reilly said.

BP is spending around $41billion on cleaning up the spill and to cover damages, but investigations into the disaster are far from over.

News of the Gulf of Mexico drilling is expected to outrage environmentalists, but comes as a welcome development for the embattled oil firm.

The company is also reeling after a Swedish tribunal last month ruled a £10billion deal between BP and Russia's Rosneft should be put on hold because of a dispute with shareholders at Russian partner TNK-BP.

It has put the group's shares under pressure and led to doubts over chief executive Bob Dudley, who replaced Mr Hayward following the Gulf spill.