Twenty years later the impacts of the 'Exxon Valdez' linger

The Trustee Council found 17 of 27 monitored species have not recovered. For example, researchers concluded that the high-pressure hoses used on the beaches did more harm than good. The pressure destroyed interlocking layers of gravel and flushed away fine sediments that scientists now know provided a kind of armour for the beaches during storms, helping to protect clams and mussels. The damage to the shellfish, in turn, slowed the recovery of otters, which feed on the molluscs.

Natural variability has increased the difficulty of calculating the spill’s effects. Wild pink salmon, for example, are listed as a “recovered” species, evidenced by a 2007 run estimated at 11.6 million fish. Their numbers, aided by a large hatchery operation, have rebounded from a low of 1.3 million three years after the spill. But it is hard to determine what is normal: pink salmon in the Sound before the spill varied from a high of 23.5 million fish in 1984 to a low of 2.1 million in 1988.

And while salmon are seen as a success story, the ecosystem in the sound is crippled by the failure to see a return of the huge schools of Pacific herring, which were hit by the spill just as they were spawning. The herring fishery, which provided up to half of the income of Cordova fishermen, has been closed to commercial fishing except for a few brief periods since the spill.

Scientists say they do not really understand why the herring stock has not rebounded. But they do believe that failure has reduced populations of seabirds that feed on the small fish. Investigators believe that 100,000 to 300,000 of the estimated 1 million seabirds in Prince William Sound died initially. Different species have recovered at different rates - murres have gradually returned in large numbers but other species like harlequin ducks and black oystercatchers have not - and the waterfowl may not fully recover until the herring are again healthy.

The food chain has magnified the effect of the spill in other insidious ways. Orcas, or killer whales, in the sound are afflicted by bio-accumulation of toxins. Fourteen out of the 36 killer whales in the resident Prince William Sound pod disappeared shortly after the spill. Researchers believe their lungs were seared by the toxic fumes, though orca carcasses usually sink, so no autopsy was possible.

The resident pod, which remains in the Sound and primarily eats fish, slowly is recovering. Another Prince William Sound pod of “transient” killer whales mostly eats sea mammals. As the chemicals in the spilled oil were ingested by animals higher on the food chain, the amount of chemicals, called polycyclic aromatic hydrocarbons, accumulated in marine mammals. Researchers theorise that may help doom the transient orca pod at the top of the food chain. They have “no hope of recovery”, the Valdez Oil Spill Trustee Council researchers concluded.

Fisherman Tom Copeland does not need the scientists to tell him that his old fishing grounds have not recovered. “It’s quiet in Prince William sound,” he said. “You don’t hear the birds. You don’t see the wildlife that you used to see. The ecosystem took a hell of a hit.”

Now, with Arctic sea ice disappearing, global oil companies are making plans to drill throughout the Arctic Ocean, which is estimated to contain as much oil as Venezuela and as much natural gas as Russia. The dangers of drilling and transportation in the Arctic are great. Dispersants used by oil companies do not work well at or near freezing temperatures. Booms to contain a spill cannot be used with icebergs floating in the water. The skimmer boats, tugs, and other equipment needed for quick response will be useless if they are parked far from a spill in an ice-locked inlet.

“Once the oil is in the water, you have lost most of the battle - you can’t recover it,” said Rick Steiner, a University of Alaska professor and an oil spill consultant. “I have worked on these things all over the world in the last 20 years and the take-home message is you can’t clean them up.”

To many conservationists and some residents of Prince William Sound, the lesson of the Exxon Valdez is clear: Until we stop focusing on extracting oil from ever-more remote environments, and concentrate instead on developing renewable sources of energy, another major spill in the Arctic is inevitable.

“The only real way to eliminate the risks to the environment is to get off of oil,” concludes Duchin, of Greenpeace. “It’s going to continue to happen until we break our addiction to fossil fuels.”

Says Ott, the biologist, “As long as we are going to be using this stuff we are going to be spilling it. It goes with the territory.”