Shipping lanes moved to boost dolphin numbers

There is hope for the bottlenose dolphins of the western Mediterranean after the International Maritime Organisation (IMO) agreed to shift some of the world's busiest shipping lines away from their foraging grounds.

Like other cetaceans, the dolphins' numbers have been cut dramatically over the past 20 years as a result of driftnet fishing and dense marine traffic in the areas where they congregate.

But after researchers sponsored by Earthwatch presented data proving the damage being done to the dolphins' ecosystem by the constant traffic of oil tankers, container ships and other large cargo vessels, the Spanish Merchant Navy and the IMO agreed to move the shipping lanes 20 miles to the south.

The area of concern is the Alboran Sea, the westernmost part of the Mediterranean. At the far west of the sea is the Strait of Gibraltar, the gateway to the Atlantic, an essential migratory corridor for a large variety of marine species which attracts an abundance of fish.

East of Gibraltar, near the coastal city of Almeria is Cabo de Gata National Park, which also includes offshore marine areas. But until now merchant ships have sailed straight through this supposedly protected area in enormous numbers: nearly 30 per cent of the world's maritime traffic passes through this sea, disrupting the feeding grounds. There is the ever-present menace that a tanker might run aground and break up, polluting the entire region.

"All this traffic passes very close to the shore," Ana Canadas of the Alnitak Marine Research and Education Centre, one of the leaders of the research, says. "Some years ago we saw a tanker stranded within the national park. Thank God nothing happened and it was towed away by another tanker."

The decision to shift the shipping lanes offers a reprieve for the last healthy population of bottlenose dolphins in the Mediterranean.

The dolphin population is fragmented everywhere else in the Mediterranean. Migratory activities have decreased and local populations are genetically isolated, with only two to five dolphins per group.

Off the coast of Almeria the group size is about 30 individuals - and Earthwatch and the other organisations involved in the research hope that the IMO's initiative will help to maintain these levels.

The decision by the IMO, whose implementation is being carefully followed, came after Dr Canadas and her colleague, Riccardo Sagarminaga, spent five years researching for the European Commission's LIFE-Nature project.

Apart from the two professional researchers, more than 500 international Earthwatch volunteers have been involved in the project. Its success has depended largely on the efforts of these volunteers, who set sail on the research vessel Toftevaag, and who in total have spent more than 700 days at sea, surveying 10,000 miles to develop conservation management plans for protected marine areas.

The Toftevaag, commissioned in 1910, was built for herring fishing in the North Atlantic, and so offers volunteers a taste of the life of seamen of an earlier and less destructive - although also markedly less comfortable - age.

Cetaceans still abound in the Alboran Sea, and those spotted most frequently include the common dolphin and the long-finned pilot whale as well as the bottle-nosed dolphin.

The programme's researchers set a premium on developing and applying research methods that do not disturb the animals observed, which can be extremely sensitive to intrusion. The cetaceans are studied not only for their own sake but also because, as the researchers point out, they "are part of an ecosystem and are useful as bio-indicators."

In layman's language: if the dolphins are thriving, so is much else; if they are disappearing, the ecosystem is in trouble, too.