Mexican tuna is officially dolphin-safe as far as the US is concerned, bringing a 12-year trade battle to an end.

The decision by the US Commerce Department to end what the Mexican Agriculture Ministry called a "de facto embargo" allows Mexico to export tuna despite its controversial tactic of chasing - and netting - dolphins to lead its fishermen to tuna schools.

Mexico last year threatened to take the dispute to the World Trade Organisation, a move which could have further disrupted international trade talks.

But the US's redefinition of the technique as having "no significant adverse impact" on Pacific Ocean dolphin populations has incensed environmental activists.

They say the US federal government's own data shows dolphins continue to be under threat, and that the decision amounts to caving in to Mexican pressure.

New and improved

As far as Washington DC is concerned, Mexico has addressed the problems that triggered the initial finding that its fishing methods threatened dolphins.

In Western Europe and the US, pressure groups have worked hard since the early 1990s to ensure that only tuna caught without endangering dolphins can get the coveted "dolphin-friendly" seal of approval.

The Commerce Department said Mexico's techniques had certainly killed numberless dolphins at first, but that they had since been refined to minimise the impact.

"This finding means that the definition of 'dolphin-safe' is that dolphins can be encircled or chased, but no dolphins can be killed or seriously injured in the net in which the tuna was harvested," it said in a statement.

At risk

But campaigners say the decision reeks of special pleading and the desire for an easy life.

The Earth Island Institute, an environmental pressure group, accused the Bush administration of "selling out dolphins in order to reward Mexican tuna millionaires".

The death toll each year would amount to 20-400,000 dolphins, it warned.

"The National Marine Fisheries Service has determined that depleted dolphin populations are not recovering in the Eastern Tropical Pacific, and that the cause is almost certainly... the deadly nets of the tuna fishing industry," it said.

Mexico produced about 133,000 metric tonnes of tuna in 2001, exporting about 15% of its catch with Spain as its principal foreign customer.