Hurrah! At last some good news for threatened Pacific tuna. Eight Pacific Island nations have signed an agreement to stop foreign fishing fleets taking their tuna. Our ship the Esperanza has been in the Pacific for the last seven weeks confronting unscrupulous foreign fleets that take 90 per cent of the fish, and even more of the profit.

For years fishing fleets from distant countries have plundered the Pacific's tuna, riding roughshod over the legitimate concerns of the islanders. Bigeye and yellowfin tuna are in crisis, and the economies of many Pacific islands have been devastated by the continuing plunder of their waters.

Last December some of the worst offenders - Japan, Taiwan and Korea - joined forces to block proposed conservation measures. But now a new agreement between Micronesia, Kiribati, Marshall Islands, Nauru, Palau, Papua New Guinea, Solomon Islands and Tuvalu is set to redress the balance.

Foreign fishing vessels licensed to fish in the waters of eight Pacific island countries will be banned from operating in two regions of the Pacific Commons adjacent to these countries. Since most Pacific tuna stocks - valued at US$3 billion a year - come from the waters of these countries, this will be a major contribution towards the protection of Pacific tuna. It also represents a giant stride towards making these areas into marine reserves - exactly what we have been pushing for since 2005.

Even better, the foreign boats will also be required to retain their full catches. In practice this will limit the time they spend at sea and the amount of tuna they can catch, because at present they can dump non-tuna species to make room in their holds for the more valuable catch. They'll also be required to carry fisheries observers on board at all times, and be banned from using fish aggregating devices (used to attract juvenile bigeye and yellowfin tuna) for at least three months of every year.

These conservation measures will take effect on 15 June 2008, and are another sign of progress for our global tuna campaign. Will we see similar protection of other tuna fisheries? We're working on it. Right now another Greenpeace ship, the Arctic Sunrise, is in the Med also saving tuna. And at the other end of the supply chain our activists recently shut down the stalls of the five major tuna suppliers at the world's biggest seafood fair in Brussels.