Tagging a bluefin tuna
Updated on 09 September 2009
Tom Clarke accompanies scientists from the conservation group WWF as they race to plant satellite tags on Mediterranean bluefin tuna, one of the world's most endangered fish.
Bluefin tuna belongs to a family with the scientific name Scombridae. It's from the Greek word "to hurry", and after hours of sitting around on a research ship in the choppy Mediterranean waiting to catch a bluefin we were about to find out the true meaning of the word.
Our three-man film crew found ourselves leaping down from the research boat into a bucking, rolling inflatable.
We were following a team of scientists working for WWF who are racing to plant satellite tags in bluefin – one of the world's most endangered fish – while stocks last. Struggling to keep our equipment dry, within seconds we were crashing over a few hundred metres of sea towards the boat of a sports fisherman who had hooked a bluefin.
Bluefin can swim at 60 miles an hour and can attain that speed faster than a Porsche. So if you want to catch one you have to be quick – but you also have to keep the fish as healthy as possible. In order for the tags to give scientists the crucial data the scientists need on how bluefin migrate, where they feed, and how they breed, they need the fish to survive being caught.
We arrive at the game fishing boat just in time – the powerful silver-flanked silhouette of a bluefin is visible on the end of a line a few metres away. Armed with satellite tag attached to a harpoon, one scientist makes a bold leap from our bucking inflatable onto the other deck several feet away. Our science producer Nick Scott-Plummer, armed with a handheld camera, follows to record the action.
A couple of minutes later the fish is free again. The tag should stay in place for up to 12 months. It will record the tuna's position, its depth and the type of water it's swimming in. Once it detaches from the fish it floats to the surface and relays the data, via a satellite to the researchers.
There is an urgency to their work. Catch quotas for tuna have been higher than scientific advice for decades. The Mediterranean's largest tuna fishing nations –France, Spain, Italy, Morocco and Libya – have been reluctant to take business away from their powerful fishing lobbies. And what a business bluefin is. A fish recently sold in Tokyo's fish market fetched $100,000. Japan buys 90% of Mediterranean bluefin.
Tagging data, it is hoped, will allow scientists to advise governments on areas where bluefin can be caught "sustainably" so that we can continue to eat the fish while ensuring enough survive into the next generation to breed. But before that can happen, it looks certain catching bluefin will have to stop to allow the population to recover.
Today conservationists are celebrating a major breakthrough. The European Commission's decision to back calls for a ban on the international trade in bluefin – by having it formally listed by the UN as an endangered species. It would be an unprecedented step to ban trade in a commercially important fish species. But many argue it could be bluefin's only hope.
There will now be an intense lobbying campaign by countries like Japan, who last week dispatched ambassadors to European fisheries ministries to try and get the ban overturned. Also from European national like Spain, Italy and Malta who have the most to lose.
Then there is the spectre of illegal fishing. Much of the bluefin on the market is thought to be caught illegally. Many European countries have been accused of tacitly supporting the less well-regulated fleets from the African side of Mediterranean.
Unregulated fishing, stimulated by the higher prices resulting from a trade ban, will mean conservationists will have their work cut out even if bluefin is given its well-deserved endangered status.
