Labels stating that tuna is “dolphin-friendly” are misleading consumers into believing that the fish they are eating has been caught using environmentally friendly techniques, campaigners say.

The labels indicate only that the fishing methods employed to catch the tuna have avoided the incidental killing of any dolphins. The certification system fails to assess any other measure of sustainability.

Although dolphins have been afforded a degree of protection from tuna fleets, other marine creatures are still commonly caught and killed as bycatch from tuna fishing, particularly rare turtles and sharks.

Moreover, tuna are being fished out of existence because they are being caught in unsustainable numbers, according to a Greenpeace report, Tinned Tuna’s Hidden Catch, which calls for dolphin-friendly standards to be extended to other marine species.

The use of fish aggregation devices and purse seine nets (lures and a wall of netting that encircles a school of fish) comes in for special condemnation because of the quantity of bycatch and the number of juvenile tuna that get caught and killed. Ten per cent of the fish caught using the technique are unwanted bycatch, amounting to at least 100,000 tonnes around the world annually.

Conservationists recognise the positive effect that the dolphin-friendly labels had but believe that consumers need more information to judge which types of tuna are harvested sustainably. In Britain the fish is most commonly sold in tins and the assessment by Greenpeace of some of the main brands shows that Sainsbury, followed by the Coop, offers the most sustainable canned tuna. John West and Princes were judged to be the least sustainable, largely because of their reliance on aggregation devices and purse seine nets.

Dolphin-friendly labels were a success because of their simplicity (Frank Pope, Oceans Correspondent, writes). If the tin had the stamp, you could eat the contents. Trying to eat fish that is not threatened with population collapse isn’t so easy. We need a new form of certification to help consumers to choose sustainable seafood.

A worldwide network of marine protected areas – where all fishing is banned – would give fishermen a simple rule: either you can fish here or you cannot. Even trawlers, the most destructive form of fishing, could win a sustainable seafood label if they could prove that they had not ploughed the seabed in a protected zone.

Dolphin-friendly labelling has shown that consumer choice can stop destructive fishermen. Now we need a simple sticker that says good or bad, not just for dolphins but for all life that depends on the sea.

Fishing for change

— Of the 23 commercially exploited tuna stocks, nine are rated as endangered or worse, three of which are considered vulnerable to being exhausted

— 70 per cent of tuna fishing is done using fish aggregation devices, which lure tuna to gather under a platform. From there they can be caught in huge nets called purse seines

— A tenth of everything caught in this way is unwanted bycatch

Source: Greenpeace

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