Imagine a World Without Seafood for Supper -- It's Nearer Than You Think

As I step off the train at Heysel, the vast art deco structure of the Palais du Centenaire rises like a cathedral. With its four soaring buttresses topped by statues, the Palais forms the centrepiece of the Parc des Expositions in Brussels, Belgium - a trade-fair complex built in the 1930s to commemorate a century of independence from the Netherlands. This is the temporary home of thousands of fish products from around the world as 23,000 delegates descend from 80 countries for the annual European Seafood Exposition - the world's largest seafood trade show and a grim reminder of man's dominion over the oceans.

"If I wanted people to understand the global fishing crisis, I would bring them here," says Sally Bailey, a marine program officer with the World Wide Fund for Nature, one of the more moderate NGOs combating the exploitation of the seas. Last year, one of the more militant groups - Greenpeace - managed to "close down" five exhibitors trading in critically endangered bluefin tuna, by deploying 80 activists to drape their stands in fishing nets, chain themselves to fixtures and put up banners that read: "Time and tuna are running out".

Their main target was the Mitsubishi Corporation, the Japanese car manufacturer that is also the world's largest tuna trader, controlling 60% of the market and accounting for 40% of all bluefin tuna imported into Japan from the Mediterranean. The other companies were Dongwon Industries (Korea), Moon Marine (Taiwan/ Singapore), Azzopardi Fisheries (Malta) and Ricardo Fuentes & Sons (Spain).

The day I am there, Greenpeace activists are stalking EU fisheries ministers and waiting for a chance to unfurl their banners - but the security guards thwart them. However, the gargantuan catch on display speaks for itself. At the stand run by the Sea Wealth Frozen Food Company of Thailand, the shelves are groaning with jauntily designed packets of frozen squid, surimi (minced fish) dumplings, spring rolls, samosas and deep-fried cones with shrimp tails poking out of them. In the next aisle, a frenetic chef is wok-frying prawns from Madagascar, dipping them in little square dishes of cumin, coriander, chilli powder, salt, cinnamon and garlic. At the Taiwan Pavilion, the cabinets are full of chilled and frozen tilapia, barramundi, sushi, eel and vacuum packs of tobiko - orange flying-fish roe, salty, crunchy as granola and served by a young woman in national dress who literally has not heard of sustainability. "All the boats are out there catching fish with roe," she tells me. "With so many after the same species, this is a very difficult business for us."

These halls take several hours to negotiate, and the stands seemingly go on forever - 1,650 businesses in all, together peddling most of the 147m tonnes of seafood produced globally every year. Of this, 100m tonnes is caught in the wild while the rest is farmed to satisfy an insatiable demand. Already, 1.2bn people depend on fish in their diet - and in Europe we each consume 20kg per year on average, compared to 5kg per person in India. However, as the emergent middle classes in Asia develop a taste, and a budget, for seafood - considered a luxury item until now - demand will rocket further.

What the organizers must know, but are keeping mum about, is that the oceans are in a parlous state. The UN's Food and Agriculture Organization estimates that 70% of the world's fisheries are now fully exploited (ie, fished to the point where they can only just replenish themselves), overexploited or depleted. The majority of fish populations have been reduced by 70-95%, depending on the species, compared to the level they would be at if there were no fishing at all. In other words, only five per cent of fish are left in some cases. In more practical terms, fishermen are catching one or two fish per 100 hooks, compared to 10 fish per 100 hooks where a stock is healthy and unexploited - a measure of sustainability once used by the Japanese fleet. In England and Wales, we are landing one fish for every 20 that we landed in 1889, when government records began, despite having larger vessels, more sophisticated technology and trawl nets so vast and all-consuming that they are capable of containing 12 Boeing 747 aircraft.