Caught in a trap: Tuna face a new threat

In the exclusive sushi restaurants of Tokyo, Kobe and Osaka, hungry diners eagerly watch and wait. Maki and futo rolls are passed by as customers sit patiently with chopsticks poised. Then, on the appearance of one dish, they pounce. The tuna has arrived.

In the exclusive sushi restaurants of Tokyo, Kobe and Osaka, hungry diners eagerly watch and wait. Maki and futo rolls are passed by as customers sit patiently with chopsticks poised. Then, on the appearance of one dish, they pounce. The tuna has arrived.

In nigri form - served on a small ball of rice - tuna rules the sushi world. Forget shrimp, salmon eggs and eel. It is raw slices of gleaming red flesh the Japanese crave.

Of the total worldwide catch of 1.2 million tons of tuna, the Japanese consume 600,000 tons. But there is one variety that stands out above all others; it is thunnus thynnus - the mighty bluefin. For the Japanese this is the king of fish. Its large size, colour, texture and high fat content make it so prized.

Such quality ensures it is the most expensive tuna. A 440lb specimen can fetch more than a thousand dollars. But there is another factor in its spiralling price - rarity.

The bluefin - one of seven tuna species fished commercially - can reach weights of more than 1,000lb, but that does not stop the sleek beast accelerating faster than a Porsche 911. It is found in waters from the southern Indian Ocean to the North Atlantic.

But the Japanese love bluefin so much that they have almost eaten it off the face of the Earth. By the late 1990s, stocks were down to an all time low - less than nine per cent of what they were in 1960.

Yet it appeared salvation was at hand. Like salmon and trout before it, tuna was supposed to be saved by the fish farmers. Not only would raising the fish in captivity allow wild stocks to recover, but it would ensure that a steady supply continued to flow into Japanese markets.

Tuna farming, though, was to differ in one significant way from the industry that altered the coastlines of Scotland and Norway. While farmed salmon are born and raised in captivity, the tuna are captured at sea by trawlers pulling purse-sein nets capable of swallowing an airliner. They are then carefully brought to shore for fattening up.

It meant they could guarantee Japanese markets that the fish would arrive in the prime, fattened-up state that customers so love. It seemed like an ideal, sustainable solution that could be efficiently managed.

That, at least, was the theory. Now though, the Worldwide Fund for Nature (WWF) for nature is warning that raising the fish in captivity could be exacerbating, rather than solving the problem of declining stocks.

And, as with salmon, the environmental realities of farming tuna are dawning after fragile communities pegged their economic future to it.

Captive tuna have flourished, becoming latter-day Klondykes for fishermen, especially along the southern Spanish coast of the Mediterranean, Australia and Mexico. The pens have proved a godsend for depressed coastal fishing towns and villages that were in dire need of an economic shot in the arm.

In the late 1990s, Port Lincoln on the remote Eyre Peninsula in southern Australia was a struggling fishing community on its last legs. Now it is reputed to have the highest number of millionaires per capita in the southern hemisphere.

This remarkable reversal in fortunes is attributable to one factor: tuna farming. Tuna now drives the economy in Port Lincoln. The fish-rich waters off the town of 13,000 are dotted with farms, and the £100m a year bluefish tuna industry is the largest employer on the peninsula.

The industry has brought untold wealth to a group of Croatian fishermen whose families were penniless when they emigrated to Australia and who now own extravagantly ornate mansions on the hills overlooking Boston Bay.

The farms were set up as a response to the introduction of tuna quotas in the late 1980s, which fishermen saw as a threat to their livelihoods. No longer able to go out and catch as much fish as they wanted, they sought a means of maximising their return. They had a brainwave, or so it appeared at the time. Rather than slaughtering the fish, they would ranch them instead.

Every summer, Port Lincoln's tuna farmers sail out 100 miles to the edge of the continental shelf to ambush schools of southern bluefish tuna migrating across the Great Australian Bight. They catch them in giant circular nets and tow them back to Boston Bay, where they are transferred to pens five miles offshore and fed until they are fat enough to be turned into sushi.

When the price is right on the Japanese markets, the tuna are harvested and whisked by aircraft to Tokyo, to be sold in the vast Tsukiji market and other outlets around Japan. Each fish is worth up to £800, which accounts for the wealth of the families who set up some of the world's first tuna farms.

Port Lincoln, once a depressed and run-down town, has acquired hotels, restaurants, cinemas and a spanking new marina that includes a waterfront residential development accessed by a private drawbridge.

While being fattened up, the tuna consume vast amounts of fish. Three times a day, feed boats moor up beside the farms and flick in a few tiddlers to see if the tuna are hungry. Then they lower pallets of frozen fish into a feeder cage in the middle of the pen. The tuna cruise up and lie beneath the cage, waiting for the fish to thaw and drop into their mouths.

For the tuna, it is the closest thing to being hand-fed. In the wild, they eat only once a week, and have to work hard for it. One feed boat alone leaves port every morning loaded with 20 tons of pilchards, sardines, herrings and anchovies, chosen for their high oil content and imported from California.

Six boats carrying armed security guards patrol the farms every night. With 1,800 tuna in each pen, the farmers cannot afford the theft of their valuable captives. Poachers are on the prowl, and thefts do take place.

The farms are also monitored by biologists employed by the main Japanese tuna importers, who are based in Port Lincoln during the season. They go out on the feed boats to examine the farms and then advise their companies which fish to buy when harvesting begins in late July.

The bluefish tuna of the Southern Ocean are highly prized by Japanese, who love their succulent, sweet flesh. The vast majority of the 4,000 tons of tuna kept in cages off Port Lincoln is bound for Japan.

When the fish reach the optimum weight, and when the market price of bluefin is favourable, harvesting begins. Divers plunge into the pens, grab the tuna and heave them on to the decks of waiting boats. When their numbers are thinned out, the rest are caught in conventional fashion, with a hook, line and pilchard. They reach Japan within 24 hours.

The Croatians who dominate the Port Lincoln tuna industry have been examining ways of applying their farming techniques to other large fin fish species, such as yellowtail kingfish, King George whiting, mulloway and snapper. The "tuna barons" have also exported their expertise to Croatia, where their relatives have established operations to farm the northern bluefin.

It is a move that has been welcomed by communities desperate for work and by Japanese traders who know they can easily shift thousands of tons of the creature.

There is just one problem. Wild bluefin remain locked in a battle for survival. The waters off the coasts of Spain, Sicily and Croatia have proved ideal for rearing captive tuna. They may also prove to be the species' graveyard.

The WWF says Japanese imports have risen by 21 per cent over the past three years.

The spike in tuna farming threatens to destroy the already overfished wild tuna in the Mediterranean, the WWF warned, noting that the practice is not subject to stringent controls. Yet with Libyan, Turkish and Maltese farmers all keen for a larger slice of the lucrative market, the prospects for stock recovery look bleak.

On a recent trip to tuna farms near Alicante in southern Spain, Don Staniford, an expert in aquaculture, was able to see tuna being fattened up for the sushi restaurants.

Mr Staniford, author of Cancer of the Coast: the environmental and public health disaster of sea-cage fish farming, has spent years highlighting the many problems associated with salmon, trout and cod farming. He is deeply concerned about the future of the bluefin.

"The idea that raising tuna in captivity could help wild stocks recover is frankly ludicrous," said Mr Staniford. He explained that the animals face all the problems experienced by salmon and cod, but the pressure on wild numbers was all the greater because the penned fish were actually plucked from the oceans.

Furthermore, with the tuna being a carnivorous fish, its voracious appetite meant that other fish stocks had to be heavily fished to feed it. While it takes three tons of wild fish to produce one ton of salmon and five tons of wild fish to produce one ton of cod, it takes a massive 20 tons of wild fish to fatten up just one ton of tuna for market. The effects on wild fisheries are devastating, he warned. Yet the European Union continues to fund the expansion of tuna farms in the Mediterranean.

Such subsidies could lead to commercial extinction of the endangered bluefin tuna within just a few years, the WWF warned this week. The conservation group said tuna farming jumped by 50 per cent last year in the Mediterranean to reach 21,000 tons. A catch at this level "is not compatible with the conservation of a healthy bluefin tuna population," it warned.

The rapid expansion of the industry since the late 1990s has been aided by EU subsidies of up to £15m, according to the report. "These subsidies should be immediately eliminated as they are directly resulting in overfishing of the bluefin tuna and could lead to the collapse of the stock in the region within the next few years," said Simon Cripps, director of the WWF's global marine programme.

The WWF argument was rejected yesterday by the European Commission which argued that tuna farming is conducted under strict conditions and its output is limited by national fishing quotas.

Gregor Kreuzhuber, a spokesman for the European Commissioner for agriculture and fisheries, Franz Fischler, said that the method deployed was irrelevant to the amount of fishing that takes place. He said: "It is not a free for all. Tuna that has been caught and is subsequently fattened is deducted from the overall quota of fish that can be taken from the sea."

But environmentalists argue that better policies must be employed. They argue that some fish are not even logged for quotas because they are not actually landed. "Some fish are caught, put in pens and then shipped to Japan without being registered," said Mr Staniford.

And there was a further word of caution from Mr Staniford. Chillingly, it may not just be the health of wild fish stocks that are at risk, he warned. Last week, American newspapers reported that notices in some New England shops and restaurants will be forced to advise pregnant women and children under the age of 12 that they should not eat tuna. High levels of mercury have been found in the fish, even though most of those on the market are caught in the wild.

"We are already at a stage where mercury is being found in tuna," said Mr Staniford. "The experience of fish farming in other species is that rearing fish in high-density cages increases the concentration of pollutants in the flesh. There are now serious questions about the impact of pen-reared tuna on human health."