New Internationalist

The fall of King Tuna

Issue 431

The fate of one of the kings of the ocean could be sealed this month – as the Convention on the Trade in Endangered Species decides whether or not to add the Atlantic bluefin tuna to its list of endangered species. The future of the bluefin hangs in the balance, but the fate of tuna stocks in general is a mirror of countless other species. Sara Holden and Greg McNevin look at the state of our oceans through the eyes of one of its most highly valued species.

Photo by Gavin Newman / Greenpeace
Captive blue fin tuna inside a transport cage. The cage is being towed by a tug from fishing grounds in Libya to Tuna farms in Sicily. Photo by Gavin Newman / Greenpeace

Far out to sea in the deep waters of the Pacific, a growing swirl of fish glistens just below the surface, advertising themselves as a tempting catch for a school of yellowfin tuna. With the help of internal body temperature regulators, the tuna crank up an extra spurt of speed, powering through the waves as fast as a galloping horse into the centre of the feast.

But the feeding frenzy quickly ends as a lethal ‘fish aggregating device’ (a floating piece of debris placed to attract feeding fish) ensnares the tuna. Open ocean species like tuna are often drawn to coconuts, logs, seaweed or other objects bobbing around in the sea. When these are topped with identifying flags or GPS units, the hunter quickly becomes the hunted.

So lured, the tuna are snared in the rapidly closing net of a Taiwanese fishing boat and swung out of the water in a suffocating, writhing mass. The prized fish conserve heat, generated by physical exertion, in their circulatory system, which helps them forage in cold water and digest food quickly. But in long struggles this can cause them to risk death from overheating – they literally cook from the inside with the warmth of their own body. Once on deck they are rapidly dispatched and stacked in freezers below.

Half a world away, in the warm waters of the Mediterranean, the tuna’s bluefin cousins are also snared. This time their fate is not sealed in a fast freezer. Instead, these highly migratory fish are caged and dragged through the water in tuna ‘ranches’, to be farmed and fattened until they are old enough for market.

Why marine reserves?

Scientists and environmentalists the world over are calling for a global network of marine reserves – areas that are closed to dumping as well as to ‘extractive’ uses like fishing and mining. Within these areas there would be ‘core zones’ (home to particularly sensitive habitats or species) where no human activities are allowed.

Some coastal areas in the reserves could be open to subsistence fishing provided that it is conducted in a sustainable way with the health of the fishery in mind and only after the approval of local communities.

Nearly six years ago the UN Convention on Biological Diversity called for a network of marine reserves to be in place by 2012.

Progress has been slower than a dripping tap. According to the World Database on Marine Protection less than one per cent of the world’s oceans are now protected. Scientists propose a minimum of 20 per cent but up to 50 per cent may be required to reverse habitat degradation and plummeting fish stocks. As it is, the high seas are completely devoid of protection.

So why do marine reserves need to be so extensive and what will they deliver in return?

According to marine scientists Callum Roberts, Leanne Mason and Julie Hawkins from York University in Britain, an effective network of marine reserves should represent the full range of biodiversity. Populations in different reserves need to interact and be mutually supporting. And the reserves themselves need to be large to ensure the long-term survival of species, habitats, ecological processes and services. Also important is that the network needs to be greater than the sum of its parts. A series of isolated reserves will not give the global protection needed.

Oceans are highly complex natural systems. They contain spawning, feeding and breeding grounds – vast but delicate habitats which are home to a myriad different species and ecosystems, bound together under the sea.

Maintaining that balance is the key. And bigger is better. Allowing fish to grow large allows them to become more productive – bigger fish produce more fish. Marine reserves can benefit adjacent fisheries both from the ‘spillover’ of adult and juvenile fish beyond reserve boundaries and by the movement of eggs and larvae. Inside the reserves, fish and other sea creatures increase in size and individuals live longer.

Marine reserves could also benefit migratory species like tuna and sharks if they were set up in places where these fish are highly vulnerable – such as nursery grounds or spawning sites.

One of the primary reasons for creating marine reserves is the preservation of fish stocks. But reserves are also seen as essential to protecting the global marine environment from pollution.

Tuna are often touted as the world’s favourite fish, used in everything from cat food to high-class sashimi. The demand is endless but the supply is clearly finite. The much-publicized health benefits of a low-fat, high-protein diet have resulted in an insatiable global appetite for tuna. In the last 50 years, 90 per cent of big predatory fish like tuna have vanished – wiped out in one generation.

Overfishing is the curse of every ocean and almost all fisheries. According to the UN Food and Agriculture Organization, three-quarters of all fish stocks are in trouble, in decline, or struggling to recover from exploitation. More and bigger boats are chasing fewer, smaller fish – reaching far beyond their home ports and all too often into the waters of other countries less able to compete. The European fleet alone has a catch capacity two to three times greater than its seas and oceans can sustain. Floating factory ships can stay at sea all year round. The Annelies Ilena, newly built and launched just a few months ago, can catch a third of a million tonnes of fish a year – enough to supply double the entire yearly fish demands of Hong Kong.

And then there are the pirate fleets from countries like Thailand and China that take up to 19 per cent of the global catch. In some regions, like West Africa, this figure is substantially higher. Billions of dollars of illegally caught fish are served up on legitimate plates worldwide as pirate boats launder their catch through insufficiently monitored ports or by transferring to so-called legitimate vessels far out to sea. The high price for key species like bluefin tuna and Patagonian toothfish are white gold for the pirates. A single bluefin can fetch as much as $100,000 in Tokyo’s main fish market.

Local fishing communities have no hope of competing. Fisherfolk have little choice but to work the foreign boats in their own waters and watch as vital food is frozen for markets abroad or wasted, thrown back dead or dying as unwanted ‘by-catch’. Industrial fishing nets can be the size of a football pitch, so-called ‘long-lines’ can stretch for more than 100 kilometres, barbed with thousands of hooks. Levels of by-catch can be up to 90 per cent of the haul. Sharks, turtles and dolphins are indiscriminately snared. Other extreme fishing methods, like bottom trawling, literally tear up the ocean floor as vast nets with giant rollers wipe out entire habitats and species.

Climate change and oceans

Healthy oceans can curb the effects of global warming. Scientists have shown that robust marine ecosystems act as a giant sponge to soak up the additional CO2. Another good reason for supporting a network of global marine reserves.

  • In 2002, the 500 billion tonne Larsen B ice shelf in Antarctica, which covered an area twice the size of greater London, disintegrated in less than a month.
  • In 2005, the British Antarctic Survey announced that 87 per cent of the area’s glaciers have retreated over the past 50 years. In the past 5 years, the retreating glaciers have lost an average of 50 metres per year.
  • The entire Antarctic ice sheet holds enough water to raise global sealevels by 62 metres.
  • In July 2005, independent scientists aboard the Greenpeace ship Arctic Sunrise discovered that Greenland’s glaciers are melting at an unprecedented rate. The Kangerdlugssuaq Glacier on the island’s east coast is retreating at a rate of 14 kilometres per year.
  • Greenland’s massive ice sheet locks up more than six per cent of the world’s fresh water. If the ice were to melt fully it would cause sea levels around the globe to rise by over six metres.

Where the wild things are no more, fish farming and ranching is becoming more prevalent as a solution to over-fishing. But the lesson of the Mediterranean tuna is testament to the flawed process, regardless of the target species.

Tuna are migratory – a round trip of 18,000 kilometres is the norm for some. In the Mediterranean the juvenile tuna are caught and penned in giant cages, swimming in endless meshed circles as they are dragged across the sea to tuna ranches for artificial fattening.

In order to feed the once-wild fish, more fish need to be caught. The irony of fish farming worldwide is the amount of fish it takes to grow a fish. Depending on the species, up to 20 kilos of wild fish may be needed to raise 1 kilo of farmed fish. Species like salmon require diets heavy with fishmeal and fish oil: it can take four and eight tonnes of wild fish to make one tonne of each respectively. The system is the epitome of ‘robbing Peter to pay Paul’.

A huge proportion of industrial fishing is for feed, not food. Intensively farmed cows, chickens and fish are all at least partly fed on fishmeal. However, the so-called ‘trash fish’ used for fishmeal are also often the staple diet for local communities. But instead of feeding families the stocks are scooped up, then ground and dumped as pellets into feeding ponds and troughs. Where farms are close to wild stocks, the farming process can also have devastating impacts on natural fish populations – spreading parasites and disease. At the same time, farming releases various toxins into the water. A wide variety of chemicals and drugs may be added to aquaculture cages and ponds in order  to control viruses, bacteria, fungi and other pathogens. The use of antibiotics also brings a potential risk to public health as over-use of these drugs can result in the development of antibiotic-resistant bacteria that cause disease in humans.

Fish farming also consumes a vast amount of space, resulting in the destruction of mangrove forests and other important coastal ecosystems. Elsewhere, coastal communities have been forced to relocate to make way for industrialized shrimp ponds.

The ocean conveyor belt

Powerful ocean currents occur throughout the world, driven by differences in water temperature and salinity. One of the best known, the Gulf Stream, gives Europe its relatively mild climate, provides vital upwellings of ocean-bottom nutrients, and increases the oceanic absorption of carbon dioxide.

  • Recent studies warn there may already be slower circulation over the Scotland-Greenland deep ocean ridge.
  • Dilution of the ocean’s salinity from melting Arctic ice and/or increased precipitation could switch off, slow down or divert the conveyor belt, with massive impacts across the globe.
  • Higher temperatures impact the entire marine food web. For example, phytoplankton, which lives under sea ice, feeds small crustaceans including krill. Melting ice will mean less krill – and krill feeds many whale species.
  • Whales and dolphins strand themselves in high temperatures. The great whales also risk losing their feeding grounds in the Southern Ocean around Antarctica because of the melting and collapse of ice shelves.
  • Whole species of marine animals and fish simply cannot survive in warmer waters. Some penguins, for example, have decreased by 33 per cent in Antarctica due to habitat decline.

Often farmed fish suffer from skin lesions, parasites and other diseases associated with being kept confined. Pollutants in the ocean mean that wild stocks also carry contaminants back into the food chain. Scares about mercury levels in tuna and other oily fish in northern latitudes have caused some countries to recommend that pregnant or nursing women avoid eating them altogether. Worldwide, ocean pollution is a growing problem. Plastic that does not degrade is often ingested by fish or marine animals, while oil spills and general garbage contaminate fisheries – we dump three times more rubbish into our oceans than we take out as fish.

In the Pacific, where 50 per cent of the world tuna catch is netted, a trash vortex of plastic that can stretch for thousands of kilometres endlessly circles between ocean currents.

The facts of ocean degradation are no longer in dispute. The tragedy is that the regional government bodies put in place to ‘manage’ fish stocks have comprehensively failed to do so. The proposal to have Atlantic bluefin tuna protected under the Convention on International Trade in Endangered Species is not a sign of good management – it is a desperate intervention to save a species.

Photo by Paul Hilton / Greenpeace
Activists on an inflatable boat next to the world’s biggest tuna fishing vessel, the Albatun Tres. The ship can take 3,000 tonnes of tuna in a single trip, almost double the annual catch of some Pacific island countries. Photo by Paul Hilton / Greenpeace

The oceans are carved up into management regions. Each regional fisheries management organization (RFMO) is made up of nations with a vested interest in the region or the stocks. The International Commission for the Conservation of Atlantic Tuna (ICCAT) has overseen a decline in tuna stocks year after year, despite annual advice from their own government scientists to reduce the catch and close spawning grounds. But the governments in ICCAT are not unusual. Almost every fish stock in every ocean is a lesson in fishing to the edge, not investing in the future.

Our oceans house more than 80 per cent of life on Earth – the UN has declared 2010 as the Year of Biodiversity. But the declaration will be hollow unless there is significant change.

The story of tuna is the story of the oceans and at the moment it makes grim reading. But we can take hope in the knowledge that the oceans are highly resilient – if we give them space. With the right protection and strong international agreements, almost all the troubled waters can be calmed. We need a global network of marine reserves covering 40 per cent of the world’s oceans, combined with international and regional agreements to ensure the remaining 60 per cent is used sustainably and fairly. 

It is possible to turn the tide on the destruction of the oceans.   But we need to start moving on it now.

Sara Holden worked as a television journalist before joining Greenpeace in 2000, where she combines journalism and activism. With parents who met while sailing, she is equally at home on the deck of one of the Greenpeace ships out in the ocean, or behind a laptop screen. Frequently she does both at the same time.

Formerly a freelance technology journalist, Greg McNevin now works in communications for Greenpeace international. He is currently focused on ending whaling in the Southern Ocean, by helping Greenpeace Japan activists Junichi Sato and Toru Suzuki fight a landmark court case after being arrested for exposing large-scale corruption in the whaling industry.

Find out more...

1 If you eat fish, know what you are eating. Always ask your retailer where the fish is from and how it was caught. If they don’t know, don’t buy. To find out more, check out the seafood ‘red list’ which catalogues fish that are commonly sold in supermarkets but carry a high risk of being sourced from unsustainable fisheries. www.greenpeace.org/international/seafood/

2 Sign the Greenpeace petition for the global network of marine reserves: www.greenpeace.org/international/campaigns/oceans/marine-reserves/roadmap-to-recovery

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