Dangerous biological stowaways could easily be banished from ships' ballast. It's a disgrace that rich nations won't play ball, says Fred Pearce
THEY called it the blob that ate the Black Sea. Thirty years ago, a ship from North America sailed up the Bosphorus and dumped ballast water containing comb jellyfish from back home. The invader ? Mnemiopsis leidyi ? went crazy, gobbling up plankton and triggering a catastrophic decline in marine life, including commercial fisheries. At one point its biomass reached a billion tonnes, 10 times the world's annual fish landings.
Around a decade later an unknown ship, probably from the Bay of Bengal, discharged ballast water into the coastal waters of Peru, releasing a strain of cholera that contaminated shellfish. People ate the shellfish and the disease spread, killing 12,000 across Latin America.
Right now, the same thing, or something worse, could be happening almost anywhere. A United Nations treaty agreed in 2004 requiring ships to install kit to kill off biological stowaways in their ballast water has still not been ratified by enough nations to come into force. Its day may come when the environmental protection committee of the UN's International Maritime Organization (IMO) meets in London in May. We can hope so, but that has been said many times before.
This delay is a disgrace. Environmental problems often remain unfixed because the solutions are too hard or too expensive or the problem itself is contested. But this one continues to grow because of the indolence of governments, the prevarication of shipping companies and the inattention of environmental groups who, had they waged a serious campaign, would surely have prevailed by now. Why aren't Greenpeace and its ilk shutting down ports till they enforce ballast water clean-up?
Most cargo ships and tankers need ballast to avoid capsizing, especially when they are empty. The most convenient source is the sea. Ships take water on board after offloading cargo and discharge the ballast when they take on a new load ? often in a port thousands of kilometres away.
We are talking about a lot of water. A large ship can carry 60,000 tonnes of ballast. The 70,000 or so vessels that would be covered by the treaty transport more than 7 billion tonnes of ballast water round the world each year, says David Smith, head of technical services at the Plymouth Marine Laboratory in the UK. At any one time the world's ballast water contains an estimated 7000 different species in the form of seeds, spores, plankton, bacteria and the eggs and larvae of larger creatures.
Ecologists say that alien species are the second biggest threat to the planet's biodiversity after habitat destruction. Marine species are among the most enthusiastic invaders, and the global transport of ballast water is the single biggest cause of their spread. That's how the European zebra mussel got into North America's Great Lakes, where billions of dollars were spent to keep it from blocking irrigation channels and water pipes. That is how the dinoflagellates that cause toxic "red tides" spread round the globe, how Chinese mitten crabs reached Europe, how Asian kelp made it to southern Australia, and how Mediterranean mussels came to carpet the coast of South Africa.
The Mediterranean, the world's busiest sea, has 900 alien species in its waters, mostly discharged from ballast tanks. A new one arrives every nine days, according to the UN Environment Programme. Not all alien species cause trouble. Most are harmless. But the risk of a new zebra mussel or comb jellyfish or disease infestation is ever present. So why the delay in addressing the threat?
To come into force, the Ballast Water Convention requires 30 nations to ratify the treaty, which they have ? but those nations must hold the registrations for 35 per cent of the world's merchant shipping tonnage. So far the ratifiers only rack up a smidgen over 29 per cent.
The prime villains are the small nations that offer "flags of convenience" to foreign shipping lines so they can benefit from low taxes and lax regulations. Of the major flag of convenience nations, only Liberia, the Marshall Islands and Antigua and Barbuda ? which together hold about 17 per cent of the world's shipping tonnage ? have ratified. Panama, the Bahamas, Malta and Cyprus, which collectively account for 30 per cent, have not.
But perhaps the real scandal is that many industrialised nations, which enjoy lecturing small nations about their environmental inadequacies, have also chickened out. If the US, UK, Germany, Italy and Japan got off their high horses and ratified the convention, their collective tonnage would instantly trigger the treaty into force. They should.
The technology is available. The IMO has certified more than 20 commercial treatment systems involving various combinations of filtration, irradiation, ozone, heat, electrolysis and biocides.
Admittedly, retrofitting the fleet will be costly ? up to $500,000 dollars per ship for the biggest vessels ? and take time. But a study by the environment group WWF suggests that the economic cost of dealing with existing invasive species from ballast water is more than three times the cost of preventing more. And the polluter should pay.
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