Economic Crisis Could Spread Invasive Species

The global economic crisis could worsen the spread of invasive species in the oceans, according to a new study.

In the first quarter of 2009 cargo passing through Singapore, the world's largest port, was down 13.7 percent compared to the same period last year, and major shipping hubs around the world showed similar declines.

In total, some 10 percent of the global fleet of container ships and nearly a quarter of all refrigerated cargo ships sat idle, many of them waiting months for work.

For now, all is well. Thousands of ships are riding out the downturn in the warm teeming waters of Southeast Asia, where anchorage fees are cheap. They're accumulating hefty living rinds of barnacles, mussels, crabs and fish, but they're not leaving port as often, so the potential to spread invasive hitchhikers around the globe is minimal.

But Oliver Floerl of New Zealand's National Institute of Water and Atmospheric Research worries that all that could change when the economy picks up again. A large ship could have up to 80 tons of 'biofouling' accumulated on its hull, and merchant companies will be strapped for cash after the long layover, making them less likely to pony up six-figure sums to clean off all the crud.

The trouble starts when ships put in at their destination harbors. Operators want to lose the stowaways as soon as they can afford it -- biofouling costs thousands in reduced fuel efficiency -- and cleaning can dump a mess of foreign species onto the sea floor.

"Australia, New Zealand and the United States already have hundreds of non-indigenous species in their coastal ecosystems," Floerl said. "Ballast water management programs have been put in place, but it hasn't been extended to biofouling."

Many of the interlopers simply can't survive in their new ecosystems. But some species latch on and thrive, morphing into super predators or simply out competing native organisms for space.

For example, Floerl cited the Asian green mussel (Perna viridis), which has overrun coastal water in Australia and New Zealand and threatened commercial fishing industries.

"I think this is one of the most difficult environmental problems we have," Peter Bryant of the University of California, Irvine said. "And there's very little progress being made right now."

For years, ships' hulls have been painted with an anti-fouling chemical called tributyltin, Bryant pointed out. But the compound is devastatingly toxic, and many countries are in the process of ratifying an international ban. For now there are very few promising alternatives.

"We don't want to be sensational about this; it's not as though we're heralding the arrival of hundred of invasive species to coastal waters around the world," Floerl said. "But we do see this as a significant problem and as a wake-up call for people to think about the problem of biofouling."