By Stephen Leahy
BROOKLIN, Canada, Dec 16 2005 (IPS)

Five years of unprecedented international scientific study of marine life has revealed some mysteries of the oceans, but much more remains hidden.

Tiny carnivorous sponges, a tuna that swam 40,000 kilometres in 600 days, and a new technology that will revolutionise fisheries management are among the many highlights of the world’s first census of the oceans at its halfway point.

“Over 90 percent of the Earth’s biosphere (the part of the Earth that supports life) are in the oceans,” said Ron O’Dor of Dalhousie University in Nova Scotia.

“The oceans are full of life from the surface to mid-ocean depths and 10 metres deep in ocean bottom sediments,” O’Dor told IPS.

O’Dor is the chief scientist for the Census of Marine Life (CoML), a global partnership of 1,700 scientists from 73 countries with a 10-year mandate to investigate life in the seas. The CoML is to complete its work in 2010.

“[The] immense scale challenges the census,” says Victor Gallardo of Chile, vice-chair of the Census Scientific Steering Committee.

But what has become clear is that despite their vast size, the oceans are in peril.

“At least 75 percent of the commercial fish stocks are in trouble because of over-fishing,” said Julia Roberson of SeaWeb, an environmental NGO based in Paris and Washington.

Governments and fisheries have to do a better job managing fish stocks, while retailers and restaurants need to steer clear of endangered fish species, Roberson said in an interview from Paris.

Public awareness about unsustainable fisheries is growing, according to the first-ever European survey of seafood and oceans released Dec. 14. It found that of the people surveyed in four European countries, 86 percent would prefer to buy seafood labeled as environmentally responsible.

And 40 percent are willing to pay five to 10 percent more for seafood identified as eco-friendly, the study by the Seafood Choices Alliance showed.

Similar surveys reveal that while North Americans are generally less aware of the problems of fisheries, a large majority want more information about the oceans and fish stocks so they can make better choices when buying and eating fish, she said.

Climate change also poses an enormous but unpredictable threat to life in the oceans, says Joshua Laughren, director of marine conservation for World Wildlife Fund – Canada.

Climate change is raising the temperature of the oceans, which has led to the bleaching of coral reefs in many parts of the world. While reefs usually recover from bleaching, if water temperatures remain too high for too long, corals die.

But when the warm water is also slightly more acidic, then reefs are at much greater risk, as are other species.

Rising levels of carbon dioxide in the atmosphere have not only raised water and air temperatures, they are making the oceans more acidic, says O’Dor. Seawater absorbs carbon from the atmosphere, where it reacts to form carbonic acid.

“Oceans are already more acidic and it’s only going to get worse as atmospheric carbon levels continue to rise,” he said.

Given the climate change threats, if fisheries do not come to grips with biodiversity losses soon, there will be little left to save, warned Laughren. Fish catch quotas are currently set with little information and quotas are cut only after stocks are in steep decline, he said.

“The collapse of the North Atlantic cod is all too typical an example and one we haven’t learned the lessons from,” Laughren noted.

However, the Census’ “fish with chips” project promises to bring 21st century science to fisheries. Fish carrying almond-sized computer chips on the west coast of Canada and the U.S. are scanned by devices on the ocean floor when they pass over, like an electronic tag on a car passing through a highway tollbooth.

Nearly 3,000 salmon have been tagged so far, revealing surprising and substantial differences in where they swim, their distribution and survival.

With this technology every fish species of commercial interest could be closely monitored, providing 1,000 times the information currently available, says O’Dor.

“That’s the proper way to manage the multi-billion-dollar fisheries industry,” he said.

If funding is available, the CoML team aims to cover the entire western North American coast by 2010, with a goal of replicating the network on continental shelves worldwide.

For deep-sea species like tuna, another type of long-lasting electronic tag has revealed a Pacific bluefin tuna that crossed the Pacific Ocean three times in 600 days, a distance of 40,000 kms, greater than Earth’s circumference.

That unexpected traveling tuna would have been considered part of the U.S. tuna stocks, then part of Japanese stocks, leading to greatly overestimating how many tuna there really are, said O’Dor.

This summer, CoML researchers showed that Atlantic bluefin tuna also criss-cross the Atlantic, but fisheries officials manage them as if there were two independent populations on either side of an imaginary line in the middle of the ocean.

“We have better information now but changing attitudes is much more challenging,” said O’Dor.

CoML hopes to involve many more marine scientists and roll out these and other new technologies over the next five years.

“We need to decide what we want the oceans to be,” he said.

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