Census of Marine Life: Large animals in danger of dying out

The Census of Marine Life looked for the first time at the history of exploitation of the oceans. It found that on average large fish and marine mammals have declined by 90 per cent since records began. Endangered species include the blue whale, sea turtles and birds like the albatross.

The study also found a decline in phytoplankton, the microscopic creatures that live in the bottom of the ocean and sustain much of the seafood eaten by humans. The census was commissioned in 2000 to find out the state of marine life, amid growing concern about overfishing and mineral exploitation. It involved more than 2,700 scientists in 80 countries across the world.

One study by Boris Worm and Heike Lotze at Dalhousie University looked at historical records to see how life in the ocean has changed over time. They studied catches, sightings and even restaurant menus and photographs of family fishing trips to see how the population of different fish species and mammals have changed. Also archaeological finds and historical records that show what people are hunting and eating.

The study of around 100 species, including sharks, seals and cod, showed that on average numbers have declined by around 90 per cent since records began.

Fish such as swordfish being caught now are much smaller than in the past. And creatures at the bottom of the food chain known as phytoplankton had declined globally, according to observations from ocean-going vessels since 1899. Ron O'Dor, a senior scientist at the Census, said mankind's greed has had a catastrophic effect on the ocean. He said every mammal, shellfish or large fish that is used by humans is in danger of dying out. "The pristine ocean is a very distant memory," he said. "There are only a few areas of the world where oceans are non-impacted by humans." The census found that altogether there are around one million species in the ocean. Almost 250,000 have already been found by scientists, while 750,000 are yet to be discovered.

Some 6,000 new species were discovered in this census, including a hairy "yeti crab", a 20ft long squid and a shrimp that was thought to have died out 50 million years ago.

However Dr O'Dor said these new species could also be lost unless attitudes change. "In some ways the problem of marine life is it is too delicious for us to eat and too beautiful for us to wear," he said. "But these species are running out and we need a reversal of attitudes in the 21st Century. "Ninety per cent of the big fish are gone – but if we leave them alone they could come back." The Census has generated a website, iobis.org, on which anyone can see the distribution of a species in the ocean from a giant database of names and "addresses" of marine creatures.

From : The Telegraph

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