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Census of the seas

First global count of marine life logs 230,000 species — but scientists warns of mass extinctions

world Updated: Aug 04, 2010, 00:57 IST
Hindustan Times

First global count of marine life logs 230,000 species — but scientists warns of mass extinctions.

It has been the biggest and most comprehensive attempt ever to answer that age-old question — how many fish are there in the sea?

A 10-year study of the diversity, distribution and abundance of life in the world’s oceans attempts just that.

The Census of Marine Life estimates there are over 230,000 species in our oceans.

“From coast to the open ocean, from the shallows to the deep, from little things like microbes to large things such as fish and whales,” said Patricia Miloslavich of Universidad Simón Bolívar, Venezuela.

It also covers crabs, plankton, birds, sponges, worms, squids, sharks and slugs.

A team of over 360 scientists around the world surveyed 25 regions, from the Antarctic through the temperate and tropical seas to the Arctic.

Main threats

Overfishing, degraded habitats, pollution and the arrival of invasive species. But more problems are around the corner: rising water temperatures and acidification thanks to climate change and the growth in areas of the ocean that are low in oxygen and, therefore, unable to support life.

Among their findings

A fifth of the world’s marine species are crustaceans such as crabs, lobsters, krill and barnacles. Add in molluscs (squid and octopus) and fish and that accounts for nearly half the species in world’s seas.

Species often used in conservation campaigning — whales, sea lions, turtles and sea birds — account for less than 2% of the species in the oceans.

Enclosed seas such as the Mediterranean, Gulf of Mexico, China’s shelves, Baltic, and the Caribbean as having the most threatened biodiversity.

The most diverse regions are around Australia and south-east Asia.

Australian and Japanese waters contain more than 30,000 species each and are among the most biologically diverse in the world.

The manylight viperfish (Chauliodus sloani) is the most “cosmopolitan” marine creature with a presence in around a quarter of the world’s seas.

The number of marine fish species known to science stood at 16,764, and was growing at around 100 a year. There are believed to be 22,000 fish species in the world.

ht epaper

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