Wednesday, February 20, 2008

Catastrophic extinction in the Anthropocene: now for the sharks

Sharks were old when Dinosaurs pounded the ground. 100 million years ago they looked like those that live today.

Now they're headed for extinction.

Ocean's fiercest predators now vulnerable to extinction

Sharks are disappearing from the world’s oceans. The numbers of many large shark species have declined by more than half due to increased demand for shark fins and meat, recreational shark fisheries, as well as tuna and swordfish fisheries, where millions of sharks are taken as bycatch each year.

Now, the global status of large sharks has been assessed by the World Conservation Union (IUCN), which is widely recognized as the most comprehensive, scientific-based information source on the threat status of plants and animals...

...Research at Dalhousie University over the past five years, conducted by Baum and the late Ransom Myers, demonstrated the magnitude of shark declines in the northwest Atlantic Ocean. All species the team looked at had declined by over 50 per cent since the early 1970s. For many large coastal shark species, the declines were much greater: tiger, scalloped hammerhead, bull and dusky shark populations have all plummeted by more than 95 per cent.

A 50% decline in about 30 years. In the geologic record we use to track extinctions this is meteor-impact fast.

We truly live in the Anthropocene. Of course it may be a relatively brief geologic era; if so the sharks might squeak through ...

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