Campaigners say that sea life -- particularly at the top of the food chain -- is suffering to such an extent that there will eventually be no fish left if action drastic action is not taken to protect the oceans.

More than 70 percent of the world is covered by oceans. There are currently more than 4,000 marine protected areas covering just over 1 percent of the oceans, but the vast majority of reserves have only limited protection.

According to Professor Callum Roberts, of the University of York, one of the leading campaigners and author of The Unnatural History of the Sea, only about 0.1 percent of the sea is completely protected from all exploitation. This should be between 25 and 45 percent to give marine species the best chance of recovery, he said.

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