Fish, sharks, whales and other marine species are in imminent danger of an "unprecedented" and catastrophic extinction event at the hands of humankind, and are disappearing at a far faster rate than anyone had predicted, a study of the world's oceans has found.

Mass extinction of species will be "inevitable" if current trends continue, researchers said.

Overfishing, pollution, run-off of fertilisers from farming and the acidification of the seas caused by increasing carbon dioxide emissions are combining to put marine creatures in extreme danger, according to the report from the International Programme on the State of the Ocean (Ipso), prepared at the first international workshop to consider all of the cumulative stresses affecting the oceans at Oxford University.