Ocean's decline threatens survival of many species

(AFP/Getty)

The world's oceans face an unprecedented loss of species comparable to the great mass extinctions in pre-history, a major report suggests.

The seas are degenerating far faster than anyone has predicted, the report suggests, due to the cumulative impact of climate warming, seawater acidification, widespread chemical pollution and gross overfishing. The coming together of these factors is now threatening the entire marine environment with a catastrophe "unprecedented in human history", according to the report, which was published by a panel of leading marine scientists brought together in Oxford by the International Programme on the State of the Ocean (IPSO) and the International Union for the Conservation of Nature (IUCN). The stark suggestion made by the panel is that the potential extinction of species, from large fish at one end of the scale to tiny corals at the other, is comparable to the five great mass extinctions in the geological record, during which much of the world's lifeforms died.

"The findings are shocking," said Dr Alex Rogers, professor of conservation biology at Oxford University and IPSO's scientific director. Reviewing recent research, the panel of experts found "firm evidence" that the effects of climate change, coupled with other human-induced impacts such as overfishing and nutrient run-off from farming, have already caused a dramatic decline in ocean health. Not only are there severe declines in many fish species – to the point of commercial extinction in some cases and an "unparalleled" rate of regional extinction of some habitat types, such as mangrove and seagrass meadows – but some whole marine ecosystems, such as coral reefs, may be gone within a generation.