All this has happened fairly recently. Cod have been caught off Nova Scotia for centuries, but their systematic slaughter began only after 1852; in terms of their biomass (the aggregate mass of the species), they are now 96% depleted. The killing of turtles in the Caribbean (99% down) started in the 1700s. The hunting of sharks in the Gulf of Mexico (45-99%, depending on the variety) got going only in the 1950s.

The habitats of many of these creatures have also been affected by man’s activities. Cod live in the bottom layer of the ocean. Trawlermen in pursuit of these and other groundfish like pollock and haddock drag steel weights and rollers as well as nets behind their boats, devastating huge areas of the sea floor as they go. In the Gulf of Mexico, trawlers ply back and forth year in year out, hauling vast nets that scarify the seabed and allow no time for plant and animal life to recover. Off New England, off west Africa, in the Sea of Okhotsk north of Japan, off Sri Lanka, wherever fish can still be found, it is much the same story.

Coral reefs, whose profusion of life and diversity of ecosystems make them the rainforests of the sea, have suffered most of all. Once home to prolific concentrations of big fish, they have attracted human hunters prepared to use any means, even dynamite, to kill their prey. Perhaps only 5% of coral reefs can now be considered pristine, a quarter have been lost and all are vulnerable to global warming.

... contd.