Overfishing, wasteful fishing and destructive fishing take a large toll of the fish and all other life in the sea: more than half the important commercial fish species have been overfished; every year several million tonnes offish and other animals are caught incidentally and discarded, and modern equipment such as bottom trawls and indestructible nylon nets which, lost overboard, become permanent fish traps, spread devastation. Coral reef exploitation, oil exploration, land erosion, dams on major rivers all affect the seas, while much of the agricultural pesticides and the industrial toxic wastes end up there too. Fish provide much-needed animal protein for humans. As more than half the marine productivity is within 200 miles of the shore, which is where 98 per cent of the world’s fish catches are made, the need for good management is clearly urgent.