Many environmentalists believe that the world's overexploited and ailing oceans will soon replace tropical rainforests as the most pressing global ecology issue. Commercial fishing techniques -- especially large-scale driftnets and bottom trawling -- inadvertently and unnecessarily kill huge numbers of ocean animals and destroy the ocean floor. Yet while these and other perilous conditions have seriously reduced harvest levels of fish worldwide, more people than ever before, 1 billion, rely on fish as their main source of animal protein, making it the fifth largest agricultural commodity in the world.