Criminal slash-n-burn deforestations by ecological idiots trying to replace crops & forests with cattle is simply just another move in the direction of desertification. Finally, lowering the watertable must create an ecological response, perhaps by killing a spring or a stream. The relationships among nutrition, dissolved gases and other environmental factors like temperature and pollution are little known.

Wild fishes caught have leveled off since the mid-1980s. Many stocks of fishes are fished so heavily that their future is threatened. Still, the world’s appetite for fish has continued to increase, particularly as urban populations and incomes grow in developing countries. Aquaculture—fish farming—has arrived to meet this increased demand. Production of fishes from aquaculture has exploded in the past 20 years and continues to expand around the world.

As prices for most food commodities fall, fish prices are expected to rise, reflecting demand for fishes that outpaces the ability of the world to supply it. From 45 million metric tons in 1973, total fish consumption jumped to more than 91 million tons in 1997.

The majority of global production comes from freshwater aquaculture (58 % in 1999), followed by mariculture (36 %) and brackish water fishing (6 %).