Aquaculture

Aquaculture is the controlled cultivation of aquatic organisms, such as fish, mollusks, crustaceans, and plants. Aquaculture may take place in oceans, rivers, lakes, ponds, or manufactured tanks. The first known records of aquaculture are from China, circa 889–904 c.e., where carp was farmed in flooded rice fields. This system took advantage of excess water, while at the same time fertilizing the earth and clearing the land of weeds. Thirty percent of the marine products consumed today come from aquaculture, which is currently the world's fastestgrowing food producing sector.

Aquaculture has experienced rapid growth and expansion on a global scale since the 1980s, while most wild-capture fisheries are in decline. International development agencies and state and local governments herald aquaculture as a means of economic development, resource diversification, and food security. Some scientists argue that it can be a strategy for taking the pressure off of wild fish stocks in order for them to recover. On average, seafood accounts for 16 percent of all animal protein in the human diet, making it the most important single source of high-quality protein.

Aquaculture is a global phenomenon, with a diversity of scale and levels of market integration. In some countries, aquaculture is practiced at a subsistence level, while other countries are internationally engaged in an industrialized process of fish production and export. Asia is the world leader in aquaculture production, due to its historical foundation in the process. Latin America has experienced a sharp rise in aquaculture production, with an average growth rate of 18 percent per year during the 1990s. The market is expanding most rapidly in North America, growing by approximately 13 percent per year in recent years.

The primary increase in aquaculture products has occurred in Low Income Food Deficit Countries, further reinforcing the view that the practice is a nutritional and economic resource. Many countries, including the United States, have encouraged aquaculture research and development as a means to meet the growing demand for seafood products in the face of a significant decline in wild populations. If environmental and social needs can be met, [Page 62]aquaculture might help alleviate poverty and hunger, while generating employment, though the actual effects of its rapid promulgation on local populations remain controversial.

Aquaculture at the industrial scale is relatively new and is still in the process of adaptation. Some concerns have emerged that the cultivation of certain species on intensive scales is ecologically harmful. Although aquaculture occurs in a controlled environment, cases of escapes, contamination, and spread of disease have been documented, all of which may harm the natural ecosystem in the surrounding area. For example, studies in Chile have shown that escaped salmonids can colonize their new, nonnative environment, resulting in resource competition and potentially altering local ecosystem processes. Shrimp production in Asia and other parts of the world has resulted in the deforestation of mangroves and wetlands in order to create space for shrimp ponds. The cultivation of carnivorous fish depends on the extraction of wild fin-fish that are converted to meal for fish food. In some parts of the world, this has meant depleted stocks for local fishermen, who still depend on these species for a supplement to their diet or for income. Experts have recently recommended that endemic herbivorous or filter feeders be farmed, rather than nonnative carnivorous species, in order to avoid some of these potential problems. Another suggested solution is to farm exclusively in terrestrial, man-made tanks where all stages of production could be managed, including the disposal of waste.

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