Aquaculture

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Variant III

Aquaculture, the controlled or semi-controlled production of aquatic plants and animals, has considerably increased since the early 1980s. This increase has been in response to declines in commercial harvests of wild stocks of fish and shellfish. Oceans of the world are currently at maximum sustainable yield. As global population grows, demand for fish and shellfish increases, and the percentage of aquatic products grown in aquaculture must likewise rise to meet the supply of those products. Projections for increased production are in the range of 40–100 mmt (million metric tons) of new aquaculture production by about the year 2030.

There are fewer than thirty large species-specific aquaculture industries globally. However, there are over twenty-five thousand species of fish and there are estimates that one thousand new species are being evaluated for their culture potential. As a subsistence enterprise, aquaculture has been practiced for over four thousand years. As a series of large industries, aquaculture is less than fifty years old, often stimulated by declining wild stocks of fish. The channel catfish industry, which only began in the late 1960s in the southern United States, is illustrative of a relatively young industry. Today, over 90 percent of the U.S. supply of Atlantic salmon is cultured. In 1980, that figure was only a fraction of 1 percent. Inevitably, as new aquaculture species are brought into culture settings, new diseases are identified that were previously unknown. In the past ten years, new viral diseases have been identified in shrimp and salmon, both of which caused large-scale losses from production facilities.

Of the approximately 25 mmt of global aquaculture production, there are only a few industries that produced over 1 mmt in 1996. Several of the species of Asian carp and the common carp account for the largest industries. Silver carp production was 2.2 mmt, grass carp production was 1.8 mmt, bighead carp production was 1.1 mmt, and common carp production was 1.5 mmt. Virtually all of this production occurred in China with the exception of common carp, which is raised throughout Europe. Of the species typically available in U.S. markets, pen-raised Atlantic salmon accounted for 0.4 mmt, rainbow trout production for 0.3 mmt, channel catfish production for 0.2 mmt. Production of several invertebrates was significant. Shrimp production was 0.9 mmt, oyster production was 1.1 mmt, mussel production was 1.0 mmt, and clam production was 1.0 mmt. Production of brown seaweeds was 4.5 mmt and red seaweed production was 1.6 mmt. Thus, the largest aquaculture industry is the production of brown seaweeds, largely for nonfood use. In the beginning of the twenty-first century a greater demand has not resulted in increased production yet.

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