Shrimp Aquaculture in Taiwan

Shrimp aquaculture has been taking place in Southern Taiwan for several hundred years, and the country is known as the forerunner of shrimp aquaculture development. The earlier extensive, low yield methods have been replaced by semi-intensive and intensive methods, which depend on large inputs and high-density stocking.

The `blue revolution’ in shrimp aquaculture began in 1968, and there was a gradual shift from milkfish to shrimp. Trash fish was introduced as a feed, taking advantage of trawler by-catches. In 1984, a huge increase in shrimp aquaculture took place. Taiwan’s exports, especially to Japan, increased exponentially. By 1997, Taiwan was producing 21 per cent of Asia’s cultured shrimps, the highest output for the region.

However, Taiwan was unable to keep its production at 1987 levels due to a series of serious environmental problems that have since been shown to be inherent to much of the industry in Asia. The gold-rush mentality of many of the investors in this highly profitable industry, resulted in poor management decisions being made. Almost every single patch of mangrove forest was sacrificed to the industry and other development projects, which became highly concentrated along the coasts. Little attention was paid to environmental issues, and this led to actions like overstocking (60 to 100 shrimp per square metre), having too many crops a year (3 to 3.5), and using processed feeds indiscriminately. Soon diseases typical of large-scale monocultures struck at epidemic proportions. Viruses, bacteria and infecting protozoa’s decimated crop after crop, and since farmers dumped their wastewaters directly into canals and coastal waters, their neighbours began to pump this contaminated water into their ponds.

Another major problem was the indiscriminate use of dangerous chemicals and antibiotics to culture fish and shrimp. This overuse, apart from decreasing the resistance of shrimps to diseases, also adversely affected the coastal environment and caused health risks to farmers and shrimp consumers. With diseases rampant in 1988, the use of chemical controls failed miserably, and only 30,000 metric tons was produced that year. Between 1988 and 1989 Taiwan’s share of production in Asia plummeted from 21 per cent to 4 per cent as a result of

widespread viral disease among shrimp. The industry paid a heavy price for the unsustainable management practices and over-expansion without consideration for the natural environment.

In addition, the overexploitation of ground water supplies by investors also proved unsustainable. Over-pumping caused large amounts of ground subsidence in the areas where intensive shrimp culture had boomed. In some areas land sunk several metres in just a few years.