Read the excerpt below and then answer the following question.
Unlike commercial fishing, which is the harvesting of wild fish, aquaculture is raising fish for harvest under controlled conditions. Aquaculture is an ancient practice; there is evidence that eels were raised by aboriginal people in Australia as early as 6000 BC. A series of channels and dams were built in a flood plain to contain eels; the fish were captured in woven traps, smoked, and eaten year-round. The Chinese also began to use aquaculture a long time ago; around 2500 BC, carp were raised in lakes in China. Early Christian monasteries in Europe adopted the Roman practice of raising fish in ponds. Those approaches were used until the development of hatcheries in the eighteenth and nineteenth century, when native wild fish such as trout and salmon began to experience declining populations. In the United States, brook trout were being hatched and raised in upstate New York as early as 1859; by 1866, artificial fish hatcheries had been established in the United States and Canada, as the techniques of artificial fertilization and the subsequent hatching of eggs began to be developed. Their techniques were soon widely used throughout North America and Europe.
Commercial salmon farming began to be established in the 1970s, at about the same time that restrictions establishing the 200-mile limit fishing zones were put into place. Japan was one of the first countries to develop hatchery programs and extend those programs to full aquaculture. By the late 1990s, hatchery-based salmon harvests made up about 80 percent of Japan's total salmon production.
Aquaculture has become one of the primary sources of fish in the United States and around the world. The Food and Agriculture Organization of the United Nations has estimated that aquaculture has grown by about 8% per year over the past thirty years; at the same time, catches from the wild have either remained constant or dropped due to diminishing fish stocks.
In paragraph form, identify and explain the central idea of the passage. Describe at least one way the author could make the support more effective. Be sure to use proper grammar, diction, syntax, and voice.
