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TYPES OF AQUACULTURE OPEATIONS

Aquaculture operations range from small, backyard water gardens to energy-intensive, large commercial farms encompassing hundreds of hectares. Aquaculture is sometimes combined with agriculture as in rice–fish farming, or in duck–fish ponds. It is also practiced as polyculture, where a variety of species occupying different ecological niches are cultivated together. Aquaculture involves many levels of intensity and complexity, from gravity-fed ponds with little or no inputs, to intensive systems that use aeration, supplemental feeds, antibiotics, and genetically modified species.

Systems for rearing fish depend on the environment and the objective of the aquaculture operation. In the United States and worldwide, the most common rearing unit is the pond, although other types of units are also used: cages, net pens, flow-through raceways, and recirculation tanks. Efficient farm management and careful water-quality management are keys to a successful operation, regardless of the culture unit. With poor water quality, for example, fish exhibit higher incidence of disease. In addition, poor water quality often yields effluents (wastewater and byproducts) that can have negative environmental effects.

Small skiffs shuttle 80-meter-circumference salmon rearing pens around the harbor at a commercial fish farm in Dover, Tasmania, Australia. Pens must be moved periodically to reduce negative impacts of fish waste on substrate environments below the pens.

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