Large-scale commercial culture of tilapia is limited almost exclusively to the culture of three species: Oreochromis niloticus, O. mossambica and O. aureus. Of the three tilapia species with recognized aquaculture potential, the Nile tilapia, O. niloticus, is by far the most commonly used species in fish farming.

Growout strategies for tilapia range from the simple to the very complex. Simple strategies are characterized by little control over water quality and food supply and by low fish yields. As greater control over water quality and fish nutrition are imposed, the production cost and fish yield per unit area increases. Across this spectrum, there is a progression from low to high management intensity.

In traditioanal pond culture of tilapia, proper environmental conditions are maintained by balancing the inputs of feed with the natural assimilative capacity of the pond. The pond s natural biological productivity (algae, higher plants, zooplankton and bacteria) serves as a biological filter that converts the wastes through natural biological processes.

Increasing stocking densities places increasing demands on the production system. Additional energy inputs in the form of labor, water exchange, aeration and feeds are all required to sustain the intensive system. As pond production intensifies and feed rates increase, supplemental aeration and some water exchange are required to maintain good water quality. For densities above 1.5-kg per square meter, aeration is usually required. There is a point where the incremental returns are not worthy of the additional inputs and risks. Increasing the intensity of the system does not necessarily reflect an increase in profitability.

All tilapia production systems must provide a suitable environment to promote the growth of the aquatic crop. Critical environmental parameters include the concentrations of dissolved oxygen, un-ionized ammonia nitrogen, nitrite nitrogen, and carbon dioxide in the water. Other important parameters include nitrate concentration, pH, and alkalinity levels within the system. To produce tilapia in a cost effective manner, production systems must be capable of maintaining proper levels of these water quality variables during periods of rapid fish growth. To provide for such growth, tilapia are fed high protein pelleted diets at rates ranging from 1.0% to 30% of their body weight per day depending upon their size and species.

Numerous options for holding broodfish, fry, fingerlings, juveniles, sub-adult and adult tilapias are available to the prospective farmer. The options include ponds, tanks, raceways, hapas and cages. Tanks and raceways involve considerably greater expense to construct but offer greater control. They are usually used in intensive and super-intensive culture of tilapias. Ponds are much cheaper to construct and allow management to stimulate natural productivity more readily. The major drawback of pond culture of tilapias is the greater risk of uncontrolled reproduction, which will occur if certain measures are not taken to minimize this possibility. Ponds are used in extensive, semi-intensive and intensive tilapia production. Pond culture is by far the most common method being employed throughout Latin America because it is the cheapest method and also is one of the best.

Ponds are the traditional and inexpensive way to hold spawning populations of broodfish. In some parts of the world, the pond system has been made more efficient through the use of cages or net enclosures (hapas). Basically, the hapas are fine mesh net enclosures that are about 40 square meters in size and arranged into units within a larger pond. This segregates the pond into more easily managed units. On a per unit area basis, tanks are the most efficient method of collecting and raising fry, followed by hapas and simple ponds.

In aquaculture, no two situations are alike. Each project must be carefully crafted to meet the expectations of the owners, while giving diligent consideration to the limitations and strengths inherent in the proposed venture.

Marketing the Product

The total aquaculture production of tilapia was reported to be 1,265,800 tons in 2000. International trade is growing rapidly, especially between Central American producers (Costa Rica, Ecuador and Honduras) and the United States, and between Asian producers (Taiwan, China, Indonesia and Thailand) and the United States and Japan. There is also modest trade between Jamaica and the United Kingdom. The largest exporter, Taiwan, supplies Japan with high-quality tilapia fillets for the sashimi market, and ships frozen tilapia to the United States market (40,000 tons in 2001). Taiwan exports about 70 percent of its domestic tilapia production. Thailand and Indonesia export less than 5 percent of their production.

Viet Nam has also recently entered the world tilapia market, and China exported 12,500 tons to the United States in 2001. Zimbabwe, thanks to the efforts one vertically intigrated operation, now also produces fresh and frozen fillets for the EC market.

In the United States, tilapia is now the third most imported aquaculture product by weight (56,300 tons in 2001), after shrimp and salmon. United States imports have been growing strongly and are forecast to grow further in the future. Long-term tilapia prices are expected to decrease, and this should lead to increased exports to the United States, as well as to Europe, which is still a largely undeveloped market for tilapia.