15 Tilapia Fish farming

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Tilapia, young and mature, of Tamil Nadu

ilapia is the fifth most important fish infish farming. Because of their large size, rapid growth, and palatability, tilapia are the focus of major farming efforts. Like other large fish, they are a good source of protein and popular among artisanal and commercial fisheries. Most such fisheries were originally found in Africa, but outdoor fish farms in tropical countries, such as Papua New Guinea, the Philippines, and Indonesia, are underway in freshwater lakes. In temperate zone localities, tilapia farming operations require energy to warm the water to tropical temperatures. One method uses waste heat from factories and power stations. China is the largest tilapia producer in the world, followed by Egypt.

Commercially grown tilapia are almost exclusively male. Cultivators use hormones, such as testosterone, to reverse the sex of newly spawned females. Because tilapia are prolific breeders, the presence of female tilapia results in rapidly increasing populations of small fish, rather than a stable population of harvest-size animals.

Other methods of tilapia population control are polyculture, with predators farmed alongside tilapia or hybridization with other species.

Whole tilapia fish can be processed into skinless, boneless fillets: the yield is from 30 percent to 37 percent, depending on fillet size and final trim. The use of tilapia in the commercial food industry has led to the virtual extinction of genetically pure bloodlines. Most wild tilapia today are hybrids of several species.

Nutrition

Tilapia have very low levels of mercury, as they are fast-growing and short-lived, with a primarily herbivorous diet, so do not accumulate mercury found in prey. Tilapia is a low saturated fat, low calorie, low carbohydrate and low sodium protein source. It is a source of phosphorus, niacin, selenium, vitamin B₁₂ and potassium.

Farm-raised tilapia (the least expensive and most popular) has a high fat content, though low in saturated fats. According to research the nutritional value of farm-raised tilapia may be compromised by the amount of corn included in the feed. Short-chain omega-6s in corn accumulate in the fish. The ratio is worse than is found in beef. Widespread publicity encouraging people to eat more fish has seen tilapia being purchased by those with lower incomes who are trying to eat a well-balanced diet.

Exotic species

Tilapia are unable to survive in temperate climates because they require warm water. The pure strain of the blue tilapia, has the greatest cold tolerance and dies at 45 °F (7 °C) while all other species of tilapia will die at a range of 52 to 62 °F (11 to 17 °C). As a result, they cannot invade temperate habitats and disrupt native ecologies in temperate zones; however, they have spread widely beyond their points of introduction in many fresh and brackish tropical and subtropical habitats, often disrupting native species significantly. In the United States, tilapia are found in much of Florida, Texas and a few other isolated areas, such as power plant discharge zones. Many state fish and wildlife agencies in the United States, Australia, South Africa and elsewhere consider them an invasive species.