The geographical range for culturing tilapia in outdoor tanks is dependent on water temperature. The preferred temperature range for optimum tilapia growth is 82° to 86°F. Growth diminishes significantly at temperatures below 68°F and death will occur below 50°F. At temperatures below 54°F, tilapia lose their resistance to disease and are subject to infections by bacteria, fungi and parasites. In the southern region, tilapia can be held in tanks for 5 to 12 months a year depending on location.
The southernmost parts of Texas and Florida are the only areas where tilapia survive outdoors year-round. Elsewhere, tilapia must be overwintered in heated water. Flow-through systems are only practical for year-round culture in temperate regions if geothermal water is available. In the winter it would be too expensive to heat water and soon discard it. There has been some promising research on the use of heated effluents from power plants to extend the growing season. Indoor recirculating systems are more appropriate for year-round culture because buildings can be insulated to conserve heat and the heated water is saved through recycling.
Indoor recirculating systems have potential for extending the geographical range of tilapia culture throughout the U.S. Systems could be located in urban areas close to market outlets.
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Health Articles
An Open Letter regarding recent reports that low-fat fish like tilapia are unhealthy. (July 16, 2008)
Eating fish, especially oily fish, at least twice per week is recommended for heart disease prevention. Fish is low in total and saturated fats, high in protein and essential trace minerals, and contains long-chain omega-3 fatty acids (EPA and DHA). Oily fish rich in these healthy omega-3s include salmon, trout, albacore tuna, sardines, anchovies, mackerel and herring. Our omega-3 needs can also be met by eating less-oily (lower-fat) fish more often.
Tilapia and catfish are examples of lower-fat fish that have fewer omega-3s than the oily fish listed above, but still provide more of these heart-healthy nutrients than hamburger, steak, chicken, pork or turkey. Actually, a 3 ounce serving of these fish provides over 100 mg of the long chain omega-3 fatty acids EPA and DHA. Considering that this is about the current daily intake of these fatty acids in the US, even these fish should be considered better choices than most other meat alternatives. Since they are also relatively low in total and saturated fats and high in protein, they clearly can be part of a healthy diet.
US Department of Agriculture statistics indicate that farmed tilapia and catfish contain somewhat more omega-6 fatty acids than omega-3. Most health experts (including organizations such as the American Heart Association and the American Dietetic Association) agree that omega-6 fatty acids are, like omega-3s, heart-healthy nutrients which should be a part of everyone's diet. Omega-6 fatty acids are found primarily in vegetable oils (corn, soybean, safflower, etc) but also in salad dressings, nuts, whole-wheat bread, and chicken.
Replacing tilapia or catfish with "bacon, hamburgers or doughnuts" is absolutely not recommended.
Signed:
William S. Harris, PhD, FAHA
Sr. Scientist and Director
Metabolism and Nutrition Research Center
Sanford Research/USD
Sioux Falls, SD
(605) 328-1304
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