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Tank culture of Tilapia

Tilapia grow well at high densities in the confinement of tanks when good water quality is maintained. This is accomplished by aeration and frequent or continuous water exchange to renew dissolved oxygen (DO) supplies and remove wastes. Culture systems that discard water after use are called flowthrough systems while those that filter and recycle water are referred to as recirculating systems.

Intensive tank culture offers several advantages over pond culture. High fish density in tanks disrupts breeding behavior and allows male and female tilapia to be grown together to marketable size. In ponds, mixedsex populations breed so much that parents and offspring compete for food and become stunted. Tanks allow the fish culturist to easily manage stocks and to exert a relatively high degree of environmental control over parameters (e.g., water temperature, DO, pH, waste) that can be adjusted for maximum production. With tanks, feeding and harvesting operations require much less time and labor compared to ponds.

Small tank volumes make it practical and economical to treat diseases with therapeutic chemicals dissolved in the culture water. Intensive tank culture can produce very high yields on small parcels of land. Tank culture also has some disadvantages. Since tilapia have limited access to natural foods in tanks, they must be fed a complete diet containing vitamins and minerals. The cost of pumping water and aeration increases production costs. The filtration technology of recirculating systems can be fairly complex and expensive and requires constant and close attention. Any tank culture system that relies on continuous aeration or water pumping is at risk of mechanical or electrical failure and major fish mortality.

Backup systems are essential. Confinement of fish in tanks at high densities creates stressful conditions and increases the risk of disease outbreaks. Discharges from flow-through systems may pollute receiving waters with nutrients and organic matter.

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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.


William S. Harris, PhD, FAHA
Sr. Scientist and Director
Metabolism and Nutrition Research Center
Sanford Research/USD
Sioux Falls, SD
(605) 328-1304