Oreochromis A. Günther,1889
Sarotherodon W. P. E. S. Rüppell, 1852
Tilapia Smith, 1840 (Tilapia, Wikipedia)
The family Cichlidae is characterized by long dorsal fins, with some varieties being brightly colored. This group includes many popular aquarium fish. Tilapia is native to Africa and Asia, but has been distributed heavily, worldwide. The tilapias are second only to carps in popularity as a finfish culture species worldwide. This group has only very limited production in the US (like carps), though interest in tilapia culture in the US is growing.
Tilapia, photographed at Brunswick Community College Aquaculture facility (North Carolina
Tilapias are a tropical species, which die when exposed to water temps below 55ºF. This, along with regulatory hurdles, has contributed to the lack of commercial culture in the USA.
Despite the lack of domestic production, tilapia is now the second most widely marketed cultured warmwater fish in the USA (behind channel catfish). About 85% of the filets sold in this country originate from foreign aquaculture operations.
American Tilapia Association and Marketing of Tilapia in the USA
Most domestic tilapia are produced in indoor recirculating systems, then sold to live markets. Prices of live tilapia have plummeted to as little as $0.90/lb, due to overproduction for this limited market. This price falls below the break-even price for most US producers. There has been some recovery, but prices of $1.50/lb and higher are probably gone for good.
Some producers have switched to alternative species, while others have tried to enlarge their facilities (economies of scale) utilizing improved technology to lower production cost. Marketing plans for may include processing tilapia into filets to compete with overseas producers, and emphasizing on freshness and quality.
There are three genera under the common name of tilapia.
Tilapia (genus) includes three species that build nests on the substrate. Some of these species are cultured, but this genus does not include the major culture species.
Two others are Sarotherodon sp. and Oreochromis sp.
These are the mouthbrooders, the genera that brood eggs and newly hatched larvae within the mouth after eggs are laid.
Large-scale commercial culture of tilapia is limited almost exclusively to the culture of three species:The genus Oreochromis includes the three major culture species:
1. Oreochromis niloticus
2. Oreochromis aureus
3. Oreochromis mossambica
Of the three tilapia species with recognized aquaculture potential, the Nile tilapia, Oreochromis niloticus, is by far the most commonly used species in fish farming.
From Tilapia Farming
Nile tilapia (Oreochromis nilotica)
Nile Tilapia, Oreochromis niloticus
The Nile tilapia is a native of the Nile River, North African waters and Middle East. Sometimes called St. Peter's Fish, because it is also a native of the Sea of Galilee, and thought by some to be the fish Jesus multiplied to feed the masses at the Sermon on the Mount.
The Nile tilapia is likely the most widely cultured tilapia species. This species (or a hybrid with the blue tilapia) is most often cultured in recirculating aquaculture systems in the US.
Blue tilapia (Oreochromis aurea)
Blue Tilapia, Oreochromis aurea
Based on an image at Auburn University
Blue tilapia is the second most cultured, hybridized with Oreochromis nilotica. The blue tilapia breeds at a smaller size and earlier age than Nile tilapia (2-3 months vs. 5-6 months) and is more tolerant of high salinity and low temperature than many other species.
Various hybrids of blue tilapia and other tilapia species tend to be intermediate in tolerance of low temperature and high salinity.
Blue tilapia exhibits great skill at seine avoidance. It seeks out low spots and lies on its side during seining operations.
Black tilapia or Java tilapia. (Oreochromis mossambica)
Black Tilapia, Oreochromis mossambica
Based on an image from Zoozipcode
Like blue tilapia... black tilapia spawns at an early age (2-3 months). It is also relatively tolerant of high salinity.
A hybrid between the mossambica female and nilotica male is known to be fast-growing.
Other Notable Hybrids
spirulus x aurea: hardy cross that will live and grow in full-strength seawater.
mossambica x hornorum: cross which produce offspring with red flesh, and may contribute to improved marketing in some areas of the US, such as Florida.
Developing Countries and Tilapia
Tilapia are cultured in ponds in tropical and sub-tropical developing countries throughout the world. Various species and hybrids of tilapia have been widely introduced throughout South America, Africa and Asia by US Peace Corps, US Agency for International Development (USAID), British VSO, the United Nations Food and Agriculture Organization (UNFAO) and a large number of non-government organizations.
Tilapia has become an important source of economical, but high-quality protein in places where it is needed most.
Tilapia are also produced in conjunction with hog and/or duck production in developing countries. Hog or duck pens are constructed alongside or even on stilts directly over the ponds. Waste may move directly into the ponds, providing organic fertilization spurring the production of plankton and benthic invertebrates which are hence eaten by the fish. Some tilapia will consume animal wastes directly.
See Use of organic residues in aquaculture. However, use of animal waste fertilizer is not a popular method in U.S. fish culture. The use of animal waste as a source of fertilizer or food for fish creates marketing problems, and naturally would be a source of public health concern.
Pond Production in the United States
Tilapia and its hybrids are used for forage species in ponds for largemouth bass and sometimes used as forage for catfish broodstock. Pond production of tilapia as food for human consumption is largely limited to the southern states, Florida, Texas and Southern California. Tilapia die when water temperatures fall below 55ºF, so with the exception of a few areas of the US, tilapia will not survive through the winter.
All-male tilapia or sterile hybrids are stocked in ponds to prevent breeding, which would result in overpopulation and stunting. Fingerlings are stocked during the spring in high density, which may range between 5,000-10,000 per acre. Very high production is possible in ponds (up to 10,000 lbs/acre) since tilapia are very tolerant of poor water quality associated with high daily feeding rates.
Disadvantages in Marketing Tilapia
Nearly all of the fish are harvested within a short period in late fall before water temperatures reach lethal levels. Processors and other buyers prefer a steady, year-round supply which creates a major problem with marketing. Tilapia have a tendency to pick up severe off-flavors associated with high feeding levels in ponds which also makes them difficult to market.
Tilapia Cage Culture
Tilapia have been successfully cultured in cages. There is no need for an all male population or sterile hybrids, since tilapia can not reproduce in large-mesh (1/2") cages. Eggs and milt fall through the bottom of the cage and are not picked up by mouth-brooders. In the US, these problems are increasingly being addressed by using tank culture methods in indoor, temperature-controlled water recirculation systems.
Recirculating Aquaculture Systems
"Tank Culture of Tilapia"
There have been substantial attempts to produce tilapia in indoor recirculating aquaculture systems, both in experimental settings and on a commercial scale by private industry. While tilapia production in these systems is technically feasible, most of the attempts at commercial production have been unprofitable and have failed. However, there are some success stories using this technology, and new ventures have arose in lieu of business failures. Many newer enterprises are attempting to avoid the pitfalls discovered during earlier attempts and some show promise, but for the time no established procedures exist for commercial tilapia culture. Eventually, with continued improvements, recirculating aquaculture systems may become a more visible segment in commercial industry.
Stocking rates in recirculating system tanks are planned as to limit the total number of lbs. of fish per gallon of water, thus the total amount of feed added each day. Most commercial systems limit fish to holding capacity (feeding rate of 2% of body weight/day) that ranges from 0.25 lbs/gallon to 0.8 lbs/gallon for tilapia. Tilapia can be stocked at such high density because they are generally tolerant of poor water quality. Attempts to grow other species at such high density, such as hybrid striped bass have shown little success.
Tilapia are able to withstand low DO concentrations coupled with high ammonia levels for varying periods of time (which also depends on temperature, pH, etc.) Generally, tilapia are more tolerant of such conditions than most cultured species. Since such conditions are encountered for short periods of time in recirculating systems, tilapia are an ideal species for this type of production.
Interest has developed in commercial recirculating systems for tilapia due to year-round temperature control, lack of off-flavor problems, and demand for live tilapia in large cities in the Northeast, Midwest and West Coast. For continued growth of tilapia production in recirculating systems, producers must find ways to compete effectively in fresh dressed and frozen tilapia. This places them in direct competition with commercial producers overseas, where production costs with ponds are far lower than production costs of U.S. recirculating systems. Domestic tilapia producers face competition from cheap foreign imports, which are similar to the problems faced by many other domestic manufacturers.