Tilapia

This article is about the fish that fall under the term tilapia in common usage. For species belonging to the genus Tilapia, see Tilapia (genus).

Tilapias
Nile tilapia (Oreochromis niloticus niloticus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Cichlidae
Subfamily:	Pseudocrenilabrinae
Tribe:	Tilapiini
Genera
Oreochromis (about 30 species) Sarotherodon (over 10 species) Tilapia (about 40 species) and see text

Tilapia (Template:Pron-en) is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia inhabit a variety of fresh water habitats including shallow streams, ponds, rivers, lakes, and estuaries. Most tilapia are omnivorous with a preference for aquatic vegetation and detritus. Historically they have been of major importance in artisanal fishing in Africa and the Levant, and are of increasing importance in aquaculture (see tilapia in aquaculture). Tilapia rarely become problematic invasive species in new habitats, whether deliberately or accidentally introduced due to their inability to survive in cool waters, (generally below 60 degrees fahrenheit, below 15.6 C). (See tilapia as exotic species).

Etymology

The common name tilapia is based on the name of the cichlid genus Tilapia, which is itself a latinization of thiape, the Tswana word for "fish." The genus name and term was first introduced by Scottish zoologist Andrew Smith in 1840.

Tilapia go by many names. The moniker "St. Peter's fish" comes from the account in the Christian Bible about the apostle Peter catching a fish that carried a shekel coin in its mouth, though the passage does not name the fish. While the name also applies to Zeus faber, a marine fish not found in the area, one tilapia species (Sarotherodon galilaeus galilaeus) is found in the Sea of Galilee where the account took place. This species has been the target of small-scale artisanal fisheries in the area for thousands of years. In some Asian countries including the Philippines, large tilapia go by pla-pla while their smaller brethren are just tilapia. The Hebrew name is amnoon (אמנון). The Arabic name is mushṭ (مشط) (comb) because of its comb-like tail. Tamil speakers use jilaebi .

Aquaculture

Main article: Tilapia in aquaculture

Tilapia is the third most important fish in aquaculture after carps and salmonids, with production reaching 1,505,804 metric tons in 2002. Because of their large size, rapid growth, and palatability, tilapiine cichlids are the focus of major aquaculture efforts, specifically various species of Oreochromis, Sarotherodon, and Tilapia, collectively known colloquially as tilapias. Like other large fish, they are a good source of protein and a popular target for artisanal and commercial fisheries. Originally, the majority of such fisheries were in Africa, but outdoor aquaculture projects in tropical countries such as Papua New Guinea, the Philippines, and Indonesia are underway in freshwater lakes.[2] In temperate zone localities, tilapiine farming operations require energy to warm the water to tropical temperatures. One method uses waste heat from factories and power stations.

Commercially grown tilapia are almost exclusively male. Often, to reverse the sex of newly spawned female tilapia, all the spawned tilapia are exposed to large doses of hormones such as testoterone. Additionally, many of these genetically altered "food" tilapia are fed diets that contain growth hormones in order to acheive acceptable growth rates for the commercial food industry. Being prolific breeders, female tilapia in the ponds/tanks will result in large populations of small fish. Whole Tilapia fish can be processed into skinless, boneless (PBO) 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 in the species. Most tilapia found in the wild today are a genetic mixture and hybidization of several tilapia species.

Nutrition

Tilapia have very low levels of mercury because it is a fast-growing and short-lived fish that mostly eats a vegetarian diet and therefore does not concentrate mercury found in prey.

Farm-raised tilapia has very low levels of omega-3, the primary fatty-acid nutritionists look for in fish, but high in omega-6 fatty acids. A diet with a high ratio of omega-6 to omega-3 is suspected to cause inflammation. It is not clear if this poor ratio of omega-6 to omega-3 is due to the corn and/or soy based diets typically fed to farm raised Tilapia, natural fatty acid levels, or a combination of the two. It should be noted that this study has not survived positive peer review, and is highly suspect in both it's accuracy and conclusions.

Non-indigenous populations

Main article: Tilapia as exotic species

Tilapia are unable to survive in the United states outside of extreme southern Florida and a few other isolated areas such as power plant discharge zones due to their intolerance of cool water. Arizona maintains tilapia hatcheries to stock the canals that serve as the drinking water souces of for the cities Phoenix, Mesa, and others to greatly reduce the purification costs. Arkansas stocks many public ponds and lakes for aquatic vegetation control, as a robust forage species, and for anglers.

Tilapia serve as a natural, biological control for most aquatic plant problems. As consumers of floating aquatic plant, duckweed watermeal (Lemna sp.), most "undesirable" sunmerged plants, and most forms of algae. In the United States and countries such as Thailand,, Tilapia are becoming the plant control method of choice in many water bodies by reducing or totally eliminating the need to use toxic chemicals and heavy metal based algaecides to attain the same levels of plant control. The pure strain of the Blue Tilapia, Oreochromis Aurea, has the greatest cold tolerance and dies at 45 degrees farenheit while all other species of tilapia will die at a range of 52 to 62 degrees(11-16.7 C). Tilapias' inability to survive the normal climates of virtually any water source in the United States virtually eliminates the fear of the species as an "invasive" Tilapia also provide an abundant, natural food source for aquatic predators. Tilapia rarely compete for the same food sources of other "pond" species of fish. By consuming and converting plants and nutrients unused by other fish species and by substantially reducing oxygen depleting detritus, adding tilapia will often increase a pond's "carrying capacity" as well as increase the overall health and food sources of most other species of fish in the water. In Kenya tilapia were introduced to help control mosquitoes which cause malaria. They consume mosquito larvae, which reduces the numbers of adult female mosquitoes, the vector of the disease (Petr 2000). Negative effects rarely outweigh the benefits of introducing tilapia to temprate waters and due to little education and myths about tilapia, many state fish and wildlife agencies in the United States still considered them as an invasive species. In climates that do not support water temperatures above 65 degrees(18.3 C) year round, tilapia have proven to be of great benefit with no signs of harming the habitat of any other fish species.

In aquaria

Larger tilapia species are generally viewed as poor community aquarium fish because they eat plants, dig up the substrate and fight with other fish. However, tilapia are often raised in aquariums as a food source due to their tolerance for high stocking densities, poor water quality, and rapid growth. The smaller West African species, such as Tilapia joka, and those species from the crater lakes of Cameroon are more popular. In specialized cichlid aquaria tilapias can be mixed successfully with non-territorial cichlids, armoured catfish, tinfoil barbs, garpike, and other robust but peaceful fish. Some species, including Tilapia buttikoferi, Tilapia rendalli,Tilapia mariae ,Tilapia joka, and the brackish-water Sarotherodon melanotheron melanotheron, have attractive patterns and are quite decorative.

See also

• Tilapia in aquaculture

References

• FAO Fishery Information, Data and Statistics Service (1993). "Aquaculture production (1985-1991)". FAO Fisheries Circular. 815. FAO: 20–21.
• Petr, T. (2000): Interactions between fish and aquatic macrophytes in inland waters. A review. FAO Fisheries Technical Papers 396.
• Trewavas, Ethelwynn (1983): Tilapiine fish of the genera Sarotherodon, Oreochromis and Danakilia. Published by the British Museum (Natural History), London. 583 pages. ISBN 0-565-00878-1

External links

• Tilapia en Hidalgo