Tilapia

From Free net encyclopedia

{{Taxobox | color = pink | name = Tilapia | image = Tilapia_buttikoferi1.jpg | image_width = 200px | image_caption = Tilapia buttikoferi in an aquarium | image2 = Tilapia.jpg | image2_width = 200px | image2_caption = Nile tilapia, artificial red morph | regnum = Animalia | phylum = Chordata | superclassis = Osteichthyes | classis = Actinopterygii | ordo = Perciformes | familia = Cichlidae | subdivision_ranks = Genera and species | subdivision = Oreochromis A. Günther,1889
Oreochromis aurea - Blue tilapia
Oreochromis macrochir - Longfin tilapia
Oreochromis mossambicus - Mozambique tilapia
Oreochromis niloticus niloticus - Nile tilapia
Oreochromis urolepis urolepis - Rufigi tilapia
Oreochromis urolepis hornorum - Wami tilapia
Sarotherodon W. P. E. S. Rüppell, 1852
Sarotherodon galilaeus galilaeus - Galilee or mango tilapia
Sarotherodon melanotheron heudelotii - Senegal cichlid or mango fish
Sarotherodon melanotheron melanotheron - Blackchin tilapia
Tilapia Smith, 1840
Tilapia buttikoferi - Zebra tilapia
Tilapia mariae - Spotted tilapia
Tilapia rendalli - Redbreast tilapia
Tilapia sparrmani - Banded tilapia
Tilapia zillii - Redbelly Tilapia
}}

Tilapias are a large African and Near Eastern fish that are the focus of major fishing and aquaculture efforts. They are members of the Cichlid family and resemble perch or bass in general shape, but as with all cichlids they have a single, long dorsal fin instead of two, as is typical of perch and bass. They inhabit a variety of fresh and, less commonly, brackish water habitats from shallow streams and ponds through to rivers, lakes, and estuaries. Most tilapias are omnivorous with a preference for soft aquatic vegetation and detritus.

The name tilapia comes from the genus Tilapia, which is itself a Latinisation of a Tswana word for "fish", thiape [1], coined by Smith in 1840 [2]. An alternative common name for tilapia is St. Peter's fish because of the account in Matthew 17:24-27 about Peter catching a fish that carried a shekel coin in its mouth. While the Bible does not describe the fish in question in any detail, the tilapia Sarotherodon galilaeus galilaeus is certainly common in the Sea of Galilee and has been the target of small-scale artisanal fisheries for thousands of years. However, because a number of other fish have also been called St. Peter's fish, such as the John Dory, the most common name in the English language for these fish is simply tilapia. In some cases a variation is used, for example redbreasted tilapia for Tilapia rendalli. Restaurants and producers of frozen or convenience meals often avoid using the tilapia name and instead refer to the fish as whitefish or perch; this is especially common in Europe and the US where consumers are largely unfamiliar with tilapia as a food fish.

Broadly speaking, tilapias of the genus Tilapia are substratum spawning cichlids, meaning that the fish form pairs, lay the eggs on the substrate, and then guard the eggs and fry. Tilapias of the genus Sarotherodon are mouthbrooders, with either both parents or just the male looking after the eggs or fry. Finally, tilapias of the genus Oreochromis, by contrast, are also mouthbrooders but in this case it is normally the female that looks after the eggs and fry. Groups of male Oreochromis form leks where they compete with one another for opportunities to mate with the females. Beyond this, they show no interest in the eggs or fry and do not extend any broodcare to their offspring at all.

1 Fisheries and aquaculture
2 Tilapia as a biological control
3 Tilapia as an invasive species
4 Tilapia in aquaria
5 Tilapia in Asian cuisine
6 References
7 External links

[edit]

Fisheries and aquaculture

Although their meat is somewhat bland compared with halibut, salmon, or sea bass, tilapia are a good source of protein and a popular target for artisanal and commercial fisheries. The majority of such fisheries are in Africa, but accidental and deliberate introductions of tilapia into freshwater lakes in Asia have allowed large fisheries to develop in countries such as Papua New Guinea, the Philippines, and Indonesia [3].

Tilapia are also among the easiest and profitable fish to farm. This is due to their omnivorous diet, mode of reproduction (the fry do not pass through a planktonic phase), tolerance of high stocking density, and rapid growth. In some regions the fish can be put out in the rice fields when rice is planted, and will have grown to edible size (12–15 cm, 5–6 inches) when the rice is ready for harvest. One recent estimate for the FAO puts annual production of tilapia at about 1.5 million tonnes, a quantity comparable to the annual production of farmed salmon and trout [4]. Unlike salmon, which rely on high-protein feeds based on fish or meat, tilapia will eat a vegetable or cereal based diet.

Part of the success of tilapia farming has been the readiness with which they have been assimilated into the cuisines of many countries. They are widely sold and used as white fish in the United States, for example, particularly in places far from the sea where saltwater fish are expensive. However, most tilapia farming is in Asia and Africa, and significant tilapia agriculture programmes exist throughout the tropics. In temperate zone localities where tilapia could not survive the ambient climate, farming operations use waste heat from factories and power stations [5].

[edit]

Tilapia as a biological control

Tilapia are a potential biological control for certain aquatic plant problems. They have a preference for a floating aquatic plant, duckweed (Lemna sp.) but also consume some filamentous alga [6]. However, these benefits are often outweighed by the negative aspects of tilapia as invasive species (see below).

[edit]

Tilapia as an invasive species

Tilapia are native to Africa and the Levant, but have been widely introduced into tropical fresh and brackish waters around the world. Some introductions, as in Florida and Texas, were unplanned, most likely caused by aquarium specimens being released by their owners after the fish grew too large [7]. More often, however, the fish have been introduced deliberately for commercial or industrial scale aquaculture. Because tilapia are large, fast growing, highly fecund, and tolerate a wide variety of water conditions (even marine conditions), once introduced into a habitat they generally establish themselves very quickly. In many places, particularly Florida and Australia, feral populations of tilapia have had detrimental effects on ecosystems.

[edit]

Tilapia in aquaria

Tilapia are generally not viewed as good aquarium fish because they are large, eat plants, and tend to be very disruptive, digging up the substrate and fighting with other fish. Only a relatively few species, most notably the brackish water species Sarotherodon melanotheron melanotheron, have become at all popular among aquarists. Because of their large size a big tank is essential, and since they are greedy and fast-growing, a large filter is important as well. In general, inexperienced aquarists should avoid tilapia.

On the other hand, they are hardy and easy to keep, provided they get enough space. They mix well with non-territorial cichlids, armoured catfish, tinfoil barbs, garpike, and other robust but peaceful fish. Some species, including Tilapia buttikoferi, Tilapia rendalli, and Sarotherodon melanotheron melanotheron are attractively patterned and decorative fish.

[edit]

Tilapia in Asian cuisine

Apart from the very few species found in the Levant, such as Sarotherodon galilaeus galilaeus, there are no tilapias endemic to Asia. However, species originally from Africa have been widely introduced and have become economically important as food fish in many countries. China, the Philippines, Taiwan, Indonesia and Thailand are the leading suppliers and these countries altogether produced about 1,100 thousand metric tonnes of tilapia in 2001, constituting about 76% of the total aquaculture production of tilapia [8]. Chinese cuisine in particular has adopted the tilapia enthusiastically, where it is used in much the same way as carp.

In Taiwan, tilapia is also known as the "South Pacific crucian carp," and since its introduction, has spread to aquatic environments all over the island. Introduced in 1946, Tilapia have made a considerable economic contribution, not only providing the Taiwanese people with food, but also allowing the island's fish farmers to break into key markets such as Japan and the United States. Indeed, tilapia has become an important farmed fish in Taiwan for both export and domestic consumption [9].

The Chinese name "Wu-Kuo" given to the fish known on the market as Taiwan tilapia was created from the surnames of Wu Chen-hui and Kuo Chi-chang, who introduced the fish into Taiwan. The two men, who had been soldiers in World War II pilfered some tilapia fry from Japan. Soon, they introduced the fish into the market. Within twenty years, tilapia had become an integral part of Taiwanese life, and raising tilapia had become a major source of income for many people. Kuo Chi-chang, though, was thwarted in his aspirations, and until his death in 2000 lived a life plagued by regret. [10]

When tilapia was introduced into Taiwan in 1946, the island had been devastated by World War II and was in a state of poverty. Because tilapia were easy to breed and could be kept in small fish ponds and rice paddies, it was seen as a cheap protein source useful for nourishing post-war Taiwanese villagers. Gradually, as Taiwan became a wealthier society, tilapia has lost its popularity to other seafood. Tilapia became known as the "poor-man's fish" and carried with it the memories of the past post-war era.

The Taiwan tilapia is a hybrid of Oreochromis mossambicus and Oreochromis niloticus niloticus.

An example of tilapia in Chinese cuisine: braised tilapia

Pan fry the fish until both sides are slightly brown.
Pour in 2 table spoons of soy sauce to the fish. Also add scallions, ginger slices, sugar, cooking wine, vinegar, tomato slices, and tofu. Then add a cup or two of water.
Simmer for 5-10 minutes.

[edit]