Tilapia as exotic species

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Throughout much of the tropics, tilapiine cichlids native to Africa and the Levant have been widely introduced into a variety of aquatic systems. In the U.S. states of Florida and Texas, tilapia were originally introduced to curtail invasive plants. [1] In an effort to meet the growing demand for tilapia, humans have farmed these fish in countries around the world. Capable of establishing themselves into new ponds and waterways, many tilapia have escaped aquaculture facilities across much of Asia, Africa, and South America. [2] [3] In other cases, tilapia have been established into new aquatic habitats via aquarists or ornamental fish farmers. [4] [5]


Because tilapia are generally large, fast growing, breed rapidly, and can tolerate a wide variety of water conditions (even marine environments), tilapia establish themselves into new habitats rather quickly. In doing so, tilapia often out compete native fish, create turbidity in rivers by digging, and can reduce available sun light for aquatic plants. Tilapia greatly affect and alter local habitat. Many environmental problems wrought by tilapia have been observed in different locations, including Australia, the Philippines, and the United States. [6] [7] [8]

Tilapia by country


During the 1970s, tilapia were imported to Australia and introduced into the warm tributaries of North Queensland. These early introductions of tilapia were intended to act as a form of biological control, combating the growth of weeds and proliferation of mosquitos. [9] Later genetic studies indicated that at least two separate introductions to the native creeks and rivers occurred. [10] As early as 1979, there were established populations of spotted tilapia (Pelmatolapia mariae) and convict cichlid (Amatitlania nigrofasciata) in the cooler climate of Victoria; in a pond warmed by a power station. [11] In 1981 they were also noted to be present in the waters of Carnarvon, Western Australia. [12]

Ten years later, feral populations of tilapia were documented throughout Queensland and Western Australia as the geographical range of tilapia continued to increase. [10] By 1991, waters surrounding the Queensland cities of Brisbane, Townsville, and the Gascoyne River in Western Australia were filled with Mozambique tilapia (Oreochromis mossambicus).

Immature Mozambique tilapia, Oreochromis mossambicus, caught in the Endeavour River, near Cooktown, Australia. Dec. 2007. Jensens Crossing fish survey Dec07 029.jpg
Immature Mozambique tilapia, Oreochromis mossambicus, caught in the Endeavour River, near Cooktown, Australia. Dec. 2007.
Noxious Pest

The ecological impacts of tilapia on Australian rivers, creeks and ponds have been significant. Dramatic decreases in native fish populations were, in part, due to the aggressive predation and competition for food by tilapia. [13] Impacts on riparian habitat were further fostered by tilapia digging (increasing river turbidity) and the establishment of nests. Native fishes, invertebrates, and other organisms have experienced a reduction in stream access and cover as a result of tilapia activities.

Tilapia are listed as a noxious pest in Queensland, Australia, [14] and are spreading rapidly into previously untouched and relatively pristine river systems such as the Endeavour River near Cooktown and the Eureka Creek. [15] [16] In 2017, spotted tilapia were found extending their range northward into warmer waters, in a tributary of the Mitchell River, with the potential to affect important barramundi and prawn fisheries in the Gulf of Carpentaria. [17] There are concerns that Mozambique tilapia will invade the rivers of the Murray-Darling Basin. [18] [19]

As tilapia can thrive in fresh, brackish and salt water habitats, [20] it is thought that tilapia can quickly infest neighbouring rivers. Tilapia, like eels or bull sharks, can enter new river systems via the sea.

Galapagos Islands, Ecuador

Tilapia have been introduced into Laguna Junco, a volcanic caldera in the Galapagos Islands. [21] Within the caldera, there is an absence of native freshwater fish. Several invertebrates endemic to the Galapagos, specifically within the Laguna Junco caldera, spend all or part of their lifecycle in freshwater. The Galapagos dragonfly, is a prime example of an endemic Galapagos invertebrate. Tilapia therefore pose a significant threat to the Galapagos dragon fly and other endemic animals. As of 2007, The Ecuadorian Park Service is developing a plan to rid the Galapagos Islands of tilapia. International assistance in the form of US Aid for International Development and the US Geological Survey will supplement The Ecuadorian Park Service.

It is important to note that tilapia have also been introduced to South America. In addition, many parts of Latin America house tilapia in aquaculture pens. Many of these fish have escaped and now populate riparian habitats throughout much of Latin America.


The Mozambique tilapia (Oreochromis mossambicus) is known as "Mujair" in Indonesia, having received its name from Moedjair who introduced this fish in the Serang River on the southern coast of Java in 1939. [22]


During World War II Oreochromis mossambicus was introduced to Singapore by the Japanese, who had brought the fish from the island of Java. Hence the fishes' local names, Japanese fish and Java fish. Tilapia were once abundant in the fresh and brackish waters off the north coast of Singapore. Since the late-1980s however, populations of feral tilapia have declined. Recently introduced cichlid hybrids (red tilapia O. mossambicus x O. niloticus, possibly also O. honorum and O. aureus) have crossbred with populations of Oreochromis mossambicus, possibly contributing to the decline. Inter-species hybrids tend to produce fewer fry per brood than spawning by fishes of the same species. In addition, hybrids classified as O. niloticus may have inherited a diminished tolerance for saline conditions, thus restricting the environments in which tilapia can be found.

United States

Salton Sea

The Salton Sea is California’s largest body of inland water. During the early twentieth century, the Colorado River overflowed into a series of irrigation canals. From 1905-1907, river water collected into the Salton Sea basin, later forming the Salton Sea. [23]

Shoreline, Salton Sea. Shoreline along the Salton Sea..jpg
Shoreline, Salton Sea.

For the past century, river runoff and evaporation have greatly increased the salinity of the Salton Sea. Presently, the introduced tilapia (hybrid Mozambique x Wami) are the main fish that can tolerate the high salinity levels. [23] [24] Other tilapia, including redbelly, are present in nearby waters, but no longer able to survive the high salinity in the Salton Sea itself. [24] The tilapia are a part of the reason for the decline in the rare native desert pupfish. [25]

History of fish and fish introductions to the Salton Sea

Historically, the Colorado River has often flooded the Salton Sea basin. During the Pleistocene era, an ancient body of water named Lake Cahuilla was the last in a series of ancient lakes within the region. Today, ancient remnants of fish species that once lived in Lake Cahuilla can still be unearthed in the Salton Sea basin. Fossil evidence of fish species include machete (Elops affinis), bonytail (Gila robusta), and stripped mullet (Mugil Cephalus). [26]

Several decades after the formation of the Salton Sea, The California Department of Fish and Wildlife introduced several species of oceanic fishes into the Salton Sea. These species originated from the Gulf of California and included some of the following, orangemouth corvina (Cynoscion xanthulus), bairdiella (Bairdiella icistia), sargo (Anisotremus davidsoni), and threadfin shad (Dorosoma petenense). [27] The tilapia (Oreochromis mossambicus) was most likely introduced to the Salton Sea sometime during the 1960s. [26] The exact time and location of tilapia introduction remains largely unknown, although speculation points to farmed tilapia escaping into the Salton Sea. [26]

Tilapia diet

Adult members of the tilapia Oreochromis mossambicus prey upon a variety of organisms within the Salton Sea. The polychaete worm Neanthes succinea is an important part of tilapia diet. [28] In addition to polychaete worms, adult tilapia regularly feed upon phytoplankton, copepods, smaller fishes and barnacles. [29] Limited to smaller prey items, juvenile tilapia are dependent upon phytoplankton and small Salton Sea invertebrates. Oreochromis mossambicus is an adaptable species of tilapia. During periods of food scarcity, Oreochromis mossambicus feeds on fish waste and other detritus. [30]

Avian fauna and Salton Sea tilapia

Oreochromis mossambicus plays an important role in the ecology of the Salton Sea. This tilapia, along with several other fish species, provides food for hundreds of birds. Many of these birds are migratory, and utilize the Salton Sea as an important destination for resting and feeding along the Pacific flyway. [31]

Tilapia bones, Salton Sea shoreline. Tilapia bones Salton Sea.jpg
Tilapia bones, Salton Sea shoreline.

Environmental stresses

High salinity concentrations, algal blooms, agricultural runoff, hypoxia, wind events and temperature variability all contribute to fish die-offs in the Salton Sea. The high concentrations of tilapia in the Salton Sea (relative to other fish species) signify that tilapia often constitute the largest percentage of dead fishes during periods of excessive environmental stress. During fish kills, tilapia often wash ashore en masse. [32]

See also

Related Research Articles

<span class="mw-page-title-main">Cichlid</span> Family of fishes

Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses (Labridae), in the order Perciformes, but molecular studies have contradicted this grouping. On the basis of fossil evidence, it first appeared in Tanzania during the Eocene epoch, about 46–45 million years ago. The closest living relative of cichlids is probably the convict blenny, and both families are classified in the 5th edition of Fishes of the World as the two families in the Cichliformes, part of the subseries Ovalentaria. This family is large, diverse, and widely dispersed. At least 1,650 species have been scientifically described, making it one of the largest vertebrate families. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000.

<span class="mw-page-title-main">Tilapia</span> Common name for many species of fish

Tilapia is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes, with the economically most important species placed in the Coptodonini and Oreochromini. Tilapia are mainly freshwater fish inhabiting shallow streams, ponds, rivers, and lakes, and less commonly found living in brackish water. Historically, they have been of major importance in artisanal fishing in Africa, and they are of increasing importance in aquaculture and aquaponics. Tilapia can become a problematic invasive species in new warm-water habitats such as Australia, whether deliberately or accidentally introduced, but generally not in temperate climates due to their inability to survive in cold water.

The Wami tilapia is a tilapiine cichlid that grows to over 20 cm in length and is considered a useful food fish in Tanzania and the island of Zanzibar, where it may have been introduced by man. It is tolerant of brackish water and grows well in saline pools, making it particularly suitable for aquaculture by communities living close to the sea. Like other tilapia it is an omnivore and will feed on algae, plants, small invertebrates, and detritus. The common name refers to the Wami River.

<span class="mw-page-title-main">Nile tilapia</span> Species of fish

The Nile tilapia is a species of tilapia, a cichlid fish native to parts of Africa and the Levant, particularly Israel and Lebanon. Numerous introduced populations exist outside its natural range. It is also commercially known as mango fish, nilotica, or boulti.

<i>Oreochromis</i> Genus of fishes

Oreochromis is a large genus of oreochromine cichlids, fishes endemic to Africa and the Middle East. A few species from this genus have been introduced far outside their native range and are important in aquaculture. Many others have very small ranges; some are seriously threatened, and O. ismailiaensis and O. lidole possibly are extinct. Although Oreochromis primarily are freshwater fish of rivers, lakes and similar habitats, several species can also thrive in brackish waters and some even survive in hypersaline conditions with a salinity that far surpasses that of seawater. In addition to overfishing and habitat loss, some of the more localized species are threatened by the introduction of other, more widespread Oreochromis species into their ranges. This is because they—in addition to competing for the local resources—often are able to hybridize.

<span class="mw-page-title-main">Spotted tilapia</span> Species of fish

The spotted tilapia, also known as the spotted mangrove cichlid or black mangrove cichlid, is a species of fish of the cichlid family. It is native to fresh and brackish water in West and Central Africa, but has been introduced to other regions where it is considered invasive.

<span class="mw-page-title-main">Aquaculture of tilapia</span> Third most important fish in aquaculture after carp and salmon

Tilapia has become the third most important fish in aquaculture after carp and salmon; worldwide production exceeded 1.5 million metric tons in 2002 and increases annually. Because of their high protein content, large size, rapid growth, and palatability, a number of coptodonine and oreochromine cichlids—specifically, various species of Coptodon, Oreochromis, and Sarotherodon—are the focus of major aquaculture efforts.

<span class="mw-page-title-main">Mozambique tilapia</span> Species of fish

The Mozambique tilapia is an oreochromine cichlid fish native to southeastern Africa. Dull colored, the Mozambique tilapia often lives up to a decade in its native habitats. It is a popular fish for aquaculture. Due to human introductions, it is now found in many tropical and subtropical habitats around the globe, where it can become an invasive species because of its robust nature. These same features make it a good species for aquaculture because it readily adapts to new situations. It is known as black tilapia in Colombia and as blue kurper in South Africa.

<span class="mw-page-title-main">Lake Buhi</span>

Lake Buhi is a lake found in Buhi, Camarines Sur in the Philippines. It has an area of 18 square kilometres and has an average depth of 8 metres (26 ft). The lake lies in the valley formed by two ancient volcanoes, Mount Iriga and Mount Malinao. It was created in 1641, when an earthquake caused a side of Mount Asog to collapse. The resulting landslide created a natural dam that blocked the flow of nearby streams. Another theory suggests that it was created by the eruption of Mt. Asog, which is now dormant.

<i>Monodactylus argenteus</i> Species of fish

Monodactylus argenteus is a species of fish in the family Monodactylidae, the moonyfishes. Its common names include silver moonyfish, or silver moony, butter bream, and diamondfish. It is native to the western Pacific and Indian Oceans, including the Persian Gulf, Red Sea, and associated estuaries, such as the Mekong Delta.

<i>Alcolapia</i> Genus of fishes

Alcolapia is a genus of small fishes in the family Cichlidae. Their native range is restricted to margins of Lake Natron and Lake Magadi, as well as similar conditions in nearby hot springs, in Kenya and Tanzania. They live in waters that are warm, hypersaline and alkaline. Species from this genus have also been introduced to Lake Nakuru and Lake Elmenteita. They are the only fish in their range.

<i>Oreochromis leucostictus</i> Species of fish

Oreochromis leucostictus is a species of cichlid native to Albertine Rift Valley lakes and associated rivers in DR Congo and Uganda. It has now been introduced widely elsewhere East Africa, and is believed to have negative ecological impact, particularly on native tilapias. This species is reported to reach a standard length of up to 36.3 cm (14.3 in), but is usually much smaller. It is exploited by small-scale fishery and aquaculture operations.

<i>Oreochromis variabilis</i> Species of fish

Oreochromis variabilis, the Victoria tilapia, is a species of African cichlid native to Lake Victoria and its tributaries, Lake Kyoga, Lake Kwania, and Lake Bisina (Salisbury), as well as being found in the Victoria Nile above Murchison Falls. This species can reach a standard length of 30 cm (12 in). This species is important to local commercial fisheries and is potentially important in aquaculture. It is also found in the aquarium trade.

<i>Oreochromis aureus</i> Species of fish

The blue tilapia is a species of tilapia, a fish in the family Cichlidae. Native to Northern and Western Africa, and the Middle East, through introductions it is now also established elsewhere, including parts of the United States, where it has been declared an invasive species and has caused significant environmental damage. It is known as the blue kurper in South Africa.

<span class="mw-page-title-main">Fishing industry in Laos</span>

The fishing industry in the land-locked country of Laos is a major source of sustenance and food security to its people dwelling near rivers, reservoirs and ponds. Apart from wild capture fisheries, which is a major component of fish production, aquaculture and stocking are significant developments in the country. Historically, fishing activity was recorded in writings on the gate and walls of the Wat Xieng Thong in Luang Prabang dated 1560. For many Laotians, freshwater fish are the principal source of protein. The percentage of people involved in regular fishing activity is very small, only near major rivers or reservoirs, as for most of the fishers it is a part-time activity.

<span class="mw-page-title-main">Fishing on Lake Victoria</span>

Lake Victoria supports Africa's largest inland fishery, with the majority of the catch being the invasive Nile perch, introduced in the Lake in the 1950s.

<span class="mw-page-title-main">Redbelly tilapia</span> Species of fish

The redbelly tilapia, also known as the Zille's redbreast tilapia or St. Peter's fish, is a species of fish in the cichlid family. This fish is found widely in fresh and brackish waters in the northern half of Africa and the Middle East. Elsewhere in Africa, Asia, Australia and North America, it has been introduced as a food fish or as a control of aquatic vegetation. Where introduced, it sometimes becomes invasive, threatening the local ecology and species. The redbelly tilapia is an important food fish and sometimes aquacultured.

<span class="mw-page-title-main">Oreochromini</span> Tribe of fishes

Oreochromini is a tribe of cichlids in the Pseudocrenilabrinae subfamily that is native to Africa and Western Asia, but a few species have been widely introduced to other parts of the world. It was formerly considered to be part of the tribe Tilapiini but more recent workers have found that the Tilapiini sensu lato is paraphyletic. Despite this change, species in Oreochromini are still referred to by the common name tilapia and some of the most important tilapia in aquaculture —certain species of Oreochromis and Sarotherodon— are part of this tribe. In contrast, several species have small ranges and are seriously threatened; a few are already extinct or possibly extinct.

Oreochromis mortimeri, the Kariba tilapia or kurper bream, is a species of cichlid, formerly classified as a Tilapiine cichlid but now placed in the genus Oreochromis, the type genus of the tribe Oreochromini of the subfamily Pseudocrenilabrinae. It is found in the rivers of south central Africa especially the middle Zambezi where it is endangered by the spread of invasive congener Oreochromis niloticus.


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