Oreochromis aureus
Encyclopedia
Oreochromis aureus is a species of fish in the Cichlidae family. 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.
fish with a high tolerance for brackish water
. Adults are usually 5 to 8 in (127 to 203.2 mm) in length and weigh 5 to 6 lb (2.3 to 2.7 kg); the largest recorded specimen was more than 21 inches (533.4 mm) long and weighed more than 10 pounds (4.5 kg). Blue Tilapia are mouthbrooders, and broods range from 160 to 1600 eggs per female. O. aureus is primarily herbivorous, but will occasionally consume zooplankton
; the young include small invertebrates in their diet.
, Niger
, Benue
and lower Nile rivers in Africa to the Jordan River in the Middle East. Through introductions
the fish can be found in the United States in Texas
, Alabama
, Florida
, and Nevada
. It has also been established in Central
and South America
, and Southeast Asia
. The original stocks of O. aureus in the United States were from Israel
.
, in Gainesville, Florida
. It is a major management problem for the National Park Service
due to its predominance in Taylor Slough
in Everglades National Park
, where it has changed the fish community structure. The species is also expanding its range in Texas, is responsible for inhibition of the population of Largemouth Bass
in Lake Trinidad, and is implicated in the unionid mussel declines in two bodies of water in Texas. It is also blamed for a severe decline in native fish populations in Warm Springs Natural Area.
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
, through introductions
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
it is now also established elsewhere, including parts of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, where it has been declared an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
and has caused significant environmental damage.
Description
The Blue Tilapia is a freshwaterFreshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
fish with a high tolerance for brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
. Adults are usually 5 to 8 in (127 to 203.2 mm) in length and weigh 5 to 6 lb (2.3 to 2.7 kg); the largest recorded specimen was more than 21 inches (533.4 mm) long and weighed more than 10 pounds (4.5 kg). Blue Tilapia are mouthbrooders, and broods range from 160 to 1600 eggs per female. O. aureus is primarily herbivorous, but will occasionally consume zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
; the young include small invertebrates in their diet.
Range
Oreochromis aureus is native to Northern and Western Africa, and the Middle East, from the SenegalSénégal River
The Sénégal River is a long river in West Africa that forms the border between Senegal and Mauritania.The Sénégal's headwaters are the Semefé and Bafing rivers which both originate in Guinea; they form a small part of the Guinean-Malian border before coming together at Bafoulabé in Mali...
, Niger
Niger River
The Niger River is the principal river of western Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in southeastern Guinea...
, Benue
Benue River
The Benue River is the major tributary of the Niger River. The river is approximately 1,400 km long and is almost entirely navigable during the summer months...
and lower Nile rivers in Africa to the Jordan River in the Middle East. Through introductions
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
the fish can be found in the United States in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
. It has also been established in Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
. The original stocks of O. aureus in the United States were from Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
.
Invasive species
Since its introduction into Florida in 1961 the fish has increased its range and frequency of occurrence. It is now the most widespread foreign species in Florida, with established populations as far north as Lake AliceLake Alice (Gainesville, Florida)
Lake Alice is a small lake on the University of Florida campus in Gainesville, Florida, USA.The lake is a wildlife area and is one of the few areas in incorporated Gainesville where one may view live alligators. The university's bat house is near the lake. The Baughman Center sits on the southwest...
, in Gainesville, Florida
Gainesville, Florida
Gainesville is the largest city in, and the county seat of, Alachua County, Florida, United States as well as the principal city of the Gainesville, Florida Metropolitan Statistical Area . The preliminary 2010 Census population count for Gainesville is 124,354. Gainesville is home to the sixth...
. It is a major management problem for the National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...
due to its predominance in Taylor Slough
Taylor Slough
Taylor Slough, located in the southeastern corner of the Florida Everglades, along with the much larger Shark River Slough farther to the west, are the principal natural drainages for the freshwater Everglades....
in Everglades National Park
Everglades National Park
Everglades National Park is a national park in the U.S. state of Florida that protects the southern 25 percent of the original Everglades. It is the largest subtropical wilderness in the United States, and is visited on average by one million people each year. It is the third-largest...
, where it has changed the fish community structure. The species is also expanding its range in Texas, is responsible for inhibition of the population of Largemouth Bass
Largemouth bass
The largemouth bass is a species of black bass in the sunfish family native to North America . It is also known as widemouth bass, bigmouth, black bass, bucketmouth, Potter's fish, Florida bass, Florida largemouth, green bass, green trout, linesides, Oswego bass, southern largemouth...
in Lake Trinidad, and is implicated in the unionid mussel declines in two bodies of water in Texas. It is also blamed for a severe decline in native fish populations in Warm Springs Natural Area.