Amistad gambusia
Encyclopedia
The Amistad gambusia was a small fish
known only to occur in Goodenough Spring, Val Verde County, Texas
, a tributary
of the Rio Grande
. This species was eliminated in the wild when construction of the Amistad Reservoir
in 1968 submerged Goodenough Spring under approximately 70 feet of water. The United States Fish and Wildlife Service
(FWS) listed the Amistad gambusia as endangered
in 1980, at which time it occurred only in captivity. The two captive populations, held by the University of Texas System
and the Dexter National Fish Hatchery in New Mexico
, died or were eliminated through hybridization and predation
. The FWS ruled the Amistad gambusia extinct in 1987, and removed it from the endangered species list.
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
known only to occur in Goodenough Spring, Val Verde County, 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...
, a tributary
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
of the Rio Grande
Rio Grande
The Rio Grande is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico – United States border. Its length varies as its course changes...
. This species was eliminated in the wild when construction of the Amistad Reservoir
Amistad Reservoir
Amistad Reservoir is a reservoir on the Rio Grande at its confluence with the Devils River 12 miles northwest of Del Rio, Texas, USA. The lake is bounded by Val Verde County on the Texas side of the international border, and the state of Coahuila on the Mexican side of the border...
in 1968 submerged Goodenough Spring under approximately 70 feet of water. The United States Fish and Wildlife Service
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
(FWS) listed the Amistad gambusia as endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
in 1980, at which time it occurred only in captivity. The two captive populations, held by the University of Texas System
University of Texas System
The University of Texas System encompasses 15 educational institutions in Texas, of which nine are academic universities and six are health institutions. The system is headquartered in Austin and has a total enrollment of over 190,000 students...
and the Dexter National Fish Hatchery in New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, died or were eliminated through hybridization and predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
. The FWS ruled the Amistad gambusia extinct in 1987, and removed it from the endangered species list.