Mexican golden trout
Encyclopedia
The Mexican golden trout (Oncorhynchus chrysogaster) is a species of fish
in the Salmonidae
family. It is endemic to Mexico
.
, males can easily be identified from females due to their much longer jaws or kype. Mexican golden trout are brightly colored with blue parr marks on both males and females along the side of the body. Purple scaling is visible along the lateral line
. Both sexes also have bright golden-yellow belly coloration. The top of the fish and the tailfin are covered in small black spots with much larger spotting on the dorsal fin
. The pectoral fins, pelvic fin and anal fin are light orange in color with white tips. Due to their harsh and small stream habitat the Mexican golden trout remains small even when fully grown. Adults rarely reach over a foot long with the maximum size probably being 10 inches (25cm).
, Rio Sinaloa, and Rio Culiacan drainages in the Sierra Madre Occidental
.
created by small cienegas
(spring-fed marshes) above 5,000 feet. The surronding landscape is dominated by deep canyons, scrub forest, evergreens and hardwoods.
.
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...
in the Salmonidae
Salmonidae
Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...
family. It is endemic to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Description
The Mexican Golden Trout is sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, males can easily be identified from females due to their much longer jaws or kype. Mexican golden trout are brightly colored with blue parr marks on both males and females along the side of the body. Purple scaling is visible along the lateral line
Lateral line
The lateral line is a sense organ in aquatic organisms , used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail...
. Both sexes also have bright golden-yellow belly coloration. The top of the fish and the tailfin are covered in small black spots with much larger spotting on the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
. The pectoral fins, pelvic fin and anal fin are light orange in color with white tips. Due to their harsh and small stream habitat the Mexican golden trout remains small even when fully grown. Adults rarely reach over a foot long with the maximum size probably being 10 inches (25cm).
Distribution
Mexican Golden trout have an extremely limited range, being found only in the pristine high-elevation headwaters of the Rio FuerteFuerte River
The Fuerte River is a river in the northwestern Mexican state of Sinaloa. It begins at the junction of the Verde and Urique rivers, on the Sierra Madre Occidental mountain range. It flows generally southwest for a distance of 290 km, emptying into the Gulf of California at Lechuguilla Island,...
, Rio Sinaloa, and Rio Culiacan drainages in the Sierra Madre Occidental
Sierra Madre Occidental
The Sierra Madre Occidental is a mountain range in western Mexico.-Setting:The range runs north to south, from just south of the Sonora–Arizona border southeast through eastern Sonora, western Chihuahua, Sinaloa, Durango, Zacatecas, Nayarit, Jalisco, Aguascalientes to Guanajuato, where it joins...
.
Habitat
Mexican golden trout are limited to small streams known as arroyosArroyo (creek)
An arroyo , a Spanish word translated as brook, and also called a wash is usually a dry creek or stream bed—gulch that temporarily or seasonally fills and flows after sufficient rain. Wadi is a similar term in Africa. In Spain, a rambla has a similar meaning to arroyo.-Types and processes:Arroyos...
created by small cienegas
Cienega
A cienega or cienaga is a Spanish Colonial term for a spring, that is in use in English in the southwestern United States. A cienega usually is a wet, marshy area at the foot of a mountain, in a canyon, or on the edge of a grassland where groundwater bubbles to the surface...
(spring-fed marshes) above 5,000 feet. The surronding landscape is dominated by deep canyons, scrub forest, evergreens and hardwoods.
Status and threats
Due to their small range and highly sensitive, isolated habitat Mexican golden trout are considered vulnerable. The biggest threats being human development and the possiblity of competition/interbreeding with hatchery Rainbow troutRainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....
.
Sources
- Contreras-Balderas, S. & Almada-Villela, P. 1996. Oncorhynchus chrysogaster. 2006 IUCN Red List of Threatened Species. Downloaded on 4 August 2007.
- "Mexican golden trout." Fish Art by Joe Tomelleri. N.p., n.d. Web. 31 Aug. 2011.
- Behnke, Robert J., and Joseph R. Tomelleri. Trout and salmon of North America . Chanticleer Press ed., 1st ed. New York: Free Press, 2002. Print.