Not evaluated (IUCN 3.1)
|Subspecies:||O. m. aguabonita
O. m. gilberti
O. m. whitei
|Oncorhynchus mykiss aguabonita
The golden trout or California golden trout (O. mykiss aguabonita) is a sub-species of the rainbow trout native to California. It closely resembles the juvenile rainbow trout. The golden trout is native to Golden Trout Creek (tributary to the Kern River, Volcano Creek (tributary to Golden Trout Creek), and the South Fork Kern River. Another variant, Little Kern golden trout (O. m. whitei), was historically found only in the Little Kern River but is now found in other nearby creeks, as well. The golden trout was designated the state fish of California in 1947.
Originally placed in the species Oncorhynchus aguabonita taxonomists now classify the golden trout as a subspecies of the rainbow trout, Oncorhynchus mykiss, placing it with several other subspecies commonly known as redband trout, Oncorhynchus mykiss ssp.
The golden trout has golden flanks with red, horizontal bands along the lateral lines on each side and about 10 dark, vertical, oval marks (called "parr marks") on each side. Dorsal, lateral and anal fins have white leading edges. In their native habitat, adults range from 6–12 in (15–30 cm) long. Fish over 10 in (25 cm) are considered large. Golden trout that have been transplanted to lakes have been recorded up to 11 lb (5 kg) in weight. The world record golden trout was caught by Charles S. Reed, on August 5, 1948, from Cook Lake in the Wind River Range. That fish was 28 in (70 cm) long and weighed 11.25 lb (5.1 kg).
On June 22, 2012, angler Rick Mickelsen landed a potential All-Tackle Length record golden trout while fishing Golden Lake, Wyoming, USA. Mickelsen, a native of Wyoming, was casting a nymph fly and needed 15 minutes to land the 21 inch (54 cm) trout. As required for every All-Tackle Length record, Mickelsen’s fish was released alive after proper measurements and photos were taken.
The golden trout is commonly found at elevations from 6,890 feet (2,100 m) to 10,000 feet (3,000 m) above sea level, and is native only to California's southern Sierra Nevada mountains. Preferred water temperature is 58–62 °F (14–17 °C) but they can tolerate temperatures in degraded streams on the Kern Plateau as high as 70 °F (21 °C) so long as those waters cool during the night. The only other species of fish indigenous to the native range of California golden trout is the Sacramento sucker (Catostomus occidentalis occidentalis).
In 1892 the California golden trout was originally described by David Starr Jordan, the first President of Stanford University, as Salmo mykiss agua-bonita. The fish was named after the Agua Bonita Waterfall where the first specimens were collected, at the mouth of Volcano Creek, at the creek's confluence with the Kern River. A century later they were listed as Oncorhynchus mykiss aguabonita in Behnke's Native trout of western North America.
In 1904 Stewart Edward White communicated to his friend President Theodore Roosevelt, that overfishing to lead to extinction of the golden trout. In White's novel The Mountains, he wrote about the threatened golden trout on California’s Kern Plateau. Roosevelt shared White’s concern and, through U.S. Fish Commissioner George M. Bowers, dispatched biologist Barton Warren Evermann of the U.S. Bureau of Fisheriest to study the situation. In 1906 Evermann published The Golden Trout of the Southern High Sierras. Based on morphology, Evermann accurately described four forms of this native fish: Salmo roosevelti from Golden Trout (Volcano) Creek, Salmo aguabonita from nearby South Fork of the Kern River, Salmo whitei (named in recognition of Stewart Edward White) from the Little Kern River, and Salmo gilberti, the Kern River rainbow.
Genetic studies have since clarified three groups of trout native to the Kern River: California golden trout (O. mykiss aguabonita) native to the South Fork Kern River and Golden Trout Creek (tributary to the Kern River mainstem but the historic course of the South Fork Kern River and now only separated from it by a lava flow and ridge of sediment), Little Kern River golden trout (O. mykiss whitei), and Kern River rainbow trout (O. mykiss gilberti).
Years of overexploitation, mismanagement and competition with exotic species have brought golden trout to the brink of being designated as "threatened". Introduced brook trout (Salvelinus fontinalis) outcompete them for food, introduced brown trout (Salmo trutta) prey on them and introduced rainbow trout (O. mykiss) hybridize with them, damaging the native gene pool through introgression. Populations have been in steady decline for decades.
In September 2004, the California Department of Fish and Game signed an agreement with federal agencies to work on restoring back-country habitat, heavily damaged by overgrazing from cattle and sheep, as part of a comprehensive conservation strategy.
Translocations outside of endemic range 
For sportfishing, the California golden trout underwent many twentieth century translocations into multiple Western states and established populations survive in California, Idaho, Montana, Utah, Washington and Wyoming. Populations in the high-elevation lakes in the Ruby Mountains, Nevada, have died out.
Chuck Yeager and the New Mexico population 
When Colonel Chuck Yeager introduced one of his commanding officers, General Irving "Twig" Branch, to the Sierra Nevada populations of golden trout, Branch ordered Yeager and Bud Anderson to introduce the species to the mountain streams of New Mexico. However, the New Mexico populations have also died out.
In his second autobiography, Press On, Yeager details his annual fishing trips to catch golden trout which he extols as one of the best game fish and best eating fish to be found.
- "Oncorhynchus aguabonita". Integrated Taxonomic Information System. Retrieved 24 January 2006.
- Froese, Rainer and Pauly, Daniel, eds. (2012). "Oncorhynchus aguabonita" in FishBase. February 2012 version.
- Wyoming Game and Fish Department <http://www.webcitation.org/5hghgbg5I>
- IGFA World Records
- Record Golden Trout, Peacock Bass, Butterfly Kingfish and More!-IGFA August 2012 Hot Catches
- Journal of Applied Ichthyology, Volume 16 Issue 3 Page 117-120, June 2000<http://www.blackwell-synergy.com/doi/abs/10.1046/j.1439-0426.2000.00147.x>
- Stanley J. Stephens, Christy McGuire, Lisa Sims (2004-09-17). Conservation Assessment and Strategy for the California Golden Trout (Oncorhynchus mykiss aguabonita) Tulare County, California (Report). California Department of Fish and Game. http://www.tucalifornia.org/cgtic/GTCAssessmnt&Strategy9-04.pdf. Retrieved 2012-10-14.
- Edwin Philip Pister. "California Golden Trout: Perspectives on Restoration and Management". Fisheries 35 (11): 550–553. Retrieved 2012-10-14.
- David Starr Jordan (1892-07-24). "A description of the golden trout of Kern River, California, Salmo mykiss agua-bonita.". Proceedings United States National Museum xv: 481–483. Retrieved 2012-10-16.
- Robert J. Behnke (1992). Native trout of western North America. Monograph No. 6. American Fisheries Society. p. 275. ISBN 9780913235799.
- Barton Warren Evermann, Oliver Peebles Jenkins, Chancey Juday (1906). The golden trout of the southern high Sierras. Government Printing Office. p. 51. Retrieved 2012-10-15.
- Molly R. Stephens (2007). Systematics, genetics and conservation of golden trout. Ph.D. dissertation. (Thesis). University of California Davis. http://genome-lab.ucdavis.edu/people/Stephens/Dissertation_Stephens_FINAL_hiqual.pdf. Retrieved 2012-10-14.
- Pam Fuller and Matt Neilson (2012-03-29). "Oncorhynchus mykiss aguabonita (Jordan, 1892)". USGS Nonindigenous aquatic species (NAS) database. Retrieved 2012-10-14.
- Yeager, Chuck and Janos, Leo. Yeager: An Autobiography. Pages 348-351 (paperback). New York: Bantam Books, 1986. ISBN 0-553-25674-2.