The golden trout, the state fish of California, is native to the Kern Plateau, which is typically characterized by high altitude and prolonged winters.
The golden trout (Oncorhynchus mykiss aguabonita) is a subspecies of the rainbow trout (Oncorhynchus mykiss), which is found in the Golden Trout Creek and South Fork Kern River.
Also known as the California golden trout, it was previously thought to be a separate species, mainly because of its bright, distinctive color pattern. Owing to its magnificent color, it is also called the 'Fish from Heaven'. It was declared the state fish of California by the state jurisdiction in 1947.
It is a small-sized fish with orange or red cheeks, olive-green back, and golden lower sides. Parr marks are present along the lateral line, while larger spots grace its fins and tail. Its pectoral, pelvic, and anal fins are bright orange in color. The size of an adult may range from 19 - 20 cm in streams and 35 - 43 cm in lakes.
Of the several species of trouts, the golden trout is the least productive species, which is evident from the various conditions that are required for spawning it.
The favorable conditions for spawning include warm temperature (at least 10 °C, preferably 16 - 18 °C), fine substrate, and minimum water velocity. When this fish finds suitable substrate, it lays eggs on or under it.
However, hatching of the eggs is disturbed by many factors, including flooding of habitat and/or drying of water.
Habit and Habitat
Adult golden trouts feed on insects like mayflies, stoneflies, ants, spiders, worms, and beetles, along with larvae of other insects. They also rely on planktons, plant detritus, small fish, and eggs of other trouts.
These fish prefer high-elevation watersheds, as those are basically very clear and cold. The species is native to the watersheds of Sierra Nevada Mountain range, where food is scarce due to high altitude and prolonged winter conditions.
Various conservation methods have been implemented at the state and federal level in order to preserve this rainbow trout subspecies. In 1978, for instance, 300,000 acres of land was converted into Golden Trout Wilderness. In 1991, it was enlisted in the U.S. Fish and Wildlife Service's Endangered Species List and Forest Services Sensitive Species List.
Despite these measures, there has been no increase in their population. The main reason being its hybridization with the rainbow trout. Studies have revealed that this trout species is very sensitive to breeding with other trout species, especially the rainbow trout.
The rate of hybridization is increased by poor land management plans, particularly in the Inyo National Forest. In order to minimize the chances of hybridization, a management strategy is implemented whereby the water of the South Fork Kern River is chemically treated to remove other non-native trout species.
Other reasons for the decline in golden trout population include the destruction and/or modification of their natural habitat and competition with the non-native species. Despite the state and federal regulatory activities, the population of this species has decreased to such an extent that it is on the verge of extinction.