Golden Trout Scientific Facts

Native to a small area in California, the golden trout, oncorhynchus mykiss aguabonita, is a subspecies of the rainbow trout. Also called the California Golden Trout it is native to the Kern Plateau in the southern Sierra Nevada Mountains in California. The plateau is 8,000 to 12,000 feet above sea level and contains coniferous forest tundra. The trout inhabits shallow streams and lakes with riparian communities where it finds its main food.

Characteristics

The golden trout is between five to seven inches long and has a yellow gold to olive green color on its belly and sides. It has two brilliant red stripes. One runs from the last lower fin to in front of the gill, and the other is on the lateral line beginning at the seventh lateral spot and also runs to the gill. They give perfect camouflage which protects them from both prey and predator. It has very small scales with a body depth of 3.5 inches. There are small black spots on the fins with a black border and white tips. They have more spots than most Rainbow or Brown trout. Golden trout have seven to ten large lateral spots.

Habitats

The habitat of the golden trout is in two main areas, the South Fork Kern River and the Golden Trout Creek. This area is in federal control and has been protected by federal and state efforts for the last 50 years including:

• In 1947 making it the State Fish of California
• In 1978 creating 300,000 acre Golden Trout Wilderness
• In 1991 adding it to the U.S. Fish and Wildlife Service’s Endangered Species List as category 2 species
• Added to the Forest Services Sensitive Species List

The Kern Plateau was formed by the Kern River, volcanic activity and glaciations for the past million and a half years. They left a landscape with high waterfalls that make fish migration difficult. The fish in these high elevation streams and lakes became secluded and evolved over 100,000 years into the golden trout.

Subspecies

The coniferous tundra has Ponderosa pine, Western Spruce and Lodgepole pine. There are many meadows also that contain wild flowers and other vegetation that support many insects including gnats, mayflies, stoneflies, mosquitoes, ants, spiders, beetles, dobsonflies, worms and larvae that make up most of the diet of the golden trout. Other sustenance is plankton, small fish, vegetable detritus and trout eggs. These vary with the temperature changes of the seasons. Because riparian production, stream production and trout growth all stop with the onset of winter, golden trout have the lowest productivity of any trout.

Other Information

In the spring, when the water begins to warm, the larva and phytoplankton begin to grow again and the trout start to find places for nests. They will spawn only when the water temperature reaches 10 degrees Celsius which is at the end of April or the beginning of May. Peak spawning is in June or July when the water reaches 16 to 18 degrees Celsius. Temperature is not the main variable for spawning.

The choice of nest, water velocity and substrate size are dependent variables for trout spawning, and they always choose the finest sand. When the trout find the right place to make a nest, they thrash their tails to make a depression and lay many eggs under and on top of the sand.

Golden trout have evolved to prefer slower moving water for spawning because the plateau is full of flat meadows. When the snow melt comes onto the plateau it causes flooding, so the lakes and streams swell they do not become rapids. If the winter is extra long, the spawning may begin only late in the summer. At that time it is quite warm and evaporation is too rapid to allow the eggs time to hatch.

The golden trout is susceptible to hybridization with rainbow trout that has been artificially stocked in its habitat. This has made the species almost disappear, however, efforts have been made to stop breeding with non-native trout.

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