The Kern River Rainbow (Oncorhynchus mykiss gilberti) is a subspecies of the Kern River Golden Trout. The Golden Trout are thought to be derived from the rainbows that were isolated about 70,000 years ago by both glacial and tectonic activity. It is suspected that 10,000 years ago, Redband Rainbows or Coastal Rainbows migrated from the Northern Sacramento Basin to the Kern River System by way of the San Joaquin drainage into Lake Tulare. This was a period of very wet climate conditions. The Redbands hydridized with the Kern River Goldens to produce an unique subspecies, the Kern River Rainbow. This fish had a distinctive "rainbow trout" appearance with the coloration and spotting pattern but retained the "Golden Trout" aspect with the distinctive, yet fading, Parr Marks and Red Stripe along it's lateral line.
Much of the integrity of this subspecies has been lost within the Kern River system due to stocking of hatchery-bred rainbow trout throughout the 1900's. Only since 1990, has non-native trout stocking been discontinued. Recent genetic testing indicates that the purest strains of Kern River Rainbows occurs in the Kern River from the confluence of Durrwood Creek (5 miles below the confluence of the Little Kern River) to the headwaters in Sequoia National Park. These Kern River Rainbows are genetically distinct from the other rainbows found further downstream. Genetic sampling found that the rianbows below Johnsondale Bridge have hybridized with stocked rainbows to such an extent that they could no longer be considered "Kern River Rainbows".
Pure strains of Kern River Rainbows are being reared at the Kern River Hatchery in Kernville. A program is in place to re-introduce these pure strains into it's historical range and keep non-native trout out of the upper river.
The Kern River Rainbow can be distinguished by irregularly shaped spots that are both above and below the
lateral line. The spots decrease as the extend towards the belly. Coloration is similar to the Coastal Rainbow
trout, however the Kern River Rainbow has a distinct red stripe with faint parr marks along the lateral line.
The dorsal, pelvic, and anal fins have a white tip. You will also find orange tints along the belly.