Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Once widely distributed in the Kern River system, California; now occurs in the Kern River from Durrwood Creek upstream to Junction Meadow; populations established through transplantation occur in Rattlesnake Creek and Osa Creek and possibly upper Peppermint Creek and others (Moyle 2002).
Habitat Type: Freshwater
Comments: Clear, cold mountain streams of moderate to large size and high water quality.
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 5
Comments: Very few if any genetically pure populations are extant.
Comments: Uncommon in native range. No population estimates exist (1990).
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: T1 - Critically Imperiled
Reasons: Small range in southern California; threatened by hybridization/introgression with non-native rainbow trout and by poor watershed management.
Global Short Term Trend: Decline of 10-30%
Comments: Populations have not stabilized.
Global Long Term Trend: Decline of 70 to >90%
Degree of Threat: Very high - high
Comments: Primary threats include continued introgression with introduced rainbow trouts (genetically distinctive fishes that can be assigned to this taxon no longer exist in most areas), habitat losses from poor watershed management (grazing, logging, roading building), and unpredictable events such as floods, drought, and fire (Moyle et al. 1989, Moyle 2002). Negatively impacted as a result of the Flat Fire of 1976; subsequent landslides filled in pools and silted spawning areas (Moyle et al. 1989). Introduced beavers have significantly altered the river in Sequoia National Park, reducing habitat availability for trout (see Moyle 2002). Populations can withstand rafting, swimming, and catch-and-release fishing.
Biological Research Needs: Determine life history requirements.
Global Protection: None. No occurrences appropriately protected and managed
Comments: Much of the remaining habitat is in Sequoia National Forest (about 29 km) and Sequoia National Park (about 40 km) (Moyle 2002).
Needs: Protect sites that still contain this species.
Kern River rainbow trout
The Kern River rainbow trout (Oncorhynchus mykiss gilberti) is a localized subspecies of the rainbow trout (Oncorhynchus mykiss), a variety of fish in the family Salmonidae. It is found in a short section of the main stem of the Kern River and several tributaries in the southern Sierra Nevada mountains in California. The Kern River rainbow trout is a "Species of Special Concern" in the state of California due to habitat loss and hybridization with other native and non-native trout in their range.
The Kern River rainbow trout is one of three subspecies of O. mykiss that are all endemic to the Kern River basin, sharing the headwaters of the river with the Little Kern golden trout and Golden trout. Some of the existing range of the Kern River rainbow trout lies within the California Golden Trout Wilderness.
Kern river rainbow trout are endemic to the Kern River and tributaries in Tulare County, California. Its current range is drastically reduced from its historic range. Remnant populations live in the Kern river above Durrwood creek, in upper Ninemile, Rattlesnake and Osa creeks, and possibly in upper peppermint Creek. Kern river rainbows have been successfully introduced into the Kaweah-Kern river and Chagoopa creek. Its historic range in the main stem of the Kern River it probably extended downstream below where Isabella Dam is today and upstream in the South Fork of the Kern River as far as Onyx creek., The subspecies has been extirpated in the Kern river from the Johnsondale bridge downstream. The Kern River trout hybridize with nonnative, introduced stocks of rainbow trout, and Behnke (2002) doubts that pure Kern River rainbow trout still exist in their historic range. Recent genetic analyses however suggest that some un-hybridized populations still exist.
- "Oncorhynchus mykiss gilberti". Integrated Taxonomic Information System. Retrieved 18 November 2013.
- Behnke, Robert J.; Tomelleri, Joseph R. (illustrator) (2002). Trout and Salmon of North America. The Free Press. pp. 104–114. ISBN 0743222202.
- "Fish Species of Special Concern". California Department of Fish and Wildlife. Retrieved 2013-11-18.
- "ECONOMIC VALUE OF GOLDEN TROUT FISHING IN THE GOLDEN TROUT WILDERNESS, CALIFORNIA". caltrout
.org. Retrieved 2013-11-17.
- "Salmon, Steelhead and Trout in California-Status of an Emblematic Fauna". UC Davis Center for Watershed Sciences. Retrieved 2013-11-18.
- "California's Golden Treasure, Our State Fish". caltrout
.org. Retrieved 2013-11-17.
- "Kern River Rainbow Trout". caltrout
.org. Retrieved 2013-11-16.
- "Kern River Rainbow Trout (native)". California Department of Fish and Wildlife. Retrieved 2013-11-17.
Names and Taxonomy
Comments: This subspecies formerly was listed as a population of golden trout (taxon aguabonita) (Schreck and Behnke 1971), then was shown to be effectively isolated genetically and physically (Gold and Gall 1975). It is sufficiently distinct genetically (Berg 1987) and meristically (Gold and Gall 1975) to warrant subspecies status. Subspecies gilberti is genetically intermediate between coastal rainbow trout (subspecies gairdneri) and the Little Kern River golden trout (subspecies whitei) (closer to the former) (Berg 1987), and it may have originated through hybridization and introgression between subspecies gairdneri and whitei, followed by isolation (Berg 1987). Behnke (1992) grouped the Kern and Little Kern golden trout as one subspecies (gilberti) of O. mykiss. He stated that they could be recognized as separate subspecies (gilberti and whitei, respectively) provided they are kept together in the same species (O. mykiss). Behnke indicated that whitei may be indistinguishable from gilberti. Behnke (2002) treated these forms as three subspecies: Golden Trout Creek golden trout or California golden trout (O. mykiss aguabonita), Kern River rainbow trout (O. mykiss gilberti), and Little Kern River golden trout (O. mykiss whitei).
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