August 21, 2010 – The Biogeography of the California Whiskered Trout

Species Name: Oncorhynchus punctatus vibrissa (after A. S. Fitch, 2007); common names: whiskered trout, truite barbue, trucha barbuda, Sticky Ricky

Description: The whiskered trout was recognized as a variant species of trout because of its unique barbels. The waters in which trout are found vary widely in temperature and tend to be relatively unclear with a low reflective rate. The whiskered trout in particular has adapted very well to this environment by the development of sensory organs. The fish developed two very distinctive barbels or whiskers on its jaw which typically reach a length of about one tenth of the body length. These barbels were adapted for both passive and defensive reasons. The barbels greatly extend the fish’s ability to detect food sources and enable the fish to “taste” food without having to ingest it. Having this advantage also makes it difficult for predators, particularly anglers, to catch it with conventional means. Whiskered trout attain an average length of twelve to thirty-six inches, although specimens of fifty inches have been recorded. Whiskered trout have fewer spots on their back and tail than your average rainbow or brown trout. Native trout of all species typically have seven to ten large black circles along their lateral. The rule is the more predominant the “spots,” the closer to native blood the individual trout is. Typically, the purest trout have the most lateral spots and the brightest colors. The whiskered trout’s singular lack of these indicators is a testament to its relatively recent hybridization.

Evolution: The Salmoniform order of boney fish evolved a special niche for spawning in freshwater and living out their adult lives in the oceans. Through allopatric speciation, California whiskered trout parallel six other sub-species of the ancient rainbow trout. The coastal rainbow invaded deep into the waters of California and south into Mexico 25,000 to 20,000 years ago during a population boom (Walters, 1997). Subsequently, barriers had also formed through geomorphic disturbances around the same period. The last glaciations of the Pleistocene killed off most of the habitat throughout the Sierra Nevada. Only certain pockets by sheer chance of location were not severely disrupted by these events. Through isolation, the original rainbow trout had been disrupted within adaptations range and were able to divergently evolve into a subspecies with a separate genotype all together (Gall, Bannon, 1982). The distinctive barbels and large size of the whiskered trout are noticeable evolutionary strategies for survival. Though highly susceptible to hybridization and degeneration to the rainbow trout, the whiskered trout traits are a product of heritable variation (Carpenter, 2005).

Errata: Oncorhynchus punctatus vibrissa (“Whiskered Trout”) are widely distributed, but unusual varieties of the subspecies are notable, particularly in bodies of still water in Southern California. Of particular interest is a variant subspecies recently found to inhabit Lake Cachuma in Santa Barbara County which has an unusually thick skin and sharp spines on its dorsal and pectoral fins. Anglers targeting rainbow trout in this body of water have claimed to catch whiskered trout weighing as much as eight pounds, though there are no official Fish and Game confirmations of either the catch or the weight. This variant subspecies is reputed to put up a fight which initially leaves the angler in no doubt that it is a large rainbow trout, and local anglers have reported fighting such fish for as long as 15 minutes on light tackle (Johnson, R., Norrington, W., Clarke, K., Keller, E. 2007. Varietals of Oncorhynchus Punctatus Vibrissa in Santa Barbara County. In Fitch, A.S., ed. Hunters Lie in Wait; Fishermen Wait and Lie.). While rare, such catches have attained a cult status amongst local anglers. The Santa Barbara whiskered trout variant is locally referred to as a “Sticky Ricky,” apparently in honor of Rick Johnson (Ibid.), one of the first aquatic researchers to report catching one in Lake Cachuma.

Article by Bill Norrington

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Oncorhynchus punctatus vibrissa or “whiskered trout,” a variant trout subspecies recently found in Lake Cachuma in Santa Barbara County

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Rick Johnson with a whiskered trout he caught at Lake Cachuma in 2007 using light spinning gear and a worm on 4 lb. test line while doing aquatic research

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August 19, 2010 was Whiskered Trout Appreciation Day, and your editor, Professor Keith Clarke, and visiting Professor Paul Longley (University College London) and his daughter were duly invited to do aquatic research on such trout varietals in Lake Cachuma by Rick Johnson (recently retired senior consultant with UCSB’s Office of Instructional Consultation). True to form, Rick caught another “Sticky Ricky,” while the rest of us settled for rainbow trout. Photo of Dr. Longley’s rainbow trout catch by Bill Norrington

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Typical rainbow trout caught at Lake Cachuma during aquatic research expeditions range from 12 to 20 inches

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Professor Keith Clarke with a record setting brown trout

Permission to print the above article on Harbor News, was provided by the author – Bill Norrington.