Are the kokanee salmon in Lake Crescent at Olympic National Park a genetically unique population that dates back several thousand years to when the lake was formed, or are they progeny of hatchlings released nearly a century ago?
That's a question the park's fisheries biologists are trying to solve, with the help of the Lower Elwha Klallam Tribe. The project is entering its third and final year. Last week the park and tribal biologists planned to gather tissue samples from 60 kokanee for genetic analysis. The samples were to be obtained using non-lethal capture and sampling methods that entailed taking a small portion of the caudal fin, and then releasing the fish back into the lake.
“Information gathered through this study will help guide us in successfully managing Lake Crescent’s kokanee population, as well as the lake’s other fish species," said Olympic Superintendent Karen Gustin in a park release.
Biologists believe the genetic analysis will determine if Lake Crescent kokanee are the progeny of hatchery fish released into the lake between 1914 and 1939, or a unique native population that adapted to the lake following the landslide event that separated Lake Crescent from Lake Sutherland and the Elwha watershed several thousand years ago.
Under a cooperative agreement between park and tribe, biologists have used hydroacoustic surveys to determine distribution, population size and spawning locations of kokanee in the lake. After spawning locations have been identified, redd counts are conducted to determine spawner abundance.
Kokanee, the resident or land-locked form of sockeye salmon, are the primary food source for Beardslee and Crescenti trout, both of which are endemic populations occurring only in Lake Crescent. Despite the importance of kokanee to the lake’s food chain dynamics, little is known about this population's status, life history and genetic origin.
Comments
I have camped on Lake Crescent several times.