Fisheries biologists from Olympic National Park and the Lower Elwha Klallam Tribe have entered the final phase of a three-year investigation into the kokanee salmon population in Lake Crescent.
The project continues this week as park and tribal biologists collect tissue samples from 60 kokanee for genetic analysis. Using nonlethal capture and sampling methods, biologists will carefully remove a small portion of the caudal fin and release 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 National Park Superintendent Karen Gustin.
The genetic analysis will determine whether Lake Crescent kokanee are the progeny of hatchery fish released into the lake between 1914-1939 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 landlocked 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, little is known about this population’s status, life history and genetic origin.