GUNNISON, Colo. -- To obtain a better understanding of kokanee salmon and predation on that species by lake trout and other fish at Blue Mesa Reservoir, Colorado Division of Wildlife aquatic biologists are conducting research work at the reservoir located west of Gunnison.

The research will examine several issues: how many kokanee fingerlings are consumed by predator fish on their way to Blue Mesa Reservoir shortly after they're released from the Roaring Judy Hatchery; the population, life cycle and diet habits of lake trout; the amount of predation by perch which were illegally planted in the reservoir several years ago and have a self-sustaining population; and continued assessment of kokanee population trends.

The reservoir is a very productive fishery on which the DOW has relied for many years as the primary water for kokanee salmon production in Colorado. But during the last 10 years the kokanee population in the lake has dropped precipitously primarily due to predation by lake trout. Rainbow trout survival has also declined significantly because of lake trout predation.

The first part of the research will look at survival of kokanee fingerlings after they're released from the Roaring Judy Hatchery. Each spring, some of the fish are eaten by brown trout as they make their way down the East River and Gunnison River and into the reservoir.

The young fish were released the evening of April 27 and biologists electro-fished at spots in the Gunnison River on April 28. The stomach contents of brown trout and rainbow trout caught will be examined.

At various locations throughout the reservoir during May, nets will be set to catch other fish and determine the amount of kokanee they're eating. All samples will be submitted to researchers from Colorado State University who will conduct a diet analysis.

"The intent of this work is to assess predation on kokanee," said Dan Brauch, aquatic biologist for the DOW in Gunnison. "The more we can learn about the extent of all predation the better we can manage the reservoir for multiple species."

Another part of the research will look more closely at the overall population, health and diet of lake trout. Nets will be set for 45-minute periods throughout the reservoir for 3-4 days a week through May. Lake trout caught will be measured and weighed, and some will be marked and released so that their size and overall health can be evaluated if they're recaptured in the future. Lake trout larger than 30 inches captured in nets will be released to maintain trophy lake trout fishing opportunities.

Throughout the summer DOW biologists also will conduct their annual sonar and netting work to help estimate overall fish populations.

Anglers can aid in recovery of kokanee by harvesting lake trout, which are excellent to eat. The limits at Blue Mesa for lake trout are liberal - the bag and possession limit is eight fish per person. Spring is an excellent time for lake trout fishing at Blue Mesa Reservoir.

For more information about Blue Mesa Reservoir, go the DOW's web site: http://wildlife.state.co.us/Fishing, and click on Blue Mesa Reservoir Management.

For more news about Division of Wildlife go to: http://wildlife.state.co.us/news/index.asp?DivisionID=3

For more information about Division of Wildlife go to: http://wildlife.state.co.us.