ANNUAL FALL LAKE TROUT MANAGEMENT OPERATIONS TO BEGIN AT BLUE MESA RESERVOIR
Colorado Division of Wildlife Press Release
GUNNISON, Colo. -- As part of the continuing effort to restore balance to the fishery at Blue Mesa Reservoir, the Colorado Division of Wildlife will soon begin its second annual fall operation to reduce lake trout populations in the reservoir.
During the Colorado Wildlife Commission's Las Animas workshop on Oct. 7, DOW biologists briefed commissioners on changes to the management plan, including experimenting with overnight netting operations that will focus on areas where they expect to increase capture of lake trout. Based on a population model developed in collaboration with Colorado State University, biologists explained that they needed to increase the take of lake trout in order to restore kokanee populations.
"Our population studies show that even with the removals last year, the lake trout population continues to grow," said Dan Brauch, aquatic biologist in Gunnison for the DOW. "If the lake trout population cannot be controlled, there is a very serious risk that we'll lose the kokanee salmon."
Brauch added that even with the removal project, lake trout will continue to be abundant in the reservoir and provide ample trophy and recreational opportunities.
"We want to assure anglers that we are working hard to restore a balance in the fishery so that everyone can enjoy pursuing the species of their choice," he said.
The DOW's fall management work is expected to begin Oct. 13. All of the work will be scheduled for Mondays through Thursdays. Work will be suspended on the weekends.
The lake trout management project was initiated in 2009 to reduce the overpopulation of lake trout in the reservoir. Highly efficient predators, Blue Mesa's lake trout are decimating the kokanee salmon population, biologists say. Lake trout are also taking a toll on rainbow trout.
Angler surveys demonstrate that kokanee salmon is the preferred species for anglers at Blue Mesa. On average, 65 percent of the total summer catch at the reservoir is kokanee. In comparison, just 10 percent of the catch is lake trout.
Last year, the DOW captured and removed about 1,300 lake trout. Operating under 2009 management guidelines, the agency tagged and released about 100 fish over 30 inches in length.
In order to expedite kokanee salmon recovery the CSU model indicates removal of lake trout up to 38 inches is necessary. This year, any lake trout caught that is 38 inches or less will be removed. All larger lake trout will be released.
DOW biologists estimate that over 1,700 lake trout exceeding 30 inches exist in the lake. The proposed changes in netting strategy are expected to result in the harvest of between 100 and 200 lake trout between 30 and 38 inches long, while significantly increasing the take of smaller trout.
Removing larger fish will help to reduce the lake trout population's reproductive potential. Larger trout have a disproportionate impact on the kokanee population. Trout larger than 38 inches will be released to sustain the reservoir's trophy lake trout fishery.
When possible, the culled fish will be cleaned, frozen and then distributed to the public by the DOW.
Blue Mesa Reservoir has long been the most productive kokanee fishery in Colorado, providing more than 60 percent of the eggs needed to stock kokanee fingerlings in 26 other lakes and reservoirs throughout the state. The value of the kokanee fishery in Colorado is estimated at $29 million.
Kokanee feast on abundant zooplankton which occurs naturally in the water. Every year, they return to the Roaring Judy Hatchery where they are spawned.
In turn, kokanee provide a key food source for trophy lake trout production at Blue Mesa. Without an abundant kokanee population, biologists predict the lake trout fishery will go into a long, slow decline.
The DOW will continue annual fish surveys to monitor the population of all species in the reservoir. Removal of lake trout will be adjusted based on those surveys.
"Supporting kokanee salmon is the top fishery priority at Blue Mesa," Brauch said. "Lake trout management will be an ongoing, long-term project."
The DOW has recommended removal of the bag limit for lake trout less than 38 inches in length as part of the Five Year Review of Colorado’s fishing regulations.
Find more information on the DOW's Blue Mesa Fishery Management program at: wildlife.state.co.us/Fishing/Management/BlueMesaReservoirFisheryManagement.htm