IDFG Keeping A Close Watch On Henrys Lake!

HENRYS LAKE - Keeping a close watch on conditions at Henrys Lake is nothing new to IDFG Biologists. Varying ice conditions combined with fluctuating amounts of aquatic vegetation can lead to conditions where the amount of dissolved oxygen (DO) available for fish can reach dangerously low levels. So far this winter, despite the best efforts of IDFG, DO levels in some parts of the lake have dropped enough to cause concern. In the early '90's, concerns over winter die-off caused by lack of DO prompted IDFG to install a system to aerate a small portion of the lake. The purpose of the aerators was to create areas of open water so that natural mixing of oxygen could occur. Dropping DO levels last December caused IDFG to start up the aerators. DO levels will be monitored at various locations across the lake until all the ice melts. While a small of number of assorted trout and sculpin mortalities have been observed, the actual impact of this winters harsh conditions won't be known until sometime in May. Each spring biologists use gillnets to help monitor the population, but even that isn't necessarily a great predictor of the fishing. According to Regional Fishery Manager Jim Fredericks, "The true test of how the winter affects the fishery won't be until the season opens on Memorial weekend". But according to Fredericks, "right now there's no reason to think the fishery will be affected, as mortality seems pretty limited-I certainly wouldn't label it a winterkill at this point". Presently, IDFG officials have observed fish congregating to the areas around the lake with the highest levels of oxygen, such as the stream mouths, Staley Springs, and the aerated area in front of the hatchery. While Mother Nature take control of one part of the unfolding drama, IDFG does its best to write other chapters of the story. At Henrys Lake Hatchery, Damon Keen has been busily spawning fish for the past two weeks to collect eggs for the million plus fingerlings that will be released next fall. "I'm confident that we'll get all of the eggs we need for our 2004 planting". Anyone wishing to learn more about conditions at Henrys Lake can contact the Upper Snake Regional Office at 525-7290 or the Henrys Lake Hatchery at 558-7202.