State fisheries biologists are rethinking the formula used to make policy for winter lake levels at Lake Pend Oreille in an effort to improve kokanee salmon recovery.
Since the 1990s, the Idaho Department of Fish and game has relied on formulas tied to egg-to-fry survival rates when making winter pools recommendations for the lake.
But the Bonner County Daily Bee reports that new data is raising questions about the formula.
Initially, survival rates ranged between 6 and 15 percent. But rates have increased recently, even in years when the lake has been drawn down to lower levels.
The accuracy of the survival rate is important because it's the scientific basis for recommending a higher winter pool of 2,055 feet above sea level and the lower pool of 2,051 feet.