For the week of August 8 - 14, 2001

Silver Creek Preserve may restrict morning fishing

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Due to this summer’s drought, The Nature Conservancy may ask fly fishers to refrain from fishing on the Silver Creek Preserve during early morning hours later this month.

Mark Davidson, assistant manager of the preserve, said a voluntary closure could be announced within a week, but at the moment conditions do not warrant restrictions.

Some anglers have expressed concern over low levels caused by this summer's dry conditions, but the staff has been monitoring the stream regularly.

Silver Creek's flows have dropped due to the drought, from a norm of 120 cubic feet per second to around 80 cfs. The combination of low flows, warmer water temperatures, and the abundance of aquatic vegetation causes dissolved oxygen levels to decrease, which then adversely affects trout. Optimal stream conditions for trout consist of water temperatures between 50 and 60 degrees and dissolved oxygen levels between 8 milligrams per liter to 9 milligrams per liter. Trout become increasingly stressed if water temperatures hover near 70 degrees or if dissolved oxygen levels fall below 5.1 milligrams per liter.

During the past couple of; weeks, the average morning water temperature at the Silver Creek Preserve has been 56 degrees; the average afternoon temperature has been 63 degrees. Dissolved oxygen levels have been around 5.2 milligrams per liter during the morning hours.

If dissolved oxygen levels hover under 5, Davidson said that voluntary restrictions will take place. Last year, The Nature Conservancy asked anglers to voluntarily refrain from angling between 5 a.m. and 9 a.m. That system worked sufficiently to not necessitate more stringent closures.

"We don't want to alarm the public," says Davidson. "There have not been fish kills, nor is this an emergency situation. But we do want to err on the side of caution. By keeping the public informed, we believe we can best help this blue-ribbon fishery."

Anglers are encouraged to phone The Nature Conservancy's Silver Creek Visitor Center, west of Picabo, at 788-2203 for the latest updates.

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