Extended dry weather is prompting state wildlife officials to impose afternoon and evening fishing restrictions on three central Montana rivers.
The so-called hoot-owl closures begin Friday on portions of the Dearborn, Smith and Sun rivers.
Montana Fish Wildlife and Parks' drought policy calls for fishing closures when maximum daily water temperatures reach at least 73 degrees for three consecutive days.
State officials say water temperatures of 77 degrees or higher can be lethal to rainbow and brown trout, which prefer temperatures in the mid-50s.
In a related step, the state plans to tell the owners of 37 water rights in the Smith River basin that they must stop diverting water from the river. Officials say that will help protect the fishery.