The hoot-owl restrictions primarily affect anglers and recreational users of the Madison, Beaverhead, and Sun rivers. These measures are designed to reduce fishing pressure during the hottest parts of the day, when fish are most vulnerable to stress from warm water temperatures and low oxygen levels. Prolonged exposure to such conditions can lead to fish mortality, particularly for cold-water species like trout. The restrictions are a precautionary step to ensure the sustainability of fish populations and the health of Montana's aquatic ecosystems.