High temperatures and low river flows, combined with high angling pressure, can increase stress on fish populations this time of year. That can lead to issues including disease outbreaks, decreased growth rates, and increased mortality.
Hoot-owl restrictions, which prohibit fishing from 2 p.m. to midnight, are in place on several Montana rivers and waterbodies right now to protect fish. No such restrictions are in place for eastern Montana's warm-water fisheries, but fish still experience stress amidst heat and low water levels.
It is not uncommon to see limited fish kills occur during heat spells, particularly in small streams like the Tongue and Powder rivers or small prairie ponds when water temperatures can exceed 90 degrees. However, if people notice an unusual volume of fish die-offs, they are encouraged to notify FWP.
Anglers can help to reduce stress on fish by avoiding fishing during the hottest parts of the day. Catch-and-release anglers are urged to get fish to the net or in hand quickly, keeping them in the water and reviving them prior to releasing them back into the river. As the summer warms, Montana offers many other angling options with better conditions for fish, including larger lakes or reservoirs or higher-elevation lakes and streams.
Before you head out, check FWP's current Waterbody Closures and Restrictions map for the full list of closures and hoot-owl restrictions across the state. Learn more and check out the map here: https://fwp.mt.gov/.../current.../waterbody-closures