The following is a news release from Yellowstone National Park.
Yellowstone National Park responded to high water temperatures and unprecedented low stream flows in rivers and streams by instituting a fishing closure during the afternoon and evening as of July 24. Conditions at the time were stressful and even fatal for trout.
Park scientists have monitored flow and temperature data since the closure. Temperatures of Yellowstone’s rivers and streams have cooled, and flows have improved. Water temperatures are now well below thermal thresholds for trout and flows are returning to long-term averages.
Since conditions have improved, the fishing closure on park rivers and streams has been lifted as of Aug. 20, and anglers can resume fishing all day (sunrise to sunset) as specified in the Fishing Regulations booklet.
Anglers: Do not play hooked trout to exhaustion. Gently handle and release them quickly after they have revived. Your cooperation will protect the park fisheries and may preclude the need to prohibit fishing again this season should conditions worsen in rivers and creeks.