High Temp Fly Fishing Risks

Fly fishing for trout is one of life’s great joys, connecting anglers to the beauty and tranquility of rivers and streams. However, as water temperatures rise, particularly during the heat of summer or prolonged droughts, fly fishing can become dangerous—even deadly—for trout populations.

Trout are cold-water fish, thriving best in water temperatures ranging from 45°F to 65°F. When temperatures approach and exceed 68°F, trout become stressed, making them highly vulnerable to illness, injury, and death. At these higher temperatures, the dissolved oxygen levels in the water drop significantly, impairing the trout’s ability to recover after being caught.

Catching trout in warm water exhausts them to the point that they often cannot revive after release. Even fish that appear healthy upon release can later succumb due to lingering stress and depleted oxygen.

Anglers can help protect trout by:

  • Carrying a thermometer to check water temperatures before fishing.
  • Avoiding fishing altogether when water temperatures exceed 67°F.
  • Fishing during cooler parts of the day, such as early morning or late evening.
  • Seeking out higher elevation streams or shaded, cooler sections of rivers.

Responsible angling practices during periods of elevated water temperatures are essential to ensuring healthy trout populations for generations to come. Let’s enjoy our rivers sustainably by knowing when to give the trout a break.

Tight lines!

– Patrick Iverson, Communications Chair

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Truchas Chapter

Truchas Chapter of Trout Unlimited, a local membership of over 500 and the national organization of more than 300,000 members, is dedicated to conserving, protecting and restoring North America’s cold-water fisheries and their watersheds.