(AP) — Trout need cool water to survive, but record heat this summer has driven water temperatures to lethal levels for fish. On the Yellowstone River near Livingston, Montana, California resident Mike Wever waded into the swiftly-moving water Friday with a fly fishing rod in one hand. Yellowstone, for example, has restricted fishing due to high water temperatures during five of the past six years. The consequences aren't just ecological; trout fishing is closely entwined with the economy in many Rocky Mountain communities. Climate change, she said, is changing the size and timing of the mountain snowpack, and that's contributing to river heat waves.