Rising temperatures threaten to reduce western trout habitat

Water temperatures above about 70°F are lethal for trout. Since temperatures are generally rising in the American West, and the relatively cold water from melting snow is diminishing earlier in the year, stream water temperatures are increasing, reducing the areas suitable for trout.

That is one major reason why the nonprofit organization Trout Unlimited said in a recent report that “[l]osses of western trout populations may exceed 60% in certain regions.” The report, titled Healing Troubled Waters: Preparing Trout and Salmon Habitat for a Changing Climate: cites several scientific reports as supporting information.[[Williams, Jack E., Amy L. Haak, Nataniel G. Gillespie, Helen M. Neville, and Warren T. Colyer. “Healing Troubled Waters Preparing Trout and Salmon Habitat for a Changing Climate.” (PDF) 2007. Trout Unlimited.]]

For general information on this subject, see also a recent report by the Seasons' End organization, published by the Bipartisan Policy Center.[[ Wildlife Management Institute. “Seasons' End Global Warming's Threat to Hunting and Fishing.” (PDF) Bipartisan Policy Center, 2008.]]

The consequences of reduced trout habitat are not just ecological; they are also economic. In Montana alone, the fishing industry contributes about $300 million to the state’s economy.