The Science of Coldwater Fisheries and Climate Change

salvelinus_confluentus_11We’ve been talking generally about climate change lately, but haven’t drilled down into some of the studies illuminating the potential impacts of climate change on our trout and salmon waters.  TU, of course, published our own report, Healing Troubled Waters, in 2007, but much other work exists showing the potential impacts trout and salmon and their coldwater ecosystems face from a changing climate.  Below is a collection of papers, reports, and studies conducted by university researchers, non-profits, and government agencies looking at how trout and salmon will fare in a changing climate, along with selected excerpts from some of these publications.  You can look in the “references” section of these reports for even more sources.  Have other studies you’ve come across?  Please post them in the comments section!

Selected quotes from the research below:

“U.S. Forest Service scientists predict that over half of the wild trout populations will likely disappear from the southern Appalachian Mountains because of the effects of warming stream temperatures.8 Losses of western trout populations may exceed 60% in certain regions,9 with potential losses of migratory bull trout as high as 90%.”

Healing Troubled Waters

“Not only are hot trout becoming uncomfortably common in the watershed—so are the number of river closures during fishing season on favorite rivers like the Blackfoot, Clark Fork and Bitterroot. ‘When Fish, Wildlife & Parks first came out with its drought policy plan, we thought this would be an issue about every five years. Instead we’re seeing elevated temperatures in traditional trout waters almost every year,’ says fisheries biologist Pat Saffel.”

Low Flows, Hot Trout

“Those familiar with the Firehole River attributed the fish kill to unnaturally high water temperatures, one of the
indicators of a warming climate. In fact, July 2007 was the hottest July ever recorded in nearby Montana. Biologists, climatologists, and other members of the scientific community believe that the increased frequency in the past 20 years of hot and dry summers and warm winters in the West reflect an overall change in the world’s climate.
What occurred on the Firehole River last summer is indicative of a growing problem that is appearing more frequently in trout streams throughout the American West. In Colorado, Wyoming, Utah, New Mexico, and other western states, record high air temperatures coupled with drought and reduced snowpacks are taking a toll on trout populations, including those of some of the nation’s best known fishing destinations.”

Trout in Trouble:  The Impacts of Global Warming on Trout in the Interior West

“A strong correlation between mean annual air temperatures and contemporary bull trout distributions suggests climate plays an important role in determining population boundaries… Recent trends in stream temperatures driven by increasing air temperatures, decreasing flows, and increasing wildfires indicate losses and fragmentation of thermal habitat networks may already be occurring.”

Bull Trout and Climate


Low Flows, Hot Trout:  Climate Change in the Clark Fork Watershed

Bull Trout and Climate

Trout in Trouble:  The impacts of Global Warming on Trout in the Interior West

Season’s End:  Global Warming’s Threat to Hunting and Fishing

Global Climate Change and Fragmentation of Native Brook Trout Distribution in the Southern Appalachian Mountains

Healing Troubled Waters

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