Throughout America's Rocky Mountain West, rivers and streams are getting hotter and drier, presenting new challenges for trout already struggling with road building, habitat fragmentation, pollution and other man-made disturbances. Pictured: A brook trout swims in a native stream.
Image: Eric Engbretson, U.S. Fish & Wildlife Service
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Dear EarthTalk: A fisherman friend of mine told me that trout populations in the interior West of the U.S. are already shrinking due to global warming. Is this true? And what is the long term prognosis for the trout?
—Jon Klein, Portsmouth, N.H.
Most scientists agree that the effects of global warming are starting to show up all around the world in many forms. Throughout America’s Rocky Mountain West, rivers and streams are getting hotter and drier, presenting new challenges for trout already struggling with habitat fragmentation and pollution.
A recent report by the Natural Resources Defense Council (NRDC) and Montana Trout Unlimited (MTU) found that global warming is shrinking cold-water fish habitat, threatening the trout and other fish that depend upon it. Scientists believe that the nearly five degree (F) temperature increase forecasted for the Interior West could reduce trout habitat by half in this century, sending trout populations into a tailspin.
While declines in trout population are bad for local ecosystems and biodiversity, they are also bad for people—especially sport fishers and those employed by the billion dollar recreation industry. In Colorado, sport fishing contributes $800 million to the state’s economy each year and supports 11,000 jobs. In Montana, angling generates $300 million annually. Trout fishing also brings in big dollars to New Mexico, Utah, Wyoming and Idaho. “Hotter temperatures are shutting down our most popular streams during the height of the fishing season,” says MTU’s Bruce Farling. “The closures are becoming an annual event when trout are stressed by warm water and low flows. The implications…are clear: fewer trout and fewer opportunities to fish.”
A U.S. Forest Service (USFS) study found that between 53 and 97 percent of natural trout populations in the Southern Appalachian region of the U.S. could disappear due to warmer temperatures predicted by global climate change models. The three species of trout in question—Brooks, Rainbows and Browns—are already barely hanging on due to road building, channelization and other man-made disturbances.
“As remaining habitat for trout becomes more fragmented, only small refuges in headwater streams at the highest levels will remain,” says biologist Patricia Flebbe of USFS’s Virginia-based Southern Research Station. “Small populations in isolated patches can be easily lost and, in a warmer climate, could simply die out,” she warns, adding that Southern Appalachia trout fishing may become “heavily managed.”
“Trout are one of the best indicators of healthy river ecosystems; they’re the aquatic version of the canary in the coalmine,” says NRDC’s Theo Spencer. “This is our wake up call that urgent action is needed today to reduce heat-trapping pollution that causes global warming.”
NRDC is calling for swift enactment of climate change legislation and for limiting logging and road building near trout streams to ensure enough shade to maintain cooler water temperatures. Also, they say, placing fallen trees and branches and boulders into rivers and streams will help provide shelter for fish and create deeper pools that collect cooler water. Keeping pesticides and fertilizers out of watersheds will also improve the quality of habitat and likelihood of survival for trout species facing an uncertain future.
CONTACTS: NRDC, www.nrdc.org; MTU, www.montanatu.org; USFS, www.srs.fs.usda.gov
EarthTalk is produced by E/The Environmental Magazine. SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk, P.O. Box 5098, Westport, CT 06881; earthtalk@emagazine.com. Read past columns at: www.emagazine.com/earthtalk/archives.php. EarthTalk is now a book! Details and order information at: www.emagazine.com/earthtalkbook.
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7 Comments
Add CommentIn my opinion, another example of a Scientific American article demonstrating their bias towards the drama and false hysteria of global warming vs. fairly and accurately reporting facts and data.
Reply | Report Abuse | Link to thisPoints raised in this article
1. Throughout Americas Rocky Mountain West, rivers and streams are getting hotter and drier-
What is the data source for this conclusion...especially the hotter part. If stream levels are actually lower, doesn't that almost always make them warmer? Might the cause be that the "to many humans" are taking more water from the rivers???
2. Scientists believe that the nearly five degree (F) temperature increase forecasted for the Interior West could reduce trout habitat by half in this century-
Again, what is the source for the forecasted 5 degree temperature rise??? What computer model has been shown to accurately forecast this??? Has it been accurate over the last 10 years??
3. A U.S. Forest Service (USFS) study found that between 53 and 97 percent of natural trout populations in the Southern Appalachian region of the U.S. could disappear due to warmer temperatures predicted by global climate change models.
So once again, a computer model which has not been shown to be accurate is referenced to illicit support for a dire consequence being predicted.
This article is total Crappie...lol
In my opinion, another example of a Scientific American article demonstrating their bias towards the drama and false hysteria of global warming vs. fairly and accurately reporting facts and data.
Reply | Report Abuse | Link to thisPoints raised in this article
1. Throughout America’s Rocky Mountain West, rivers and streams are getting hotter and drier-
What is the data source for this conclusion...especially the hotter part. If stream levels are actually lower, doesn't that almost always make them warmer? Might the cause be that the "to many humans" are taking more water from the rivers???
2. Scientists believe that the nearly five degree (F) temperature increase forecasted for the Interior West could reduce trout habitat by half in this century-
Again, what is the source for the forecasted 5 degree temperature rise??? What computer model has been shown to accurately forecast this??? Has it been accurate over the last 10 years??
3. A U.S. Forest Service (USFS) study found that between 53 and 97 percent of natural trout populations in the Southern Appalachian region of the U.S. could disappear due to warmer temperatures predicted by global climate change models.
So once again, a computer model which has not been shown to be accurate is referenced to illicit support for a dire consequence being predicted.
This article is total Crappie...lol
Approximately 600,000 thousand years ago, the volcano at Yellow Stone erupted and buried much of the the Western United States under several feet of volcanic ash. I'm sure every single fish in any stream or lake choked with that much ash died.
Reply | Report Abuse | Link to thisIf global warming (anthropogenic or otherwise) kills all the trout, something will evolve to replace them when the next ice age sets in.
Sometimes we have an incredibly short view of the future.
Global warming is probably happening. After all, there's nothing so special about the last few thousand years that we should somehow expect that climate stops changing just because our history is short. As for the health of the habitat in which western trout first originated and continue to hold on, it is more a question of human impacts from grazing, mining logging, and unsound resource management practices over the last 150 years ,more than simple warming. One straight line correlation (and therefore one not likely to be found in any complex natural system) is the one that correlates drought with warming. I'm not sure how this was originally connected but in noting the small provincial sense of geography that people in Europe and North America have as a foundation for understanding Earth's systems, they naturally would associate deserts with regions to the south, and therefore warmer, to them in their temperate climates. Of course, the closer you get to the equator, where it is really warm, it actually gets wetter, and throughout the history of the planet since the end of the last glacial maximum, every period of warming (and there have been several far more rapid and extensive than this current one seems to be) has been accompanied by increased precipitation. Deserts can be the result of a number of conditions but the major ones, like the Sahara, The American southwest and the Kalahari or Australia's outback, are the result of descending air masses called Hadley Cells. In warmer times those cells have more moisture. So, the trout have survived worse and will no doubt do fine as a species with some streams going extinct and others becoming more viable, that is unless humans try to manage to keep conditions non-chaotic as nature has prepared them to be by countless years of adaptation to change. Wish we humans could do something like that too.
Reply | Report Abuse | Link to thisCO2 CANNOT CAUSE GLOBAL WARMING--
Reply | Report Abuse | Link to thisBASIC PHYSICS.
Many people in the lay media and govt. do not have an adequate background in physics. Because if they did, they would know that CO2, a gas, cannot cause global warming. I am not saying there is or is not any global warming--all I intend to show here is about one specific substance, CO2, cannot cause global warming, given the laws of physics. Here is why.
Those who attack CO2 claim that CO2 is causing global warming, as a "green house gas".
So let us focus on the physics of the greenhouse.
I will first state some basics of heat transfer and how a greenhouse works, and then prove
that CO2 cannot be a greenhouse gas.
Heat is conducted in only 3 different ways: conduction, convection and radiation.
A green-house is basically like a glass house (that uses cheaper substitutes instead of glass, but the idea is the same). A glasshouse, being made from transparent glass, allows the energy from the sun in the form of sunlight to enter the glass house. As it hits the various objects inside, they absorb the energy, become warm, and release the energy back in the form of heat.
However, the transparent glass, that let the light energy in, limits this transfer of heat out by the 2 of 3 means: it blocks conduction and convection .
The glass blocks heat loss by conduction because it is glass--a material that is a bad conductor of heat. It blocks heat loss by convection, because convection can only take place in liquids and gasses, and glass is a solid.
So light energy gets in, but much of the heat energy the light was converted to cannot get out, making the glass house warm.
CO2 simply cannot cause a glass-house effect, because it cannot:
a. block heat transfer by conduction, because it is not a solid even.
b. block heat transfer by convection, because it is not a solid.
c. its release of energy as radiant heat is no different than of other colourless gases such as O2 and N2, so it cannot change the amount of heat that is radiated out into space.
Conclusion: CO2 cannot cause global warming.
I thought Global warming got busting because of all those filthy lying scientist who just want more money. So the answer to the heading of this is, Global warming wont affect the fish at all.
Reply | Report Abuse | Link to thisThe please explain the OBSERVED drop in trout numbers, the OBSERVED drying of streams in summer and many other OBSERVED phenomena.
Reply | Report Abuse | Link to thisBTW Aristotle - I think some basic schooling is in need for you, too many errors to even comment on.