Nature & Environment
Climate Change Could Result in Extinction of Montana Cutthroat Trout
Thomas Carannante
First Posted: May 28, 2014 09:26 AM EDT
According to ecologists, climate change has affected the temperatures of Montana streams. The waters have gotten warmer over the past 30 years and a new study says that's responsible for the declining populations of cutthroat trout.
Known as one of the American West's most highly prized fish, the cutthroat trout (also known as the Westslope cutthroat trout) is one of two subspecies of native cutthroat found in Montana. In recent years the trout has been threatened by habitat loss as well as hybridization with rainbow trout.
Ecologists and researchers with the U.S. Geological Survey analyzed summer water temperatures in Montana's Flathead basin between 1978 and 2008 to see if this had any effect on the cutthroat trout's presence. This 30-year period of the waters underwent significant warming, which the researchers believe spurred hybridization because the warmer water increases interactions between the native trout (Westslope cutthroat) and non-native trout (rainbow).
The rainbow trout were introduced in the Western United States' lakes and streams decades ago in order to give anglers more fish to catch, gaining a reputation as a hard-fighting game fish. They also adapted better to the rising water temperatures than the cutthroat trout because they possess a greater tolerance for such environmental changes.
This suggests that rising water temperatures actually influence evolutionary processes through accelerating invasive hybridization. This can result in genomic extinction for many species, especially the Westslope cutthroat, which has survived in local streams for over 12,000 years.
"During a subsequent 30-year period of accelerated warming, hybridization spread rapidly and was strongly linked to interactions between climatic drivers-precipitation and temperature-and distance to the source population," reads the study's abstract. "Specifically, decreases in spring precipitation and increases in summer stream temperature probably promoted upstream expansion of hybridization throughout the system."
Although there are still plenty of cutthroats in Montana, they are now in danger of becoming hybrids with the rainbow trout because the species will no longer be separated as the water gets warmer. The rainbow used to stay down in the valleys because the water was warmer, as opposed to the cutthroat who stuck around at high elevations because the water was colder.
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First Posted: May 28, 2014 09:26 AM EDT
According to ecologists, climate change has affected the temperatures of Montana streams. The waters have gotten warmer over the past 30 years and a new study says that's responsible for the declining populations of cutthroat trout.
Known as one of the American West's most highly prized fish, the cutthroat trout (also known as the Westslope cutthroat trout) is one of two subspecies of native cutthroat found in Montana. In recent years the trout has been threatened by habitat loss as well as hybridization with rainbow trout.
Ecologists and researchers with the U.S. Geological Survey analyzed summer water temperatures in Montana's Flathead basin between 1978 and 2008 to see if this had any effect on the cutthroat trout's presence. This 30-year period of the waters underwent significant warming, which the researchers believe spurred hybridization because the warmer water increases interactions between the native trout (Westslope cutthroat) and non-native trout (rainbow).
The rainbow trout were introduced in the Western United States' lakes and streams decades ago in order to give anglers more fish to catch, gaining a reputation as a hard-fighting game fish. They also adapted better to the rising water temperatures than the cutthroat trout because they possess a greater tolerance for such environmental changes.
This suggests that rising water temperatures actually influence evolutionary processes through accelerating invasive hybridization. This can result in genomic extinction for many species, especially the Westslope cutthroat, which has survived in local streams for over 12,000 years.
"During a subsequent 30-year period of accelerated warming, hybridization spread rapidly and was strongly linked to interactions between climatic drivers-precipitation and temperature-and distance to the source population," reads the study's abstract. "Specifically, decreases in spring precipitation and increases in summer stream temperature probably promoted upstream expansion of hybridization throughout the system."
Although there are still plenty of cutthroats in Montana, they are now in danger of becoming hybrids with the rainbow trout because the species will no longer be separated as the water gets warmer. The rainbow used to stay down in the valleys because the water was warmer, as opposed to the cutthroat who stuck around at high elevations because the water was colder.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone