A group of researchers just published a thorough study of the effects of hybridization on Montana’s cutthroat trout population . . .
Cutthroat trout, a prized and legally protected fish species in Montana, are increasingly threatened by a growing trend of hybridization with non-native rainbow trout, according to research published last month in the scientific journal Global Change Biology.
A group of researchers from the University of Montana, the U.S. Geological Survey, Montana Fish, Wildlife and Parks and the University of Alaska analyzed Montana’s historical fish-stocking records and 35 years’ worth of genetic data collected by state biologists, finding that hybridization between the two species is increasing across remaining geographic range for genetically pure cutthroats.
For decades, fisheries managers in Montana and elsewhere in the Western U.S. stocked rivers and lakes with non-native rainbow trout, a popular sport fish that easily established breeding populations in the state’s waterways. The state abandoned the practice in 1969, but interbreeding between rainbows and the closely related cutthroats has resulted in a proliferation of hybrids and has eroded the native fish’s genetic pool throughout most of its range.
Aquatics biologist Clint Muhlfeld has just published a paper showing a correlation between climate change and hybridization of cutthroat and non-native rainbow trout . . .
In his published research, aquatics biologist Clint Muhlfeld has detailed the plight of an obscure stonefly endemic to Glacier National Park’s high-elevation streams and revealed how a trout’s ear bone contains a geochemical diary of its liquid migrations.
But his most recent study will appeal to his largest audience yet, not only by virtue of the scope of the revelation, but also the size of the platform.
Muhlfeld, an aquatic ecologist at the U.S. Geological Survey’s Glacier Park field office, is the project leader of a study that links the rapid hybridization between a native Montana trout species and an invasive species in the Flathead River system to climate change.
Glacier Park is trying to keep non-native lake trout out of Quartz Lake . . .
Glacier National Park officials are seeking public comment on a project that would modify and improve a fish barrier designed to stem the invasion of lake trout in Quartz Lake.
Considered one of the last best strongholds for native fish in the entire Columbia River Basin, Quartz Lake’s native fish populations include bull trout, which are classified as a threatened species under the Endangered Species Act, as well as westslope cutthroat trout and mountain whitefish.
Native fish populations in Glacier National Park have been compromised by the invasion of non-native fish species into the park’s lakes and streams, and lake trout are being targeted as the chief culprit.
Sally Mauk, news director at KUFM, Montana Public Radio, runs a twice-monthly column in the Missoulian. Her most recent discusses the world-wide spread of rainbow trout from its native home on the Pacific Rim. I’ve tossed it in here because it is pretty interesting and because there’s a North Fork connection.
Here’s an excerpt from the North Fork reference . . .
And then there’s the Frankenstein effect. All this mucking with nature has created fish hybrids, especially in waters where rainbow and westslope cutthroat trout have interbred. Halverson was fishing once in the North Fork of the Flathead, where it’s catch-and-release only for westslope cutthroat, when he caught a trout that was so hybridized, he was stumped.
Dan Testa has an excellent piece in the Flathead Beacon discussing trout studies in the North Fork — on both sides of the border — and the general importance of this sort of baseline study in connection with the upcoming UNESCO scientific mission to study threats to Waterton-Glacier Park.
Here’s a sampler . . .
The research of these scientists is likely to be heavily relied upon by members of a United Nations fact-finding mission arriving in the region some time in the next year to determine whether Waterton-Glacier International Peace Park should be designated a “World Heritage Site in Danger.” The unanimous June vote in Seville, Spain, by a 21-country panel of the United Nations Educational, Scientific and Cultural Organization (UNESCO) could mean widespread attention will once again be drawn to the issue of threats from mining and drilling operations in southeastern British Columbia along the headwaters of the North Fork, which serves as the western boundary of Glacier National Park.