Warming temperatures could cut in half suitable trout habitat in the West over the next 70 years.
The latest alarming report comes from a team of 11 scientists from Trout Unlimited, the U.S. Forest Service Rocky Mountain Research Station in Boise, Colorado State University, the U.S. Geological Survey and the University of Washington Climate Impacts Group. The study, published today in the peer-reviewed science journal Proceedings of the National Academy of Sciences, , predicts native cutthroat could decline by up to 58 percent.
Rainbow trout may drop by 35 percent and brown trout by 48 percent. Surprisingly, brook trout, introduced from eastern streams, could decline by as much as 77 percent.
"The study looks beyond temperature increases to the role of flooding and interactions between species, said Seth Wenger, the paper's lead author. That give fisheries managers and groups like Trout Unlimited, Wenger’s employer, tools for reducing the impacts.
Wenger recommends restoring and reconnecting coldwater drainages and by protecting existing healthy habitat largely located on public lands.
"Essentially, Trout Unlimited is already protecting remaining strongholds and restoring degraded habitat - exactly the kind of things that need to be done to reduce the impact of a changing climate on coldwater fisheries in the West," Wenger said.
Chris Wood, president and CEO of Trout Unlimited called the report a wake up call.
“It is imperative that we accelerate the scope and the pace of that work if we are to have healthy trout populations and the irreplaceable fishing opportunities they provide through this century," Wood said.
"The study used data from nearly 10,000 sites throughout the western United States. It also compared different climate models.
Some models predicted more warming than others, but under even the most optimistic model, cutthroat trout populations in the West could decline by 33 percent, the study said. Idaho’s three cutthroat species, westslope, Yellowstone and Bonneville, have all been studied for listing as endangered species.