# Science Provides a Glimpse into a Possible Future for Anglers

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Warmer waters are threatening some of the most highly sought after fish species across the country. To better visualize the future, scientists are working to understand how changing conditions might affect our country's culture and heritage.

Fishing is one of our nation’s most enduring pastimes.  Not only is it an activity that draws millions of people outdoors each year, but it also generates nearly $50 billion annually. But now, warmer waters are threatening some of the most highly sought after species across the country – from Wisconsin’s walleye to Montana’s westslope cutthroat trout. To better visualize the future, scientists are working to understand how changing conditions might affect sport fishing, an activity which supports local and state economies and is an important part of our country’s culture and heritage. Scientists are already seeing a variety of changes in how fish reproduce, grow and where they can live as temperatures and habitat conditions change. The examples below are just a few of the many studies funded by the U.S. Geological Survey’s National Climate Change and Wildlife Science Center (NCCWSC) and the Department of the Interior Climate Science Centers (CSCs) that provide a glimpse into what the future may hold for fishing communities across the country. Anglers fish for cutthroat trout at the National Elk Refuge. Credit: Lori Iverson, USFWS. (Public domain) The future is not all doom and gloom, however. Results from these studies help state agencies, resource managers, and conservation organizations proactively plan for the future and act to protect the fish and habitats that are so valued by anglers nationwide. Cutthroat Trout: Loss of Iconic Native Fish to Hybridization? In the northern Rocky Mountains, native cutthroat trout face an uncertain future. A recent study, funded by NCCWSC, revealed that as water temperatures warm, hybridization is increasing between native and invasive trout, which could mean danger for the iconic cutthroat trout – a favorite among catch-and-release anglers. The study found that as water temperatures warm, the introduced rainbow trout, which prefer these warmer waters, are moving into cutthroat streams, where they are mating with the native fish. The result: populations of hybrid fish. The spread of hybridized westslope cutthroat trout across the northern Rocky Mountains is driven by widespread introductions of invasive rainbow trout combined with the warmer water temperatures and lower spring precipitation. Unfortunately, this means that native cutthroat could lose the unique traits that have allowed them to thrive for thousands of years in cold mountain streams. The good news for the Rockies, however, is that management strategies, such as translocation of species and habitat modification, can help to conserve biodiversity and prevent genomic extinction of remaining native cutthroat populations or even entire lineages of the species. Walleye in Wisconsin: Worries for a Favorite Fish? In the Great Lakes region, warming temperatures are creating conditions that favor some fish species while threatening others. Populations of walleye, one of the most sought after species among Wisconsin’s anglers and a fish that prefers cooler water, have been declining over the last 30 years. Conversely, largemouth bass, which thrive in warmer waters, have been increasing. In a 2016 study, funded by the Northeast CSC, scientists surveyed more than 2,100 Wisconsin lakes and identified characteristics of lakes where walleye or largemouth bass were most likely to thrive; they found that both species were strongly influenced by water temperature. The researchers predict that 60-89% of the study lakes could become more suitable for largemouth bass and less suitable for walleye as climate change causes lakes to get warmer overtime. Brook trout. Credit: Tyler Wagner, USGS. (Public domain) In a state where freshwater fishing is valued at more than$1.5 billion, these changes could have big impacts on the sport-fishing culture and economy. Going forward, the scientists plan to expand their study to include a similar analysis of lakes in Minnesota and Michigan.

Eastern Brook Trout: More Driving and Less Fishing?

As if the declines of some of the nation’s favorite fish weren’t bad enough, a third study, also funded by NCCWSC, focused on eastern brook trout, shows that anglers may have to spend more time in their cars to access native fish in the future!

The eastern brook trout, a culturally and economically important fish that supports angling throughout the Appalachian Mountains, thrive in small cold-water streams and lakes. However, warming temperatures are expected to reduce available coldwater habitat and result in a more restricted brook trout distribution – which means fewer angling opportunities.

Over the next 70 to 80 years, changing coldwater habitats could cause the driving distance required to fish for wild brook trout to increase – significantly for some. For example, the driving route from Philadelphia to the nearest brook trout stream could be up to 250 miles – much longer than the current 48 miles. Anglers in the southern part of the brook trout range would experience the most dramatic increases in trip length. In Cleveland, Tennessee, for example, driving distance could reach upwards of 500 miles, whereas the current average distance is less than 50 miles.

Although cumulatively, these results sound like a lot of bad news, there is a silver lining. These studies, and others across our network, are providing crucial information to resource managers and planners tasked with making important decisions and management actions  (like choosing which streams to focus conservation or re-stocking efforts) for the conservation and protection of fish populations and habitat for the future.