Photo courtesy of Rick Wollum
“Trout fisheries have enormous cultural, economic and ecological importance in Montana and worldwide, yet even Montana’s resilient trout fisheries could be vulnerable to future climate change. ”
The northern Rocky Mountains in Montana support some of North America’s most popular trout fisheries, valued at more than $750 million year annually, representing more than 20% of the spending by tourism in the state. This economic value is primarily driven by nonresident fishers who spend, on average, $690 fisher-day, as compared to $90 fisher-day by resident fishers. However, the cold-water fisheries that support this substantial tourism industry may be at risk as this region warmed at twice the global average rate over the past century, contributing to warmer water temperatures, lower summer stream flows, and increasing frequency and severity of drought events.
Researchers with the U.S. Geological Survey, Montana Fish, Wildlife and Parks and the University of Montana co-authored the study titled “Socioeconomic resilience to climatic extremes in a freshwater fishery,” published in Science Advances.
“Trout fisheries have enormous cultural, economic and ecological importance in Montana and worldwide, yet even Montana’s resilient trout fisheries could be vulnerable to future climate change,” said Timothy Cline, a USGS scientist and the paper’s lead author, in a news release.
Climatic changes are shifting the abundance and distribution of trout species across the region. The combined effects of these climatic changes may significantly affect popular trout fisheries by shifting both fish and fishers across space, with potentially severe socioeconomic consequences. Therefore, understanding how climate change will affect social, economic, and ecological components of cold-water fisheries will be critical for enhancing resilience and adaptation of fisheries and local communities.
Using Montana FWP recreation monitoring data to analyze how climate change impacted 3,100 miles of the state’s rivers between 1983 and 2017, the study found that the concentration of anglers doubled overall within that 34-year time period, and severe drought conditions significantly impacted the distribution of fishing pressure across the study area. Among the study’s findings:
As flows dropped and water temperatures rose, anglers moved to other areas where waters were colder. These cold-water river segments supported 10 times more anglers than warm-water segments.
The study found that nonresident fishing pressure was more variable across space and time than resident anglers, indicating that nonresident anglers were more flexible to adapt to climate-induced changes in fishing conditions and management closures. In contrast, resident anglers were less willing/able to travel to other areas in response to drought, and they often continued to fish along rivers by their homes, even when the conditions were stressful on trout.
While Montana’s fishing economy has demonstrated resilience during past periods of drought — particularly those in the late 1980s, early 2000s and in 2017, the study’s authors expect new challenges will emerge as the climate warms throughout the coming decades. “Montana’s fisheries are renowned for their trout, and trout require cold, clean, connected habitat to survive,” he said. “As the climate warms, a lot of those attributes are changing rapidly.”