Hosted by the University of Nevada, Reno’s Tahoe Institute for Global Sustainability at the Lake Tahoe campus, experts met for an international workshop from March 2-4 focused on five species of giant trout, collectively known as taimen, found across Europe and Asia. These species are increasingly affected by dams, climate change, and unsustainable harvest. The workshop brought together University faculty and experts from Europe, Mongolia, China, Japan, the United States and Russia, as well as scientists from the Wild Salmon Center, and the Prince William Sound Science Center. A representative from the Summit Lake Paiute Tribe provided local context on efforts to protect Nevada’s own iconic fish, the Lahontan cutthroat trout.
“One of our priorities is to do conservation work based in science,” said Mendsaihan Bud, scientist with the Mongolian Institute for Geoecology and Geography. “It was great to learn from scientists who are conducting research similar to what we do in Mongolia, and to catch up on latest findings from global experts.”
The world’s largest trout
Taimen are freshwater megafauna, fish that can exceed 30 kilograms (66 pounds) and function as apex predators in their ecosystems. Despite their ecological importance and global reputation among fishers, all five species face mounting pressures.
“One of my favorite areas to work is on giant trout that we have been discussing at this workshop,” said Matthew Sloat, science director at the Wild Salmon Center. “We know very little about what it takes to protect these fish, so a lot of our work this week has been focused on filling in some of those knowledge gaps and focusing on ways to conserve them.”
Taimen share life history traits that make them especially vulnerable: they are long-lived, slow growing, migratory fish that need healthy, connected habitats to survive. Across all cases, the same core threats emerged: hydropower development and dams that fragment rivers and block migration; climate change that warms and reduces freshwater flows; and unsustainable harvest and illegal fishing that further weaken small populations.
Concrete outcomes: Science, policy and global coordination
Beyond sharing data and case studies, the workshop produced tangible next steps aimed at accelerating conservation action. Participants initiated a collaborative scientific paper that will synthesize current knowledge across all five species, identify critical research gaps, and provide a roadmap to guide future conservation strategies for the world’s largest trout.
“Climate change is certainly a global threat to fish populations,” said Olaf Jensen, professor at the University of Wisconsin at the center for limnology. “The good news, though, is that in rivers without disrupted water flow, fish are still able to take refuge from the heat through long distance travel. If we keep habitats intact and barrier free, fish are able to adapt in a way that allows them to handle some climate change.”
In addition, experts compiled and exchanged updated population data to inform forthcoming revisions to International Union for Conservation of Nature Red List assessments for species whose conservation status requires review. Updated, science-based assessments are essential for guiding national protections and conservation priorities. Together, these outputs represent a coordinated effort to link research, policy and on-the-ground conservation across continents.
A Nevada connection
The discussions linked to science and conservation efforts in Nevada because of strong parallels between taimen and Nevada’s largest fish, the Lahontan cutthroat trout. Capable of reaching a weight between 40 and 60 pounds, the Lahontan Cutthroat trout is culturally significant to Tribal communities and prized in recreational fisheries but now occupies only about 2% of its historic lake habitat and less than 10% of its historic river and stream habitat in self-sustaining wild populations. Like its Eurasian relatives, the Lahontan cutthroat trout has been shaped by dams, water diversions, climate pressures and historical overharvest. Its story reflects the same pattern seen across Europe and Asia: large migratory trout are highly vulnerable to river fragmentation and environmental change.
“I’m excited that we’re all here together learning about trout species around the world,” said Zeb Hogan, research professor in the Department of Biology at the University of Nevada, Reno. “It was also great to hear from a Summit Lake Paiute Tribe representative about local issues facing the Lahontan cutthroat trout population and compare them to other trout species worldwide.”
Making a global difference for research and conservation
University faculty and students have worked in Mongolia’s central steppe since 2004, partnering with local communities to support river and fisheries conservation and to train early-career professionals. This work has helped foster a conservation ethic and a fly-fishing community in Mongolia, and it has been featured in The Wall Street Journal and National Geographic Adventure. Past Taimen expeditions have contributed to discoveries about Taimen biology and population genetics and fish diversity, growth rates, and the development of new tools for assessing river health and identifying fish.