The Rio Grande cutthroat trout, icon of Southern Colorado and New Mexico, after years of fighting for survival with the help of countless human hours, will not find itself on the endangered species list. The U.S. Fish and Wildlife Service recently announced the trout is not in danger of extinction or likely to become so in the foreseeable future, after two and half decades of review and conservation work.
After completing a final review, the Service concluded that the Rio Grande Cutthroat trout’s current status in the mostly remote water ways of Colorado and New Mexico doesn’t meet the definition of a threatened or endangered species, and won’t be listed under the Endangered Species Act.
“CPW staff have worked tirelessly for decades to ensure Rio Grande cutthroat trout continue to persist,” said Matt Nicholl, Colorado Parks and Wildlife’s assistant director of aquatic wildlife. “The responsibility of successfully managing this species deeply aligns with our mission, and we are thankful for the continued support and collaboration with all of the partners who have made this announcement possible.”
Over the course of the past three decades, biologists from Colorado have added 94 populations of pure Rio Grande cutthroats to 239 miles of stream, through chemical reclamations and habitat and connectivity enhancements related to these species.
The Rio Grande cutthroat trout is one of 14 subspecies of cutthroat trout. It lives in mostly remote, mountainous streams in New Mexico and southern Colorado. The fish is a colorful red, orange and yellow, peppered with dark spots.
Rio Grande cutthroat trout can be found in high-elevation streams and lakes of the Rio Grande, Canadian and Pecos River drainages in Colorado and New Mexico, making it the southern-most cutthroat trout. Currently, the fish only occupies 12 percent of its historic habitat in about 800 miles of streams. Biologists estimate that 127 conservation populations now exist in the two states, and 57 of those populations are considered to be secure.
“The Rio Grande cutthroat trout has been New Mexico’s state fish since 1955,” said Amy Lueders, the Service’s southwest regional director. “This fish is extremely important for recreational angling in New Mexico and Colorado and management efforts have focused on population restoration, habitat improvement and research. We are thankful to the Rio Grande Cutthroat Trout Conservation Team because their continued work, along with efforts by other partners, will support the health of both the subspecies and its habitat into the future.”
To complete its life cycle, the cutthroat trout needs a network of slow and fast streams with clear, cold, and highly oxygenated water and highly biodiverse streambeds.
Since 2003, Colorado Parks and Wildlife and multiple partners, including federal agencies, states, tribes, municipalities, non-government organizations and private landowners, have worked to conserve the species and implement long-term management actions to ensure its persistence and survival.
A series of collaborative frameworks of this group was updated in 2013 and again in 2023 with a conservation agreement and conservation strategy that aimed for long-term conservation.
“This decision is in response to all of our hard work between all of our partners,” said CPW aquatic biologist Estevan Vigil. “The whole Rio Grande Cutthroat Conservation Team, this is a win for all of us and shows we’re working hard to conserve the species without making that federal protection necessary and that we are making gains for the species. The decision to not list the Rio Grande cutthroat doesn’t mean we can stop. It just means we are on the right track.”
The past, present and future threats to the Rio Grande cutthroat trout have been monitored and evaluated closely. The primary factor impacting the survival of the subspecies is the presence of nonnative species of trout, including rainbow trout, brook trout and brown trout. The conservation populations of Rio Grande cutthroat trout, or populations with less than 10 percent genetic introgression from nonnative trout, occupy approximately 12 percent of the species’ historical range. Additional threats include habitat loss, reduced habitat connectivity and whirling disease.
Those other fish will outcompete, prey upon and hybridize with Rio Grande cutthroats. As a result, pure populations of Rio Grande cutthroat trout are restricted primarily to headwater streams to avoid an overbearing mix of disease and genetics.
View the U.S. Fish and Wildlife Service’s findings here.
The trout has had a specialized team focusing on its survival throughout the restoration effort. The Rio Grande Cutthroat Trout Conservation Team is made up of state agencies in New Mexico and Colorado, as well as federal agencies, tribes, and non-government organizations.
In the past 10 years, the conservation team has conducted 13 population restorations by removing nonnative trout and reintroducing Rio Grande cutthroat trout.
The Rio Grande Cutthroat Trout Conservation Team meets in January each year to coordinate rangewide goals and objectives. Vigil said the team serves to provide checks and balances to each other to make sure holistic goals are met.
“Following that meeting, we all go back to the areas we manage and divide and conquer all summer to meet the goals set of conserving this species,” Vigil said. “Through this shared commitment to collaborate and take actions, the future for this native species is bright throughout the Rio Grande Basin.”
The conservation team has conducted 13 reclamation projects to restore the fish to its native streams in the past decade, and additional projects in Colorado will soon lead to further conservation populations.
Recognizing declines, CPW began conservation efforts for this species in the early 1980s. Work included genetic testing, invasive species removal, habitat protection and enhancement, and broodstock development.
In Colorado, Rio Grande cutthroats are spawned in the wild by CPW biologists and eggs are raised at the Monte Vista Hatchery. Since 2020, CPW has stocked 24 waters with Rio Grande cutthroats raised at the hatchery.
A new conservation population of Rio Grande cutthroat trout was designated in 2023 when a survey revealed multiple age classes of the species following a successful 2015 restoration project on the Roaring Fork drainage upstream of Goose Creek in the Weminuche Wilderness.
Recent reclamation projects also have been conducted on the North Fork and South Fork of Trinchera Creek, Sand Creek, and Rito Hondo Reservoir, but those populations won’t count as conservation populations until future surveys reveal multiple age classes of Rio Grande cutthroats.
“We are continuing to reclaim waters for native cutthroat trout by removing non-native fish and restocking with natives,” Vigil said. “We have a lot of projects and some in the process of being rebuilt. We know we are making good progress on the conservation of the species, and this is confirmation we are doing our jobs correctly and making progress.”
Over the past two years, species experts from CPW have served on the Technical Advisory Team to support USFWS in developing a Species Status Assessment. This included thorough input on early drafts of the assessment and enhancing scientific accuracy and defensibility of this document to support the final decision.
“CPW biologists played a significant role in the writing of this strategy, which details specific conservation actions and collaborative approaches that will reduce and/or eliminate threats to the long-term viability of the species,” said CPW senior aquatic biologist Jim White. “Following this announcement from the USFWS, we look forward to continued partnership with the conservation team as we continue to advance conservation goals for these unique species.”