Native trout make slow, steady recovery in Colorado despite drought, other challenges

By Todd Malmsbury

After years of recovery work and challenges that have included wildfires and a prolonged drought, Colorado Division of Wildlife (DOW) officials are reporting good progress in creating new populations of Colorado River, Rio Grande, and greenback cutthroat trout both in the wild and at state hatcheries.

Populations of the state’s native trout subspecies had dwindled dramatically before greenback cutthroat recovery efforts began in the 1970s. The state’s bid to return cutthroat trout to their historic range took on a new perspective in 1997 when the Colorado Wildlife Commission issued a high-priority directive guiding management polices and long-term goals.

State biologists are now seeing the payoff. Colorado currently has twenty-nine conservation populations of greenback cutthroat trout; seventy-six conservation populations of Rio Grande cutthroat trout; and 171 conservation populations of Colorado River cutthroat trout.

When the greenback conservation program began in 1973, the state could claim only two naturally occurring populations of the subspecies. Since then, fourteen more wild populations have been discovered, and the state has added thirteen restored populations. Colorado met its state de-listing goal when it achieved ten populations of Rio Grande cutthroat in 1985. In 1998, the state had eighty-seven stream populations of conservation-rated Colorado River cutthroats and nine lake populations.

“We have made some extraordinary progress in six years,” said DOW Senior Fish Biologist Sherman Hebein, referring to Colorado River cutthroat recovery efforts.

While overall cutthroat numbers have improved, some individual populations are small and at greater risk of extirpation, which means the recovery program will likely continue for years to come. State and federal biologists recently conducted a range-wide review of the status of Colorado River cutthroats, and results are expected to be released soon.

“Cutthroat trout have inhabited the state for thousands of years, and wildlife aquatic biologists and hatchery technicians are committed to preserving the region’s natural legacy,” said Tom Nesler, native fish species coordinator for the DOW’s species conservation section. “Our cutthroat subspecies have been pushed back from their historic range, and we are attempting to secure these three native trout subspecies so they can continue to form part of our aquatic wildlife heritage.”

Biologists blame the decline of Colorado’s cutthroats on hybridization with rainbow trout and competition with other non-native trout that were introduced to the state a century ago. Habitat destruction, poor water quality, drought, and human activities such as gold mining have also taken a toll on the speckled fish with crimson neck markings.

As a result of these impacts, the greenback cutthroat has been listed federally as a threatened subspecies, and the Colorado River cutthroat has been displaced from more than eighty percent of its historic range, inhabiting only smaller headwater streams and high-altitude lakes.

Concern for the Colorado River and Rio Grande subspecies has prompted environmental groups to petition for their listing as well. However, recent assessments by the U.S. Fish and Wildlife Service recommended against their listing because multi-state recovery efforts have been effective in reversing declines and reducing threats to the two subspecies.

“We have three very active conservation programs for our three native cutthroat subspecies,” Nesler said. “The condition of the Colorado River and Rio Grande cutthroats is such that the trout’s status and our accomplishments have precluded any need to have them protected by federal listing. We have demonstrated that we are actively trying to improve the status of these two trout subspecies and are trying to create new populations and expand habitat.”

Nesler and others said native cutthroat populations are making a slow and steady recovery because of the creation of new wild populations, the creation of captive populations in state hatcheries for stocking purposes, and interagency collaboration on goals and strategies among federal and state wildlife biologists in Colorado, Utah, Wyoming, and New Mexico.

In 1999, Colorado joined other state, federal and private entities in signing the Tri-State Colorado River Cutthroat Trout Conservation Agreement with Utah and Wyoming. Earlier this year, the state signed the Rio Grande Cutthroat Trout Conservation Agreement with New Mexico. DOW officials said Colorado could not have progressed as far and as quickly as it did without the cooperation of the U.S. Forest Service and the Bureau of Land Management.

While Colorado currently has enough greenback cutthroat trout to meet its recovery goal, wildlife officials acknowledged that a prolonged drought has had a negative impact on some populations and that fish have been rescued from rapidly drying streams.

Rich Kolecki, Colorado’s hatchery chief, who oversees twenty facilities in the statewide system, said securing sufficient cutthroat populations in state hatcheries to stock lakes and streams is vital to recovery efforts. As such, hatchery technicians must develop broodstocks to increase or amplify the number of fish available for restoration projects.

In essence, hatchery personnel are helping nature by increasing the survivability of the eggs and fry, which in the wild can experience up to ninety-nine percent mortality. In Colorado, cutthroat trout that are rescued in the wild are taken to isolation units in Salida and Rifle before they are transferred to one of several quarantine facilities around the state. Hatchery personnel are then able to develop new broodstocks from the offspring of rescued fish.

“We are very careful about bringing live fish into our state hatcheries because of disease that the parent fish may carry; however, their eggs can be disinfected,” Kolecki said.

Kolecki said cutthroats are more sensitive to poorer water quality. Hatchery technicians must put the fish in first-use water and feed them a special, more expensive diet that is fortified with protein, amino acids, and double vitamin packs.

“They are high-maintenance fish, but they are important high-maintenance fish.,” Kolecki said. “A lot of the problems that these species are having are directly associated with humans. Now that we have the ability and the technology to address these situations, it’s part of our mission to save them.”

Pure subpopulations of the greenback can be found in the Arkansas and the South Platte basins. DOW hatcheries presently have two pure greenback broodstocks from the Arkansas and South Platte rivers and four Colorado River cutthroat broodstocks from the White, Colorado, Dolores and San Juan rivers.

Dan Brauch, a DOW aquatic biologist in Gunnison who is involved with interstate efforts to recover cutthroat trout, said Colorado wants to establish additional pure, non-hybridized populations of Colorado River cutthroat trout on six major rivers on the Western Slope, including the Yampa, the White, the Colorado, the Gunnison, the Dolores and the San Juan drainages.

“The entire Western Slope region is within the Colorado River cutthroat range. The long-term goal is to maintain current populations and establish new ones, and to ensure that the Colorado River cutthroat trout as a subspecies remains in good condition,” Brauch said.

Brauch said another goal for Colorado is to manage the recovery effort in a way that provides angling opportunities for fishermen. Because native cutthroat trout have become less common than other salmonids, many anglers search for opportunities to catch them.

For now, greenback populations at recovery sites must be released back into state waters if they are caught. Greenbacks have also been stocked in high lakes and may be harvested. Most conservation populations of Colorado River cutthroat trout and Rio Grande cutthroat trout are also protected with catch-and-release regulations. Anglers should check the appropriate regulations before stopping at a specific fishing site, wildlife officials said.

Brauch is confident Colorado’s cutthroat recovery efforts are heading in a positive direction, despite the drought, wildfires and other challenges.

“If there are enough quality sites out there we can continue to fish recreationally for cutthroats. Certainly, that’s part of what we are trying to maintain,” he said. “We’ve been able to establish many more populations. We’ll continue to monitor those populations that have been impacted by the drought, and work as hard as we can to try to assist in their recovery.”

For more information about Colorado’s native cutthroat trout, visit http://wildlife.state.co.us/species_cons/wildlifeindanger/cutthroat.pdf and http://wildlife.state.co.us/aquatic/cutthroat/index.asp