Native cutthroat trout to return to high country

Native cutthroat trout to return to high country

Oct. 19, 2000

BY THE COLORADO DIVISION OF WILDLIFE

DENVER — The natives are returning to Colorado’s high country. By the end of the decade, the Colorado Division of Wildlife hopes to have most high country lakes stocked with native cutthroat trout, instead of non-natives, for angler recreation. The transformation comes as a result of a Colorado Wildlife Commission policy directive in 1997 to give priority to native species in AAA waters — high-altitude wilderness lakes and streams known for their purity and secure aquatic habitats. Restoring native cutthroats through stocking, as well as developing self-sustaining populations in their historic range, is among the division’s highest priorities, according to Aquatic Resources Manager Eddie Kochman.

"The division recognizes the importance of managing Colorado’s native cutthroat to assure their long-term well being," Kochman said. "High priority will be placed upon providing adequate numbers for stocking throughout the state’s high country." In fact, the process has already begun. In the northeast region, including the South Platte River headwaters, 160 waters are deemed to be suitable for stocking of greenback cutthroat trout. Since 1996, about half of those lakes have been stocked with cutthroat every other year.

All fish stocked in AAA waters must, by division policy, be certified free of whirling disease. Whirling disease is a parasitic infection of trout and salmon caused by a microscopic amoeba that produces a spore. The water-borne parasite (Myxobolus cerebralis) may not directly kill trout, but fish heavily infested can become deformed or exhibit the erratic tail-chasing behavior from which the disease gets its name. Eventually, heavily infected young fish may die.

In the southeast region, about 140 AAA waters in the Arkansas River headwaters are eligible for cutthroat stocking. Those waters also have been stocked every other year since 1996.

The CDOW plans to maintain the same stocking schedule this year for greenbacks in both the South Platte and Arkansas basins.

In the Rio Grande Basin 55 lakes and 13 streams have been stocked with Rio Grande cutthroat fingerlings periodically since 1993. In 1998, 24,000 fish were stocked in 23 AAA Rio Grande Basin lakes. This year 22,000 Rio Grande natives are scheduled to be stocked in 23 AAA lakes in September, and another 8,000 are scheduled to be stocked in a AAA brood lake.

In the western region, comprising all river drainages west of the Continental Divide except the North Platte, there could be an estimated 500 AAA waters eligible to be stocked with native cutthroats. No decision has been made on the number of those AAA waters to be stocked, but it should be a high percentage of the eligible waters, according to Gunnison-based division biologist Dan Brauch.

"I will be looking to maximize my use of Colorado River natives to stock high lakes and streams, and I expect many of the other biologists will do so as well," Brauch said. Little stocking has taken place on the Western Slope since 1996 due to concerns over whirling disease.

Stocking of Colorado River cutthroats in this region could resume in the next few years as the supply of whirling disease-free fish increases. In the meantime, biologists have located hundreds of populations of cutthroat trout on the Western Slope that may be fished. These lakes are stocked to provide angler recreation and the current bag limit is eight fish east of the Continental Divide and six fish on the Western Slope – two from rivers or streams and four from lakes, unless otherwise posted. Due to lack of spawning areas and short growing seasons, most of the lakes to be stocked cannot support natural reproduction. Cutthroat populations in those lakes can be maintained only through periodic stocking, Kochman said.

In addition, the Division also has established greenback, Rio Grande and Colorado River native trout recovery populations, which are intended to provide self-sustaining populations of pure or nearly pure native cutthroats in their historic watershed. Angling is allowed on most recovery populations, but it is generally limited to flies and lures only, with immediate return to the water required.

Division efforts overcame a troubled history:

While the Wildlife Commission’s directive brought a more systematic approach to returning native cutthroats to their historic range, it wouldn’t have been possible without the dedicated efforts of CDOW biologists throughout the past century. Those biologists found and protected populations of native cutthroats and encouraged their propagation.

By the early 1900s, Colorado’s native trout had been all but displaced from their former range, due to habitat degradation, over-fishing, competition from non-native species and crossbreeding with rainbow trout.

The Rio Grande cutthroat: back from the brink

Division biologist Lloyd Hazzard proved to be the Rio Grande cutthroat’s salvation when his crew discovered a few small populations in the San Luis Valley in the mid 1960s. At that time, pure strains of the subspecies were thought to be extinct. Those fish were moved to reclaimed waters to develop a broodstock, which became the source of fish for recovery efforts and stocking beginning in 1975. By 1996, the number of Rio Grande cutthroats stocked was at an all-time high, with 41,000 fish stocked in 42 waters.

Colorado River cutthroats: The fish were there, but what a job

Colorado River cutthroats, however, found a haven in Trapper’s Lake, and those fish became the brood source for continuous stocking efforts dating back to 1904. While Trapper’s Lake provided a secure brood source in those early years, Division employees endured many hardships in bringing those eggs out of the remote lake, according to recently discovered records.

At times, division employees were away from home for weeks, on horseback, afoot, and on snowshoes working to recover the fish. They would take spawn, build screens on irrigation headgates and paddles on the ditches, and generally take care of the fish population. One such trip lasted from Thanksgiving until just before Christmas, according to the records.

From the mid 1980s to 1995, the DOW stocked an average of 425,000 Colorado River cutthroats each year, with a high of 674,000 fish stocked into 277 waters in 1988.

The greenback cutthroat – Colorado’s state fish – rescued from oblivion

Like its Rio Grande cousin, the greenback cutthroat was thought to have become extinct until two tiny populations were located in streams in Boulder and Larimer counties in 1957. The greenback was listed as endangered under the Endangered Species Act by the federal government in 1973. Since then, fish propagated by the Division from those two populations have brought the subspecies back from near extinction, allowing it to be upgraded to "threatened" in 1978. To commemorate the successful recovery effort, the greenback cutthroat was officially named Colorado’s state fish in 1994.

Today, the greenback’s recovery has progressed to the point where it could be removed from the federal endangered species list in the foreseeable future.

With hundreds of lakes to choose from now and more in the future, the return of the natives to Colorado’s wilderness lakes bodes well for fishing in these high country jewels.

And it restores a beautiful piece of our natural history to its rightful place.