Multi-step strategy in place to conserve native Rio Grande cutthroats
One of Colorado’s most-elusive native cutthroat trout species has a firmer grip on the future.
Colorado Parks and Wildlife, the New Mexico Department of Game and Fish, federal agencies and several American Indian tribes recently updated a multistep strategy to conserve and protect the Rio Grande cutthroat trout.
The agreement, said John Alves, southwest region senior aquatic biologist for Colorado Parks and Wildlife, may help keep the fish off the Endangered Species list.
The Rio Grande cutthroat is one of Colorado’s three remaining native trout subspecies, along with the Colorado River and the Greenback cutthroat trout.
A fourth native trout, the Yellowfin, is considered extinct.
The conservation effort began in 2003, said Alves, who has been involved with the program since it’s inception.
“This is a voluntary agreement, but all the parties are dedicated to working on important Rio Grande cutthroat trout issues,” he said.
The recent addendum ensures the effort is a 10-year plan, “which is about as far out (ahead) you want to go,” Alves said.
As with all native fish (and most other native wildlife), the historic range of Rio Grande cutthroat trout has been reduced over the past 150 years because of numerous changes on the landscape, both natural and manmade.
Drought, fires, water and habitat changes, hybridization with rainbow trout and other species of cutthroat trout, and competition with brown trout and brook trout have all taken their toll.
Today, Rio Grande cutthroat trout populations are restricted to only 12 percent of historic habitat in approximately 800 miles of headwater streams and lakes of the Rio Grande, the Canadian River and the Pecos River in Colorado and New Mexico.
Most of the lakes in the Sangre de Cristo Range in southern Colorado and northern New Mexico have been stocked with Rio Grande cutthroat, Alves said.
“We stock a lot of high lakes, at least all the ones we can reach,” Alves said. “But some are so steep the pilots don’t want to fly to them.”
These isolated lakes serve as repositories for pure Rio Grande cutthroats.
“Since most of these lakes don’t have a lot of reproduction, we can stock them every other year (with pure Rio Grande cutthroats) and eventually the nonnative cutthroats and rainbow trout will die off,” Alves said.
Alves also said drought and fire aren’t intrinsically bad.
“Fire and drought have caused problems but can prove to be opportunities as well,” he said. “Fire may destroy all the fish in a stream, making it possible to build some barriers and reintroduce Rio Grande or other native fish.
“Same thing with drought. We’ve lost a few populations here and there, but one population we thought we had lost was found, just a few survivors in a puddle.”
Those isolated survivors contributed to a restored population once water came back to the stream.
For more than 20 years, agency biologists have been searching for Rio Grande cutthroat populations, studying habitat and restoring the species to streams.
That work and more will continue under the conservation agreement.
“The Rio Grande cutthroat trout is unique,” said Kirk Patten, assistant chief of fisheries for the New Mexico Department of Game and Fish. “It is found only in the southwest and has the distinction of being the southernmost distribution of any form of cutthroat trout.”
The trout, considered a species of “greatest conservation need” by New Mexico and as a “species of special concern” in Colorado, has been considered “warranted” for listing under the ESA since May of 2009 but was precluded pending higher priority listings.
A decision by the Fish and Wildlife Service is scheduled for September.
“Hopefully, the work we’re doing will keep this fish off the ESA list,” Alves said.
Alves said the large parcels of private land going back to Spanish land grants have protected several populations of the Rio Grande cutthroat trout from nonnative fish introductions.