Aquatic biologists worked recently to move some Rio Grande cutthroat trout from harm’s way in the San Luis Valley.
On July 18, to prevent losing fish in rain-caused debris flows from the Spring Creek Fire, Colorado Parks and Wildlife biologists removed 33 trout from West Indian Creek. The trout in that creek have existed there for thousands of years as an “aboriginal” population, said Estevan Vigil, CPW aquatic biologist in the San Luis Valley.
“The creek is tiny, but Rio Grande cutthroat thrive there,” Vigil said. “We collected fish of various sizes and identified three different age classes, which indicates good natural reproduction.”
The creek is located on private land on the west flank of the Sangre de Cristo mountain range.
There are likely many more fish in the creek, but by removing some of them CPW is maintaining the genetic diversity of these trout which can be added to the overall Rio Grande cutthroat population in Colorado and New Mexico. The fish were taken to CPW’s hatchery in Monte Vista and will eventually be moved to a lake where brood-fish are held. Those fish are spawned by hand and the offspring are stocked in headwaters streams of the Rio Grande.
Over the years, CPW has conducted numerous fish-rescue operations to conserve the various sub-species of native cutthroat trout in Colorado.
CPW, along with the state of New Mexico has restored these trout in 752 miles of streams and 129 separate conservation populations. Over the last 150 years the historic range for the trout has been reduced due to a variety of changes to the landscape and water quality along the Rio Grande drainage. Rio Grande cutthroat trout now only exist in part of their historic range.
The pure strains of the Rio Grande and other cutthroats are stocked only in pristine high-elevation streams and lakes.
“Removing these fish and adding them to the breeding operation will be very beneficial to the overall Rio Grande cutthroat trout conservation program,” Vigil said.