Local Fish Species

Rainbow

by Kathy Davis
Chaffee County Times
Buena Vista
While brown trout make up 90 percent of the Arkansas River’s trout population, a small population of rainbows provides anglers with an occasional surprise catch.

The Arkansas rainbows are all stocked by the Division of Wildlife. They are bred from wild fish and so carry the vivid coloring and red stripe so prized by anglers. They are stocked as fingerlings, large enough to be largely immune to whirling disease but small enough to develop wild instincts.

Despite predation from larger browns, some of these fingerlings do grow to as large as 20 inches on the primarily insect diet this river affords. They tend to be caught in cooler and more highly aerated fast water than are browns. Rainbow populations throughout the West have been hit hard by whirling disease, an introduced parasite transmitted by tubifex worms. Although the Arkansas River was the original river determined to be a whirling disease habitat, whirling disease has not had an impact on the rainbow populations. Management of whirling disease includes fish habitat and hatcheries. The policy of The Division is to stock with negative fish. Hatcheries have switched to using spring water. The only hatchery using surface water is Chalk Cliffs Rearing Unit. Stocking fish from this hatchery are transported to waters that are non-habitat for rainbows, mainly on the eastern plains of Colorado. Browns, originally imported from Western Europe where the disease is endemic, are largely immune to the disease’s skeletal deformity and neurological damage. Whirling disease, along with the spring timing of the rainbow spawn and corresponding fry emergence coinciding with spring runoff, makes natural reproduction ineffective for rainbows. They are in the river, though, and can grow to good size. And their vibrant colors will put a smile of appreciation on any angler’s face.

Cutthroat

Greenback cutthroats are a secret gem of some Arkansas basin high lakes and streams. One of four original trout species in Colorado, greenbacks were severely over-fished by early settlers, almost to the point of extinction. They were out-competed and/or hybridized by non-native trout. In fact, greenbacks were listed as an extinct species in 1937 before two small populations were discovered in northern Colorado.

Since then, a prolonged process of removing non-native trout from certain lakes and streams and reintroducing greenbacks has led to a remarkable recovery. In fact, greenbacks have been downgraded from near extinct to threatened status. Greenbacks are found in the Rock Creek drainage, due west of the Leadville fish hatchery. They are also found in Lake Fork Creek drainage above Turquoise Reservoir and Middle Fork of the South Arkansas River from Boss Lake upstream. Many high lakes support populations of what the Division of Wildlife terms “recreational greenbacks,” hybrids whose genetics are primarily greenback but not the pure strain that has been the recovery effort’s focus.