Colorado Parks and Wildlife has stocked a tiny, but important fish on USDA Forest Service land for the first time.

According to a June 9 press release, CPW aquatic biologists and USDA Forest Service rangers and biologists put more than 18,000 northern redbelly dace into a small groundwater-fed creek on Pawnee National Grassland last month. Not only was the first time the state-endangered fish species had been stocked on Forest Service land in Colorado, but it was the first time the species had been stocked on any federal land nationwide in two decades.

Considered to be state-endangered ‘Tier 1,’ the northern redbelly dace is designated to be at the highest level in terms of conservation need. Colorado is home to only approximately six self-sustaining populations of the species, all located in the South Platte River Basin. Wildlife officials describe the species as a sort of ‘canary in a coal mine,’ with a population’s welfare serving as an indicator for when an aquatic environment is becoming unstable. If the northern redbelly dace disappear, something is wrong.

In order to form a sustainable population, the species requires cool, vegetated, slow-moving perennial water in ponds and streams that are absent of non-native predatory fish and pollution. Because of how fragile a population can be when a habitat doesn’t meet those requirements, it’s rare to find a site where stocking would be feasible.

Only about two to three inches in length, the northern redbelly dace is classified as a true minnow, named for a red stripe that forms on the stomach of male fish during breeding season. While the species is widely found in the United States and Canada, that’s not the case in Colorado with the local population having been decimated by non-native species since the 1950s. Of the six known populations in Colorado, a single population is indigenous. The other five self-sustaining populations were stocked from this indigenous West Plum Creek drainage population – the result of 30 attempts.

The fish involved in the recent stocking were spawned and raised at the Native Aquatic Species Restoration Facility, which is located in Alamosa and rears 12 fish species with a focus on those that are considered at-risk.

“A cornerstone goal of CPW’s native aquatics team is to maintain biodiversity within our state,” said Matt Haworth, CPW Platte River Basin Native Aquatic Species Biologist. “By proactively restoring northern redbelly dace to more locations on the landscape, we are building species resiliency with a long-term target of successful reproduction in the wild that would no longer need the support of stocking.” 

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