From the Associated Press via The Durango Herald:
The New Mexico Game and Fish Department announced Wednesday that the fish were released into the river in late October. Roundtail chub were once found throughout the Colorado River basin, including the San Juan River and its tributaries in New Mexico, Colorado and Utah. The species was listed as threatened under the New Mexico Wildlife Conservation Act in 1975 and uplisted to endangered in 1996.
They were stocked in the San Juan near the confluence with the Animas River, high in the system in the hope that they will disperse downstream into suitable habitat.