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Endangered Silvery Minnow and Water Quality Issues

Date Posted: September 25, 2001

The Middle Rio Grande river in New Mexico is home to Federally-listed endangered Rio Grande silvery minnows (Hybognathus amarus). Lack of precipitation and diversion and consumption of water have altered the natural rise and fall of water levels within the River. These factors combined with the pollutants that enter the water from agricultural and urban run-off, wastewater discharge and other unidentifiable sources, have altered water-quantity and -quality within the River and may have degraded or eliminated minnow habitat. To ensure the continued survival of this species, the impact of these changes in water-quantity and -quality must be fully understood. The New Mexico Field Office’s Environmental Contaminants (EC) Program is looking at one piece in this puzzle. Working with the Middle Rio Grande Collaborative Workgroup, Middle Rio Grande Coordinating Group, New Mexico Department of Game and Fish, and the U.S. Geological Survey’s Biological Resources Division, the EC Program is developing studies to determine if pollutants affecting water-quality are also affecting the survival, growth, and behavior of silvery minnows. Studies will thoroughly evaluate fish health and will look for pollutants in sediment and water at sites where minnows are found as well as sites where the fish were once found but are now absent. Studies that look at the minnow’s diet are also being considered. If it is determined that water-quality is affecting silvery minnows, this information can be used to help make recommendations on how to eliminate or minimize impacts from the pollutants.

Joel Lusk 505-346-2525, ext. 109.

Last updated: June 12, 2015