Endangered Species Program
Conserving the Nature of America
Episode
16
  • Spotlight Species

Featured Species | Rio Grande Silvery Minnow (09:29)

Host: Sarah Leon with Aimee Roberson

Rio Grande Silvery Minnow (click to view larger)
Rio Grande silvery minnow
Photo credit: Aimee Roberson/USFWS

Overview

Status: Endangered/ Listed on July 20, 1994
Scientific Name: Hybognathus amarus
Description: The future looks a little brighter for the Rio Grande silvery minnow, one of America's most critically endangered species. U.S. Fish and Wildlife Service (Service) biologists recently confirmed that minnows stocked in the Big Bend reach of the Rio Grande in Texas are successfully spawning. This is a major step in establishing the small, shiny fish outside the middle Rio Grande.

In December 2008 the Service, with support from various partners including Texas Parks and Wildlife and the National Park Service, began the silvery minnow reestablishment project in Big Bend National Park. Over 900 thousand hatchery-raised minnows have been released into four locations within Big Bend National Park since the project's beginnings, but it wasn't until this spring that biologists found what they were hoping for—silvery minnow eggs.

"We got the news right before Mother's Day this year," said Aimee Roberson, Fish and Wildlife biologist. "So it felt kind of fitting to be able to say 'Happy Mother's Day' to the silvery minnow." According to Roberson, the spawning shows the project could potentially be successful in reestablishing the silvery minnow in Big Bend—a stretch of the Rio Grande this species has been absent from since 1960.

"The Rio Grande silvery minnow was once one of the most widespread native fish in the Rio Grande and Pecos River, found from northern New Mexico to the Gulf of Mexico at Texas," said Roberson. But the construction of dams and reservoirs, modification of river flows, habitat fragmentation and decreasing water quality all took a toll on the fish. "When we began releasing fish into the Big Bend reach of the Rio Grande in Texas, the species only occupied about 5 to 6 percent of its historic range."

The recovery project plans to stock fish in the Big Bend reach for four years. The goal is to create self-sustaining populations in at least three areas of the minnow's historic range outside New Mexico's middle Rio Grande. According to Roberson, the silvery minnow reestablishment project is a really important step in fulfilling the recovery goals laid out in the Rio Grande Silvery Minnow Recovery Plan.

"It's really exciting, after working several years on this project, to see this result," said Roberson. "I think it's indicative that we are moving in the right direction and moving towards successfully reestablishing the species in the Big Bend Reach."

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Last updated: December 31, 2012