ALBUQUERQUE, N.M. (AP) — About 15,000 Rio Grande silvery minnows are now swimming in the river as part of a decades-long effort to keep the tiny fish from disappearing.
Buckets containing the latest batch of fish were poured into the river last week by staff from Albuquerque’s BioPark. In all, more than 800,000 minnows have been released since 2000 through a partnership that focuses on endangered species living in the middle Rio Grande.
The minnow had a chance this year to rebound since the river got a boost from healthy snowmelt in the higher elevations.
The favorable flows resulted in spawning so no captive-bred fish were needed to augment the wild population.
Still, some environmentalists are concerned that without changes in the way the Rio Grande is managed, the minnow won’t have a chance to make it on its own without continued human intervention.
Jen Pelz, the wild rivers program director with the environmental group WildEarth Guardians, said the river had one of its best years in decades in 2019 and yet the spring spawning densities dwindled by the fall because of what she described as a failure by officials to prioritize a connected flowing river.
She pointed to diversions along the river that have made it impossible for the fish to pass without the use of buckets wielded by workers with the U.S. Fish and Wildlife Service.
“This is just irresponsible,” Pelz said. “The health of the silvery minnow is directly reflective of the health of the riparian corridor, and people who want a river running through their community need to start demanding a more sustainable approach.”
Albuquerque Mayor Tim Keller also acknowledged that the well-being of the minnow is an indicator of the health of the Rio Grande. He said the city’s conservation efforts are making a difference.
Listed as endangered in 1994, the tiny fish was once abundant throughout the Rio Grande basin from Colorado to Texas and into Mexico. It's now found in a fraction of its historic range as the river system has seen dam building and the straightening of its once meandering channels.
In New Mexico, federal biologists say the Rio Grande has lost two of its native species in recent decades. Five additional species have been extirpated from the river over the years, and the silvery minnow faces an uphill battle after its population was hammered by last year's dry conditions.
Parts of the river south of Albuquerque did go dry in 2018, prompting wildlife managers to organize rescue missions for the minnow. More than 70,000 of the tiny fish had to be moved to flowing parts of the river.
Kathy Lang, curator of the ABQ BioPark’s Aquatic Conservation Facility, said last week’s minnow release is important for studying how the species matures.
The fish are tagged with small colored markers so biologists will be able to tell how long the fish are surviving in different parts of the river.
As part of the work, eggs also are collected each year from the wild population and reared at the BioPark’s aquatic center.