ABQ BioPark releases 48,000 Rio Grande silvery minnows this fall

Dec. 5, 2018 - This November, the ABQ BioPark continued its cooperation with the Middle Rio Grande Endangered Species Collaborative Program by providing 48,000 Rio Grande silvery minnows for release into the river. An additional 18,000 fish will be provided for release in February.

According to Kathy Lang, curator of the ABQ BioPark’s Aquatic Conservation Facility, 2018 was a difficult year for wild Rio Grande silvery minnows. Although there was some spawning, the ongoing drought and low water levels led to poor conditions for survival of larval fish (or for adult fish). As a result, the US Fish and Wildlife Service requested a total of 213,000 Rio Grande silvery minnows from the three fish hatcheries in New Mexico that raise the endangered fish.

The Rio Grande silvery minnow, a 2- to 4-inch long fish, was once one of the most common species in the Rio Grande, but by 1994 its population had declined so greatly that it was added to the federal Endangered Species List.

The BioPark has been part of the recovery program for the Rio Grande silvery minnow since 2000. Each spring, staff from the BioPark’s Aquatic Conservation Facility collect eggs from the Rio Grande to hatch in tanks at the BioPark, and also breed additional minnows from previously collected broodstock. Fish destined for release are “tagged” with a small colored mark before their release so biologists can monitor the success of the program. Tagging also allows biologists to monitor some aspects of the minnows' behavior and how long the fish are surviving in different parts of the river.

Releasing fish with slightly different tags in November and February may indicate which release time gives the Rio Grande silvery minnows the best chance of surviving. Additionally, biologists hope to be able to determine if fish released in February will be ready to spawn in 2019.  

Watch footage from the ABQ BioPark's 2014 minnow release.