NMSU branding

New Mexico State University

New Mexico State University

News Center

NMSU grows endangered fish in the middle of the desert

Fish aren't supposed to live in the desert, miles from the nearest permanent source of water, but that isn't stopping New Mexico State University from growing thousands of silvery minnows and potentially other endangered fish at the "A" Mountain Geothermal Fish Culture and Research Facility.

Endangered silvery minnows swim inside a tank at the NMSU "A" Mountain Geothermal Fish Culture and Research Facility. (NMSU Photo by Justin Bannister)

"The silvery minnow is a unique organism. They really represent the yellow canary in the mine," said Colleen Caldwell, an affiliated faculty member at NMSU's Department of Fish, Wildlife and Conservation Ecology. "Most ecologists say we are all tied together. If one species is affected, so are the others."

The silvery minnow has been listed as an endangered species since 1994. Researchers say at one point, it lived along nearly the entire stretch of the Rio Grande. Today, the minnow is found in less than 10 percent of the river, mostly in central New Mexico.

The fish culture facility's mission is to help preserve the species. For the last eight years, they have brought in new fish eggs and sometimes baby fish to grow and eventually breed.

"In 2000, there were no eggs produced naturally in the wild," Caldwell said. "That's why what we are doing is so important."

The fish culture facility is located at the base of "A" Mountain, east of Las Cruces and is home to approximately 7,000 silvery minnows. It has a capacity for more than 50,000.

"It wasn't being used, and we wanted to increase our teaching and research potential," Caldwell said. "If it wasn't for this, our students wouldn't be able to even touch a real fish in our department. I think it's important for students to be able to interact with this species."

Researchers take pride in not wasting water inside the building. All of it is reused after being filtered through a combination of natural and low-cost procedures. An ultra violet light is used to kill water-borne pathogens that survive the filtration process. Additionally, the building is designed to take advantage of the area's geothermal-heated water - water that is naturally heated under the earth's crust.

"Fish slow down in the cold. They stop eating and don't grow. In the winter, we use the geothermal water to heat the water in the facility," Caldwell said.

There are two additional vacant buildings at the site. While the university is still trying to find tenants for the other buildings, Caldwell hopes to eventually use one of them to raise endangered amphibians.

"We are seeing a lot of amphibians, especially those native to this region, showing up endangered or imperiled," she said.

Inside the fish culture facility, the silvery minnow feast on algae growing inside their tanks as well as a specialized diet recently formulated by Caldwell and her colleagues.

"We've developed a special diet through four years of research. It's much better than the store-bought brand."

She explained the fish food they were buying in stores could sometimes be old. Plus, she found it didn't have enough nutrients for the silvery minnow. Her fish now feed on a mix of proteins with a supplement of vitamins. Caldwell said it helps with disease and in preventing spinal deformities.

"It gives us quality, fertilized eggs. The hatch is excellent," she said.

Currently, the facility is preparing to grow bonytail chub, for which they also will develop a special diet. The fish is native to New Mexico and Arizona, but has trouble reproducing in the wild - a phenomenon that could be linked to changes in their habitat.