Feds, irrigation district say keep your wheels off of the silvery minnow

Tire tracks lead into pools where U.S. Fish and Wildlife Service biologists sampled for and found silvery minnow on Aug. 26, 2024 in the Rio Grande channel in the Isleta Reach. (Courtesy of Middle Rio Grande Conservancy District)

A recent uptick in off-roading by trucks and other vehicles in the Rio Grande near Belen has prompted the U.S. Fish and Wildlife Service and the local irrigation district to issue a warning to the public: stop, or face further consequences.

The Rio Grande is currently drying between Albuquerque and Socorro, trapping fish in shallow waters and pools, including the endangered silvery minnow.

There is a tenuous strip of water in the river running in the Isleta reach south of Albuquerque, buoyed by federal releases of water imported from the San Juan-Chama Project and water leased from farmers in the area.

Further south, in the San Acacia reach between Belen and Socorro, an estimated 18 river miles are dry, with some reconnection along the river from rains.

With low waters, federal officials and local irrigation authority at the Middle Rio Grande Conservancy District said they’re concerned that people driving off-road vehicles in the riverbed may be “illegally killing and harassing the silvery minnow,” in an Aug. 29 news release.

The U.S. Fish and Wildlife Service said in the release that anyone performing an act that would “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect” an animal protected under Endangered Species Act faces a fine up to $50,000, up to a year in prison, or both.

‘We know that they’re there’

This area is a crucial stretch of habitat for the endangered fish, which now only lives in the Rio Grande between Cochiti Dam and Elephant Butte Reservoir.

“I can appreciate that it’s probably a really fun activity, but it does not coincide well with our attempts to manage that very critical ribbon of habitat for endangered species,” Casey Ish said about the vehicle activity in the riverbed in Valencia County.

Ish, a Water Resources Specialist for the Middle Rio Grande Conservancy District, said staff have seen anywhere from 40 to 50 vehicles in the riverbed on Friday or Saturday evenings in the summer.

“At the end of the day, we’ve got vehicles driving up and down a river, and that’s just not acceptable,” Ish said.

Rivers and streams are not explicitly mentioned in state laws limiting off-highway vehicle use , but the law prohibits driving in structures used to water livestock and wildlife, or driving “in a manner that has a direct negative effect on or interferes with persons engaged in agricultural practices.”

The New Mexico Department of Game and Fish says on its website it is illegal to operate off-road vehicles “in a way that damages environment, plants, animals or creates excessive noise.”

Ish said the hope is that with new signs posted, the matter would not escalate to police involvement, but also said this has been a challenge in recent years.

“Simply put, I think most of them probably know that it’s not allowed, but that that doesn’t really deter them,” Ish said.

With less water in the Rio Grande, silvery minnows have no room to flee from fast-moving vehicles, said Andy Dean, a U.S. Fish and Wildlife biologist.

“We found about 50 silvery minnow and right where tire tracks were going through, so we know that they’re there,” said Dean, the head for the federal government of the New Mexico Ecological Services Field Office.

Another concern, he said, is that off-road drivers are trespassing on irrigation district lands or potentially polluting the remaining riverbed with fluids and oils.

Enforcement like this has not been tried before, Dean said. The first step is installing signs with warnings about the silvery minnow along the Rio Grande near Belen, to hopefully deter off-roaders.

“If it doesn’t work, then we’ll probably ask law enforcement to start doing some regular patrols down there and start issuing citations,” Dean said.

‘The minnow is the only reason we still have water’

The Rio Grande silvery minnow is a small fish, about four inches long, often a shimmery green and yellow with a cream underbelly, with small eyes and a small mouth.

The minnow is the remnant of a wilder river, historically populating the Rio Grande from Española to the Gulf of Mexico. However, with loss of habitat from climate change, and human reshaping of the river alongside the minnow’s with a unique spawning technique and short lifespan, the fish remains on the edge of extinction.

WildEarth Guardians, a conservation nonprofit who has sued the federal government on behalf of the minnow, applauded the agency for taking steps to address threats to the endangered species.

“WildEarth Guardians supports the effort to prohibit any habitat destruction, including off-road vehicle use near Belen,” said Daniel Timmons, the Wild Rivers program director for the nonprofit. “That said – off-road vehicles are not the primary threat to the silvery minnow. The more concerning thing is that the river is so dry that you can drive a four-wheeler through it.”

Rescuing silvery minnows like ‘slapping a Band-Aid on a severed limb’

Before the 1990s, River drying was rarer on the Rio Grande, but a combination of climate change lessening the snow supply and increased agricultural demand have exposed more sandbed, especially in the San Acacia reach, hurting the minnow’s survival.

Timmons said it’s crucial to understand that the river drying isn’t solely climate change, but is human-driven from irrigation needs.

“In particular it’s being diverted at Isleta by (Middle Rio Grande Conservancy District),” he said. “It’s pretty clear from the gage data that there’s a lot more water in the river above Isleta diversion dam than there is below it.”

A 2023 review by the U.S. Fish and Wildlife Service predicts that river-drying will continue, and be one of the largest threats to the minnow’s survival.

The silvery minnow is misunderstood, Dean said, saying that while it’s been framed as a detriment to farmers and ranchers, it’s the reason the river can be a wildspace in any capacity.

“The minnow is the only reason we still have water in the river. If the minnow didn’t exist in the river, there wouldn’t be any regulatory ability for us to limit the amount of water that is taken out,” Dean said. “It’s helping provide a corridor of recreation and a green portion of the valley.”