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In the second year of a spawning experiment, the Los Lunas Silvery Minnow Refugium has seen positive results.
The refugium applied for and was awarded a contract from the Bureau of Reclamation in 2010, said refugium assistant manager Alison Hutson.
“They wanted to try and define where the minnows preferred to spawn,” Hutson said.
Since the small fish were declared an endangered species and efforts began to try to rebuild their numbers, there has been an ongoing debate of just where they preferred to spawn in the Rio Grande.
Did they prefer the deeper, faster moving water in the river channel or the slower shallows of the over-bank areas?
Answering that question could help find solutions to river flow issues such as the Rio Grande is experiencing this year.
Not only could the experiment answer questions about how much water the fish wanted and needed to spawn, but it could reveal other triggers that caused the event.
“If we are only relying on natural cues, we don’t even know what they all are,” Hutson said.
Refugium manager Douglas Tave said there were a couple of cues that could safely be assumed.
“They spawn at a certain time of the year, so warmer temperatures seem to be a cue,” Tave said.
The uniqueness of the refugium is that it mimics the Rio Grande. There are no chemicals used to treat the water, no food pellets for the fish. Larger predators that could wipe out the population are kept at bay, but if a hungry raccoon wanders in, the minnows are fair game.
Last year, Hutson and Tave put the man-made river at the refugium through its flood cycle, but there was no spawning.
This year, they started the flood on April 24.
Since there was no significant spring melt runoff this year, Tave said they had to rely on historical data to recreate the river flows. The level of the “river” was left high for a week, then brought back down. The next flood began on May 7.
Three days later, Hutson spotted the new fish.
By getting the minnows to spawn in the refugium, there is the potential to use the data produced to help direct management of the river.
“There are things we can do here that can’t be done on the river, that we can observe,” Tave said. “What we do here costs pennies versus dollars on the river. One of the central purposes of the refugium is to learn how to manage the water in the river, so that it benefits both the minnow and local irrigators.”
— This article appeared on page C1 of the Albuquerque Journal
