Alamosa – As it turns out, suckers aren’t born every day – especially Rio Grande suckers.
Once abundant in the Rio Grande and its tributaries, the small, mottled brown fish had almost vanished from Colorado by the early 1980s.
That’s when wildlife biologists found about 100 suckers in Conejos County’s Hot Creek. It was then thought to be the species’ last large-scale population.
The effort to save the suckers recently received a tremendous boost with the discovery of a new population in Crestone Creek, in the Baca National Wildlife Refuge in Saguache and Alamosa counties.
Wildlife officials say the discovery is significant because it brings them one step closer to the goals of the suckers’ recovery plan, which calls for establishing three populations in the Rio Grande’s major drainages.
“We’re suddenly two-thirds of the way there,” said John Alves, the Colorado Division of Wildlife’s aquatic biologist in the San Luis Valley.
In late 2004, Alves got a call from a refuge manager who asked him to look at fish that workers had found in Crestone Creek.
Those fish turned out to be Rio Grande chubs, also a rare, native species.
Knowing that the chub and suckers prefer the same kind of streams, Alves returned in October 2005 and took samples.
“As soon as I saw it, I knew it was a Rio Grande sucker,” Alves said.
Alves believes the fish are likely a genetically pure strain given the creek’s isolation.
If they are, the Crestone Creek suckers will prove to be crucial to restocking efforts in the San Luis Valley.
The Colorado Division of Wildlife has been stocking San Luis Valley creeks with suckers raised at the native aquatic species restoration hatchery in Alamosa.
The hatchery obtained most of its Rio Grande sucker brood stock from New Mexico fish.
While those fish are genetically similar to their Colorado cousins, they have been difficult to raise in captivity.
Jennifer Logan, assistant hatchery manager, said the fish spawn easily, but getting the newborn fry to eat has been difficult.
“We’ve tried brine shrimp and other feeds, but they seem to be very particular,” Logan said. “We’ve just got to find something that works.”
And once adults, the suckers prove to be quite nasty.
“Many of them have just turned out to be more territorial than we knew,” Logan said.
Alves said that if the Crestone Creek suckers turn out to be a genetically pure strain – not hybridized with other suckers – then they can be used as brood stock.
He added: “They may be better adapted to the San Luis Valley than the New Mexico suckers.”
Staff writer Kim McGuire can be reached at 303-820-1240 or kmcguire@denverpost.com.
