A regional aquatic team for Colorado Parks and Wildlife, geared up in waders, waterproof neoprene socks and safety gloves, moved along last week in the waters of the lower Dolores River.
The venture on Wednesday was a fishing operation near the Dove Creek Pump Station to survey native fish populations.
The team was led by CPW’s Southwest Region native aquatic species biologist Daniel Cammack, who, along with a group of biologists and conservationists at CPW, closely monitor the Dolores River annually.
The goal that day involved scooping up as many roundtail chub as possible. The silver and olive-gray fish would be transported back to the agency’s hatchery in hopes of rebuilding the population in better years to come.
Crews carefully navigated over angular rock. They were unable to see the river bottom because of the river’s turbidity that day. The color of water was brown, recently muddied after a bout of heavier rain and last month when the Ferris Fire burn scar received its first flush. There were larger deposits of ash. Sediment, bits of charcoal and scorched wood floated in the wake.
“Let’s collect everything. Hold it in the tank,” Cammack told the crew during initial electrofishing instructions. “We might just do a quick count.”
There was nothing but a green sunfish to collect after about 40 minutes.
This, on a brighter note, also meant there were no non-native smallmouth bass, which pose an existential threat to the native fishery.
There was more water than usual last week, as flows had increased from the roughly 5 cfs base release from McPhee Dam.
Recent rain was a factor, as well as CPW had just released a pulse flow – a newer concept the agency started last year. Every dozen days or so, CPW sends a pulse flow down to the canyon to cool off the stream and to create better conditions for fish trapped in isolated pools during drought years.
The team then hauled electrofishing gear to the famed Snaggletooth Rapid, coming up short except for a bullhead catfish in a gill net, CPW spokesperson John Livingston said later. The expedition turned to Slick Rock Canyon to fish isolated pools using a seine net, but nothing was caught.
“Safe to say, impacts from the fire and the first monsoon event have essentially wiped out or displaced all fish,” Livingston said. “It will take years to rebuild the fishery off just this initial impact alone, not to mention future monsoons and runoff introducing more ash and debris.”
The stretch referred to starts below McPhee Reservoir, flowing more than 100 miles until merging with the San Miguel River.
It is seen by CPW biologists as a particularly significant stronghold for the residential roundtail chub, bluehead sucker, flannelmouth sucker and a secondary fourth native, the Colorado River sculpin, which all together support the health of the wider ecosystem that spans 87 more miles to reach the Colorado River.
The team at CPW uses 30 years’ worth of data to understand trends and the overall fishery health at multiple sites, often tagging fish and monitoring their movements throughout the basin.
The river that winds through remote canyon country is described as complex and “dynamic” by Cammack. Unlike the Dolores River above the dam, the section below is managed in releases from McPhee and generally 70% to 80% of the water from the reservoir is diverted for agricultural purposes and needs, he said.
The lower Dolores greatly depends on annual precipitation amounts. The reservoir is operated as a fill and spill system. The goal is fill McPhee as full as can be. On big, snowy years, McPhee fills and then starts to spill out and larger magnitude floods flow down the lower Dolores.
It can go from substantial spillover years to very low ones in a drought where it’s essentially reduced to isolated pools.
The water levels this year are concerningly low, Cammack said, not just for the fish pool but agricultural users experiencing the same shortages. He added, “everyone is hurting.”
“On a year like this, they did not fill McPhee. They didn’t even really come close,” he said. “So, we never saw a significant flood like what would be sort of a normal year for the river.”
He believes that baseline altogether is shifting and a drier trend is becoming more consistent.
“One of the things that’s really disturbing and visible to the public – that anyone who goes down to the Dolores River sees – is a drying river. They might even see fish dying in pools,” he said. “It’s a bad scene on a year of this kind, but zooming out even beyond just this – this is becoming more frequent.”
On top of exceptional drought are impacts from the nearby Ferris Fire burn scar.
On a good year, or for example, the commonly described “epic year” of 2023 for snowpack, burned wood is traded instead for river rafters, who float along towers of red rock while grasping a view on par to the Grand Canyon.
“So, you’ll have a big boom year like 2023, and then you’ll have a handful of years where there’s almost no one in the canyon,” he said. “It’s just like boom or bust.”
CPW may be changing strategies internally. Though the river is never going to be brought back to its full glory, Cammack pointed out there’s some resilience in the system, especially in the heartiness of its native fish.
“These species are under siege in many ways,” he said. “So, it’s whatever we can do to come together collectively to maintain some of these values in places, with agricultural users and recreationists and ecologists working together.”
The crews had better luck later on at the San Miguel/Dolores confluence, where they recovered 100 roundtail chub and an additional eight bluehead sucker, which were transported for conservation to the John W. Mumma Native Aquatic Species Restoration Facility by Alamosa.
Livingston said the fish will serve a large purpose, allowing biologists to spawn them and introduce their offspring back into the Dolores River.
“It was really good for us to salvage those fish we did,” he said. “They probably wouldn’t have made it.”
awatson@the-journal.com
