Southwest Colorado reported a record kokanee salmon spawn this year.

Colorado Parks and Wildlife aquatic biologists spawned roughly double their usual kokanee salmon at Lake Nighthorse and the Dolores River in 2021, making up for slow spawning efforts elsewhere in the state and allowing the agency to fully stock broodstock lakes in 2022.

“We really had a banner year,” Jim White, an aquatic biologist with CPW, said in a news release. “It was not a year we were expecting, as we’ve typically been around 1 (million) to 1.5 million eggs at Nighthorse. With the water level so low in the Dolores River and McPhee Reservoir, we really weren’t expecting many fish to make it upstream there, either. But there was a nice, single-thread channel they were able to make it up from, and it turned out to be a great year there with close to 2,000 females spawned.”

CPW biologists collected 2.8 million kokanee eggs from Lake Nighthorse and 1.2 million eggs from the Dolores River, according to CPW.

The Dolores tally marked a record for the river, more than double the annual average take of 500,000.

At Lake Nighthorse, CPW broke its record for spawns in a single day. A crew of three collected eggs from 1,743 kokanee over three or four hours, White said on CPW’s podcast Colorado Outdoors on Tuesday.

That comes out to about 10 spawns per minute.

The total from Dolores came as a particular surprise.

“Our first spawn take was out at the Dolores State Wildlife Area, and when we showed up out there in mid-October, there were hardly any fish,” White said on Colorado Outdoors. “… We were really concerned that the fish were all bottled up and trapped in the low reservoir.”

White attributed the successful spawn later in the fall to reservoir levels and storms that energized the fish.

“With the Dolores operation, we have had a series of these low reservoir levels interspersed with some higher reservoir levels and that seems to kick off this productivity and growth in the fish,” White said.

While Lake Nighthorse and the Dolores River fared well, parts of the state struggled to bring in the fish they normally do.

Blue Mesa Reservoir and the Roaring Judy Fish Hatchery near Gunnison usually have one of the largest kokanee runs in the country. Roaring Judy collects on average 7.2 million eggs per year and has taken up to 17 million in extraordinary years.

“We do depend on Blue Mesa to provide often the bulk of eggs for restocking,” CPW aquatic biologist Dan Brauch said on Colorado Outdoors.

In 2021, Blue Mesa produced just 2.3 million eggs, marking the second consecutive year with a spawn less than 3 million. CPW took 34,000 eggs from Ridgway Reservoir.

CPW aquatic biologists attribute the decline in spawning to drought, predation from lake trout and gill lice, which attach to the gills of kokanee and prevent fish from breathing normally.

“We were dealing with reduced habitat for kokanee due to the drought,” Brauch said. “In past years, we’ve been in a situation where we can provide eggs for other waters from Blue Mesa, but this year we will depend on other waters, primarily Nighthorse, to help us cover what we need next year. There is year-to-year variability in egg take numbers, and we hope to see our numbers here rebound in the near future to where we have extra eggs to support other waters again.”

In all, CPW collected 8.5 million kokanee eggs in 2021, down from the annual average of 11 million, said John Livingston, spokesman for CPW’s Southwest Region.

CPW needs about 11 million eggs to restock 26 lakes and reservoirs across the state.

The agency relies on eight of those lakes and reservoirs for the broodstock that sustains Colorado’s kokanee population. The other 18 serve as recreational waters.

“With that 8.5 million (kokanee), they’ll be able to fully stock those broodstock lakes and then also have some for those recreational waters,” Livingston said.

Eggs collected from Lake Nighthorse and the Dolores River were more than CPW’s Durango hatchery needed, so CPW sent the remaining eggs to other hatcheries across the state to help with reduced spawns, said senior aquatic biologist John Alves.

The hatcheries will raise the fish over the winter and stock them out when they reach 2 inches in length next spring.

Blue Mesa Reservoir receives on average 3.5 million kokanee salmon per year, while Lake Nighthorse receives about 160,000 and the Dolores River 200,000.

The banner year for Southwest Colorado kokanee was a pleasant surprise for White, who could return the favor to Brauch and other aquatic biologists across the state.

“There are years we rely on other parts of the state when we are down on egg takes, so it’s awesome in a year like this to turn around and be able to help other biologists and bodies of water that traditionally have more kokanee in them,” White said. “It was surprising for us down here this year, but we were fortunate to have a lot of fish.”

Livingston said 2021 once again highlighted CPW’s collaborative efforts to maintain healthy fish populations in Colorado.

“It’s always good for us as a team to be able to keep this program going and help each other out,” he said. “It may not always be a record year down here in the Southwest, and we’ll be relying on getting eggs from elsewhere. It’s great during a year like this to be able to help out some of those other hatcheries and make sure we’re stocking those other waters as well.”

ahannon@durangoherald.com