Skip to contents
Environment

What 3 million little kokanee salmon can tell us about Colorado’s drought

The celebratory release of kokanee salmon from Roaring Judy hatchery ensures that the fish so popular with anglers continue to propagate – even in drought-ravaged waters

Story first appeared in:

On a cold April evening, a few dozen people gathered inside the humid Roaring Judy Fish Hatchery north of Gunnison. Adults and kids hovered over the sides of 22 concrete tanks filled to the brim with millions of kokanee salmon fry — 3.1 million to be exact. 

The 2-inch fish flipped their fins and swam in circles as they waited for the biggest event of their young lives: their release into Blue Mesa Reservoir by way of the East River. 

At 7 p.m. Seth Firestone, the hatchery manager, yelled for everyone’s attention. 

“We’re gonna go ahead and start opening the drains,” Firestone said. “All right, let’s go!”

The annual kokanee release from the Roaring Judy Fish Hatchery marks the start of an important journey for Colorado’s salmon population. The tiny fish swim downriver to Blue Mesa Reservoir, where they spend about four years growing up before swimming 30 miles back up river to the hatchery where they spawn and, well, die. 

Austin Smith, left, an employee of the Roaring Judy Fish Hatchery, gets some help from Parker and Megan Spann and their mom, Layne Spann ,emptying a trough filled with kokanee salmon fry during the annual spring release from the hatchery. (Photos by Dean Krakel, Special to The Colorado Sun)
Seth Firestone, manager of the Roaring Judy Hatchery, talks with visitors during the open house.
Seth Firestone gets some help from Zac Lauerman as he helps move kokanee salmon fry out of a trough and into a drain that will carry the fish into the East River.

Colorado Parks and Wildlife hatchery technicians harvest eggs, and when numbers are greater than 4 million, they are used to restock 26 reservoirs across Colorado. Five other hatcheries around the state raise kokanee, the landlocked version of sockeye, but for years, the most prolific annual kokanee spawn has been on the grounds of Roaring Judy. 

For years, the Gunnison hatchery has led the state in the annual harvest of kokanee eggs. But drought and obligation to demands downstream in the Colorado River Basin are drawing down water levels and robbing the kokanee of their habitat. Biologists estimate that the once deep and cool pool where fish thrive and grow to provide opportunities for sport anglers at Blue Mesa Reservoir is now 70% smaller than normal. As drought continues to challenge water levels downstream, the Roaring Judy has had to rely on other hatcheries around the state to supplement its annual egg harvest.

The 30-mile swim is “school” for the tiny fish

As Firestone ceremoniously muscled open the first tank, water immediately swirled toward the drain like a bathtub — carrying thousands of kokanee salmon along with it. 

The small crowd, mostly current or former Colorado Parks and Wildlife employees and their families, cheered and watched as the millions of small fish started their journey toward underground pipes before dumping into the East River.  

Hatchery employees moved from tank to tank to release water. Once the levels were low enough, technicians jumped into the tanks and used large squeegees to move water and fry along. Their job was to make sure each fish made its way out of the hatchery to the river. 

The journey to Blue Mesa doesn’t take long. 

Each trough containing kokanee salmon fry at the Roaring Judy Hatchery near Almont has a drain that feeds into a pipe that will release the fry into the East River. (Photos by Dean Krakel, Special to The Colorado Sun)
Casen Foltz, age 10, from Gunnison watches kokanee salmon fry pour out of a pipe from the Roaring Judy Hatchery into the East River.

“Most of them are to the reservoir by the time the sun is coming up,” Firestone said. 

Each year, the kokanee release is planned in the evening around the time of the new moon. Aquatic biologist Dan Brauch said the dark sky helps improve the odds that the small fish make their way downriver without being eaten.  

Recommended

Colorado finds “forever chemicals” PFAS in 100% of fish sampled in three big counties 

“So the nighttime conditions are as dark as possible to try to minimize predation by trout in the river system,” Brauch said. “Trout are visual predators, so the more light there is, the more they’re able to prey on kokanees as they travel.” 

Despite the planning, about 10% of the fish don’t survive the swim.

The journey from the hatchery to the reservoir provides an important lesson for each fish that does survive. The long swim is “school” for the fish, imprinting lessons they’ll need to return when they are mature. 

“If we stock these fish into Blue Mesa, they don’t make their way back,” Brauch said. “So it must be learned as part of their downstream journey because it’s necessary for them to go through that journey to get back.”

In the spring, 3.1 million kokanee are released. And in the fall, roughly 30,000 mature kokanee swim back up the Gunnison and East rivers to the Roaring Judy hatchery to spawn. 

Eggs are collected, then incubated inside the hatchery

When kokanee salmon swim upriver each fall, they arrive in the spawning ponds below the hatchery. Fish technicians spend months manually squeezing the eggs and milt from each spawning fish. They collect the eggs, disinfect them with iodine and take a final count before starting the incubation process in the hatchery. 

Once the kokanee are sent downstream, the hatchery work shifts to rainbow trout.

“Every year is the same in a way, it’s always a cycle,” said Kristi Miller, who has worked as a fish hatchery technician at Roaring Judy for 11 years.

On the evening of the kokanee release, Miller brought her two young sons to take part in the celebration. The boys walked along the chest-high tanks, sometimes using a small mesh net to collect the dead salmon fry floating on the surface.

A Colorado Parks and Wildlife worker collects eggs from kokanee salmon. (Via CPW)
Mature kokanee salmon swim with each other. (Via CPW)

Stocking Colorado reservoirs with kokanee dates back to 1951. Lake Granby used to retrieve the most kokanee eggs in the state, but conditions in the lake, like invasive species, have caused the kokanee population there to decline over the years. 

Blue Mesa started stocking the fish in 1965 for fishermen and recreation. And in the early ’90s, the reservoir claimed the largest population of kokanee salmon in Colorado. Despite a few years of low egg production, on average Roaring Judy still boasts the largest kokanee spawn in the state.

Recommended

22 years of drought in Colorado, rest of the Southwest is worst stretch in 1,200 years, study shows

There are five hatcheries where the eggs are fertilized and incubated during the winter months. Roaring Judy is unique in that the fish swim upriver to the hatchery to spawn. Other hatcheries retrieve eggs from various lakes and reservoirs where kokanee are stocked each year.  

The fish serve an important role in the ecology of the reservoir. Kokanee feed on zooplankton and are an important food source for the lake trout population. 

Kokanee also are a draw for sport fishermen. Each year, anglers visit from around the state to fish for salmon from January through August. And hundreds of people show up in October and November for “Fish Fridays,” when the hatchery gives away spawned salmon to anyone with a Colorado fishing license.

Drought and demands of the Colorado River have reduced habitat by 70%

Andy Cochran, the owner and operator of Gunnison Sports Outfitters, has worked as a guide on Blue Mesa for 22 years, fishing the reservoir by boat in the summer and from the ice in winter. He said catching kokanee is fun: They are acrobatic fish that jump out of the water and bite hard on fishing lines.

As for taste, Cochran said, kokanee makes for great table fare. 

“A lot of people who are salmon connoisseurs say kokanee is a lot sweeter than any other wild salmon,” said Cochran. “I’ve been told it’s the number one preferred salmon.” 

Cochran has noticed a downward trend in tourists arriving to fish for kokanee salmon over the past decade. He’s also noticed a decline in kokanee populations. He attributes some of the downswing to the continued drought that has impacted the reservoir.

Colorado’s kokanee salmon run to spawn in this YouTube video posted by Colorado Parks and Wildlife. (Via CPW)

The water levels in Blue Mesa have seen near-record lows in the past two years. The lowest occurred in 1984, when the reservoir sat at a mere 24% of full capacity. It’s currently at 29% of capacity, nearly 30 feet lower than the same time last year. 

Drought had already pushed water levels low in 2021, but an emergency release last fall to prop up water levels in Lake Powell made an already empty reservoir even emptier.

Recommended

500,000 acre-feet of water will be released from Flaming Gorge reservoir in Wyoming to protect Lake Powell

Firestone, the hatchery manager, said Roaring Judy has seen lower egg harvests in the past two years, and several factors are challenging the kokanee salmon population in Blue Mesa. Drought, warming waters and gill lice have combined to drive the recent declines. 

“The number one factor is lack of habitat, the reservoir is 28% of volume,” Firestone said. “You are missing over 70% of habitat, and it’s really hard to get numbers you need when well over half the lake isn’t there to support the fish.”

Historically, the egg harvest at Roaring Judy Fish Hatchery has accounted for 60% of the kokanee eggs gathered in Colorado. The hatchery supplies 26 reservoirs. But last year Roaring Judy was forced to supplement from other hatcheries and reservoirs, including Lake Nighthorse in Durango, to make its goal. 

Roaring Judy harvested 2.3 million eggs in 2021 —  about a third of the historical average of 7.6 million; 2020 was worse — the harvest totaled 1.9 million. To successfully release 3.1 million fry, the hatchery needs 3.5 million eggs.

Last fall, Colorado Parks and Wildlife responded to the dismal egg harvest with some creative solutions. They set up a Merwin trap to catch fish that did not swim upstream to spawn. The hatchery recovered 300,000 additional eggs using this method. 

The kokanee release is always a long-awaited event by hatchery technicians. Roaring Judy staff spend months tending to the eggs as they hatch and grow. And they spend the rest of the winter preparing for the release.

Kokanee salmon fry wait in holding troughs at the Roaring Judy Hatchery. Each trough holds 135,000 fry. The hatchery will raise 3.1 million salmon. Only a fraction will survive to make the journey back upriver. (Dean Krakel, Special to The Colorado Sun)

On the evening of the release, Firestone worked against the clock to make sure every single salmon fry was out of the hatchery within the hour to create an overwhelming, safety-in-numbers effect on predators. If the fish swim tight together while heading downriver, they’re more likely to survive.

Around 8 p.m., the tanks were empty and the hatchery crew looked happy and satisfied. Firestone let out a sigh of relief; the project was complete and it was time to celebrate. 

“It’s kind of like a party for us,” he said. “It’s the end of the season, as far as the kokanee goes.”

Photography by Dean Krakel, Special to The Colorado Sun.

This story first appeared in Colorado Sunday, a premium magazine newsletter for members. Become a Basic+ Member to get Colorado Sunday in your inbox every week.


We believe vital information needs to be seen by the people impacted, whether it’s a public health crisis, investigative reporting or keeping lawmakers accountable. This reporting depends on support from readers like you.