A record year of kokanee salmon spawning on the Dolores River paired with exceptional numbers at Lake Nighthorse in Durango will allow Colorado Parks and Wildlife (CPW) aquatic biologists to fully stock waters in the spring of 2022.
It was a surprising year for the southwest corner of the state and will help offset some below-average spawn takes elsewhere in Colorado.
“We will have enough eggs to stock all over our broodstock lakes and some of our recreation waters,” said CPW Senior Aquatic Biologist John Alves. “We were able to get a surprisingly big spawn this year from the Dolores and a great year from Nighthorse, and some of those eggs were sent to other hatcheries to help out in other areas.”
Fall is the season for spawning kokanee salmon. The landlocked Pacific sockeye salmon do well in Colorado’s lakes and reservoirs but lack natural spawning areas. As the fish make their way upstream out of the reservoirs to seek spawning areas, CPW is able to capture the fish and recover and fertilize the eggs.
Statewide, CPW collected an estimated 8.5 million kokanee salmon eggs this season. Lake Nighthorse contributed 2.8 million eggs to that total, while the Dolores River produced its record year of 1.2 million eggs. That more than filled the Durango Fish Hatchery, which allowed for more eggs to be sent to the Pitkin and Roaring Judy hatcheries.
“We really had a banner year,” said Jim White, CPW aquatic biologist in the Durango area. “It was not a year we were expecting, as we’ve typically been around 1 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.”
Also in the Southwest Region, the East River at Roaring Judy Fish Hatchery above Blue Mesa produced 2.3 million eggs, and another 34,000 eggs were taken from Ridgway Reservoir.
The Roaring Judy Fish Hatchery in Almont normally boasts the largest kokanee salmon run in the U.S. and has previously averaged a take of 7.2 million eggs per year. But for the second consecutive year, that number was less than 3 million.
CPW aquatic biologist Dan Brauch in the Gunnison area said the run was late this year, and he was able to maximize the egg take by using a Merwin trap net in Blue Mesa Reservoir to capture kokanee and continue spawning through the Thanksgiving holiday week. That yielded an additional 300,000 eggs, Brauch said.
“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.”
For White, the opportunity to send eggs out to additional hatcheries made the weeks of hard work even more valuable. His team’s previous record at Lake Nighthorse was 1,161 female spawns in a single day. This year, his crew had multiple days of more than 1,500 spawns.
“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.”
Each year, 26 lakes and reservoirs are stocked with kokanee salmon. Anglers enjoy the opportunity to catch kokanee, and the tasty fish are easy to fillet and cook. White called them an ideal sportfish because they don’t concentrate much mercury, occupy parts of a lake that no other fish occupy, and primarily eat zooplankton and not other fish.
At Blue Mesa, kokanee salmon are the most sought-after fish by anglers.
“It is a species that is prevalent in large numbers, is easy to catch, and is good to eat,” Brauch said. “There really aren’t any other species that provide the opportunity for significant catch and harvest in our large cold-water reservoirs.”
At Blue Mesa, predation from lake trout along with gill lice has been a problem for the kokanee population. Brauch has seen great success in limiting the effects of lake trout by implementing a lake trout harvest tournament for the last two years. Brauch said there may be signs of the kokanee population adapting to combat the effects of gill lice, too.
Kokanee grow quickly and typically live about four years and naturally die after spawning. CPW conducts kokanee salmon giveaways to make sure the meat is not wasted.
At Lake Nighthorse, CPW gave away more than 16,000 kokanee to people wanting fish who hold a valid fishing license. Even fish that had already died did not go to waste. Hundreds went to feed sled dogs at the Durango Dog Ranch.
Eggs are taken to hatcheries where they are disinfected and enumerated. Eventually, eggs will eye-up and then be stocked out as 2-inch fish the following spring.
Blue Mesa Reservoir typically receives 3.5 million kokanee salmon per year. Lake Nighthorse will receive about 160,000 kokanee, and the Dolores River above McPhee Reservoir will get roughly 200,000.
Next fall, the process of spawning will start all over again across the state.
“Working with kokanee is a large part of the work we do here in Gunnison,” Brauch said. “That time of year when you’re working the spawn to keep the kokanee program going is part of what makes the job so enjoyable.”
Article and photos by John Livingston. John is the Southwest region public information officer for Colorado Parks and Wildlife. Podcast hosted by Mark Johnson. Colorado Parks and Wildlife is a nationally recognized leader in conservation, outdoor recreation and wildlife management.