Fall brings many changing colors, including kokanee salmon. Normally, Utahns flock to Strawberry Reservoir, east of Provo, to celebrate the fish’s autumn metamorphosis. This year’s hurrah, however, had to be canceled because the guests of honor weren’t showing up.
The fish is non-native to Utah, and was introduced to the reservoir to keep the “prolific” chub in check, said Scott Root, a conservation outreach manager at the Utah Division of Wildlife Resources. When they aren’t spawning, the kokanee are a “beautiful silver on the outside and they're just fluorescent red on the inside,” Root said.
But when it comes time to spawn, “they almost turn inside out,” he said.
“The kokanee stop eating pretty much at that point. And their innards, their internal organs pretty much turn to mush because they have just one thing on their mind, and that's to spawn before they die.”
As they journey upstream along the Strawberry River, some of the salmon are diverted to a fish trap and egg catching facility located at the end of a boardwalk near the reservoir’s visitor center. It’s a great spot for fish watching, Root said.
“It's hypnotic to sit there and watch these fish kind of work their way up into the facility.”
In previous years, the usual watch party has attracted as many as 3,000 visitors, Root said. This year’s event, which was scheduled for Sept. 17, was officially canceled in advance because the fish weren’t coming.
As of Sept. 19, Root said about 200-300 female kokanee have been processed at the egg catching facility.
“Most years at this time, we'll have like a couple thousand fish,” he said. “It’s probably about the latest I've ever seen them in my 30 years.”
The recent heatwave that blasted the state may be to blame for the fashionably late fish, though Root couldn’t say that with certainty.
“Strawberry River isn't that deep in most places. So I'm sure that did kind of warm the water temps up a bit,” he said. “Trout in general and salmon, they like those cooler temps.”
Chris Penne, an aquatics manager at the division of wildlife, agreed with Root’s heatwave speculation. However, he added that in other parts of the state, hot and dry weather actually seem to be associated with earlier than normal salmon runs.
Exploring the relationship between hot weather and the timing of the runs hasn’t been a priority for the department, Penne said.
“With all the programmatic goals that we have as a state agency for managing fish, we really haven't had the luxury of looking at that,” he said. As the populations are still robust, “it's just a mystery that we've left hanging for the moment.”
Climate change doesn’t seem to be impacting the health of the kokanee salmon populations — at least not yet, Penne said.
“A lot of reservoirs and lakes do what's called stratification during the summertime,” Penne explained. “And what that means is the water separates into typically three distinct layers.”
The top layer has the oxygen fish need, while the bottom layer has the cooler temperatures they need, he said. The middle layer is the “Goldilocks zone” where they have both.
“That middle layer is probably going to get a little bit thinner over time, which means they're going to have less and less habitat that they want,” Penne said.
The lifecyles of the salmon raised at the facility could be another reason they are spawning late this season. Penne said that eggs collected at different times hatch at different times.
After the eggs hatch and the “fry” grow to about three inches, they are often stocked in tributaries near the fish trap, Root said.
“At around 3 years of age, they often return to the same general location to spawn and then die...and the cycle repeats itself,” he said.
Penne said DWR is careful to ensure that eggs are collected throughout the spawning season, though sometimes eggs collected early on may fare better than those collected later, or vice versa.
Don’t worry, fish fans. Whatever the cause for the delay, Root said there are some kokanee salmon to see right now at other spots at the reservoir. And more are on the way.
“As it gets cooler, I fully expect them to come up here in the coming days and be more visible in the stream as well,” he said.
