SALT LAKE CITY, Utah, June 26, 2024 (Gephardt Daily) — A radio fish-tracking program is showing results for Utah wildlife officials’ study of trout spawning.
“For the past 20 years, we’ve worked with private landowners and Trout Unlimited to reduce the obstacles Bonneville cutthroat trout face in Chalk Creek in Summit County,” says a Utah Division of Wildlife Resources news release. “We recently turned a roughly 15-mile-long section of the creek into a study area.”
“On Sept. 21, 2022, we electro-shocked two portions of Chalk Creek. As the stunned fish floated to the surface, we took 40 Bonneville cutthroat trout – between 9 and 16 inches long – and surgically implanted radio transmitters in them.
“After releasing the fish, one of our biologists visited the area regularly — radio antenna and tracking device in hand — to monitor their movements. He monitored the fish from October 2022 to November 2023.”
Here are his major findings:
Predation, especially by large, fish-eating birds, appears to be a significant threat. Fourteen months after the study began, 24 of the 40 fish had died. Some succumbed, presumably, to the rigors of the spawn, but several of the transmitters were found on the ground under trees with large bird nests in them.
As suspected, tributaries are important spawning areas. Most of the 40 trout migrated into either the South Fork of Chalk Creek or the East Fork of Chalk Creek during the spawning period, the DWR said. Some tagged fish stayed in the main creek, but it is not known whether they spawned there.
Trout in rivers and streams often face obstacles when it’s time to spawn. For example, culverts and other items placed in the water can create barriers that are difficult to get past. And structures that divert water from the stream can lead fish into shallow ditches from which it’s difficult to escape.
But the DWR study found what are thought of as barriers to fish may not be. “The cutthroats navigated some areas we thought they’d have a difficult time making it through.
“During this study, diversions also didn’t pose as much of a threat to the fish as we thought. None of the fish ended up entrapped in a ditch or other man-made waterway.”
