The use of herbicide on home lawns and gardens was the likely culprit in a number of brown trout deaths in Laramie’s Spring Creek in late May, according to the state Game and Fish Department.
According to a news release, Laramie residents contacted the regional office of the Wyoming Game and Fish Department on May 26 after finding several dead brown trout in Spring Creek.
Fisheries biologist Steve Gale conducted an evaluation of Spring Creek from 15th Street downstream to Eighth Street and observed numerous dead trout within that section. Multiple size classes of brown trout were affected, but no other species of fish was found dead.
Brown trout are the most abundant fish species in Spring Creek.
Gale’s tests of the creek’s water quality revealed no problems, so he sent more than 20 of the dead fish to the department’s laboratory for examination.
“Our meter measures the quality at the time of testing, so whatever had happened had already gone through the system,” he said.
Brandon Taro, coordinator for the department’s Fish Health Program, said an examination of the fish indicated that herbicides were responsible for the deaths.
“All the fish had enlarged livers, which is consistent with the effects of herbicides on fish,” he said.
Laramie regional fisheries Supervisor Bobby Compton told Cowboy State Daily that a heavy rain in late May caused runoff tainted with herbicide to enter the creek.
Gale said algae were dead from where a storm drain empties into the creek below the 15th Street Bridge downstream to the Ninth Street Bridge. The algae above the storm drain were still green and apparently unaffected.
Compton noted that while this type of poisoning isn’t common, it does happen every two to five years when the city experiences a heavy rain. While he doesn’t expect any long-term effects from the deaths, he did point out that the incident could be prevented.
The department’s news release included recommendations for how Laramie residents can safely use herbicides to avoid such poisonings in the future.
“Proper application, storage and disposal would definitely eliminate this type of situation,” Compton said.
