PELICAN LAKE, Uintah County — Pelican Lake is known as a home to big bluegill fish and largemouth bass. But in the next few weeks, access to the lake will be closed and the fish will be killed with a rotenone treatment.
Rotenone is a naturally occurring compound (derived from the roots of a plant) that is commonly used to kill fish, according to Utah Division of Wildlife Resources officials. But why do the fish in Pelican Lake need to be killed off in the first place?
Between 2008 and 2009, common carp was released into the lake. Since then, the carp have been declining the quality of the bluegill fish, according to Utah Division of Wildlife Resources regional aquatics manager Trina Hedrick.
“In 2016, agency representatives and anglers that make up the Pelican Lake Management Team made the decision to remove common carp from the lake,” Hedrick said in a news release. “The only way to completely eradicate carp is through the use of rotenone.”
Hedrick mentioned that this is the perfect time to do the rotenone treatment because of low water levels due to drought. Low water levels ensure that carp can’t escape the treatment.
Utah Division of Wildlife Resources spokesman Mark Hadley said that rotenone only poses a threat to fish, not people, pets or wildlife. However, the lake will be closed to access from Oct. 10 to Oct. 31.
Once the chemical is released, the fish will die in a matter of hours, Hadley said. Biologists will assist with cleanup, and the chemical will dissipate by the time the lake opens back up.
Hedrick said that they already have the fish that will repopulate the lake.
"We’ve been holding large bass and healthy bluegill that we took from Steinaker Reservoir over the past two years,” Hedrick said in the news release. “We can begin stocking the lake once it starts refilling with water.”
Restocking is tricky because largemouth bass prey on bluegill, Hedrick said. To make sure the bluegill have time to re-establish in the lake, largemouth numbers will be kept low for now.
Hedrick said restocking the fish needs to be done slowly, but surely to ensure a healthy regrowth. The food supply for the fish also goes down with the rotenone treatment, so only enough fish to fit the food supply will be restocked at first.
“There shouldn’t be any reason that (the fish population) shouldn’t bounce back”, Hedrick said.
She estimates that it will take three years for the bluegills to grow to a catchable size.
Hadley said the campground near Pelican Lake will be kept open during the lake's closure, and she encourages people to come to the lake and fish to their heart’s content until the lake is closed. Hadley said there is no current limit on the bluegill you can keep and the limit on largemouth bass has been doubled to 12 fish a day.
Another infestation occurred recently in Maple Lake in Payson Canyon.
DWR regional aquatics manager Chris Crockett said goldfish were illegally placed in the lake and have begun to threaten the quality of the trout. Crockett said the goldfish are competing with the trout for food and are eating plants that decrease the lake's water quality.
As a result, wildlife officials have decided to also do a rotenone treatment sometime in October to kill all the fish in Maple Lake.
“We don’t anticipate any impacts to downstream fisheries or water quality,” Crockett said in a DWR news release. “We’ll restock the lake with trout in spring 2019.”
Hadley said the lake will be closed for 14 days after the treatment. The timing is good because Payson Canyon is currently inaccessible due to a forest fire and the Maple Lake campground is closed for the season, wildlife officials said.
Hedrick said that rotenone treatments are only used when completely necessary. In the case with Pelican Lake, carp have been affecting the quality of bluegill and largemouth bass caught.
“We’re hopeful that with our new management of these waters that we shouldn’t have to do (the rotenone treatments) again,” Hedrick said.