Carp are a common sight in many Utah lakes and waterways, and in most cases, aren’t considered a major threat to the other fish species in those waters.
That’s not the case in Utah Lake west of Provo, where an exploding population of the large fish has taken over and been threatening an endangered species for decades.
State wildlife managers are fighting back in an attempt to reduce and hopefully eliminate the carp population in the lake in what has become a year-round effort. A total of 60,000 pounds of carp were removed through a hole in the ice in one day at Utah Lake last week, and crews have been going back for more on a daily basis as weather allows, said David Tinsley, a commercial fisheries observer for the Utah Division of Wildlife Resources who has been working on the project for three years.
Since 2009, about 10 million pounds of carp have been removed to help the endangered June sucker. Utah Lake is the only place in the world where June suckers are found.
The weapon of choice for the fishermen involved is a 600-yard long net called a bag seine. The fishermen cut large holes through the thick ice and work the massive net under the ice until it reaches the shoreline, then pull it back in through the hole. Tinsley said the crew usually hauls in about 700 to 800 pounds of carp each time the net is deployed.
He said crews can typically bring in more carp during open-water season because they can do two or three times as many hauls per day when there is no ice on the lake.
“It’s a lot more of an involved process on the ice,” he said. “It takes more effort to do one haul with ice on the lake as opposed to ice-off.”
However, with the carp population exploding in recent decades to the point where it now makes up 91 percent of the biomass found in the lake, the removal effort has to be continuous. Also, the carp move slower in the winter, which makes it easier to round them up.
Carp don’t prey on the June sucker, but they voraciously consume the vegetation that provides food and habitat necessary for the June sucker’s survival. Between 80,000 and 100,000 June suckers are raised in hatcheries each year for release into the lake, but biologists hadn’t seen a naturally produced sucker in the lake for a long time until about two years ago, when one was found in the Hobble Creek Restoration Area.
Much of the carp that are harvested are composted into fertilizer, while some of them serve as feed for mink farms.
Tinsley said it’s difficult to say whether the carp population in Utah Lake is declining as a result of the removal project, but said that anecdotally, he has seen an increase in vegetation under the water. The project started in 2009, and a feasibility study found that it could take six years of constant work before the population starts to decline.
“The goal is to reduce the population by ‘x’ number,” Tinsley said. “Then the population won’t be able to keep up, and eventually it will crash.”