Increased cutthroat survival shows value of pike suppression in Lake Coeur d’Alene

The killing of predatory northern pike in Lake Coeur d’Alene has started to pay dividends for cutthroat trout, according to fishery managers

Since 2015, the Coeur d’Alene Tribe and Idaho Fish and Game have used gillnets in Windy Bay to kill northern pike.

Prior to 2015, on average only 1% of all cutthroat juveniles returned to their spawning grounds. Since suppression efforts started, the juvenile trout that left Lake Creek in 2015 have returned at a rate of 2.5%. Juveniles that left in 2016 returned at 4.2%, and juveniles that left in 2017 returned at 4.5%, said Angelo Vitale, fisheries program manager for the Coeur d’Alene Tribe.

“We are now seeing numbers of spawning adults returning to Lake Creek that exceed anything we have seen in the 23 years I’ve worked here,” Vitale said in an email.

Put another way, 100 spawners came up Lake Creek in both 2015 and 2016, said Jon Firehammer, a fisheries research biologist with the tribe. This year, between 450 and 500 spawners returned.

“They are rebuilding again,” Firehammer said. “We were really low. It takes a little while to rebuild this run.”

The relatively low cutthroat numbers, even after pike suppression, might not seem worth it to anglers who question the decision to kill the predatory fish prized by many for thrill of the catch and their tasty meat.

Firehammer said it’s a compounding sort of success. He points out that if a 1% return produces 100 spawners, a 6.5% return could produce 650.

Prior to 2015 (the first year of pike suppression in Windy Bay), the average rate of repeat spawning for adult cutthroat was 32%; since 2015 more than 50% of adults have been found to spawn repeatedly.

“Altogether, this relaxation of this predator gauntlet has really compounded the response, the speed of the response and the potential for recovery,” Vitale said. “Ultimately, the goal for us is to recover that spawning population.”

The tribe and IDFG have received some pushback from anglers about a decision earlier this year to gillnet northern pike in the southern end of Lake Coeur d’Alene.

The tribe deployed gillnets in Benewah, Chatcolet, Round and Hidden lakes through May 24 in hopes of aiding the recovery of native cutthroat trout that spawn in Benewah Creek.

In April, the Coeur d’Alene tribe netted 251 pike in Windy Bay and 269 pike in southern end of Lake Coeur d’Alene.

It’s estimated there are a minimum of 2,500 northern pike in the shallow waters of southern Lake Coeur d’Alene. The tribe hopes to reduce the population by up to 80 percent. Pike have razor-sharp teeth and ambush their prey.

Since 2015, the tribe and IDFG have used gillnets in Windy Bay. They reduced the pike population in the bay by 80 percent during that time.