Despite hearing some public opposition, the Montana Fish and Wildlife Commission voted Thursday to eliminate the lake trout “slot limit” on the southern half of Flathead Lake, a change that has been sought by the Confederated Salish-Kootenai Tribes.

After March 1, anglers will be allowed to keep lake trout more than 30 inches long on the southern half of the lake where the tribes have management authority. 

The slot limit, in place since 1992, prohibited anglers from keeping lake trout between 30 and 36 inches long with the intent of protecting the lake’s trophy fishery. 

Mark Deleray, the state’s acting regional fisheries manager, explained to the commission that it takes about 20 to 25 years for a lake trout to reach 30 inches, so there is a limited population of fish in that size class.

Tribal fisheries biologist Barry Hansen explained that eliminating the slot limit is a component in efforts to reduce the abundance of lake trout, a non-native species that has had adverse impacts on the native and protected bull trout.

He asserted that there is “a pretty substantial stockpiling of fish” greater than 30 inches in the lake, largely because the slot limit has been in place. Hansen added that the slot limit created confusion among the public, with people wondering why there were protections for the largest lake trout — fish that arguably have the greatest predatory impact on native species — when there is an ongoing effort to reduce the lake trout population.

Montana Fish, Wildlife and Parks staffers recommended the slot limit removal largely to recognize the tribes’ “authority to change regulations on Flathead Lake within the boundaries of the Flathead Indian Reservation.”

Speaking by teleconference from regional headquarters in Kalispell, Norm Brewer of Captain Norm’s Fish-n-Fun charter business cited potential economic impacts of harming the lake trout trophy fishery. Anglers come from all over the world to fish on Flathead Lake, with economic benefits extending well beyond the charter boat business, he said.

“We feel that removing the slot limit would take away that chance of catching one of those large fish,” said Brewer.

The lake’s population of large lake trout is limited, and concerns have been raised in the past that once those fish are removed they cannot be rapidly replaced.

Bob Orsua of Mo’ Fisch fishing charters said the lake should be managed to both reduce the lake trout population but also maintain a trophy fishery because lake trout are the primary sport fishery on the lake.

He said his firm’s lake trout catch rates have steadily declined for years, and it is much more difficult to explain to people why there is a 100-fish-per-day creel limit for lake trout when it’s possible to actually catch only a few fish per day.

Another man told the commission that he questions the scientific benefits of removing the largest lake trout for the supposed benefit of bull trout. He said lake trout are “apex predators” that also are responsible for devouring young lake trout. 

Removing large trout, he suggested, could lead to greater survival of young lake trout to the possible detriment of bull trout.

“I think that needs to be addressed,” he said.

Commission chairman Dan Vermillion of Livingston said he was sympathetic to concerns that were raised, but added, “If you are concerned about those fish at the upper echelons, then release them.”

He said more needs to be done to suppress lake trout population, and he reiterated that the tribes are “exercising their management authority” on the south half of the lake.

The five-member commission voted unanimously to strike the slot limit.

The slot limit will remain in effect on the north half of Flathead Lake.