FWP seeks public comment on use of tiger trout as biocontrol

Posted by Moosetrack Megan on March 17, 2025

Montana Fish, Wildlife & Parks is currently seeking public comment on the following items:

Montana Fish, Wildlife & Parks proposes to stock tiger trout into Upper Sureshot Lake, which is in the headwaters of North Meadow Creek near McAllister. The species is not indigenous to the drainage and has not been present historically. The primary goal of the tiger trout introduction is to provide a biocontrol on the existing brook trout population.

Tiger trout are a hybrid between brown trout and brook trout. Although they are occasionally found in the wild, most tiger trout are sterile so self-sustaining populations are not possible and reports of wild tiger trout are rare. The hatchery supplying the tiger trout takes an additional step to ensure sterile fish are stocked by treating eggs in a manner that creates triploid fish. Triploid fish have an extra set of chromosomes, which also makes them sterile. Introducing tiger trout will add a natural predator for the stunted brook trout population in Upper Sureshot Lake. Tiger trout are stocked in surrounding states to provide additional angler opportunities as well as prey on stunted fish populations with the intention of reducing abundances of the existing species to improve the quality of the fishery by increasing lengths of the remaining trout.

Upper Sureshot Lake is an 8.7-acre lake that supports a wild brook trout fishery. Angler reports and gill netting surveys indicate the brook trout are primarily smaller than 10”. Initial stocking efforts will include 500 tiger trout in 2025. Stocked fish would be produced by the FWP hatchery system and follow AIS and disease testing protocols. FWP will continue gill netting efforts for several years to determine whether the introduction of tiger trout alters the size structure of the brook trout population. Opportunistic creel surveys will be conducted when staff are in the area to also assess angler use and satisfaction to help determine whether continued stocking of tiger trout would be a worthwhile effort. The stocking rate could be adjusted depending on growth rates, angler harvest, angler satisfaction, and impacts to the rainbow trout fishery as monitored via the identified management goals in the SFMP.