State wildlife agency gives boost to native rainbow trout species
Jul. 16—Most rainbow trout swimming in Montana's waters are not native to the state — with the singular exception of the redband trout in the Kootenai drainage.
While common throughout most of Montana, rainbow trout largely exist in the Treasure State because of widespread stocking. The Columbia River interior redband trout, or redband trout, is native to Northwest Montana by contrast and lives primarily in disconnected streams across the Kootenai drainage.
"Redbands are an interior rainbow trout that is native to Montana. It's something that makes them pretty unique that we want to protect because their populations are few," said Dillon Tabish, Region 1 information and education program manager for Montana Fish, Wildlife and Parks.
To preserve their numbers and encourage the prosperity of native species, Montana Fish, Wildlife and Parks is restarting a native rainbow trout stock with help from the Murray Springs Trout Hatchery near Eureka.
Redband trout are considered a species of special concern by the state. Few strong populations exist today, and the fish only occupies 20% of its historic range.
The hatchery was built in the late 1970s by the U.S. Army Corps of Engineers after the construction of the Libby Dam to mitigate habitat and fishery losses. The Corps still funds and maintains the facility, but Montana Fish, Wildlife and Parks operates and manages it.
The hatchery previously raised redbands from 2009 to 2013 before switching to Gerrard rainbows, another subspecies of rainbow trout that isn't native to Montana. The Gerrard, a larger trout, is popular for recreational fishing.
The hatchery returned to the redband this year.
"We want to focus our efforts on native trout," Tabish said of the switch.
The redband trout used to exist in drainages east of the Cascade Mountains from southern British Columbia through Washington and Oregon to Northern California. Currently, the Kootenai River drainage contains the only redband population in Montana. It is also the furthest inland penetration of the trout in the Columbia River Basin, according to the state wildlife agency.
Other rainbow trout in Montana, the nonnative ones, are descendants of coastal rainbow trout from California, starting as far back as the late 1800s.
To preserve the redband's genetic signature, Montana Fish, Wildlife and Parks is creating a redband broodstock using native genetic strains that have survived in isolated streams.
The first embryos were hatched the week of June 17. Juvenile fish could be ready to begin stocking around the region by summer 2025. Ultimately, the state will stock 25,000 fish annually.
The plan is to stock the fish primarily in lakes or in some isolated streams, according to Tabish.
"Redband rainbow trout face various threats, including invasive species, habitat loss and hybridization and competition from introduced fish. The long-term persistence of redband trout depends on continued and strategic conservation efforts," said Mike Hensler, the state wildlife agency's regional fisheries manager, in a statement.
Reporter Kate Heston can be reached at kheston@dailyinterlake.com or 758-4459.
