Plan is in the works to manage Glacier Park's fish

Harrison Lake in Glacier National Park is an idyllic body of water. Tucked in the southern end of the park, away from the crowds and traffic, it looks like paradise.

But lurking in its waters is a veritable stew of native and non-native fish, all competing for a piece of the pie. There’s native bull trout and cutthroat trout and non-native brook trout and lake trout.

Throw a line into its waters and an angler is never quite sure of what it might catch.

For its part, the Park Service would like to restore a lake like Harrison and others like it, to its natural state — native fish only. But that will take a lot of time and effort. Not only would the lake need to be rid of non-native fish, a barrier would have to be built in Harrison Creek to keep the non-native fish from migrating back into the lake from the Middle Fork of the Flathead.

But still, it’s a possibility, notes Park fisheries biologist Chris Downs. Downs and park staffers are working toward having a parkwide comprehensive fisheries management plan for Glacier. The broad plan would look at every drainage in the Glacier and how to best manage them in the future.

The park recently completed a public scoping process on the ideas for the plan and a much more precise environmental impact statement should be ready for public review by next spring.

Glacier has a lot of water. Within the park’s boundaries there are 725 lakes and or ponds, over 174 perennial marshes and wetlands, and 1,500 miles of perennial stream. The park’s aquatic ecosystems support a diverse array of amphibians and aquatic macroinvertebrates and 17 native fish species, including westslope cutthroat trout, a state-listed Species of Concern, and bull trout, listed as threatened under the Endangered Species Act.

The waters are also diverse and what’s native and not native depends on the very water itself. For example, lake trout are native species east of the divide, but not west of the divide. St. Mary Lake has burbot, while other waters do not.

The general theme, however, is to preserve native species where possible. The park is already trying to do that in Quartz and Logging lakes, where biologists have undertaken an aggressive netting program to suppress populations of lake trout in hopes of preserving the native bull trout population.

Where lake trout thrive, bull trout populations dive, almost to the point of extirpation.

The park has also started transplanting fish. Bull trout from Logging Lake were transplanted to Grace Lake, which is just upstream. Grace Lake has a waterfall in its outlet stream which protects it from migrating invaders.

More transplanting of fish could take place in the future under the new plan, Downs notes. Other suitable lakes would likely be at higher elevations, like Evangeline, which sits below Longfellow Mountain. High mountain lakes generally stay cooler and could be hedges against climate change in the future. But other lakes which have fish now, could be purged and left fishless — which was once their natural state.

The plan is a blueprint for the next two decades, Downs noted. The plan will cost money and so Glacier will consider charging for a fishing license to pay for the program. Right now, fishing is free in the park.

When the plan is completed, it will also make fisheries management in the park more streamlined. Right now, every project has to go through an environmental analysis. The new plan will roll the projects into one document.