Glacier s bull trout are on the ropes

By CHRIS PETERSON - Hungry Horse News

One word could be used to describe the bull trout situation in Glacier National Park: Bleak.

The species is on the ropes, having been shoved out of its native waters by non-native lake trout.

Lake trout have slowly, but surely, been invading Glacier Park waters since about 1959, but it s just been in recent years that fisheries biologists have begun sounding the alarm, as more and more lake trout begin showing up in lakes that never had any.

How lake trout take over is somewhat of a mystery. Lake trout don t actually eat very many bull trout, but once the non-native lakers are established, bull trout numbers plummet.

Lake trout are established in Flathead Lake. While generally a lake fish, for some reason, they also will migrate up the main rivers like the North Fork and Middle Forks of the Flathead. From there, they go up other tributaries and get into lakes.

In short, if they can swim to it, they ll eventually take a lake over.

The concern now is to preserve what bull trout populations are left. There are 17 lakes on the west side of the Divide that have bull trout populations. They range from the massive Lake McDonald to small Akokala Lake, tucked way up in the North Fork.

But only five of those lakes are considered secure, meaning they have no lake trout in them, according to a new report by U.S. Fish and Wildlife Service fisheries biologist Wade Fredenberg, and U.S. Geological Survey scientists Michael Meeuwig and Christopher Guy.

The report, Action Plan to Conserve Bull Trout in Glacier National Park, Montana, outlines management strategies for each of the 17 lakes.

The three authors presented their findings to Park staffers at a brown bag lunch on Monday.

The thrust of the effort, at least at first, is to preserve the populations in the five secure lakes, which include Upper Kintla, Trout, Arrow, Isabel and Upper Isabel.

Those lakes have secure populations for one simple reason: Lake trout can t get to them. The streams that drain the lakes have fish barriers waterfalls, that keep lake trout from migrating into them.

The lakes don t really need much management, but the report does recommend that the Park stop letting folks fish in them. Anglers probably wouldn t move lake trout into those five lakes, but with anglers can come other fish threats carried on boots, like zebra mussels and other piscatorial pests, Fredenberg noted.

Upper Kintla is already closed to fishing. Of the five, it has a very unique population of bulls, because only bull trout live there no other species exists.

If the Park doesn t close the other four lakes to fishing, then it should consider an educational effort to inform backcountry users about bull trout and their importance to the Park s ecology, the report recommends. The Park will likely implement the educational strategy and also loosen its lake trout regulations where necessary on the west side of the Park, said Jack Potter, the Park s Chief of Science and Resources Management. Lake trout regulations on the east side of the Park would remain unchanged. lake trout are native east of the Divide.

Guy noted that the bull trout is one of the Park s top predators. Fredenberg also noted that by preserving bull trout, it could also have a ripple effect through the ecosystem. What s good for bulls, for example, is also usually good for other native species, like cutthroat trout and mountain whitefish. Both are important food sources for mammals like mink and otters, and birds like bald eagles and ospreys.

Bull trout, unlike lake trout, migrate into streams to spawn. As such, they too, become a food source for mammals.

But while preserving the five secure lakes is relatively easy, the other lakes will likely prove far more difficult.

Once lake trout enter a lake, they re very difficult to remove completely. Still, the report recommends suppression efforts in lakes like Quartz and Logging. Both lakes have bull trout and good spawning habitat.

It is conceivable that a combination of perhaps netting or trapping lake trout and putting in place fish barriers to keep more lake trout from entering from downstream could stymie their numbers.

But Fredenberg cautioned there is no magic bullet to remove lake trout from a lake. Quartz and Logging pose significant challenges in that they re both backcountry waters and a long way from any roads.

Just getting equipment to them could prove challenging.

Other lakes, like Lake McDonald and Kintla Lake, while far more easier to access, probably wouldn t benefit from suppression efforts. For one, they don t have much spawning habitat and in the case of Lake McDonald, it s would be virtually impossible to keep lake trout from migrating back in the system McDonald Creek is just too big.

Bowman Lake has better spawning habitat and could be a good candidate for suppression. The problem is that Bowman has had lake trout for a long time, and historically, it wasn t as high a quality bull trout fishery compared to other Park waters.

Guy and Meeuwig plan on doing more studies of the Quartz system this summer in an effort to collect more baseline data on the bull trout fishery there.

In the meantime, lake trout have firmly made their mark on Glacier Park s native fishery and it hasn t been a favorable one not by a long shot.