Montana’s experience with walleye illegally introduced into trout waters an interesting perspective on ‘alien’ invaders

By David Majkrzak, Pelican Lake, President of Otter Tail County chapter Minnesota Coalition of Lakes

Walleye, an invasive species???

Seems like an odd statement, but that is exactly what a recent article stated about Swan Lake in Montana. Someone had illegally “introduced” walleye into this salmon and bull trout lake, and these native fish were threatened if the non-native, predatory fish, walleye, survived, and established a breeding population.

Montana does have walleye fishing, and promotes it in lakes and reservoirs across the state, but illegally moving walleye to a non-native lake makes walleye an invasive species to the new lake.  In Montana the penalty for illegal introduction of fish is a $2,000 – $10,000 dollar fine, and one year in jail. When “someone” introduces a non-native fish (or plant or other AIS) to an environment, the ecosystem will change, and native fish, plants and all organisms have to adjust and make room for the new invader. Sometimes the change cannot be measured, and many times the effect is not recognized or measurable for many years; but the change is there, and the process is not likely reversible.

We in society have to decide what changes, or level of risk, we allow our natural resources to endure.  We have to decide how aggressively we fight accidental AIS, or what level of risk we are willing to accept when non-native species are “introduced” to Minnesota lakes and rivers.

One “bucket biologist,” one careless lake user spreading AIS, or a small group promoting a non-native fish stocking, puts all our lakes at risk.

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Editor’s note: This column appeared in the recent Otter Tail Coalition of Lake Associations electronic newsletter.