Hunting invasive Canadian beavers in Finland proves difficult as eradication seems impossible

Finland’s efforts to control the invasive Canadian beaver population appear futile, with experts now admitting the species cannot be eradicated, reports Yle. A recent spring hunt in Suomussalmi, where the invasive rodent is most widespread, highlights the challenges of managing a species that has firmly established itself in Finnish nature.

The Canadian beaver, introduced to Finland in the 1930s by mistake, now vastly outnumbers the native European beaver. With an estimated 9,500–17,700 Canadian beavers compared to just 3,200–4,400 European beavers, the invasive species dominates waterways, particularly in Kainuu, where 856 active lodges were recorded last year—the highest in the country.

Hunter Veli Heikkinen, who has culled 41 Canadian beavers in his lifetime, explains that early springs and harsh winters push the animals deeper into remote areas, making them harder to track. “If you delay the hunt, you’ll come home empty-handed,” he warns. This year’s target—a lodge between two wilderness lakes—shows fresh signs of activity, with gnawed tree trunks floating in the stream.

The Canadian beaver’s introduction was an ecological blunder. In the 1930s, Finland attempted to revive its extinct beaver population by importing individuals from Norway (European beavers) and Canada. Decades later, researchers realised the Canadian animals were a distinct species, incapable of interbreeding with the European beaver due to differing chromosome counts (40 vs. 48). By then, the invasive population had already spread.

Last year, the Canadian beaver was added to the EU’s list of harmful invasive species, shifting its management from hunting regulations to stricter invasive species legislation. However, Annika Herrero, a researcher at Finland’s Natural Resources Institute, notes that even this won’t solve the problem. “Eradication is no longer possible,” she admits, adding that limited funding hampers comprehensive mapping of beaver populations.

While the Canadian beaver was once thought to outcompete its European counterpart, studies from Russian Karelia suggest the opposite: in some areas, the native species has completely displaced the invasive one. Herrero speculates that similar shifts could occur in Finland under the right conditions, though evidence remains scarce. For now, the Canadian beaver’s higher reproductive rate ensures its dominance—leaving hunters like Heikkinen to manage, rather than eliminate, the stubborn invader.