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Illegal Fish Records

Walleye caught in Swan Lake, October 2015

Throughout Montana, we have documented hundreds of unauthorized, and often illegal, introductions of fish. New introductions are discovered every year, with no indication that the rate of unauthorized placements is declining. These introductions commonly involve transport of game fish species from nearby locations that are released into new waters, often with harmful consequences for already established fisheries.

Management actions have varied, from attempts to eradicate fish by mechanical and chemical means, to accepting their inevitable presence and incorporating the new species into the sanctioned regulation of existing fish assemblages. Sometimes we enlist the help of anglers, for example by allowing large daily limits, or even unlimited harvest. Best success for eliminating new introductions has been achieved in closed and relatively small basins using fish toxicants to reset the entire fish assemblage. Our most difficult challenges occur in the large open systems where successful introduction and establishment of a new fish species is almost impossible to remove. In these situations we do what we can to mitigate harm to existing fisheries, but effective options are often quite limited. In all cases, these actions are expensive.

Do Your Part to Help! Call 1-800-TIP-MONT or submit a report online if you suspect illegal activity.

Illegal Fish Introductions

Search our database for records of illegal introductions in Montana:


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