Ten men face federal charges for allegedly poaching walleye and other protected fish from the Red Lake and Leech Lake reservations and selling them on the black market.
Authorities estimate the fair market value of the fish to be in the hundreds of thousands of dollars.
The U.S. Attorney's Office says Wednesday that authorities began investigating in July 2009.
They allege some of the men took fish from Red Lake without approval of the Red Lake Fisheries Association and sold them illegally. Other defendants are accused of netting fish from Leech Lake for commercial purposes.
Authorities say four men also sold fish they took from the Leech Lake reservation to another defendant who owns a restaurant.
Each man faces one count of the illegal transportation, sale, and purchase of fish.