MADISON, Wis. (AP) -- Four Wisconsin bait farmers have been charged with violating federal wildlife law for allegedly importing fish from other states without a valid permit.

Acting U.S. Attorney Stephen Sinnott identified the four businesses as Gollon Brothers Wholesale Live Bait of Stevens Point, Gollon Enterprises in Dodgeville, Hayward Bait and Tackle and Friesses Minnow Farm in Cumberland.

Prosecutors say the businesses transported fish with a market value totaling more than $2.5 million from other states to Wisconsin without permits. Federal and state laws ban such importation to stop the spread of certain diseases in the fish population.

Each business faces the possibility of thousands of dollars in fines.