The Department of Natural Resources added certain species of wild boar to the Michigan Invasive Species Act in late 2010 and began enforcing the new rule April 1.
DNR officials say feral swine related to the Russian or Eurasian boar have spread throughout the state and are uprooting crops, destroying wildlife habitats and carrying diseases that could spread to the state's pork industry, the Detroit Free Press reported Monday.
DNR spokesman Ed Golder compared the boars to the invasive Asian carp, which threatens the Great Lakes.
"These are Asian carp with legs," Golder said. "They pose just as serious a threat on land as Asian carp do in water."
Mark Baker, of Baker's Green Acres near Cadillac, said the rule is putting his business in danger. Baker raises Mangalitsa pigs cross-bred with the now-illegal boars and he says his swine, which he sells to area chefs, are also illegal under the law, even though they are domesticated.
"I have no problem with exterminating feral swine," Baker said Saturday. "But my pigs are my property."