State regulators will allow a fish hatchery to expand on the Au Sable River, despite objections from groups that fear it could pollute one of northern Michigan's most prized trout streams.
The Michigan Department of Environmental Quality said Friday it has granted a permit to Harrietta Hills Grayling Trout Farm.
The company plans to raise its output of rainbow trout at the facility to 300,000 pounds annually, up from 70,000 pounds at present.
Opponents such as the Sierra Club and Anglers of the Au Sable say farm-raised fish could expose wild trout downstream to a deadly sickness.
The company says its plan is safe for the river and its native fish.
DEQ Director Heidi Grether says provisions added to the final version of the permit will further protect the river.