Boaters are now banned from flushing raw sewage into Bras d'Or Lake, the inland sea in the middle of Cape Breton.

The lake attracts thousands of tourists and boaters each year.

But there have been concerns about water quality. In recent years, 48 areas have had to be closed to shellfishing because of contamination.

Federal officials said Thursday the lake is now a "no discharge zone," making it illegal for pleasure boats and commercial vessels to dump waste directly into the water.

This designation is a first for a body of water in Atlantic Canada, though it's been granted to several areas in British Columbia and Manitoba.

"Bras d'Or Lake is worthy of protection," said David Aggett, with Environment Canada.

Boaters have four years to make changes

Many boaters will now have to retrofit their vessels with holding tanks or disconnect their toilets, but they'll have four years to do it before enforcement officers start laying charges.

Officials from several federal agencies will patrol the lake this summer to educate boaters about the new rule.

But even with the ban on flushing sewage, some people in the area say contamination is still a problem in Bras d'Or Lake.

"There are other issues, like the ballast water, we'll still have to deal with," said Charlie Dennis, executive director of the Unama'ki Institute of Natural Resources, a research organization that represents the five First Nations communities on the island.

Ballast water from commercial vessels has been blamed for the introduction of species such as the green crab and the MSX parasite. Overdevelopment of the coast and siltation are other issues.