PORTLAND (AP) – A proposal targeted at recreational boaters would make Casco Bay the state’s first no-discharge area in which all dumping of sewage from boats is banned.

The state will seek permission from the Environmental Protection Agency to make the entire bay a no-discharge zone, a change that would probably take effect next summer and apply to all boats and ships with installed toilets.

Making Casco Bay a no-discharge area would cut down on the amount of bacteria in the bay and result in safer seafood, cleaner swimming beaches and a better quality of life, said Joe Payne, the Casco Bay keeper.

The group affected the most would be recreational boaters who have been ignoring marine sanitation laws and dumping raw sewage or partially treated sewage directly overboard, said Pam Parker of the Maine Department of Environmental Protection.

“No-discharge areas really are targeted at recreational boaters,” Parker said. “Fishermen, I don’t think, are going to be affected by this because they usually go . . . more than three miles off (the Maine coast) and lobster boats rarely have (toilets) installed in them.”

The designation would also affect the 700 ships that visit Portland Harbor each year and discharge partially treated sewage, Payne said. The no-discharge designation would require them to hold their waste until they are three miles off the coast.

“It is aimed at recreational boaters, but I think perhaps the larger impact is going to be reducing the discharges from the 700 ships, some of which do discharge here,” Payne said.

Most cruise ships voluntarily hold their waste until they are four miles offshore. Under the no-discharge rule, they would not be allowed to dump waste in Casco Bay even if they had advanced wastewater treatment systems.

No-discharge areas are increasing in popularity; there are already nine in New England.

Parker said the details of how the no-discharge zone would be enforced in Casco Bay have not been worked out, but the DEP will consult with local harbor masters, the Maine Marine Patrol and the U.S. Coast Guard.