TRAVERSE CITY, Mich. (AP) — The state of Michigan is designating its section of Lake Erie as an impaired waterway because of damage to fish and other wildlife caused by harmful algal blooms, officials said Thursday.

The declaration affects only the part of the lake under Michigan's jurisdiction, which is less than 2 percent. But it was required under the federal Clean Water Act after shoreline monitoring and analysis of satellite imagery showed that the western Lake Erie basin was failing to meet Michigan water quality standards, said Heidi Grether, director of the state Department of Environmental Quality.

"Michigan's portion of Lake Erie is small but, in making this determination, we signal the importance of our actions to date and our commitment moving forward to limit the incidences of severe algal blooms that impact aquatic life and wildlife in our waters," Grether told The Associated Press.

Outbreaks of blue-green algae — which is actually a type of bacteria that can produce toxins — have plagued the lake since the 1990s, at times coating large sections in pea-green slime.

Contamination in 2014 left more than 400,000 people in Toledo, Ohio, and parts of southeastern Michigan unable to drink tap water for two days. The 2015 bloom was the largest on record — covering an area the size of New York City.

This year's bloom was smaller because there were fewer storms that washed phosphorus-laden fertilizers into the lake. But toxicity levels were higher, according to scientists with the National Oceanic and Atmospheric Administration.

Michigan, Ohio and the Canadian province of Ontario agreed in 2015 to seek a 40 percent cut in phosphorus runoff into the lake by 2015. They are developing plans to meet the goal, focusing primarily on preventing overflows from municipal sewage treatment plants and encouraging farmers to use practices that prevent manure and fertilizers from flowing into tributary rivers.

A finding that a water body is impaired can lead to a federal order for stricter pollution controls. Such controls include a maximum amount of a contaminant that can exist in the water and regulation of industries and others that cause the pollution.

But for now, Michigan officials are not developing such a plan, known as a "Total Maximum Daily Load" or TMDL blueprint. Instead, they will ask the U.S. Environmental Protection Agency to give the agreement between the two states and Ontario time to work.

"We are always looking for more collaborative, voluntary approaches to trying to solve these problems," Grether said. She said using a TMDL would be "like taking a sledgehammer when you might need a pencil."

The Michigan Department of Agriculture and Rural Development's campaign for voluntary farm measures — such as planting strips of vegetation between croplands and waterways to prevent erosion — is getting results, according to the agency's director, Jamie Clover Adams. She credited that approach with a sharp drop of phosphorus levels in the River Raisin in southeastern Michigan, a Lake Erie tributary.

Some scientists and environmental advocates contend such steps won't be enough to solve the algae problem unless all farms are required to participate.

Still, Michigan's impaired-water designation under the Clean Water Act is "a crucial and encouraging first step" because it makes a cleanup enforceable under federal law, said Mike Shriberg, Great Lakes regional executive director for the National Wildlife Federation.

"Today's action needs to be a catalyst for the U.S. EPA and states of Michigan, Ohio, and Indiana to act with urgency to craft and implement a pollution-reduction plan that protects our waters from harmful algal blooms," Shriberg said.

Ohio, which has jurisdiction over a much larger section of the lake, has designated only shoreline waters and a small area near Toledo's water intake pipe as impaired.

A farm group said the designation was unnecessary and wouldn't solve the algae problem.

"Instead of encouraging constructive solutions, today's announcement sets the table for even more government mandates, largely driven by fringe groups out to dismantle Michigan agriculture," said Jim Byrum, president of the Michigan Agri-Business Association.