Toxic algae plaguing Ohio’s largest inland lake has created a negative public image that organizations and residents in the area are determined to change as they work to draw tourists back.

They’re striving to rebuild the public image of western Ohio’s Grand Lake St. Marys and using television, newspapers and social media to spread the word that the lake is improving. Meanwhile state, federal and local agencies continue aggressive efforts to control the blue-green algae fed by phosphorous from manure and chemical runoffs.

The algae, or cyanobacteria, can produce nerve toxins that have been found in detectable levels in the lake since 2009, The Lima News ( reported.

Efforts to control the algae and improve water quality have included a chemical alum treatment and other initiatives such as dredging of feeder streams and replacement of aerators that increase oxygen in the lake, and state officials are "cautiously optimistic that efforts to control the algae are helping," Dina Pierce, spokeswoman for the Ohio Environmental Protection Agency told The Associated Press.

The Lake Improvement Association is helping lead efforts to revive the 13,000-acre lake and the tourism business that relies on it — a business that has suffered since the algae outbreak and reported illnesses led to a 2010 advisory not to touch the water, take boats out or eat lake fish.

"One of the biggest issues we have is selling this place now," association president Tim Lovett told the newspaper.

The state advisory posted at three public beaches at Grand Lake St. Marys State Park is less stringent this year. Swimming, wading, swallowing the water and touching surface scum are not recommended, but there is no warning against boating or eating lake fish.

But people still think they aren’t allowed to put boats on the lake or touch the water, Lovett said.

"That stuff is totally untrue, but that’s the perception," he said.

No one denies that area tourism has declined.

An economic impact assessment prepared in 2009 by a Pennsylvania consulting firm showed that sales, wages and taxes generated approximately $193 million in Auglaize and Mercer counties and accounted for 2,487 jobs, the newspaper reported. Data from a Small Business Administration disaster declaration survey showed average business revenue was down 35 percent to 40 percent the following year — about $77 million across the region.

The Auglaize and Mercer Counties Convention and Visitors Bureau, is trying to spread the message — through television, newspapers, social media and word-of-mouth — that "the lake is open and getting better," bureau executive director Donna Grube told the AP.

"People just aren’t aware that they can go on the lake," she said.

Brian Miller, the state park’s manager, says the water quality is better compared with 2010.

He told the AP there are no longer floating mats of scum or the disagreeable odor that area experienced last year.

The lake’s boosters say tourism already has increased compared with last year. The state park campground has been close to full on holiday weekends, even though non-holiday weekends are still down, Miller said.

The park and businesses around the lake have offered discounts and other promotions, and some events canceled last year have returned. A recent lake festival featured a water ski team, and speedboat races are scheduled later this month.

Lovett said it may take a while, but at some point "this will be a showcase again.".