Groups aimed at protecting the quality of Ohio lakes affected by toxic algae are having summer fishing tournaments in hopes of reducing the carp populations and thereby decreasing the algae, which has led to warnings at some parks and beaches.

Carp feed on the bottom of the lakes and can stir up sediment containing nutrients such as phosphorus that feed the algae, so reducing the number of carp could help cut off that food supply and decrease the spread of the algae, David Culver, an algae expert and director of Ohio State University's limnology laboratory, told The Columbus Dispatch.

One advocacy group is having a fishing tournament and carp cook-off this weekend at Buckeye Lake, about 25 miles east of Columbus.

''This is a fun way to get people out here,'' said Merv Bartholow, president of Buckeye Lake for Tomorrow. ''The fishing tournament won't fix the problem, but it definitely can help.''

Anglers who participated in a similar tournament last month in western Ohio caught more than 8,000 pounds of carp at Grand Lake St. Marys, where tourism declined amid an outbreak of the troublesome, toxic blue-green algae last year. This summer was the first time officials there were using a carp-fishing event to help tackle the algae issue, park manager Brian Miller told The Associated Press ahead of that tournament.

Toxic algae prompted warnings this year at both Grand Lake St. Marys, between Dayton and Toledo, and Buckeye Lake, where the Ohio Environmental Protection Agency has warned visitors not to swim in the water at Brooks Beach. The agency removed two less severe advisories at a pair of different beaches on the lake.

The advisories haven't stopped some area residents from using the lake to cool off this summer.

''We've swam in it so many times, and we've seen nothing,'' 17-year-old Chase Runyon of Baltimore told the newspaper.

Runyon and two friends were among more than 100 people who registered for the fishing event that kicked off Friday and included a Saturday carp cook-off. The registration fee was $5, and anglers had a shot at prizes for the largest fish or the most fish caught.

Michael Little of Whitehall said he and his teenage son hoped to be competitive and win big while doing their part to fight the algae.

''If it means we can help out a little, then yeah,'' Little said. ''We love this lake.''