COLUMBUS, Ohio (AP) -- Signs describing how to recognize harmful algae that pose health risks will be up at several of Ohio's state park lakes throughout the recreational season.

The state Department of Natural Resources says color photos illustrating algae blooms that can produce toxins will be posted at beaches, boat ramps and marinas at about 14 parks.

The state also will post color-coded advisories at lakes where toxin levels test higher than acceptable. An orange sign will recommend that people with weak immune systems should not swim or walk through the water. It also will warn elderly and young people.

A red sign advising no one touch the water will be posted if lake algae is attributed to probable cases of human illness or pet deaths.