The Ontario County Public Health Department says blue-green algae blooms have been spotted at one of Canandaigua Lake's most popular swimming areas.
The health department says it's closed the swimming park and boat launch area at Kershaw Park.
People and their pets should not swim where the algae is visible.
Blue-green algae occurs naturally in bodies of water.
In periods of prolonged hot weather, the algae can become abundant causing health issues for folks who come in contact with it, including rashes, liver, and nervous system damage. It can also severely sicken pets.