The areas are not closed, but will remain under an advisory until further notice, forest service officials said in an emailed statement Saturday.
Dense areas of blue-green algae, also known as cyanobacteria, can cause rashes or illness in humans or pets, Sweetwater County, Wyoming health officials said in the statement.
Young children, pregnant women, people with weak immune systems and animals are most at risk, officials said.
People are advised to avoid contact with water in the above areas and to keep pets and livestock away from the water. Boiling or filtering the water will not remove the toxins, officials said.
People should also use caution when eating fish caught in the reservoir, officials said. Fish should be rinsed with clean water, and only the fillet should be eaten.
Anyone who comes in contact with an algae bloom should rinse off with clean water as quickly as possible, officials said.
More information about algal blooms is available at cdc.gov/habs.