Two popular beaches in southern Maine were under advisories Friday due to elevated bacteria levels.

Swimmers and beach-goers should avoid the water at Ocean Park in Old Orchard Beach and Mackerel Cove in Harpswell, according to advisories listed on the Maine Health Beaches website Friday.

Earlier this week there was an advisory in place in Kennebunkport.

A group of people play Spikeball at twilight on the beach in Aug. 2020, at Ocean Park in Old Orchard Beach. Robert F. Bukaty/Associated Press, file

The town warned beachgoers on Tuesday to avoid swimming or contacting the water in the Batson and Little rivers at either end of Goose Rocks Beach, citing elevated bacteria levels.

“In addition to repeated results showing human bacteria (DNA) in the Batson and Little rivers, the most recent testing has shown elevated levels of enterococci bacteria in these rivers,” the town said in a Facebook post on Tuesday.

The latest testing results on the town’s website, measured Wednesday, found bacteria levels in the Little River to be more than seven times higher than what the EPA considers unsafe. Levels in the Batson River were more than four times that threshold, according to the town’s test results.

No advisories were posted on the statewide healthy beaches list for the main beach at Goose Rocks on Friday.

The town said Tuesday that the water quality at Goose Rocks Beach is more difficult to maintain than at most beaches in Maine, largely because of the two tidal rivers that bookend the shore. While the two rivers experience higher than average bacteria levels, the main swimming beach does not, the town says. Bacteria levels can also be heightened at low tide.

Enterococci bacteria come from the intestinal tracts of warm-blooded animals, and they can indicate contamination by fecal matter, according to the Environmental Protection Agency. In response to the heightened levels, the town is increasing its testing from once to twice per week.