A beach on the Lagoon Pond side of Eastville in Oak Bluffs has been reopened after it was briefly closed to swimming and shellfishing due to high bacteria counts, the town health agent confirmed on Wednesday.

In an email to the Gazette, health agent Meegan Lancaster said that bacteria testing on Wednesday had lowered the five-day average of bacteria levels enough to reopen the beach.

"Our testing results are back in and the beach can reopen," Ms. Lancaster wrote. "Our new geomean is 34.31, which is below the geomean standard."

Speaking to the Gazette by phone Tuesday, health agent Meegan Lancaster said water sample testing turned up high levels of enterococci bacteria earlier in the day, forcing the beach closure.

“We test the beach weekly, and two things happened,” Ms. Lancaster explained. “One is, we have what’s called the geometric mean exceedance. So, the mean of the past five tests exceeded the state level. And then . . . the specific test sample that was pulled yesterday morning really exceeded the state number, so that’s what popped us up to metric mean exceedance.” She added:

“The value we got for enterococci yesterday was 981, it is supposed to be below 104.”

Enterococci is fecal bacteria, she further explained. “It can come from animals in the environment, like birds or dogs. It can be compounded by a couple of different sources, and it’s also pretty common for it to elevate after a rain event,” Ms. Lancaster said.

The last time the beach was closed was for one day, when health agents closed Medeiros Cove farther back in the Lagoon three or years ago, according to Ms. Lancaster.