South Beach has reopened after a shark sighting closed the popular Edgartown beach to swimming earlier Tuesday.

Edgartown parks administrator Jessica McGroarty said that the sighting occurred at 12:15 p.m., with beachgoers and a beach staff member confirming the sighting.

A bi-plane from the Katama Airfield was then sent to monitor the beach, Ms. McGroarty said, confirming the presence of a shark in the area.

“It was definitely [a shark], because the staff as well as the people on the beach could see it chasing something,” Ms. McGroarty said. “They saw the fin as well as the tail.”

Swimmers were told to exit the water after the sighting, with staff closing the beach for two hours, according to protocol. Ms. McGroarty said beachgoers were compliant with the order.

“It was fine, everybody was out of the water,” Ms. McGroarty said. “It’s just a safety issue.”

Ms. McGroarty did not have further details on the species of shark or its distance from shore. But she said the sighting was confirmed “almost smack dab in the middle” of South Beach, just east of the lifeguard shack.

The sighting is the second of the season, according to the parks director. A shark was also spotted in the South Beach area in early June.

After two hours with no further sightings, the beach reopened at 2:30 p.m. on Tuesday.

“Staff has their eyes on the water, looking for anything that could be a danger,” Ms. McGroarty said. “We just move forward from here.”