CHATHAM – Shark warning signs have been installed at all town beaches and many town landings, and lifeguards are keeping a sharp eye out for seals near designated swimming areas.

As of late last week, lifeguards had observed three seals in Oyster Pond this summer, although none were within 300 feet of the swimming beach. Because the seals did not come close to the designated swimming area, the beach was not closed, Park Director Dan Tobin said. He wasn't aware of any Chatham beach closures this season because of either seals or sharks, although several Outer Cape beaches to the north were closed due to shark sightings last week.

Vivid red and blue signs warning of the presence of sharks are now up at all town beach on both the east side and Nantucket Sound side of town, as well as at most town landings. Several other landings have signs warning people not to swim with seals.

Additional signs went up last week at Bearse's Lane, just south of Lighthouse Beach, and at Claflin Landing on Chatham Harbor and at Jackknife Cove on Pleasant Bay. There are also shark warning signs at Oyster Pond, Andrew Harding's Lane beach, Cow Yard and Ryder's Cove landing, as well as at all the south-side beaches.

Tobin said the signs were put up at the landings specifically to warn boaters that they were heading into waters where sharks were known to be present.

The signs feature a large photograph of a menacing-looking great white shark and warn that sharks are known to hunt seals in shallow water at the beach and that people have been injured and killed by white sharks along the shoreline. People are urged to call 911 in an emergency and to download the Atlantic White Shark Conservancy's Sharktivity app to receive alerts and sighting notifications.

If the signs are designed to intimidate, they seem to be doing the job, at least among the younger set. The park department received one report of a four-year-old frightened to go in the water at Cockle Cove Beach due to the sign.

“The fear is the sign is intimidating young children,” said Tobin.

Park and Recreation Commission Chairman Meredith Fry was against moving the sign to a less visible location.

“We want people to see them,” she said. The same signs are in place at most beaches along the Outer Cape, she added.

Commission member Ira Seldin worried that beachgoers may be getting desensitized to the signs. He said he saw many people pass the warning sign at Harding's Beach and not give it a second glance. The cluster of signs at Lighthouse Beach may also create confusion, Fry added.

“I think we need the signs for liability reasons,” Seldin said. “But you have to face the fact [that] people don't look at signs.”

A plan to have a harbormaster boat patrolling just off the Oyster Pond beach during town-sponsored swimming lessons has not yet been implemented; Tobin said the harbormaster department is trying to find qualified personnel to staff the boat. Once in place, the harbormaster staff member would alert lifeguards if a seal is seen in the pond, but the waters would only be closed if a seal is within 300 feet of the swimming beach.

“The fact that there's a seal in the pond is not an immediate concern for the beach,” Tobin said.