PROVINCETOWN, Mass. (AP) – Recreational boaters have been getting too close to whales off of Cape Cod, prompting experts to issue a stern warning to stay away.

“People have got to stop going on these self-guided whale watch tours,” said Theresa Barbo, spokeswoman for the Provincetown Center for Coastal Studies.

Since July 1 the center has received about a dozen reports of whale harassment, The Cape Cod Times reported on Saturday.

“There are many, many responsible boaters, but for those people who are in a pleasure craft, or a sport fishing craft and who see a whale and go in for a closer look – knowing what the regulations are – that is disgraceful behavior,” Barbo said.

The center’s educators accompany whale watch boats out of Provincetown. They report that recreational boats motor through groups of feeding whales – in one case causing a whale to dive to avoid a boat. The center has not reported direct contact between boats and whales.

The National Oceanic and Atmospheric Administration’s fisheries policy on human interaction with wild marine mammals states that “interacting with wild marine mammals should not be attempted and viewing marine mammals must be conducted in a manner that does not harass the animals.”

Todd Dubois, deputy special agent for NOAA Fisheries law enforcement, said if a whale surfaces within 100 feet of you, “you really should be securing the engine in neutral and waiting for the animal to move on. And you definitely want to be watching for calves and mothers. You never want to be separating them.”

Dubois said NOAA Fisheries is investigating the incident reports filed by the Provincetown center.