Small boats herded 39 common dolphins out of shallow water near Thumpertown Beach in Eastham Saturday evening, according to a spokeswoman for the International Fund for Animal Welfare.

The group received a report of dolphins stranded in ankle-deep water at about 7:30 p.m., but when volunteers arrived half an hour later, the dolphins had refloated and made their way to deeper waters of Cape Cod Bay on their own, said Kerry Branon, the spokeswoman.

None of the dolphins were injured, Branon said.

Volunteers herded the dolphins further offshore using small boats with acoustic deterrents, she said, and returned at low tide Sunday morning to make sure the animals had not returned to shallow waters.

“That’s a very good sign that the animals moved out to deeper water,” she said Sunday. “We are going to go back and check again at high tide.”

Branon said International Fund for Animal Welfare volunteers also helped two groups of dolphins out of nearby Wellfleet Harbor on Saturday: about 40 common dolphins and between 60 and 100 others that appeared to be Atlantic white-sided dolphins, though volunteers did not come close enough to verify the species.

As of Saturday, about 250 dolphins had been stranded near Cape Cod since January, Branon said.

“It’s a busy year for dolphin sightings on Cape Cod,” she said.

Beachgoers who see stranded marine animals can call the stranding hot line maintained by the International Fund group at 508-743-9548.