WELLFLEET, Mass. (AP) — More than 40 people — including marine mammal experts, interns and volunteers — spent several hours battling an incoming tide to help rescue seven dolphins that got stranded in the shallow waters of a Cape Cod river this week.

The International Fund for Animal Welfare first got word that the Atlantic white-sided dolphins got stranded in a shallow gut of the Herring River in Wellfleet around 7 a.m. Wednesday, and rescuers were on the scene by about 8 a.m., the organization said in a statement.

It’s not unusual for dolphins to get stranded in the area because of its shape as a hook within the larger hook of Cape Cod’s shoreline, and because of large tidal fluctuations in Cape Cod Bay.

“The dolphins appeared alert and in good health, but the day was sure to be sunny and warm and we needed to move quickly,” said Misty Niemeyer, of IFAW’s Marine Mammal Rescue & Research team.

The tide was also coming in, and dolphins often risk getting stranded again when it rolls out, she said.

The dolphins, all likely young males, were 6 to 8 feet (1.8 to 2.4 meters) in length and weighing up to 250 pounds (113 kg) and were then taken in a vehicle custom-designed to transport dolphins and released in deeper waters off Provincetown between 1:30 and 2 p.m.

“The largest and final released dolphin did appear a bit stressed, and we fitted that dolphin with a temporary satellite tag to monitor its success,” Niemeyer said. “We released the dolphins in three rounds, and eventually all swam off strong into deeper water. We are optimistic about their journey ahead.”

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