Wayne Ledwell, head of Whale Release and Strandings in Portugal Cove-St. Philip's, N.L., said the dolphins were first spotted Sunday night near Cape Ray. By late Monday afternoon, all but three of the mammals had died, the federal Department of Fisheries and Oceans said.
"It was expected because of the heavy ice pack and the strong winds that were forcing them on land," Ledwell said in an interview. "They can panic and die real quick when they're pushed onshore."
Ledwell said the ice in the area is three metres thick and jagged on both sides.
"The Gulf of St. Lawrence is chock-a-block with pack ice," he said. "That's a famous area for entrapment because of the pack ice and the way that the peninsula juts out."
White-beaked dolphins, which can weigh up to 300 kilograms, are usually among the first of whales, dolphins and porpoises to arrive in the waters around Newfoundland as spring approaches, Ledwell said.
As a result, they are also the ones most prone to getting trapped, he said, adding that a much smaller group was reported trapped offshore earlier this year.
"Mortality for them is very high," Ledwell said. "With ice conditions, it happens about once or twice a year — that we know of."
Successful rescues have been carried out in the past, with snowmobiles and pickups employed to move the trapped animals to open water.
But the strong winds and heavy ice reported Monday made such an operation almost impossible, Ledwell said.
Larry Vaters, a spokesman for the federal Fisheries Department, agreed.
"Situations when marine animals become trapped in ice are very unfortunate, but do occur in the marine ecosystem — especially when ice conditions are extreme — and should be left to take their course in most circumstances," Vaters said in an email.
"If DFO determines that a trained professional should attempt to assist a stranded marine animal, it is always undertaken with the utmost caution and with a full understanding of how the animals may respond when under stress."
Vaters said the dolphins likely died of internal injuries caused by ice pressure and suffocation under the ice.
Video footage taken by a resident and posted online shows the water tinged red with blood as the dolphins struggle to get free.
Ledwell said his records show more than 400 whales, dolphins and porpoises have been reported trapped in the ice since the 1970s.
The Fisheries Department said six blue whales — the largest animals on the planet at up to 30 metres long — were driven ashore by ice in 1987.