Rescuers who helped free more than a hundred dolphins from the Cape Cod shoreline have confirmed that the mass stranding, which started on June 28, is the largest dolphin stranding in US history.
There were two previous incidents on record in Hawaii and the Florida Keys where dolphin species were seen circling in shallow water; however, the Cape Cod stranding marked the highest number of dolphins beached in a single stranding event, according to the International Fund for Animal Welfare, which was integral to the rescue.
A final review of data and aerial imagery this week revealed that a total of 146 dolphins were involved in the stranding, Bloomberg reported.
IFAW estimated that 102 dolphins survived the multi-day event. There were 37 natural deaths, and seven dolphins had to be euthanized.
Response efforts have continued on a smaller scale for some Atlantic white-sided dolphins on July 2.
Stacey Hedman, IFAW communications director, said 11 dolphins were found stranded near Powers Landing in Wellfleet, Massachusetts.
Two dolphins were euthanized and nine were transported for treatment and relocation to deeper water.
Rescuers faced many challenges in guiding the dolphins back to open water, including difficult mud conditions and the dolphins being spread over a large area.
Efforts began on foot, as rescuers herded the dolphins into deeper waters by using small boats with underwater pingers, which make noise, to attract them.
"This stranding response was a tremendous effort for our staff, volunteers, and partners over multiple days," Hedman said.
The dolphins are now swimming with other groups of dolphins not involved in the stranding.
There is no known reason for why the dolphins became stranded.
