A pod of dolphins rescued by locals at Tokerau Beach last week is believed to have re-stranded at the Cavalli Islands with deadly results.
The Department of Conservation's Bay of Islands manager, Rolien Elliot, said 14 common dolphins became stranded on Motukawanui Island, the largest of the Cavalli Islands off Matauri Bay, during incoming tide on Friday evening.
Nine carcasses were discovered by officials from DoC and Far North Whale Rescue while the rest were presumed to have made their way back out to sea.
It could have been the same pod of common dolphins that was stranded in Doubtless Bay a few days earlier, but testing would be needed to confirm whether that was the case.
The dead dolphins were due to be buried on the island yesterday.
In the first stranding, on Wednesday afternoon, locals discovered a pod of about 20 dolphins floundering at the northern end of Tokerau Beach. While the animals did not appear distressed they were in calf-depth water and the tide was going out.
Tokerau Beach resident Glenys Urlich said the dolphins were "milling around in the shallows" and seemed reluctant to return to deeper water.
A large group of locals kept them wet and upright - dolphins can drown from water entering their blowholes if they tip onto their sides - and tried to herd them out to sea.
Eventually locals got the pod together in slightly deeper water and they swam away about 3.30pm, just before a rescue team arrived from DoC's Kaitaia office.
Mrs Urlich said Tokerau Beach had had a run of whale strandings some years ago so locals were well versed in marine mammal rescues.