Why did the stranded whales die?

Locals desperately tried to save one of four whales that died stranded on the beach east of Papamoa at the weekend.

The group tried to keep the young whale wet but it thrashed around "like mad" before dying. It was one of two juvenile gray's beaked whales that were with their lactating mothers.

The whales, a deep-sea species, were discovered near Kaituna Cut, beyond Papamoa East early on Saturday.

Department of Conservation Tauranga's community relations programme manager Katrina Knill said it was believed one of the juveniles stranded first, which led to the subsequent stranding of the others as they stayed nearby.

Samples were collected from the whales to assess whether ingestion of oil, toxins or other foreign objects could have been a contributing factor in the stranding, although no evidence has yet been found to suggest the stranding was related to the Rena.

However, it was reported on Sunday that Project Jonah conservationists had suggested there could be a link as sonar being used to salvage containers can injure nearby whales.

Bill Glover, who was in the first group of people on the scene, was quad-biking with friends on their way to go fishing.

When they arrived on site one of the juvenile whales was still alive.

"It was thrashing around wildly trying to get free. It was pointing towards the sea and there wasn't much water around it. Its tail was half covered in sand, it was lying on its side," he said.

"It was thrashing with each small wave but it couldn't move. Then it just suddenly died ... like it'd had a heart attack."

He said the whales had beached at high tide and there were barely any waves reaching them by the time the group found them.

His friend Mike Knight phoned for help as soon as they came across the stranded animals, his calls alerting Department of Conservation officials as well as members of Project Jonah.

Mr Knight said he and wife Carol tried to keep the 2.5m-long adolescent whale alive for about 30 minutes but had been unable to save it.

"We tried to keep it wet but it was fighting like mad. It was on its last legs. The more it was kicking it was digging itself in.

"It was quite scary to start with, because we didn't know what to do. We tried to concentrate on the little one, to keep it alive," he said.

"It was sad, Carol got really upset. You feel so helpless because they're so big, there's nothing you can do."

He said they had been unable to even roll the young whale upright. But Department of Conservation staff told the group that even if they had been able to float the whale it would likely have died anyway because it was still feeding off its mother's milk.

Mr Glover and Mr Knight used their quad bikes to tow the juvenile whales beyond the high-tide mark so they wouldn't float away and DoC staff organised a tractor to tow the 5m adults.

The whales were blessed by local iwi and buried on the beach after samples had been taken.

Sheryl Gibney, a life member of Project Jonah, said it was upsetting to see the large mammals dead on the beach. "I've often wondered over the last 27 years if it's just the stress of the stranding that they die so quickly.

The samples were sent away and will enable researchers to learn more about the reclusive deep-sea species.