Rescuers in New Zealand managed to coax 33 beached whales back out into deep waters Sunday, but another 15 of the pod died, a conservation official said.The 48 pilot whales stranded Saturday at Port Levy on South Island, but scores of volunteers joined Department of Conservation workers to refloat them off the shallow, muddy inlet, said the department's community relations manager, Grant Campbell.It was the third mass stranding on the New Zealand coast this summer. Some 125 pilot whales died in the two other beachings, while 43 were returned to the ocean.Campbell said that in the latest incident, residents were quick to help after spotting the whales apparently feeding in the inlet before they stranded."It's a very, very shallow bay in Port Levy, very muddy, so whether they were chasing food and got caught in the shallows, we don't know," he told The Associated Press.Whales in the pod were up to 17 feet (5 meters) -long, while a few calves were between 3 feet (1 meter) and 5 feet (a meter and a half) -long, Campbell said.Local Ted Howden said the pod stranded twice. Residents helped the whales back out to open waters Saturday, but by Sunday morning they were all back on the beach, he told TV One News.More than 80 people rallied to aid the mammals, and as the tide flowed in Sunday, "they began floating and we were able to push them out, and away they went," Howden said.By later Sunday, the survivors had been shepherded into deeper waters by a couple of boats and were swimming away, Campbell said.Specialists will carry out autopsies on two of the dead whales Monday, before the 15 dead mammals are buried high up the beach, he said.Large numbers of whales become stranded on New Zealand's beaches each summer as they pass by from Antarctic waters on their way to breeding grounds. Scientists have been unable to explain why whales become stranded.