Forty beached pilot whales were refloated by volunteers in northern New Zealand on Friday — but another 38 of the whale pod died on the sandy beach, a Department of Conservation spokeswoman said.
By early afternoon the rescued whales were off the shore and "starting to swim strongly" out to sea, spokeswoman Sioux Campbell told The Associated Press from the North Island city of Whangarei, near the stranding site.
Boats patrolled near the whales to encourage them to continue heading out to sea rather than return to Ruakaka beach — a "typical sandy, gently sloping beach" on which whales strand, she said.
The department said it was forced to euthanize a young pilot whale who was separated from the pod.
"DOC staff spent most of the day trying to help the lone whale regain its balance, and it didn't seem to be doing well," said stranding controller Steve Goddard. "We were also concerned it could still be calling the others back, given they hadn't moved further away during the afternoon."
Pod left after last death
The pod of 40 — milling about only a mile east of where the stranding occurred — moved out to sea following the death of the lone whale, he said.
About 70 volunteers and 15 department staff were standing by in case the whales turned back toward shore or begin to swim into nearby Whangarei Harbor, Campbell said.
"The real concern is that they might come back and strand," she said. "It is really quite common for pods to restrand, so we are really hoping that won't happen."
"We have not had a stranding of this size for several years," Campbell said, adding that strandings in the area were usually of "a few" whales.
Workers from nearby Marsden Point Refinery together with local volunteers helped to refloat the whales.
While a decision had yet to be made over what to do with the dead whales, officials normally have them buried near the site.
Several strandings each summer
The beached pod marked the first mass stranding of the season. New Zealand has several mass whale strandings around its coastline each summer.
The biggest recorded mass stranding on the New Zealand coast involved 1,000 pilot whales on the Chatham Islands in 1918, and the largest in recent years saw 450 of the same species beached on Great Barrier Island in 1985. Rescuers successfully refloated 324 of those mammals.
Whale experts have been unable to explain why the mammals apparently swim into dangerously shallow waters.