(AP) -- New Zealand conservation officials on Friday euthanized 10 pilot whales, the only survivors of a 24-strong pod that became stranded in a mangrove swamp.
The whales had been found earlier in the day trapped in the shallow water and mud in Parengarenga Harbor on North Island, with 14 already dead.
The mammals had been there for some time and the 10 survivors were in poor shape, said Department of Conservation area manager Jonathan Maxwell.
With worsening weather and a high tide more than eight hours away, "the chance of successfully refloating the whales was virtually nil," Maxwell said.
"Sadly, the current conditions were against these animals. The kindest thing was to end their suffering," he said. "If we felt there was a real chance we could have successfully rescued them, we would have."
Pilot whales travel in pods of family groups and when one becomes stranded, others follow to try to help and also become stuck.
Pilot whales are the most common whale species in New Zealand waters, and are normally between 13-19 feet (4-6 meters) in length.
Last week, volunteers and conservation workers successfully refloated one young Gray's Beaked whale after it stranded. Four other adult mammals died on the beach.
New Zealand has several whale strandings around its coastline each summer, with mass strandings of as many as 450 of the mammals.
Whale experts have been unable to explain why the mammals apparently swim into dangerously shallow waters.
Explore further: 15 whales die beached in NZ, 33 coaxed to sea