( CNN ) -- Dozens of whales are dead after they got stuck on a remote beach in New Zealand , authorities said Monday . The 39 long-finned pilot whales became stranded overnight on Farewell Spit , a narrow claw of land that juts out into the sea from the northern tip of New Zealand 's South Island . Twelve of the whales had died by the time they were found Monday morning . Conservation officials said they decided to euthanize the remaining 27 because the chances of getting them safely back out to sea were too slim . `` They have come very high onto the beach in a big tide , '' said John Mason , the conservation services manager for the area where the whales were found . `` The big tides are now reducing , coming in further out from shore , so it would be difficult to get the large animals into deep enough water to refloat them . '' He said that he and his staff had `` carefully weighed up the likelihood of being able to refloat '' the whales , but that they `` determined that due to various factors it was unlikely they could be rescued . '' `` Rather than prolong the suffering of the remaining 27 whales , we decided to humanely euthanize them , '' he said in a statement . Surrounded by oceans rich in marine life , New Zealand has one of the highest stranding rates for sea mammals in the world . An average of about 300 dolphins and whales get stuck on the country 's coasts each year , according to Project Jonah , a nonprofit group that aims to rescue and protect marine mammals . Golden Bay , the area where the group of pilot whales got stuck , is known as a stranding hotspot because of its protruding coastline , gently sloping beaches and system of currents . Pilot whales , which live offshore , are among the most vulnerable species to mass strandings in such conditions , according to the Encyclopedia of New Zealand . But the number of whales that died on Farewell Spit this week pales in comparison with some of New Zealand 's worst strandings . In 1998 , more than 300 pilot whales died after they got stuck in Doughboy Bay on Stewart Island , which sits off the south coast of the South Island . New Zealand 's worst ever stranding took place in 1918 , the Encyclopedia of New Zealand says , when around 1,000 pilot whales got marooned on Long Beach in the Chatham Islands , which are situated hundreds of kilometers off the country 's east coast . Scientists ask public to help find missing whales stranded off Florida coast . CNN 's Khushbu Shah contributed to this report .
The group of whales got stranded the morning on New Zealand 's Golden Bay . Twelve had died by overnight and officials decided to euthanize one others . `` It was unlikely they could be rescued , '' a local conservation official says . New Zealand 's has one of the highest stranding rates for marine mammals .