Story highlights Volunteers prevent dead whale carcasses from exploding using locally-built tools

The surviving pod of whales still risk beaching themselves

(CNN) Conservation officials have been puncturing the carcasses of hundreds of dead pilot whales stranded on a New Zealand beach to prevent them from exploding on volunteers.

"In the heat, the whales can explode, but we've taken steps to prevent that," Trish Grant, a spokeswoman for New Zealand's Department of Conservation, told CNN.

"Our staff has been puncturing the dead whales, using an implement that releases the gas (inside their carcasses) that someone local has built for us."

Excavators will be used to move the dead whales further up Farewell Spit in Golden Bay, which is on the tip of New Zealand's South Island, to a location in the nature reserve that's not open to the public.

From Friday to Sunday, around 400 whales died on Farewell Spit, the conservation department said in a statement. It's the third largest mass beaching of whales in the country's history.

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