As many as 145 whales have died after being found stranded on a remote beach in New Zealand, conservation officials said Monday. Two pods of pilot whales were discovered just over a mile apart on Mason Bay, Stewart Island, a sparsely populated island in the country’s south.

The local Māori, tribe, Ngāi Tahu, is now working with DOC to bless the dead whales and make plans for burial of the bodies.

According to DOC the reasons for whale strandings are not fully understood, but contributing factors can include “sickness, navigational error, geographical features, a rapidly falling tide, being chased by a predator, or extreme weather”.

DOC also said a group of 10 pygmy killer whales stranded at another beach over the weekend, while there were two other cases of individual whales becoming beached.

In a statement, DOC said the cases were “unlikely to be related”, but that strandings were a “relatively common” occurrence in New Zealand.