It’s been a tough month for whales. Last week, a dead sperm whale was found in Indonesia with 13 pounds of plastic in its stomach. Now, a staggering 145 pilot whales died on a beach on Stewart Island in New Zealand. Stranded in two pods, about 1.2 miles apart, the beached whales were discovered by a walker late Saturday. Half were already dead when they were found, and the other half, although still alive, were euthanized due to their irreparable condition. According to authorities, that was the most humane course of action.

Ren Leppens, of the regional Department of Conservation (DOC), said in a statement, “Sadly, the likelihood of being able to successfully re-float the remaining whales was extremely low,” due to the “remote location, lack of nearby personnel and the whales’ deteriorating condition.” While strandings are fairly common in New Zealand — there are around 85 incidents a year — most involve a single animal and not an entire pod.

Coincidentally, 12 pygmy whales were also found stranded this weekend off the northern tip of New Zealand’s North Island. Four have died, but a local marine group is attempting to re-float the remaining eight tomorrow.

The DOC isn’t entirely sure what causes whale and dolphin strandings. Possible explanations include illness, navigational errors, falling tides, or being chased out of safe, familiar waters by a predator, though researchers still haven’t come to a definite conclusion.

H/T: BBC News