Dec. 1 (UPI) -- Fifty-one whales have died after they were found beached on the shore in New Zealand less than a week after another stranding left another 145 whales dead.
The latest stranding involved approximately 80 to 90 pilot whales discovered Thursday night beached on the shore of Hanson Bay in the Chatham Islands, a group of islands located east of New Zealand, the Department of Conservation said in a statement.
As staff arrived on the scene, approximately 30-40 whales returned to the sea, with 51 remaining. All but one were dead and a decision was made to euthanize the last one due to its poor condition.
"There was no likelihood of being able to successfully save the remaining whale," DOC Chatham Islands Operations Manager Dave Carlton said. "Sadly, the decision was made to euthanize. It was the most humane thing to do."
"This is always an awful decision to have to make," Carlton added.
A mass grave was dug to bury the 51 pilot whales.
Dr. Simon Ingram, a professor of marine conservation at the University of Plymouth said in a BBC report that humans probably had nothing to do with the stranding.
"Pilot whales have probably been stranding in New Zealand since before people lived there," Dr. Ingram said. "It's probably not anything to do with what humans have done."
"It's a very dynamic ecosystem that these animals are in, so I would be very cautious in making any connection between these examples and climate change," Ingram added.
On Monday, a stranding of 145 pilot whales on the shore at Stewart Island in southern New Zealand left all of them dead.
Stranding of marine mammals is relatively common on New Zealand shores, according to the government statement, and the reason is not fully understood, but could include one or more of the following factors: illnesses, navigational errors, geographical features, rapidly falling tides, predator chases and extreme weather.
Ten pygmy killer whales were also beached ashore a 90-mile beach in Northland Sunday.
"You're talking about strandings across the entire breadth of New Zealand in a very short period of time, which naturally does cause everyone to reflect on whether those might have something to do with one another," Dave Lundquist, a technical adviser on marine species, said in a video released by the Department of Conservation. "But there's no evidence at this stage to suggest that they're directly linked."