More than two dozen long-finned pilot whales have died after stranding at Farewell Spit, a remote beach on New Zealand's South Island where such strandings often occur.

In New Zealand, long-finned pilot whales (Globicephala melas) account for the majority of mass strandings, where two or more whales or dolphins strand at one time, according to the country's Department of Conservation. (Despite their name, long-finned pilot whales are actually one of the largest species of dolphin, according to Oceana.) During past stranding events at Farewell Spit — a narrow stretch of sand at the northern end of Golden Bay — dozens to hundreds of the marine mammals have gotten stuck on shore. More than 10 pilot whale strandings have taken place at the beach in the past 15 years, AFP reported.

The most recent stranding involved 34 long-finned pilot whales, 29 of which had already perished when wildlife rangers arrived at the site on Thursday (March 17) evening, according to AFP.

The rangers quickly contacted a local marine rescue group, Project Jonah, to help them attend to the five surviving pilot whales at Farewell Spit, the conservation department wrote in a Facebook post that includes photos of the pilot whales. On Friday (March 18) morning, at high tide, the team "refloated" the animals. This process typically involves using waterproof tarps to gently move the animals into open water and allow them time to reorient before swimming away, according to Particle, an Australian science publication.

The group successfully refloated all five pilot whales, but "unfortunately, a newly stranded pilot whale has been found several kilometres away at Triangle Flat, at the base of Farewell Spit," the Department of Conservation's Facebook post reads. "It is not clear whether this is one of the five that were refloated. There is also a deceased pilot whale at this site."

The newly stranded pilot whale was euthanized, as the animal was in "poor condition, showing high signs of stress and was not going to survive," according to a tweet from Project Jonah.

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"While this event is unfortunate, whale strandings are a natural phenomenon," conservation department spokesman Dave Winterburn told AFP. "The cause of this stranding is not known."

Scientists still aren't certain why any of these mass strandings occur, Live Science previously reported. One theory suggests that whales' and dolphins' echolocation may not work well in shallow, near-shore waters and this causes the animals to become disoriented. It's also thought that, when one member of a pod strands, others are likely to follow close behind and beach themselves.

"Golden Bay is a high stranding area with Farewell Spit hooking around the northern entrance into the bay and forming extensive, many kilometres wide, intertidal sand flats," the Department of Conservation's Facebook post notes. It's possible that these shallow sand flats might be particularly disruptive to whales' and dolphins' navigation systems, making the remote beach especially deadly to the animals, AFP reported.

Originally published on Live Science.