Hundreds of Whales Wash Up On Ill-fated Island Surrounded by Sharks

Hundreds more whales have washed up in another mystery mass stranding on a New Zealand island, known to be surrounded by large numbers of sharks.

Up to 250 pilot whales could have been involved in the stranding that occurred in the Chatham Islands, on Pitt Island, according to stranded whale rescue organization Project Jonah.

The stranding comes shortly after another mass stranding occurred to the northwest of Chatham Island, where 215 pilot whales passed away. It takes the number of stranded whales in the area to 500, all within a few days.

Cetacean strandings—when marine mammals wash up on beaches—happen globally. The phenomenon is common, although scientists do not know why they occur.

Pilot whales strand on Australia beach
A picture shows another mass stranding that occurred in Tasmania, Australia in September. Pilot whales are particularly prone to stranding. GLENN NICHOLLS/Getty

Occasionally, we see mass strandings, where a huge number of cetaceans strand at once. Pilot whales are among the species most affected by this phenomenon, along with other types of dolphin.

According to the Department of Conservation, the Chatham Islands are a "stranding hot spot" for whales, with nearly half of the whale strandings in New Zealand occur here.

It is not yet clear how many whales survived the latest incident, but it is likely some will be euthanized. This is due to the remoteness of the area.

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"This is an incredibly isolated and remote part of the world, with a small population and known for great white sharks, which pose risk to both people and whales," Project Jonah said on a Facebook post.

Wildlife officials have been sent to the area to initiate rescue efforts. Project Jonah said it will post updates when they become available.

"Whale strandings remain a mystery. We don't exactly know why whales and dolphins do this," Wildlife scientist Vanessa Pirotta of the Marine Predator Research Group at Macquarie University, told Newsweek.

"Several factors might be at play here, e.g. mis-navigation, spooked by something, following a sick leader. There might be many more reasons.

"Pilot whales are social and can be found in large pods at times. Unfortunately, the clock starts ticking when a whale/dolphin strands, the longer they are out of water, the less chance they have at being released. Even if released, there's always a chance they might re-strand," Pirotta said.

Scientists have noticed that certain coastal areas are more prone to mass strandings than others. It is not clear why, but experts have previously suspected that pods can become disorientated in these areas.

Culum Brown, professor at the School of Natural Sciences at Macquarie University told Newsweek that pilot whales appear to be drawn into specific locations that "probably lots of food available."

But then, they are caught out by shifting tides.

"Mass strandings often happen at the same location multiple times, often years apart which strongly suggests they are attracted to these locations for a reason. Once they are stranded they can get re-stranded when they are freed," Brown said.

"This happens because the stranded animals attract the rest of the pod. If the pod is not willing to leave the area because their mates are stuck, that puts the rest of the pod in danger of stranding as well. It's a kind of negative feedback loop."

Brown said pilot whales strong social bonds can be at their disadvantage in this scenario.

"Pilot whales are often found in pods consisting of hundreds of individuals and big pods can also merge to become super-pods. The social bonds are very strong and while this works to their advantage in some contexts, its a big problem in the context of stranding," Brown said.