The scene on Ocean Beach, a remote beach on Tasmania's western coast, was undoubtedly tragic. Earlier this week, around 230 pilot whales had beached themselves, with half already dead by the time they were discovered. Ultimately, around 200 whales died. It's not the first time that hundreds of whales have perished on the beaches of Tasmania. But why is this happening, and why is lying on the beach so deadly?
Sadly, marine biologists aren't sure why large numbers of whales beached themselves, though one theory is that they came to shore while chasing prey, specifically squid. The Tasmanian Department of Natural Resources and Environment will analyze the whales' stomach contents during the post-mortem to see if there are any clues. Other factors include coastline shape, water temperatures, and fast-moving tides.
The social bonds between group members could also have played a role, as pilot whales communicate through clicks and whistles. A few stranded individuals calling for help could have inadvertently led others to the same fate.
There are many dangers for beached whales, including overheating and breathing difficulties. Pilot whales can weigh up to two tons – their bodies are not designed to be out of the water, and their weight can make it difficult for their lungs and other organs to work. On Ocean Beach, rescue workers kept the whales cool with wet sheets and blankets, before using construction equipment to return them to the ocean. Around 30 were lifted off the beach and then towed to deeper waters.
More about beached whales:
- Saving beached whales isn't as simple as towing them out to sea. Because they are social animals, pilot whales will try to rejoin the rest of their pod, sometimes beaching themselves for a second time. They may also get stressed or disoriented. In this week's incident, around 10 whales returned to the beach after being rescued.
- Pilot whales are members of the oceanic dolphin family, just like orcas (killer whales). They typically live in pods of 20 or 30 individuals, with a matriarch as the leader. They sometimes join up into "super pods" with around 1,000 whales.
- Almost exactly two years ago, around 470 pilot whales beached themselves in a very similar area. It was Australia's largest ever whale stranding. Only 110 of the whales could be saved.