Sep 22, 2022 - Energy & Environment

"Complete mystery": Experts baffled after back-to-back strandings killed hundreds of whales

rescuers save beached whales

Rescuers release a stranded pilot whale back into the ocean at Macquarie Heads on the west coast of Tasmania on Sept. 22. Photo: Glenn Nicholls/AFP via Getty Images

Experts are torn after two deadly mass whale strandings in Tasmania this week made international headlines, but some have floated theories for why the incidents happened.

The big picture: The Tasmanian Department of Natural Resources and Environment said in a statement that it "will assess the scene and the situation to plan an appropriate response." It response has been guided by a manual that's undergone revision since Tasmania's largest-ever mass whale stranding in 2020.

  • "Whale strandings are a complete mystery," marine expert Vanessa Pirotta told the Australian Broadcasting Corporation, "but what's really unusual here is that this is the second stranding for this week."

Details: Most of the 230 whales stranded on a beach in Tasmania this week have died, days after 14 dead sperm whales were found beached.

State of play: The ABC reports a few common theories for why these incidents happen:

  • Misnavigation: "So one could be misnavigation," ABC's marine expert Vanessa Pirotta said, adding environmental factors could also potentially come into it.
  • Herding: The fact that pilot whales are "herd species" could be a contributing factor, according to retired veterinarian David Obendorf, who previously worked with the Tasmanian environment department.
  • The calendar: "There are certain times of the year, and locations, that are prone to having a frequency of whale trappings," Obendorf told ABC.
  • Geography: The beach topography and tidal conditions could make an environment more susceptible to strandings, Obendorf added. If whales are unable to use their echolocation, they can't navigate deeper water and get embedded in the sand, which ultimately can lead to drowning.
  • Another expert agreed that Tasmania's topography makes it somewhat of a "whale trap" since the coast is close to the shelf edge where it drops off.
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