When animals wash up on beaches it is all too common that the cause is swallowing some human-produced pollutant, such as plastic. However, sometimes even the things that are meant to be dinner turn out to be a bit too much to eat. A great white shark (Carcharodon carcharias) found dead between Geraldton and Shark Bay, Western Australia, appears to have died from having a sea lion (Neophoca cinerea) sealing its throat.

A statement from the Western Australian Department of Fisheries said, “The four-metre male shark had no visible signs of injury or disease, however, it appeared the shark had a large Australian sea lion stuck inside its throat."

Two days before what is believed to have been the same shark was filmed by tourists in apparent distress.

“This could explain why the shark was exhibiting such unusual behavior in shallow waters off Coronation Beach. It is possible that the shark was trying to dislodge the blockage,” said the Department's Dr Rory McAuley. “Such a large object may have damaged the shark’s internal organs or impeded water flow into his gills, contributing to his death. Alternatively, the shark may have accidentally become stranded in his attempts to get rid of the obstruction.”

Local Brad Tapper, who filmed the shark over the weekend, told The West Australian "When we spotted it, it was about 50m off shore and we thought it was a diver or something. We went to look at it, it started kicking and thrashing around again so we thought it was time to leave."

Brad Tapper

In a sign of the gulf between Western Australian attitudes to sharks and those of the government, beachgoers attempted to pull the distressed shark out to sea, as might otherwise be done for whales. The government is in the process of killing hundreds of the apex predator, despite overwhelming expert and public opinion against the cull.

The eyes-bigger-than-his-throat shark had been tagged in January thousands of kilometers away off South Australia, “Confirmation of when and where this shark was tagged demonstrates the extraordinarily mobile nature of this species,” said McAuley.