This 4-metre shark was filmed thrashing about in shallow waters at Coronation Beach, north of Perth.
Tash Tapper, who shot footage of the shark on the beach, said the whole scene was "surreal".
Research scientist Rory McAuley said: "Such a large object may have damaged the shark's internal organs or impeded water flow into his gills, contributing to his death."
View this video on YouTube
This post has been corrected to properly credit BBC.
