A great white shark that washed ashore near Geraldton may have choked on a sea lion, an investigation into the animal’s death has found.

Earlier this week the shark, which was about four metres long, was seen thrashing in shallow waters at Coronation Beach, north of Geraldton.

Its carcass, which had been fitted with an acoustic tag, washed up on the same beach on Tuesday.

The Department of Fisheries says research scientists have found the shark had no visible signs of injury or disease, but had a large Australian sea lion stuck inside its throat.

The department’s principal research scientist Dr Rory McAuley said the shark may have been thrashing around in waters trying to dislodge the blockage.

“This could explain why the shark was exhibiting such unusual behaviour in shallow waters off Coronation Beach,” he said in a statement.

“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.”

The department has also confirmed that the shark was tagged in South Australia in January this year.

Dr McAuley says tissue and vertebral samples were taken for future genetic, age and growth, ecological and population assessment studies.

“This information will be useful in improving our understanding about white sharks,” he said.