Scientists have revealed what they think caused the mass stranding of hundreds of starfish on a beach in the South Hams.

Witnesses say they saw “hundreds if not thousands” of dead starfish swept onto Slapton Sands in Torcross at around 6.45pm on Monday, September 16.

Holidaymakers Martyn and Jill Worrall were leaving dinner at the Start Bay Inn when they witnessed the “surreal” occurrence.

Martyn said: “The waves were washing up hundreds if not thousands of starfish over about 100 yards of the shoreline in front of us.

“I went down onto the beach to see if they were alive, but unfortunately, they looked dead as they weren’t moving.

“There were more being washed in as I watched.”

The couple left shortly afterwards.

In 2016, experts at Plymouth University investigated similar cases of mass strandings and found that it occurs when starfish curl themselves into balls.

It is not known if the unusual phenomenon, known as starballing, is deliberate but marine research fellow Dr Emma Sheehan believes it could help explain why mass strandings occur.

She said: “We simply cannot say whether the starballing individuals were swept off the seabed by the strong tidal flow, or if the individuals allowed themselves to be transported.”

On Tuesday morning, around twenty lifeless starfish were spotted on the beach in front of the Start Bay Inn.

Nine years ago, a different beach in Devon attracted national news coverage after thousands of starfish washed up along a mile stretch.

Multiple news agencies reported the starfish were exhausted after spawning, causing them to drift onto the Budleigh Salterton shoreline.

Footage of starballing, captured by Plymouth University scientists, can be seen below: