The largest mass stranding in the nation in decades has claimed the lives of over 50 pilot whales in Scotland after becoming stranded on a beach on the Isle of Lewis.

Attempts to refloat more than a dozen live whales failed after authorities were notified of the event on Sunday morning at around 0600 GMT.

Rescuers later decided to euthanise the remaining stranded whales on welfare grounds. In total 55 whales died and one is believed to have survived.

The charity British Divers Marine Life Rescue (BDMLR) said one female was found with a vaginal prolapse and it suspected that the whole pod was stranded after one whale suffered birthing complications.

“Pilot whales are notorious for their strong social bonds, so often when one whale gets into difficulty and strands, the rest follow,” BDMLR said.

The Scottish Marine Animal Stranding Scheme (SMASS) said it would begin examining the bodies of the mammals to determine the cause of the stranding.

“Over the next several days we will be conducting sampling and necropsies of the pilot whales to gather as much data as possible to better understand the health of these animals and why they may have stranded,” SMASS said in a statement on Instagram.