Worried bathers at Golden Bay forwarded this picture to this newspaper and asked whether the thousands of tiny invertebrates were ‘baby’ Portuguese Manowars.

A few emails and phone calls later, they were identified by marine biologist Alan Deidun as being “By the Wind Sailors” – Velella velella. Dr Deidun said: “By the Wind Sailor or Velella velella are common at this time of year, being beached in their thousands and turning the beach blue before being bleached into a translucent white sheen. They are harmless and they have their own sail which is actually a flap and which is used for wind dispersal since these creatures float on the surface of the water.”