They're stranded on the beach after being blown ashore by strong winds.

They are Janthina Janthina – also known exotically as the violet snail or purple storm snail.

Janthina Janthina – purple storm snails feed on jellyfish. Photos: Shanie McLennaghan

And this week they littered the beach at Papamoa.

The snails are found worldwide in warm waters of tropical and temperate seas.

They float on the surface by trapping air bubbles in a balloon of clear chitin. And they feed upon pelagic hydrozoans.

Pelagic as in not close to the bottom of the sea nor the coast and hydrozoans as in jelly fish like the Portuguese man o'war.

And with the number of jelly fish along the coast this summer the snail is most welcome.

Photo: Rochelle Stewart