By-the-wind sailor (Velella spirans or Velella velella), photographed at the island of Giglio, Tuscany, Italy

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Velella velella (or Velella sprians) is a pelagic ocean dwelling species that is occasionally washed up around the coastline. Velella velella is a pelagic colonial hydroid. The float is deep blue in colour and about 10 cm long. It has short tentacles that hang down into the sea and a thin semicircular fin set diagonally along the float that acts as a sail. This sail gives the animal both its scientific ( from velum, a sail) and its common name, 'by-the-wind sailor'. The direction of the sail along the float determines which way Velella velella will travel. Velella velella feeds on pelagic organisms, including young fish, caught by stinging cells on its tentacles. The sea slug Fiona pinnata , sunfish Mola mola and violet snail Janthina janthina prey upon Velella velella.

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Size: 4672px × 3104px
Location: Giglio island, Tuscany, Italy
Photo credit: © Paul Harris / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: --wind, arcipelago, barchetta, coelenterati, colonial, del, di, giglio, hydoid, hydroid, isola, italy, jellyfish, mediterranean, pelagic, pietro, pn, sailor, san, sea, toscano, tuscan, velella