EPOW - Ecology Picture of the Week

Tiny Sailor

By-The-Wind Sailor (Velella velella), Family Porpitidae
Gearhart, Oregon, USA

Explanation:  Have you ever seen one of these washed ashore?  What an odd organism!  But it is wonderfully adapted to a harsh life at sea.

This is a "by-the-wind sailor" ... a cnidarian (the phylum that includes corals and jellyfish) and hydrozoan (the class that includes freshwater polyps and Portuguese man o' war).  This species, like others in its family, live at the surface of the water, floating free and subject to winds and surface currents.

This wayfarer is carnivorous!  It feeds on fish and other small organisms just below the water surface, with small dangling tentacles that ensnare its prey.   

The by-the-wind sailor actually sails with its flap.  They are common in warm seas of the world, although this individual washed up on a cold beach of northern Oregon, USA.  At times they can become stranded on beaches by the hundreds or thousands.  Studies have indicated that mass strandings actually add nutrients and organic matter to beach ecosystems, so even in death they play an ecological role!  
    

Information:
     Kemp, P.F.  1986.  Deposition of organic matter on a high-energy sand beach by a mass stranding of the cnidarian Velella velella (L.).  Estuarine, Coastal and Shelf Science 23(4):575-579.