By Nidina Sapkota
During springtime, groups of electric blue creatures get washed up on our local shorelines. Those deep blue electric creatures with a distinguishable transparent triangular sail are called Velella velella. So what exactly are they? They are free-floating hydrozoans that live on the surface of warm to temperate open waters. Due to their boat-like sail, they are known by names like “By the wind sailor” or “Sea Raft.” The sail uses the wind currents to carry the Valella throughout the surface of the open water.
Velella has a lifecycle made up of two main stages: the floating polyp (what you see on beaches), and the medusa (essentially a tiny jellyfish.) To reproduce, polyps located on the bottom of the Velella asexually create tiny medusae that bud off and sink into deeper water. The medusae will mature and then produce eggs and sperm, which will combine to grow into new polyps. Both the reproductive polyps and the medusae contain zooxanthellae (symbiotic algae that produce energy through photosynthesis.) Velellas feed on small prey and fish that can be caught immediately below the surface of water.
Where can you find them?
During springtime, the prevailing wind currents push these creatures towards the shore of the beach. This is why we see many Velellas lying around at the shore in the springtime. They are incredibly miniscule, being around 7 cm long. They are friendly creatures in that they are not poisonous and their sting is not harmful to humans. These fascinating, shimmering, creatures can be found all over the world, including in our own watershed. Next time you visit your local beach, look out for this living sailboat.
Photo sources: http://www.utaot.com/, http://en.wikipedia.org/wiki/Velella