|By-The-Wind Sailors in Brazil. These guys are being spotted by fishermen off the OR and WA coasts! [Photo: thedancingrest.wordpress.com]
|By-the-Wind Sailors stranded on a beach, a sight that has been reported several times in Oregon this season. [Photo: Zen Fly Fishing]
As their name suggests, these animals are relatively helpless subjects of the tides and winds, and as a result, large numbers of these animals strand on beaches if the conditions are just right. At first, they appear to be just another invertebrate, but upon closer look, it's pretty apparent that there are a number of amazing traits of these animals! Here are some basic facts about these awesome creatures.
1) Velella velella is NOT a jellyfish, although it is in the same Phylum, Cnidaria, or stinging animals.
Hydrozoans are some of the strangest animals in the seas- they are related to jellyfish and corals, but aren't really similar to either. These little animals can live independently or in colonies, like Velella, and are generally predators. They use specialized stinging cells to immobilize and then consume prey- fortunately these stinging cells are too small to injure us. Many people may mistake the harmless Velella for the dangerous (and infamous) Portuguese Man-o-War, whose adults are much bigger. Velella adults are typically less than 2-inches across.
|An array of bizarre hydrozoans, as drawn by Ernst Haeckel (1904)
Unlike a jelly, lots of individual immature Sailors come together to form one cohesive unit, which looks like one animal. This is similar to other sea creatures, such as corals or sea pens, which are my personal favorite colonial invertebrate (in case you were wondering what to get me for Christmas!) Individuals on a Sailor are specialized for functions such as structure (forming the sail, etc.), feeding, stinging (defense), or reproduction.
|Typically adult colony of Velella, representing a cooperative network of individuals forming one unit.
Colonies of Velella are segregated by sex- some colonies are only male, and some of them are only female. In addition, this animal reproduces by asexual budding- that is, each animal essentially creates thousands of clones of itself which are then released into the water column as tiny polyps, which then later transform into the adult stage called the Medusa.
|Graphic of an adult cnidarian producing a budding polyp or clone. [Darwinlearning.com]
Velella velella means 'little sail' in Latin. And that sail is essentially what their life cycle is all about. Although little is really known about how this organism spends its life, it is known that the species appears to be made up of colonies that have their sail rotated clockwise, while the other section of the population consists of sails rotated counter-clockwise. For that reason, many of the animals that art found in one stranding event will have sails rotated in a similar direction, since the wind tends to carry them one way. Other individuals with a different 'handedness' will typically be carried in the opposite direction- that is, farther out to sea.
|Top view of a Velella with a counter-clockwise rotated sail. Other individuals would have the sail rotated similarly to the right. [Illustration: Lander University]
Don't panic if you see these guys in the water or on the beach! They cannot sting you. While other cnidarians are deadly to humans (such as the Portuguese Man-O-War), smaller hydrozoans like Velella are harmless to humans. These guys drift at the surface of the water, and capture tiny zooplankton floating there. They aren't really well-adapted to eat (or sting) something much bigger than a grain of sand.
|A Portuguese Man-O-War sits on a beach. Unlike Velella, this is a pretty deadly and dangerous animal to humans.
Did you see these guys on the beach? Email me and let me know!
Here are some photos of the recent stranding at Beverly Beach, near Newport OR (Although I was a day or two late, when the animals were pretty well dried up):