Velella Stranded on the North Oregon Coast
North Oregon Coast: Purple Sail
Strewn on the beaches of Gearhart, Oregon in the summer of 2015 were thousands upon thousands of sea creatures that looked as if they had blown there haphazardly in a fierce wind. In fact they had been.
The creatures are known as Purple Sail (Velella velella), a genus of free-floating animals that usually live their lives on the surface of the open ocean. It is a curious carnivorous animal that has several common names: Sea Raft, By-the-Wind Sailor, Purple Sail, Little Sail or simply Velella. They feed on plankton that comes into contact with its tentacles, which hang down in the water below the animal. The tentacles bear cnidocysts that carry toxins which are harmless to humans, but are effective when seeking their next meal.
The Purple Sail is a small cnidarian, which is part of a specialized ocean surface community that includes the most well-known species, the Portuguese Man-O’-War (more on that one later). The Velella has no means of locomotion other than its sail-like fin and tends to float and sail downwind at a small angle to the prevailing wind. Purple Sails and other cnidarians are prey to the mollusks, sea slugs and sea snails that forage in the same parts of the ocean.
According to Wikipedia Velellas are usually deep blue in color, but their most obvious feature is small stiff sail fin that catch the wind and propels them over the surface of the ocean. Under certain circumstances and under certain wind conditions, the Velellas can become stranded by the thousands on beaches, as we have seen after fierce storms on the long stretches of sand in Gearhart, Oregon.
Velella seen by the thousands on the beach of Gearhart, Oregon
The mass stranding of the Purple Sail has been observed from British Columbia to California on the Pacific Coast and even on the west coast of Ireland in the Atlantic. The stranded animals are the polyp phase in the animal’s life cycle. Each “individual” with its sail is really a hydroid colony, with many polyps that feed on ocean plankton. These are connected by a canal system that enables the colony to share whatever food is ingested by individual polyps.
Velellas swirling with the tides on the North Oregon Coast
Each individual By-the-Wind Sailor is either a colony of all-male or all-female polyps. The colony has several different kinds of polyps, some of which are both feeding and reproductive, called gonozooids, and others protective, called dactylozooids.
The gonozooids each produce numerous tiny jellyfish by an asexual budding process, so that each Velella colony produces thousands of tiny jellyfish (medusae), each about 1 mm high and wide, over several weeks. The tiny medusae are each provided with many zooxanthellae, single-celled endosymbiotic organisms typically also found in corals and some sea anemones, that can utilize sunlight to provide energy to the jellyfish.
Toxic Cousins: Portuguese Man-O’-War
Just When You Thought It Was Safe To Go Back In The Water: Portuguese Man-O’-War
Peter Benchley wrote about the dangers of the Portuguese Man-O’-War in his book, Creature, where a swimmer was stranded in terrible pain on the beach until a passer-bye has to cover the swimmer with uric acid to numb the pain.
My father had been stung by a Portuguese Man-O’-War while he and my mother were on their honeymoon in Bermuda. The electric shock stung the fun out of several days of beach combing, raising huge welts and leaving lacerations on his chest, neck and back. Full recovery took several weeks. This lethal jelly fish is known to grow tentacles many feet long in the warm waters of the Gulf and they float with the wind and gulf stream up the Atlantic Coast in warm weather. Their tentacles are so full of toxins that they can be lethal to humans, even while the animal appears helplessly stranded on the beach.
Be grateful, West Coasters, to be able to avoid this toxic cousin of the Velella, which is not currently in our waters.
Even a beached Portuguese Man-O’-War can sting the life out of you…
Portuguese Man-O’-War Toxic … Terror of the deep
Fish-Eye View of the Portuguese Man-O’-War