One delight of walking the shore is seeing what treasures have washed up with the tide. Yesterday morning, we spotted several blue-gray colored oval shapes in the wrack.
At first glance, I thought that a trove of rare blue beach glass was underfoot. On closer examination, I realized the sapphire blue-rimmed discs had translucent triangular sails on their backs, and short blue tentacles below. Clearly, not beach glass!
It turns out that dozens of By-The-Wind Sailors, known as Velella velella had washed ashore. They are not true jellyfish, but instead are a colony of numerous tiny animals. Plankton Chronicles offers a brief narrated description of the complex structure of their anatomy.
Monterey Bay Aquarium describes them as “hydroid polyps – jelly-like invertebrates.” Ocean Sunfish are quite fond of snacking on By-the-Wind Sailors.
Found worldwide, these planktonic vessels strand on beaches of the eastern Pacific Ocean when the winter water temperature is warmer, giving them more favorable conditions. They also wash ashore when prevailing spring winds shift and push them to the west coast of North America.