Thousands of Velella velella, also known as By-the-Wind Sailors, are once again washing up on beaches along the Northern California coast. News articles and social media posts place them most recently at Baker Beach and Fort Funston.
While the piles of bright-blue, translucent sea creatures can be unsettling, this is part of a natural occurrence in the spring and early summer. If you grew up on the California coast, this is likely not your first time seeing them.
Here are a few questions answered.
What are Velella velella?
Velella velella are flat, oval-shaped, bluish sea creatures related to jellyfish, characterized by their triangular “sail” and tentacles. According to the National Park Service, the Velella can’t navigate using its sail. But when the sail catches the wind, the Velella will be blown in that direction. In fact, this distinguishes Velella from jellyfish, which drift with the ocean currents.
Fascinatingly, the direction of a Velella’s sail influences where it may “sail” in the world. Animals with left-angled sails are propelled left of downwind, ending up in the Northern Hemisphere. However, “right-handed” ones tend to end up in the Southern Hemisphere.
Why do they wash up on California beaches?
Velella are usually driven towards the coast when the winds shift, such as during a storm. As a result, in the spring and summer, they tend to wash up and die on beaches. As the Velella dries out, it becomes transparent and emits a fishy smell.
Do they sting?
The Velella’s blue tentacles contain stinging cells to capture food, but they are rarely harmful to humans.
However, Velella can pose a risk to dogs if eaten, causing gastrointestinal distress, vomiting, and diarrhea.
