A toxic marine creature known as the “blue dragon” (Glaucus atlanticus) has been spotted on Spain’s Costa Blanca, prompting local authorities to restrict beach access.
Swimming was prohibited along an 11-kilometer stretch of coastline near Guardamar del Segura, north of Torrevieja, after two specimens were discovered on Vivers beach.
Mayor José Luis Sáez announced the ban on Wednesday in a post on X, warning that residents and tourists “must stay away from this animal.” By Thursday, however, he confirmed that the alert level had been reduced to “yellow” following the conclusion of what he called a “special monitoring operation.”
The blue dragon is a type of nudibranch, or sea slug, notable for its striking blue coloration. According to Australian Geographic, the creature absorbs venom from its prey, storing it in concentrated form to deliver an even more powerful sting.
Typical symptoms from a sting include nausea, pain, vomiting, and acute allergic contact dermatitis.
While nudibranchs generally live on the sea floor, blue dragons float on the ocean surface by swallowing a small air bubble. Strong winds often carry them toward shore.
These creatures usually measure around 3 centimeters (just over 1 inch) in length. They inhabit surface waters of the Atlantic, Pacific, and Indian Oceans, and though small, their sting can pose health risks to humans.