Venomous blue dragons spark beach closures in Spain

Wednesday 27 August 2025 - 13:20

By: Dakir Madiha

Venomous blue dragons spark beach closures in Spain

The appearance of venomous blue dragons, mesmerizing yet dangerous sea slugs, has forced the closure of several beaches in Spain, sparking warnings for swimmers. Authorities have urged caution as these rare creatures, typically found in tropical and temperate waters, are now being seen along the Mediterranean coast.

Beaches on high alert

Last week, beaches in Guardamar del Segura near Alicante were closed after multiple sightings of blue dragons (Glaucus atlanticus). The City Council raised red flags across several locations, banning swimming for public safety. In a statement, local authorities warned: “Do not touch them, not even with gloves. Alert lifeguards or authorities immediately.”

Similarly, beaches in nearby Torrevieja and along the southern Andalusian coast, including Sotogrande and Santa Bárbara in La Línea, have experienced temporary closures following sightings. Earlier this summer, blue dragons were even spotted off the coast of Mallorca, marking their first recorded presence in the Balearic Islands since 1705.

What are blue dragons?

Blue dragons are a type of nudibranch, a sea slug known for its striking electric-blue color and dragon-like shape. Measuring around 4 cm, these creatures can be hard to spot as they often float upside down, exposing their white underbellies instead of their vivid blue backs.

While typically found in the Atlantic, Pacific, and Indian Oceans, their recent arrival in Spanish waters is likely due to climate change and rising sea temperatures. Easterly winds have also swept them closer to shore in recent weeks.

Why are they dangerous?

Despite their small size, blue dragons carry venom that can cause painful stings similar to jellyfish. They feed on creatures like the Portuguese man o' war, storing venom in their bodies to paralyze prey up to 300 times their size. For humans, stings can result in severe symptoms, including nausea, pain, vomiting, allergic reactions, and hyperpigmentation.

Authorities advise avoiding any contact with blue dragons and reporting sightings to lifeguards or local officials.

What to do if stung

If stung, rinse the area with salt water and apply a cold compress. Seek medical attention as soon as possible, as reactions can vary depending on individual sensitivity to the venom.

Expanding risk along the Mediterranean

With sightings now reported in Andalusia, Valencia, and the Balearic Islands, experts warn of the potential presence of blue dragons along the entire Mediterranean coast. Although still rare, swimmers are urged to remain vigilant and follow safety guidelines to avoid encounters with these venomous creatures.