A Cadiz beach has reopened under yellow flag conditions after being forced to close over the weekend when six rare ‘blue dragons’ (Glaucus atlanticus) were spotted in the shallows.
Until now, the bizarre-looking sea slug – just three to four centimetres long and known for its alien blue colouring – had only been reported along the beach of Torreguadiaro in nearby San Roque.
Its sudden appearance on Santa Barbara beach in La Linea prompted alarm among bathers, with lifeguards carrying out jet ski and boat sweeps of the coast before declaring the waters clear.
Councillor for Beaches, Rafael Leon, confirmed that while the area is now open, yellow flags will continue to fly at Santa Barbara, Levante and Sobrevela towards Alcaidesa, alongside the possible hoisting of jellyfish flags after sightings earlier in the week.
‘We are urging swimmers to exercise caution,’ Leon said, adding that any further sightings of the creature should be reported immediately to lifeguards so that beaches can be closed if necessary.
Cross-border warning
The Gibraltar government also issued a notice for its neighbouring Catalan Bay, which lies just across the airport runway from Santa Barbara.
Authorities urged bathers to immediately report any sightings to the Department of Environment’s Environmental Protection and Research Unit (58009620) and to seek medical attention at once in the event of a sting.
Why are the blue dragons here?
The arrival of the Glaucus atlanticus in Andalucian waters is linked to global warming and shifting currents, which have also carried in their prey – the dangerous Portuguese man o’ war.
The species has previously been recorded in the Canary Islands and more recently in the Balearics, but 2025 marks the first sightings in Cadiz and Campo de Gibraltar waters.
What to do if stung by a blue dragon
Although not aggressive, the ‘blue dragon’ stores venom from its prey and can release it when touched, causing pain equal to or stronger than a jellyfish sting. Symptoms include:
- Severe burning pain
- Redness and blistering
- Nausea or vomiting
- In some cases, allergic reactions
Authorities advise:
- Do not rub the affected area, as venom may spread
- Rinse with seawater (never freshwater)
- Remove any tentacles with tweezers
- Apply cold compresses to reduce swelling
- Seek medical care if symptoms persist
Read more Andalucia news at the Spanish Eye.
