The detection of several specimens of the venomous “blue dragon” sea slug - Glaucus atlanticus - has resulted in the council in Tenerife announcing the raising of a purple flag at two of its popular beaches to signal the presence of harmful marine wildlife. 

The decision made by the Granadilla de Abona Council is aimed at alerting the public to the potential danger posed by the blue dragon at El Médano and Leocadio Machado beaches.