Update 19 June: And today, all Adeje beaches are flying a red flag because of jellyfish. Be careful out there!
Original post 16 June: There are no official warnings at present, but several beaches in south Tenerife have been affected by jellyfish. Some at least have been identified by diver David Andrews Thompson as one of the most toxic species, the so-called mauve stinger or Pelagia. Beaches affected seem to range from Fañabe to El Médano, with many spotted in the Amarilla Golf area.