Safety warning for swimmers after giant jellyfish spotted off Dublin
Swimmers and surfers beware - lion's mane jellyfish have been spotted off Dublin.
The jellyfish, also known as the giant jellyfish or hair jelly, is the world's biggest and packs a powerful sting, even when washed up on the beach.
Dun Laoghaire-Rathdown County Council said warning signs have been put up in the Sandycove area of the beach, and swimmers are advised to be careful.
"As an added precaution, the lifeguard warning flags are on red and will remain in place until further notice," the council said.
Lifeguards are keeping an eye on the situation, it added.
"Lion's mane jellyfish can still deliver a nasty sting when washed up on the beach and precaution should prevail, both in and out of the water," the council said.
"These jellyfish can deliver a venomous sting and may cause medical complications.
"If you are stung and you suffer any serious symptoms, including nausea, vomiting or respiratory distress, you should seek medical attention immediately."
A number of swimmers needed hospital treatment last year when stung by lion's mane jellyfish.
Their stings can cause severe pain.
According to the HSE, the jellyfish prefers the cooler waters of the Irish Sea, in particular off Dublin.
Experts say it is not unusual to see these types of jellyfish in June.
John Leech, of Irish Water Safety, said "some people have had anaphylactic shock" as a result of being stung by the lion's mane, although this is not common.
"But there have certainly been a number of such cases in the past," he added.
He said the jellyfish's sting is "quite painful".
Mr Leech said that among the tips to help avoid being stung are to wear a wetsuit while swimming and apply Vaseline to the face and the backs of the hands.
In addition, there are sun creams that are available to buy online that can offer protection against jellyfish.
"People do use them," Mr Leech said.
He pointed out that more and more people are swimming in open water and embarking on long swims.
"You can get quite an infestation of these jellyfish come July and August," Mr Leech said.
For further information on how to treat lion's mane jellyfish stings and how to identify them, visit the Irish Water Safety on iws.ie