The pretty but potentially very dangerous Lion's Mane jellyfish, now lurking off our shores

SWIMMERS using Dublin beaches and bathing areas have been urged to be cautious as the dangerous Lion’s Mane jellyfish has been spotted.
Warning signs have been erected at lifeguard-patrolled areas as the jellyfish have been spotted there and further into Dublin Bay.
The jellyfish has been reported along the Dublin coastline and from Cork up to Donegal, which has resulted in the public being warned to steer clear of several coastal locations.
Dun Laoghaire Rathdown County Council confirmed that Sandycove beach was checked on Monday, and there were no signs of jellyfish washed up on the beach – however, visitors to all beaches are asked to be vigilant as the jellyfish may still be out in the bay.
The lifeguards will be on duty from noon until 6pm and will advise all visitors on swimming conditions.
The Lion’s Mane is one of the world’s largest species of jellyfish and can grow to be more than two metres wide, with tentacles up to 60 metres in length.
Its sting can produce blisters, irritation, muscular cramp and may even affect respiratory and heart function. Some people can also suffer from anaphylactic shock after being stung.
Cllr Cormac Devlin (FF) said: “Lion’s Mane jellyfish have particularly long hair-like tentacles which can cause a severe sting to bathers. I would urge swimmers to be cautious while swimming in Seapoint or around the coast.
“As an added precaution, lifeguard warning flags are on red and will remain there until further notice. The lifeguards and council officials are actively keeping a vigilant eye on the coastline, water and bathers.”
Lion’s Mane jellyfish are usually more commonly found along the east coast, but have been known to migrate throughout Irish waters.
In 2014, 17 of the venomous jellyfish were washed up at Sandycove and removed by the council.