Large number of potentially deadly Portuguese man-of-war prompted the closure of the Cornish beach.
RNLI lifeguards closed Perranporth beach, when you find “an unusually large number of” the-man-of-war.
The jellyfish-like creatures have tentacles with long purple in Cornwall and Wales this month, says the Marine Conservation Society (MCS).
And with sea temperatures of around 16C, there are concerns about the swimmers getting stung.
RNLI manager Dickon Berryman told the BBC, Perranporth beach has been closed “for a short period of time” while the lifeguard took the Council on the level of risk for beach visitors.
The beach has since reopened.
More on the man-of-war sightings, and other stories from Cornwall
Man-of-war were sighted at Newgale, Pembrokeshire, on the 8th of September, and the next day on the beaches around tourist destination of Newquay.
They have also been seen in Porthmelon beach on the Isles of Scilly and the Cornish beaches of Portheras Cove and Summerleaze, widemouth Bay, Perranporth, Hayle, Holywell Bay and Praa Sands. Six were reported in Gwithian.
Dr. Peter Richardson from the MCS said a man-of-war tentacles, over 10m (30ft) long, “deliver a painful and potentially fatal sting”.
“You are very pretty and look like balloons with ribbons, but picking a vented up could be very bad,” he said.
The man-of-war to retain their sting when they are wet, even if you are dead, he warned.
He advised anyone who has been stung, the tentacles from the body, as soon as possible.
Leather back turtles have been washed, because she said an increase in jellyfish, which they feed, Dr Richardson.
A leatherback turtle was found at Portreath on 9. September, and another was reported in Pembrokeshire.
The NHS recommends the use of a pair of tweezers or a clean stick and gloves, if possible, to remove man-of-war tentacles.
If the symptoms are severe, or a more sensitive part of the body has been stung, you should seek medical help.
The ba is asking people to report all sightings that could rise, while men are driven by war, across the Atlantic, through the last storms.