Just when you thought you were safe.

Earlier this year, several beaches across Cork were forced to close following a cluster of discoveries Portuguese man o’wars, a hydrozoan whose sting can be very painful, and on rare occasions even deadly, to humans.

Writing on Facebook over the weekend, Cork-based educational page The Big Jellyfish Hunt confirmed that more had been spotted at Trá an Oileain Beach near Union Hall.

“Hi folks, we have had some very large Portuguese man of war wash up in Cork the last few days. These individuals (colonies) have floats 12-18 cm long (5-7 inches). We have also had one of our first large strandings this year with ~20 reported washed up on Trá an Oilean beach near Union Hall in West Cork.

“If this continues then this will be the 6th year in a row we have had large numbers of Physalia wash up in October on Irish beaches. Many thanks to Calvin Jones of Ireland’s Wildlife and Jacob Bickerdike for sending in their observations. Please let us know if you see any in the coming days and weeks.”

The following photos were shared on the page.

Health advice for those who come into contact with Portuguese man o’war has been provided by Cork County Council.

• Ensure you don’t get stung yourself when aiding others.
• Remove any attached tentacles with a gloved hand, stick, or towel (none of these available use your fingertips).
• Do not rub the affected area (this may result in further venom release).
• Rinse the affected area copiously with seawater (do not use fresh water, vinegar, alcohol or urine).
• Apply a ‘dry cold pack’ to the area (i.e. place a cold pack or ice inside a plastic bag and then wrap this package in a t-shirt or other piece of cloth).
• Use HOT WATER for Portuguese Man o’ War stings at approximately 45° Celsius for 20 minutes.
•  If the patient is suffering from swelling, breathing difficulties, palpitation or chest tightness then transfer to the nearest emergency department urgently.
• Report any sightings on beaches@corkcoco.ie