July NUI Galway Jellyfish Researcher Provides Advice on Lion’s Mane Sightings and Stings

Following the recent increase in lion’s mane jellyfish sightings and stings experienced by swimmers across parts of Ireland, jellyfish research experts from the Ryan Institute at NUI Galway and UCC have issued the following information.

If you are stung, the Irish Water Safety authority recommends that you rinse the affected area copiously with seawater and apply a cold pack. You must seek medical attention at the nearest emergency department if you are 

Research published by NUI Galway in the international journal Toxins in 2017 showed that the best first aid treatment for a lion’s mane sting is to rinse with vinegar (or the commercial product Sting No More® spray) to remove tentacles, and then immerse in 45°C (113°F) hot water (or apply a heat pack) for 40 minutes. Dr Doyle will meet with the Beaumont Poison Centre at Beamount Hospital Dublin to discuss these findings in the next few weeks.

The lion’s mane jellyfish is a large jellyfish (up to 1 metre bell diameter) with thousands of long tentacles located beneath the bell. In Irish and UK waters, lion’s mane jellyfish can be encountered from June until late September. It is one of the least abundant jellyfish in Irish and UK waters, typically occurring as single individuals rather than in blooms or aggregations. Despite being one of the least abundant jellyfish, relatively high densities of large lion’s mane jellyfish have been recorded close to high population areas in recent weeks, and therefore stings have been a recurrent concern. Five people have now been hospitalised after being stung.

Jasmine Headlam, PhD and Fullbright Researcher from the Ryan Institute at NUI Galway, says: “We often see lion’s mane jellyfish on the east coast, where the water is cooler, around hotspots like the Forty Foot diving area in Dun Laoghaire and popular beaches like Bettystown, Co. Meath and Clogherhead, Co. Louth. In the last few weeks we’ve had reports of large adult lion’s mane from the west coast in places like Salthill, Kinvara, Carna and Oranmore in Galway as well as Newquay in Clare and even Cork harbour. We urge sea swimmers and coastal visitors to report any sightings with photographs if possible to the National Biodiversity Data Centre website and the Big Jellyfish Hunt Facebook page.

“Lion’s mane stings, though not generally considered fatal, can cause a lot of pain. Stings from large lion’s mane can be particularly dangerous, as the thousands of thin tentacles can each extend to several meters long. Initially, a sting may result in itching or localised pain that may radiate to other areas of the body, potentially progressing to severe pain within 20 minutes or more. In some cases, stings can result in Irukandji-like syndrome. This syndrome, named after a type of box jellyfish, can involve symptoms including back pain, nausea, abdominal cramps, sweating and hypertension.”

Dr Tom Doyle, zoology lecturer at UCC’s school of biological, earth and environmental sciences, added: “Lion’s mane are spreading geographically, with sightings in the Celtic Sea and Atlantic waters in recent weeks. It is not correct to say this is the first time they have been spotted on the west coast, as we had reports for the last two years, but they are particularly large and mature. The typical jellyfish lives in the water column for six to eight months, having been released as a juvenile in December, but we believe these jellyfish may have over-wintered and may be on their second season.”

Jasmine Headlam will travel to Hawaii in 2019, as a Fulbright Marine-Institute awardee, to investigate the venom of the lion’s mane jellyfish in state of the art facilities with Dr Yanagihara at University of Hawaii at Manoa.

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