“As it had never been done before, attaching a tag to a Lion’s Mane was an extremely difficult and dangerous task. Eventually we found some way of attaching the tag to the underside of the jellyfish in amongst the hundreds of meter long tentacles”, explained Dr Tom Doyle, Coastal Marine Resources Centre, Environmental Research Institute, University College Cork (UCC).
Dr Doyle is a member of a group of researchers involved in The EcoJel Project - a four year project funded by the European Union Regional Development Fund (ERDF) under the Ireland Wales Programme 2007-2013 - Interreg 4A. EcoJel is a collaboration between University College Cork and Swansea University (Wales) and aims to assess the opportunities and detrimental impacts of jellyfish in the Irish Sea.
During the last few weeks, the researchers have been investigating the behaviour of the Lion’s Mane Jellyfish in Dublin Bay by attaching tags to their underside. Tracking these jellyfish is one of the only ways we can learn how much time they spend at the surface and whether or not they are residents or just passing through. These questions are important to answer as many bathers and open water swimmers in the Dublin area have been badly stung during the last few years and more recently in the last few weeks. Indeed, a bad encounter with a Lion’s Mane may result in severe pain for 5 or 6 hours, weeping skin and back spasms.
With the help/support of Ocean Divers in Dun Laoghaire, the researchers have now followed five individuals for up to eight hours. All individuals were tagged near the famous Forty Foot bathing spot and depending on the tide (ebb or flow), the jellyfish either went north or south along the coast. One jellyfish hugged the coastline from the Forty Foot to Bullock Harbour and along to Sorrento Point never moving more than 20 metres from shore. Another jellyfish went past the entrance to Dun Laoghaire Harbour and on towards Seapoint before heading south again with the ebbing tide.
“This is a great success as only three weeks ago we had no idea of where they went and how they behaved. We now know that they these jellyfish are residents, moving about with the ebb and flow of the tide. As the jellyfish are now beginning to wash up in large numbers (they are dying off) we have stopped tagging until early next year,” said Dr Doyle.
This story originally appeared at UCC.ie
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