Life

Tuesday 17 July 2018

Jellyfish bring 'message from the sea'

A green sea turtle makes short work of a Lion’s Mane jelly in the seas off Queensland, Australia
A green sea turtle makes short work of a Lion’s Mane jelly in the seas off Queensland, Australia

Joe Kennedy

Stinging jellyfish off the Atlantic seaboard may well be an advance guard of a pending invasion. The troublesome marine wobblers encountered last week by swimmers in Galway, who sought medical attention as a result, have made their presence felt earlier than usual.

The incredible weather and global warming generally are the chief culprits. Add over-fishing and the way is clear for them to prosper, say experts. Their population explosion around these islands and in the Mediterranean is part of an international phenomenon. As predators disappear, population surges occur with greater frequency.

"This is a message in a bottle from the sea," a researcher at Barcelona Institute of Marine Sciences, Josep M Gili, has said of large numbers of jellyfish washed up on beaches. "It says 'look what is happening to me'."

Galway swimming clubs have alerted members to dangers from an old regular, the Lion's Mane (Cyanea capillata), usually found on the Irish Sea side of the country. Three people were hospitalised in Galway with Lion's Mane stings last week. Galway Water Safety has warned swimmers to stay within designated bathing areas.

Marine biologist Dr Tom Doyle of UCC says specimens are so big they appear to have "overwintered".

Jellyfish are simple marine creatures. Some species are harmless, others can deliver painful stings which can cause anaphylactic shock.

The most common nasty ones in European waters are Mauve Stingers (Pelagia noctiluca), about two inches in diameter, luminescent when agitated and mushroom-shaped with a purple and red-brown speckled bell.

The Lion's Mane, more than three feet across with a brown bell, is a painful stinger, as is a smaller blue version, the Cyanea lamarckii.

The most common 'Irish' one is the Moon (Aurelia aurita) with a bluish tinge and four pale violet horseshoes at the top of its transparent bell. Tentacles round the edge can stun small sea creatures.

Who eats jellyfish? Chinese, Koreans and Vietnamese have been harvesting them for thousands of years and in the sea swordfish and tuna chase them as do leatherback turtles which will follow them through the oceans. (Many turtles are being killed by ingesting plastic which they mistake for jellies).

There is also an "immortal" jelly called Turritopsis dohrnii, found on the sea floor near Italy, which can transform itself back to a polyp and start life again! And a more interesting one called 'the fried egg' (Cotylorhiza tuberculata) which scientists say is a potential source of raw materials for cancer treatments and antioxidants.

If you are unlucky, an old-fashioned remedy for jelly stings is vinegar - but seek medical attention for severe encounters. A good smearing with sun-block before entering the sea helps stop venom entering the skin. Lash it on. Forewarned is forearmed.

Sunday Independent

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