We open water swimmer in southeast Queensland often suffer from an influx of jellyfish, especially the ‘blubber’, sometimes called the ‘jelly’, or, more correctly, the Catostylus. It is sometimes known as the Ronald Reagan menace*.
The Catostylus is a native of Australia but has a worldwide distribution. It is especially common on the east coast of Australia. It is normally blue-ish in Queensland waters or white and other colours further south. At the time of writing, there aren’t too many of them just yet in our normal OWS grounds of the upper Moreton Bay but, as summer progresses, they may well develop into what in recent years have been plagues, making swimming both difficult (grabbing a handful with every stroke) and painful.
What causes these influxes? There is little scientific certainty about the causes of Catostylus swarms but it appears that ecosystem degradation (excessive nutrients in the water as a result of land run-off and resultant low oxygen levels) and overfishing (fish are the natural predators of jellyfish) are the main causes. There is a strong suggestion that climate change-induced water warming may also encourage their over breeding. Anecdotally, Catostylus and Bluebottles (see below) are more common in southeast Queensland when there are summer northeasterly winds. The next edition of the newsletter will contain an article on water quality, especially in the northern Moreton Bay area.
So what do you do when they are about? You can wear a neck-to-ankle stinger suit but most swimmers don’t like the associated slight restriction of movement which is much the same as wearing a wetsuit. Otherwise, if you get stung, remove the tentacles with sea water – never fresh water – and apply a cold pack or ice for 20 minutes. Do not rub, apply fresh water or apply vinegar as all these actions will cause residual stinging cells to discharge. The sting can be painful enough but not as bad as a Bluebottle sting or, unlike some jellies in the tropics, they won’t kill you.
*The Catostylus made its splash on history when, in 2006, thousands got sucked into the nuclear reactor cooling system of the USS Ronald Reagan, America’s newest, largest and most expensive nuclear aircraft carrier, when it docked at the Port of Brisbane on the first stop of its maiden voyage. I had tried a few commentaries on this little note in history but decided that DJT (I dare not even say his full name) might come and get me. Your comments would be welcome.
The Portuguese Man of War has many variants around the world but its Australian variant (Physalia utriciulus) is lovingly known as the ‘Bluebottle’. Together with the blubber, they also flourish in southeast Queensland - and just about everywhere else - with summer’s northeasterly winds. Bluebottles are unlikely to kill you (if ingested, they can cause respiratory failure) but they will certainly hurt a lot leaving large welts on the skin.
The treatment for Bluebottles is to remove any remaining tentacles (carefully), rinse in sea water (not fresh water) and place the stung area in water as hot as the patient can stand (say 400-450C) for 20 minutes. As with a Catostylus sting, do not rub, apply fresh water or apply vinegar as all these actions will cause residual stinging cells to discharge.
These are the common stingers in Southeast Queensland waters. There are many other marine stingers that may affect us but, rather than providing a full list here, I have put up a table on my website of their description, incidence, symptoms and treatment – see marine_stingers.docx
A note about the use of vinegar
Vinegar works extremely well for Box Jellyfish and their tiny cousins the Irukanji only, both of which are found, almost exclusiively, in tropical waters. Scientists still don't know why vinegar works for tropical stingers, but work it does. It’s something to do with blocking the nematocysts or stinging cells’ ability to fire.