For divers in the Gold Coast Seaway jellyfish provide a rich tapestry of life.
From terror and pain to wonder and images of togetherness, from passive prey to skilled predators, jellyfish in the seaway are like a living display in a natural history museum.
But they are not just pretty to look at and painful to touch. They are actually very successful breeders and predators that can wipe out an ecosystem of every living thing.
Owner operator of Devocean Dive Shona Low says during the summer months the blue blubber jellies and lion mane jellies keep the turtles chomping.
“They are like candy to them,” Shona says.
“Yesterday when I was diving in the seaway I saw a lot of trevally eating them. One jelly would have half a dozen fish chomping on him.
“I’ve also seen jellyfish with whole fish inside their transparent stomachs.”
A member of Shona’s diving team with a degree in marine biology, Lauren Cleary, says jellyfish may not have free will, but they fill an ecological niche as a source of food and population control.
The biggest problem with diving with jellyfish is reassuring people who have been stung by box jelly fish.
“It’s mainly a problem if we get groups of kids from Darwin where they have box jelly fish. They see them and they’re just terrified. Some of them have really bad keloid scarring,” Shona says.
Another problem is when the diving instructor get a mouthful of bluebottles.
“Because I’m an instructor I talk a lot so when I put the mouthpiece in sometimes it’s got blue bottles in it.
“Stung lips and tongue, no problem.”
Bluebottles are the worst because they stick to everything but there are strategies to deal with them.
They only fire their barbs when they come in contact with the chemicals of the skin so stinger suits, wetsuits or even Tshirts provide protection or divers can push a noodle in front of them along the surface like a shield.
Treating the stings
The Australian Resuscitation Council is the authoritative body that sets stinger treatments.
Inside the tropics: If it’s a known or suspected Irukandji or Box Jellyfish or the sting is from an unknown source use vinegar because vinegar will neutralise stinging cells.
Outside the tropics: For a confirmed bluebottle start treatment by rinsing well with sea water, then hot water 42degrees Celsius for 20 minutes or ice. Lisa Gershwin says the seawater rinsing is an important step that many people forget at their own expense. This is because jellyfish and bluebottles leave behind a slime coating that is saturated with stinging cells, and seawater will wash the slime coating away without activating the cells to inject their toxin. The sting that you experience is only 10-20 percent of the stinging cell total. If you don’t rinse with sea water first, hot water or ice activates those cells in the slime to inject. Hot water, though a superior pain reliever, also dilates the capillaries allowing faster uptake of toxins, so should not be used inside the tropics. Vinegar should be used. So be prepared with vinegar in the tropics.
Why do the jellyfish travel in groups?
Jellyfish don’t actively herd together. They are born together at the same time. When that body of water gets pushed to another location they all come with it. Blue blubber jellies and lions mane jellies form polyps that bud off on the ocean floor. The polyps prefer coastal waters in bays and harbours, so Moreton Bay to the Gold Coast’s north is a huge breeding ground and likely source of many Gold Coast blue blubber blooms.
Bluebottles are actually a colony of four different species and carry their polyps on board. They are windborne. They are born together at the same time, so when a wind blows it will blow them to land. Blue bottles are left and right handed so the wind will only blow the blue bottles that are orientated for that wind.
What do you do if you want to identify a stinger
If you suspect it could be an Irukandji or Box Jellyfish treat it with vinegar. Then you can identify it using Australian Marine Stinger Advisory Services http://www.stingeradvisor.com/ or the Jellyfish App https://thejellyfishapp.com/
Diving operator with GBR Divers Tony Fontes says jellyfish are much more amazing underwater than washed up on the beach.
“The way they undulate and their bodies pulse. If I’m diving with a camera and see a jellyfish I’ll go straight for it.”
He says on the reef in the summer months between October and April you get box jelly fish by the shore which is not an issue for divers, but you get nasty little Irukandji out on the reef which could be a problem for divers.
“The Irukandji sting is very mild like you don’t even notice it, but it’s very toxic.”
It’s not lethal but it overwhelms your heart and “ruins your holiday.”
Tony says the lifesavers at Airlie Beach near Mackay caught six box jellyfish in the last two weeks compared to only two caught last year.
“It’s a reminder why we should stay out of the water and always swim in the stinger nets.”
With summer poised for another heatwave and temperatures getting critical for a repeat of last year’s bleaching event on the Great Barrier Reef it’s interesting to reflect that though jellyfish belong to the same phylum as coral they are having the opposite reaction to climate change.
Jellyfish expert Doctor Lisa-ann Gershwin has many credentials. She is the creator of the Jellyfish App, Director of the Australian Marine Stinger Advisory Services and Author of Stung and Jellyfish: a natural history.
She says the impact jellyfish have on humans is not just related to their sting.
“Jellyfish also create problems for industry and ecosystems just by their sheer numbers. Most people aren’t quite as aware of those issues – the jellyfish blooms and the problems they cause. But they do cause blooms and that is what my book Iwas about, it’s not about stinging it’s about the bloom problems.
“Whereas one jellyfish may eat a relatively large amount of food, it’s only one jellyfish, but when you get large numbers, it’s that amount of food times millions.
“They actually have the capacity to… well… essentially suck every living thing out of the water column.
“What they do is really interesting, it’s incredibly simple but incredibly devastating, they eat eggs and larvae of other species, fish and crustaceans and things. They eat the eggs and larvae of other species and they eat the food that those larvae would eat.
“So this double whammy of predation and competition can absolutely flatten an ecosystem at the ankles.”
Most jellyfish, but not all, thrive on warmer temperatures, over fishing, pollution, sediment from human development and deoxygenated water.
They are responding to these events the opposite to coral.
So next time you see a bloom of blue blubbers, consider that jellyfish are not just animals that plastic bags impersonate or the irritating part of a surfer’s commune with nature, they are an apex predator and a species to watch as the climate warms.
IMAGE: A lions mane jellyfish in the Gold Coast Seaway provides an oasis in its tentacles for fish which it has a symbiotic relationship with (c) Shona Low