Improving prediction of deadly Irukandji jellyfish blooms

A decades-old problem in predicting Irukandji blooms has been solved by a team of our scientists, and the results could directly benefit northern Australia’s community and its tourism industry.

Last year we wrote about a new Irukandji forecasting system that Dr Lisa-ann Gershwin and her team were testing in northern Queensland.

The team were looking to prove a link between Irukandji blooms and weather conditions, based on a hindcast of previous Irukandji stings and correlating weather records, so that they could accurately predict future blooms.

Irukandji jellyfish.

Carukia barnesi, the so-called ‘common Irukandji’, taken in sampling nets at Palm Cove near Cairns. Credit: Dr Lisa-ann Gershwin.

In a paper published today in the Journal of the Royal Society, Lisa-ann and her team have presented their findings, which demonstrate a clear link between Irukandji blooms and trade winds – or lack thereof.

Says Lisa-ann, “We know that Irukandji blooms generally co-occur with blooms of another invertebrate, called salps. We also know that salp blooms are triggered by upwelling, which in northern Queensland is driven by subsidence of trade winds. Sure enough, when we investigated we found a clear connection between recorded Irukandji ‘sting days’ and days when there was little to no trade wind present.”

Around Palm Cove, a beach near Cairns where the tests took place, the southeast trade winds are the dominant wind most of the time. These trade winds cause a net downwelling pressure that pushes the water downward and out to sea. However, when these winds begin to ease in the summer months, an upwelling occurs. It is these upwellings that Lisa-ann and her team believe transport Irukandji to the top of the water column – and on towards shore.

Irukandji stings on skin.

The subtle marks of an Irukandji sting belie their deadly potency. Credit: Dr Lisa-ann Gershwin.

Finding this elusive key to Irukandji bloom prediction has been a long process.

“More than 70 years worth of work has gone into trying to accurately predict Irukandji blooms, and I myself spent 18 years attempting to establish a link,” says Lisa-ann

“It wasn’t until I came to CSIRO and collaborated with my co-authors, who are ecological and oceanographic specialists, that we made the connection.”

This early warning system could potentially allow individuals, communities, councils and governments, as well as other marine industries, to know about Irukandji blooms up to a week in advance. By being able to predict Irukandji blooms, we can reduce the direct threat to ocean-goers by closing beaches, and also reduce anxieties and uncertainties associated with areas known for Irukandji stings.

Beach closure due to Irukandji.

A beach closure at Palm Cove due to an Irukandji bloom. Credit: Dr Lisa-ann Gershwin.

Lisa-ann says this study is just the first step. Further refinements and testing mean that we could provide greater certainty in prediction, and further reduce the rate of Irukandji stings. The system also has the potential to be rolled out at a national and international level.

“However, we must reiterate that this forecasting system is not a miracle cure for Irukandji,” says Lisa-ann. “We can never remove the threat completely.

Visit our website for more information on the Irukandji forecasting system.

For media enquiries or a copy of the Royal Society paper abstract contact Kirsten Lea, +61 2 4960 6245 or kirsten.lea@csiro.au

 


Irukandji forecasting: taking the sting out of stinger season

So, what are your plans for the Christmas and New Years break? Eating? Camping? Lounging? Lazing?

Good for you. Merry Christmas. But, while you’re chowing down on some delicious sustainable prawns and watching the Aussies continue thrashing the Poms, spare a thought for our scientist Dr. Lisa Gershwin, who will be spending her down time this year on a beach near Cairns, beta testing a forecasting system for the deadly Irukandji jellyfish.

You’ve probably already heard about this tiny but toxic family of stingers. Almost invisible to the naked eye, Irukandji contain a venom which, when injected into humans, results in the following not-so-pleasant list of symptoms: excruciating muscle cramps in the arms and legs, severe pain in the back and kidneys, a burning sensation of the skin and face, headaches, nausea, restlessness, sweating, vomiting, an increase in heart rate and blood pressure, and psychological phenomena such as the feeling of impending doom. If that’s not enough for you, take a look at this YouTube video showing the effects of Irukandji syndrome in real time (scroll through to about the two minute mark if you’re particularly time-poor).

A Carukia Barnesi Irukandji specimen

A Carukia Barnesi Irukandji specimen. Check out the stingers on its bell (head) – as if its tentacles weren’t enough trouble. Charming!

Irukandji generally lurk in tropical waters, and at certain times of year (right now, for instance) they can make ocean activities for us humans pretty dangerous unless you’re wearing protection, by way of a full-body stinger suit. Even though they generally only appear near coastal areas for a few days at a time, predicting where and when has been a mystery. And not only do Irukandji have a direct impact on human safety, they also cause negative flow-on effects to tourism and local economies in affected areas.

Beach closure due to Irukandji.

Bad for business.

With studies showing their potential slow but steady drift southward due to warming ocean temperatures, things could get much worse. Can you imagine these guys popping up at Noosa Heads or Surfers Paradise for days at a time every summer?

Stinger suit fashion

Stinger suit fashion – coming to a beach near you?

This is where Dr Gershwin and her team come in. Their Irukandji forecasting system aims to provide an early warning system for communities and local councils or governments, to let them know when and where the jellyfish are going to arrive.

Says Lisa, “We want to be able to predict the conditions that are favourable for near-shore Irukandji blooms so that we can reduce not only the direct risks for swimmers coming into contact with them, but also the related anxieties and flow-on effects that their mere presence evokes.”

First up, this research involved some detective sleuthing, analysing when and where stings were occurring and linking the patterns to weather correlations like wind, tide, and current.

“Our research to date has shown that we can effectively forecast the presence of Irukandji blooms in coastal waters by studying wind patterns in particular,” says Lisa.

“For example, in north Queensland the south-east trade winds are the dominant wind most days of the summer, but every now and then they drop off for a week or so a time.

“When this occurs, that down-welling pressure is lessened and we see intrusions from the oceanic water coming up on to the shelf. We believe that this is part of the mechanism that is helping to drive the Irukandji toward the shore.”

Having successfully created a ‘hindcast’ model that has accurately predicted Irukandji patterns, Lisa and her team will now be putting the model to the test at Palm Cove, near Cairns.

For Lisa, this is going to involve getting in the water every two daylight hours for 14 days straight. In full body stinger suit and with net dragging behind, Lisa will traverse the beach attempting to detect and catch the tiny, translucent jellyfish.

If the Irukandji show up when and where the forecasting system predicts, it will be a success. If not, Lisa will use the anomalies to fine tune the system.

And of course, if you’re going to be putting yourself in a potentially deadly situation, you may as well make the most of it.

“As well as testing our forecasts, we’ll be looking for other biological indicators that occur when Irukandji are present – checking out what other sorts of species they like to hang out with,” says Lisa.

“We are also going to have a team from the Australian Venom Research Unit collecting any Irukandji that we capture to study their venom, as there is currently no antidote for an Irukandji sting.”

Sifting for Irukandji.

Sifting for Irukandji.

And finally, Lisa and her team want to look at the relationship between humans and Irukandji.

“At the moment, we have data that might say, for instance, that Irukandji stings are most likely to occur early in the morning or late in the afternoon. Is this because that is when there are more of them present? Or is it just because that is when humans are more likely to be swimming? We want to find out.”

According to Lisa, the primary goal of this project is to roll out the forecasting system up and down the Queensland coast, from Port Douglas in the north to Fraser Island in the south, and out to the reefs and islands of the Great Barrier Reef. In the long run, it could be used in other affected areas, like north Western Australia and the Northern Territory.

“The system has so many potential applications: a centralised website, an SMS advisory service, inclusion in weather reports, or even a personalised phone-app. If we could provide these types of alert services to government, industry and the general public and reduce the risk of stingers from our waters, the benefits would be enormous.”

In the mean time, the rigorous research process to improve and refine the Irukandji forecasting system continues. Stay tuned for more.


Bazinga!

By Keirissa Lawson

Bazinga graphic
The ancient Greeks would shout ‘Eureka’ to proclaim their delight at a new discovery. But what does a modern day scientist say to express that eureka moment?

Channelling Dr Sheldon Cooper from TV’s Big Bang Theory, ‘bazinga’ was what came to mind when Dr Lisa-ann Gershwin and her colleague, Peter Davie from the Queensland Museum, understood the discovery of a small jellyfish off the Australian coast represented a new species.

“Not only had we found a new species, but we also realised it belonged to a new genus and even a new sub-order of rhizostome jellyfish,” says Lisa-ann.

“It’s pretty rare to discover a new sub-order. This hasn’t happened for well over a hundred years.”

Duly named Bazinga rieki, the wee, grape-sized jellyfish measure just 15 to 20 millimetres at maturity, perhaps mistaken in the past for a juvenile of its much larger cousins.

In a paper published in the Memoirs of the Queensland Museum, Lisa-ann explains how the name is not only a reference to Sheldon’s favourite catch cry.

“The name bazinga also refers to a seven-string harp and the straight radial canals of this new species are reminiscent of such strings.”

Bazinga rieki

Bazinga rieki

Check out the Wikipedia entry on Bazinga rieki and listen to Lisa-ann’s interview on the Science Show on ABC Radio National.


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