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Trade Winds Predict Blooms of Irukandji Jellyfish

Financial planners warn that past investment performances don’t predict future results, but CSIRO researchers have ignored that principle in looking for ways to predict blooms of the tiny venomous Irukandji jellyfish.

Irukandji has been linked to two deaths, but many more are suspected. Now Dr Lisa-ann Gershwin and her team have reported a clear link between Irukandji blooms and a lull in trade winds in the Journal of the Royal Society.

“We know that Irukandji blooms generally co-occur with blooms of another invertebrate called salps,” Gershwin explains. “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.”

The south-east trade winds are the dominant wind most of the time in northern Queensland. They cause a downwelling pressure that pushes water downward and out to sea. However, an upwelling occurs when these winds begin to ease in the summer months, and this brings Irukandji to the top of the water column and towards the shore.

As a result of the research, long-range weather forecasts now give councils up to a week’s warning that they may need to close local beaches due to the risk of Irukandji blooms.