Stinger seasons to become longer and stronger
EL Nino weather cycle years produce longer and stronger stinger seasons according to research conducted by the University of the Sunshine Coast that has matched Surf Life Saving Queensland data with the Bureau of Meteorology's Southern Oscillation Index.
The 2018-19 summer has already seen a massive influx of blue bottles with more than 14,000 people treated for stings, seven of whom have been transported to hospital since December 1.
A combination of swell and wind direction, the large number of people in the water for longer periods of time because of hot, muggy conditions and warm water have all been factors in the level of impact.
2016 research by honours graduate Letricia Delaney, supervised by Associate Professor David Schoeman, has found the natural summer occurrence of blue bottles on our beaches was enhanced during el Nino years like the one we were now experiencing.
Ms Delaney, a regular beach goer, said her research had been prompted by the large numbers that had washed ashore two years ago sending her searching for a common ecology to explain the influx.
She utilised SLSQ data for all types of jellyfish to establish general trends and sting rates and combined it with climate data.
A bigger study has identified 20-year cycles existed of increased and decreased numbers, with Ms Delaney's study identifying el Nino years as producing a greater prevalence of the species.
She said more research was needed but it appeared climate change would make the impact worse bringing an increased frequency in el Nino years.
Ms Delaney said other USC studies had identified the presence of irukandji off the western side of Fraser Island over the past three years.
She said the jury was out on whether they would survive in the cooler waters further south in Moreton Bay.
Several stings by Carukia barnesi, a type of irukandji jellyfish on the west-side of Fraser Island suggested the species had established there, but as "small and delicate creatures" they were unlikely to thrive in surf beaches.
"There is currently disagreement between scientists as to whether this species of irukandji will thrive further south and more research into this area is needed. We should have more answers in the coming years," she said.
Warmer ocean waters favoured some species encouraging them to reproduce more quickly but Ms Delaney said not all types would respond favourably.
She described bluebottles as "passive floaters" with their location determined by wind, waves and currents.
Their diet mostly comprised small fish, crustaceans and molluscs with their own predator being the blue dragon nudibranch, which stores the stinging cells for its own defences.