Do you want to avoid the bluebottle bite? Here’s how you can predict where they’ll land.

If you’re among the one in six Australians to experience the bitter pain of a marine stinger such as a bluebottle, you’ll know how quickly they can end a fun day at the beach.

We can’t stop the summer winds that deliver these creatures to our shores, but we can choose the safest spots to swim.

Our research has provided the first evidence that bluebottles transport to Australian beaches.

We discovered that the direction of a beach’s wind direction is a major factor in how many bluebottles are pushed onto the shore. These findings should help beachgoers plan where they will go next.

Delicate ocean drifters

The bluebottle is a jellyfish found mostly along Australia’s east coast.

Bluebottle stings are most common while swimming. Top reasonSurf lifesavers can be accessed for assistance.

Bluebottles aren’t a single animal. They’re a floating colony of individual organisms, each variously responsible for reproducing, capturing or digesting food and catching the wind.

The bluebottle’s long, trailing tentacles are designed to sting prey and creatures they feel threatened by, including humans.

Bluebottles do not swim, but drift on the ocean’s surface. Their inflatable blue bladder acts as a sail and is sensitive to aerodynamic forces.

Currents drive a bluebottle’s long tentacles below the ocean’s surface and wind drives the sail above it.

The bluebottle as sailboat

A bluebottle’s body, including the tentacles, is not aligned with its sail.

Some sails point to one side of the body while others point to the other. This quirk is believed to help people survive.

If all the bluebottle sails were pointed in the same direction, an entire group could be blown to shore by a prevailing wind. But when half the group has sails facing the other way, some individuals are blown in a different – and hopefully less perilous – direction.

Our previous researchBluebottle drift was investigated by looking at physical equations that explain how sailboats react with currents and winds.

That research found wind force can cause right-leaning bluebottles to drift around 50⁰ left of the downwind direction, while left-leaning individuals drift around 50⁰ to the right.

Be wise when choosing a swimming spot

Our latest research looked at how winds and other environmental variables affect bluebottle beaches.

We analysed daily bluebottle numbers and stings at three Sydney beaches – Maroubra, Clovelly and Coogee – over four years. Natacha Bourg, a Masters student, was the project’s leader.

Bluebottles numbers were at their highest during summer, peaking several weeks before maximum ocean temperatures.

Bluebottle movement was previously thought to be hindered by cold temperatures. However, we found bluebottles on beaches both in winter and spring. This suggests that other factors may be at play.

Our research revealed that wind direction was the main driver of bluebottles onshore. On Australia’s east coast, both northeast and southerly winds bring bluebottles towards the beach.

Importantly, we also found that the rate of bluebottle arrivals is affected by the shape of the coastline and its orientation relative the prevailing wind direction.

Maroubra, which faces east, is the longest and most exposed of the three beaches. Maroubra had a summer northerly wind that caused bluebottles to occur at 24%.

Clovelly beach had a chance of only 4%. Clovelly is a beach that faces south and is protected by a narrow bay. However, bluebottle encounters there are more likely to occur in the southerly wind.

Coogee faces south and is slightly smaller than Maroubra. A small rocky outcrop restricts exposure to the ocean, and therefore bluebottles exposure.

Bluebottles were most common at Maroubra, followed closely by Coogee and Clovelly. This is due to their different beach lengths and orientation in relation to the prevailing winds.

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Plan your day at the Beach

These conclusions can also be applied to other beaches. We can use this information to make an educated guess about the likelihood of encountering bluebottles at any beach by comparing its orientation with wind direction.

We know bluebottles are pushed around 50⁰ left or right of the wind direction. A quick sketch on the sand or in your head may help you determine which beach is safest.

There are exceptions to this rule. Bluebottle drift can be affected by strong ocean currents, especially when winds blow less.

Bluebottle beaching is also linked to rips and the circulation water in surf zones.

And bluebottles canThey can contract and expand their sails and stinging tractacles, which could change the direction of their drift.

Bluebottles and other dangers should be avoided before you go in the water. Surf Life Saving Australia encourages all beachgoers:

• StopTake a look around you
• LookWatch out for rocks, large waves, rips and other hazards
• PlanTo ensure safety, you can swim at a patrolled area
• Visit beachsafe.org.au.

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Find out more

Further research is required to better understand bluebottles and how climate change and subsequent warming oceans will affect their drift.

Citizen science offers a powerful opportunity for citizens to learn about bluebottle distribution and size, as well as arrival at our beaches.

Next time you see bluebottles on the beach, take photos of them and upload them to This projectIn the iNaturalist App

In this way, you can help researchers discover more secrets of these beautiful marine creatures – which will hopefully lead to fewer painful bluebottle encounters.

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