Many visitors ask us about Marine Stingers which inhabit our inshore and off shore waters at certain times of the year. All oceans of the world contain jellyfish but in our area there are two particular types of jellyfish to be ultra wary of:
Box Jellyfish: Box Jellyfish are the most venomous marine animals in the world. Box Jellyfish season can start as early as October and they may be present in coastal waters and estuaries until April and in some seasons as late as May (as Box Jellyfish sometimes appear further south and sometimes a few weeks beyond the ‘official’ close of season) before disappearing until the next wet season.. Always check with local authorities for advice before swimming in the ocean; otherwise wear fully protective clothing. Never swim on your own in isolated areas. If you are stung, your chance of survival or even getting yourself to the shore is virtually zero. The pain has been described as so excruciating that you will probably go into shock and drown, even before the full affect of the venom takes place.
Our local Cairns Surf Lifesaving Queensland lifeguards in conjunction with James Cook University conduct regular ‘drags’ along coastal beaches late in the season before deciding to declare the waters safe for swimming. Stinger nets are located at our more popular coastal beaches and whilst stinger nets are designed to minimize the risks of being stung by a box jellyfish, they are by no means a guarantee of not being stung! Stinger suits that are fully enclosed afford the best protection. Box Jellyfish are not found on the Outer Barrier Reef, so you can participate in reef activities such as swimming, snorkelling and scuba diving tours.
Irukandji: Jellyfish causing Irukandji Syndrome are predominantly present in tropical Australian waters from November to May but cases of Irukandji Syndrome have been recorded from the waters off Far North Queensland for all months of the year. These species are predominantly offshore animals and are only found on mainland beaches under specific weather patterns. With long periods of north easterly breezed (approximately 7-10 days) onshore currents are produced which push these animals towards the shoreline. They are then present in these areas until the currents change and push them offshore. For North Queensland, the appearance of these animals on mainland beaches usually occurs for 3-4 days per season, however, they may be present around reefs and offshore islands right throughout the season. Originally attributed to just one small jellyfish (Carukia barnesi), the name Irukandji is now used to encompass a group of small to medium-sized carybdeids.
Irukandji jellyfish cause an initial minor skin sting followed 5-40 minutes later by severe generalised muscular pain, headache, vomiting and sweating. The sting from some species can cause very high blood pressure or have effects on the heart which may be life threatening (especially for those with pre existing health conditions). These symptoms are sometimes referred to as Irukandji Syndrome.
Recorded stings on the Outer Barrier Reef are rare but nevertheless they have been recorded. Irukandji stings and the risk of being stung can be minimized greatly by wearing stinger suits or wetsuits whilst snorkeling and diving on and around the islands and reef and at local beaches (where signs of Irukandji activity are present).
For the most relevant and up to date information on Marine Stingers is suggested that you visit The Tropical Australian Stinger Research Unit
where Fact Sheets and further information are provided.
Hundreds of thousands of people visit the Great Barrier Reef from Cairns and Port Douglas each and every year, this information is not meant to cause panic amongst potential visitors, rather it is provided to inform with the best of intentions. It is highly unlikely that you will be stung on the Outer Barrier Reef when exercising reasonable precaution. There is so much misinformation around, it’s a common misconception (furthered by the uninformed) that ‘there are no jellyfish out on the reef’ and ‘box jellyfish are the only dangerous jellyfish and they only live in coastal waters, not out on the reef’. Forgetting to mention Irukandji is not the best method by which to help ensure that all of our visitors manage to stay safe whilst visiting our Great Barrier Reef.