What Type Of Jellyfish Are In Cairns?
The two major species of jellyfish you’ll find off the coast of Cairns are the chironex fleckeri and the Irukandji. Both stingers fall under the box jellyfish category, the deadliest in the world. Whilst these fatal soft-bodied fellas are found in abundance during November to May’s warmer stinger season, yearly stings requiring medical attention rarely reach the fifties. A bad year for stings might clock in at as few as fifty to one hundred. So as long as swimmers take precautionary measures like wearing protective suits and following local guidelines, there’s still plenty of fun to be had in the beaches and seas, with very little risk.
Box Jellyfish (chironex fleckeri)
The chironex fleckeri, colloquially referred to as the box jellyfish, is the largest of the box family with a bell (head) measuring between 16 and 35cm. Their large bells eerily resemble translucent skulls floating through the deep blue, though due to their transparency they can be difficult to spot. These big boys have 24 eyes and 15 tentacles that can grow as long as 3m in length, which is (give or take) a whole foot longer than the average Aussie bloke.
You don’t want to mess with the chironex, their tentacles are covered in millions of explosive cells which release tiny microscopic darts of venom upon contact. No wonder they call it the sea wasp! In fact, marine biology legend says that one chironex has enough venom to take out 60 adult humans! Your best bet for keeping their lethal sting at bay is to don the daggy stinger suit — thankfully, the chironex also has an aversion to the colour black and will often swim away from it.
Irukandji
Several species of Irukandji also inhabit the waters off of Cairns. Where the chironex is the biggest member of the box family, the Irukandji is the smallest. Carukia barnesi and malo kingis (also known as the common kingslayer) are two specific branches of the Irukandji family that are particularly rampant on the coast of Tropical Far North Queensland.
These itsy bitsy jellies are no larger than a thumbnail and have a square-shaped bell as tiny as 12 to 30mm with 4 tentacles protruding from each corner of their bell. Their tentacles range between 5 to 50cm, and despite their size, they possess extremely fatal venom.
The Irukandji is one of those fascinating breeds of jellyfish that can reproduce all on its own, spawning clones of itself in its youth as a polyp. When the polyps develop into adolescent medusas (infantile versions of their final box-shaped form) they depart their coral-bound colonies for the great big blue.
On top of warmer weather in Cairns, a persistent north-easterly wind can bring in high volumes of Irukandji. Another sign of incoming Irukandji is sea lice. Feeling the irritating nippings of sea lice in the water or seeing clusters of sea squirts/salps (the translucent jellyfish-like blobs you often see kids playing with along the shore) are other ways of identifying potential incomings of Irukandji, as these sea critters make tasty meals.
Stinger Safety in Cairns
On the off chance that you find yourself in a nasty encounter with a box jellyfish, immediately dial 000 and seek medical attention. In the meantime, rinse your stings with vinegar for at least thirty seconds and run under warm water to dull the pain.
While the Great Barrier Reef is a wild and naturally mysterious place, rest assured that when you explore with a tour, your local skipper and crew hold your safety to the highest of standards! Check out the many day trips, overnight experiences and dive courses that will delve you into the wonderous underwater world, safely!
