South Western Stinger Factsheet

Article | Updated 5 years ago

Carybdea xaymacana

South Western Stingers are small sea jellies with a bell that never grows bigger than the size of a matchbox (<3 cm high). The tentacles can extend to 20 cm, but more commonly are 8 cm long. The bell is shaped like a box with single tentacles hanging from each of the four bottom corners. They are more distinctive than the bell, which is almost transparent. Often the shadows cast by the jelly onto the sand beneath it are more obvious than the actual animals.
The South Western Stinger is related to the deadly box jelly, Chironex fleckeri that is found in our north western waters, and the north and north east seas of Australia as far south as Gladstone, Queensland.
The South Western Stinger is a cubomedusae. These types of animals have tiny non motile polyps that bud off new polyps asexually. The small polyps then metamorphose into sea jellies which are mature and are abundant in summer.
South Western Stingers occur in quiet bays, particularly over sand. They may swim near the surface even in bright sunlight unless the sea is rough.
Carybdea xaymacana and C. rastoni (found in southern Australia and Albany) are presently the only species of box jellies recorded from temperate Australia. They are also found in other parts of the world. In Western Australia, Carybdea xaymacana is common In Geographe Bay, Perth, Rottnest Island, and Geraldton. These small jellies were previously thought to belong to the species C. rastoni but detailed morphological analyses have found they are C. xaymacana.
This jellies move toward the surface at night to feed on zooplankton and small pelagic organisms. They are attracted to lights near wharves and jetties in their search for food.
Their sting is mild to severe.
After a sharp, stinging sensation the pain may increase or lessen within 5 minutes. Initially, the skin is marked with a red line. The redness spreads, becomes blotchy, and a weal may develop.
The effects may disappear in minutes or remain painful for hours on sensitive skin. This may be followed by a persistent itch, and a brown line may remain for several weeks.
Wear protective clothing such as a lycra top, skivvy or stinger suit. Do not swim in areas where there are large numbers of jellies, and be more observant in summer. Wear a swimsuit that does not allow easy entry of a stinger at the front or back.
First Aid
  1. Liberally pour vinegar over the affected area. This treatment prevents unfired stinging cells from causing additional stinging.
  2. Remove any tentacles from the skin using tweezers or a gloved hand.
  3. Apply cold pack, and possibly a pain relieving cream, to the affected area for pain relief. This may need to be repeated for some weeks if the itchiness persists.
Loisette M. Marsh & Shirley M. Slack-Smith (2010). Field Guide to Sea Stingers and other venomous and poisonous marine invertebrates of Western Australia. Western Australian Museum. Perth, Western Australia.
A small sea stinger swimming at night

An individual of C. xaymacana off Rottnest Island, showing the transparent cube-shaped bell and the more visible tentacles hanging from the four bottom corners.
Photo by Clay Bryce, copyright WA Museum