Jellyfish: Underwater Wonders

At least a dozen different species of Lion’s Mane jellies are endemic to Australia, from the Top End to the tip of Tasmania. They come in a dazzling array of colours and patterns, from solid to speckled to spotted, and covering almost all the colours of the rainbow. One of our most exquisite is common in Port Phillip Bay, Victoria, in the summertime. Cyanea annaskala is distinctive from other Lion’s Mane jellies in its small size and its clear bell, or body, with deep-red oral arms, the frilly structures that hang down between the dozens of fine hairlike tentacles. Admire this one from a distance, however, as its microscopic stinging cells can produce a sharp sting.

The stamp photograph is by David Paul.

One of Australia’s most notorious jellies is the Blue Blubber. It has an unusual distribution pattern, with blue populations in both Victoria and Queensland disrupted by a brown population in New South Wales. The peculiar colour difference of this seasonally abundant jelly is thought to be due to symbiotic algae living in the tissues of the New South Welsh jellies, similar to the symbiosis between corals and their resident algae. The algal symbionts help supplement the jellyfish’s diet, so it can grow very large very fast without having to rely on catching plankton. Catostylus makes its home in semi-enclosed bays and harbours, where sometimes it may be so plentiful that it seems you could walk across them. In these conditions, known as blooms, they can cause problems for sea bathers, net fishermen, power plants, boats and ships.

The stamp photograph is by Paul Starosta/Getty Images.

Perhaps the most common jellyfish known across Australia is the Moon Jellyfish, comprising several different varieties around the coastline. The most prevalent, Aurelia coerulea, is found across southern Australia, from the Indian Ocean to the Tasman Sea. Aurelia polyps can be found in just about any marina, often blanketing the undersides of the floating pontoons. In the right conditions, the baby jellies budded off from these polyps can grow from the size of a sesame seed to as broad as a dinner plate in a matter of weeks. Towards late summer, as Aurelia matures, vast rafts of them may be found shoaling towards the surface, often around mid-morning and mid-afternoon, and is possibly related to their breeding or feeding behaviour. Although Aurelia can look formidable in these sorts of numbers, most people are unaffected by its sting.

The stamp photograph is by Alexander Semenov/Science Photo Library.

Quite possibly Australia’s most delightful jellyfish is Bazinga. It was named in honour of the television sit-com Big Bang Theory, where the word “bazinga” was often used to mean “ha, ha, fooled you!”. The name was given to the jellyfish in reference to its surprise discovery, where it had been hiding in plain sight in the coastal waters around Byron Bay, masquerading as the juvenile of a more common species. In fact, it turned out to be as different from other known jellyfish species as a walrus is from a house cat. Bazinga is the size of a marble at maturity, and it barely stings. The Bazinga is a lovely golden colour because of symbiotic algae living in its tissues, which it needs due to its habit of pulsating rapidly.

The stamp photograph is by Denis Riek.