Jellies are weird, gelatinous animals - it's actually not correct to call them jellyfish anymore, because they're really not fish at all. Jellies are found in all the world's seas and oceans, and some even live in freshwater! South Africa is home to a great diversity of these mysterious animals, and at the Two Oceans Aquarium, you can see and learn from them yourself at our Jelly Gallery.
Many of the jellies at the Aquarium are grown in our jelly lab by our resident expert Krish Lewis, while others are brought in from the wild. Wherever they come from, one thing is certain - jellies are fascinating:
Benguela compass jelly (Chrysaora fulgida)
The Benguela compass jelly is one of three closely related species that are endemic to the South African coast. Its umbrella’s circumference can grow up to 80cm across, which is large for a jelly, and from the top of its head to the end of its frilly oral arms, it can grow to just over 2m long. Its sting is only about as bad as a bee sting, so not terribly dangerous to humans.
The compass jelly goes through many colour changes as it matures, starting as maroon-coloured ephyrae, becoming transparent as it starts looking like an adult jelly, then becoming a light pink and developing maroon-pink compass markings once mature.
Swarms of these jellies can shut down power plants and mines, and cause great damage to fisheries and aquaculture all along the west coast of South Africa. They mainly eat other jellies (they are what’s known as “jellyvorous”), as well as plankton and fish like anchovy, horse mackerel and pilchard.
Comb jelly (Beroe cucumis)
Comb jellies, despite the name, are not true jellyfish at all, although their bodies are made up of a similar jelly-like substance. Instead of tentacles, these animals have teeth made of cilia (tiny beating hairs), which they use to eat other comb jellies. Their mouths can stretch wide enough to swallow an entire comb jelly of the same size as them.
The pretty light show that these jellies give off is not emitted by them. They have plates of cilia all along the supporting “spines” of their bodies that reflect and refract light, much like fast-moving rainbow prisms.
Box jelly (Carybdea branchi)
Box jellies are a group of animals known to have very well developed eyes and other sensory organs that help them distinguish between shapes, obstacles and movements. Because of their boxy shape, they are able to propel themselves in any direction they wish, allowing them to actively hunt fish and shrimp, rather than passively wait for the food to come to them like most other jellies.
Their sting is very painful and can leave swelling and lesions comparable to that of a wasp. Reports of cardiac arrest have been noted but to date, no one along the South African coast has died from the sting of this jelly.
Amakusa jelly (Sanderia malayensis}
Amakusa or Malaysian jellies are jellyvorous, like the compass jelly. Because of their long and delicate tentacles and oral arms, they often become tangled up in each other. For this reason, the Aquarium displays these jellies in small numbers, rather than as part of a swarm. The Amakusa jelly has a sharp lingering sting and is restricted to warmer waters on South Africa's East Coast.
Blue blubber jelly (Catostylus mosaicus)
Because of their smooth texture, blue blubber jellies and other closely related "blubber jellies" are popular ingredients in many Eastern dishes. This jelly group’s members come in many colours, including brown, maroon, cyan and white. They are very energetic swimmers, so they require lots of food to keep them going.
Unlike many other jellies that have long tentacles around their bells, blue blubbers have thousands of tiny little mouths on their eight arms that help it catch and eat food. They are commonly found in river systems along our east coast but live happily in our warmer coastal waters as well.
Moon jelly(Aurelia aurita)
Moon jellies are the most widespread jelly species in the world. There are many variations of this species and new ones are still being added. They are one of the easiest jelly species to grow and keep, thus they are popular in aquariums. They have a mild sting (another reason aquariums love them).
Upside down jelly (Cassiopea xamachana)
Upside down jellies are commonly found in mangrove ecosystems and can tolerate a wide range of salinities. This species hosts photosynthetic algae, which grow on its tentacles and provide most of the energy for the jelly’s day-to-day activities. These jellies mostly lie around and “suntan”, and only ever move if disturbed or if they need to find a better spot to “tan”.
Jellies have very complex life cycles. We can compare the jelly life cycle to that of the butterfly’s. Butterflies are caterpillars, which turn into pupa, which then later emerge as butterflies. Similarly, the jelly has polyps that transform into strobila, which bud off ephyrae (baby jellies), which then mature into jellies.
The life cycle of jellies is triggered by many environmental conditions, particularly the season and climate. Sometimes, this give the Aquarium the chance to show you rare and unusual jelly species that are not always available. Some of these ocean rarities have included crystal jellyfish, other species of compass & blubber jellies, night-light jellies and, of course, the elusive pink meanie - South Africa's rarest jelly species!
There's only one thing left to do - make your neighbours jelly and treat yourself to a Two Oceans Aquarium membership. With unlimited visits, you get unlimited chances to discover the oceans most mysterious treasures.