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What do you know about jellyfish? You have surely seen them, probably even swam among them without noticing… luckily enough. Discover why they are much more than ‘stinging beasts’ that roam our oceans, learn about jellyfish reproduction and lifecycle.

This animation is part of a set created for the jellyfish tank area in “Palma Aquarium”, learn more. The aim was to educate about the lifecycle and reproduction of these frequently misunderstood creatures.

Jellyfish are commonly known as Medusas, even though this term refers solely to their adult stage, the one unpopular among summer swimmers because of its stinging skills!

To eat and to be eaten

Throughout their lifecycle Jellyfish transform and develop in different parts of the water column, interacting on their way with other organisms within the complex ocean food chain. Adults and larvae feed on plankton and, at the same time, become precious food for other inhabitants of the pelagic zone: sea turtles, mantas and whalesharks.

It all starts with a bloom…

In summer, when temperatures raise, jellyfish blooms become a common find in coastal waters. During such events the chances of sexual reproduction of adult medusas increase. Males release their sperm into the water which will find its way to the eggs stored inside the female. The resulting union, the embryo, will be safely kept among the female tentacles until it transforms to its larval stage, the planula, which will then be released to the water column.

If this larva makes it through its free swimming days, it will drop down to the sea floor and find the right place to settle. Right at the sea bottom starts its transformation to a non-moving polyp: it will grow small tentacles to feed from particles suspended in the water. While it grows, this polyp will clone itself and stack every resulting new polyp on top, like a crown. Within this structure all polyp clones are part of a single superorganism, a colony, and are all connected by feeding tubes allowing every polyp to develop simultaneously.

When the colony members reach the appropriate size, they get ready to bud off as tiny jellyfishes, also known as ephyrae, which will again swim freely in the ocean. Some of them eventually become adult Jellyfish, ready to start the life cycle once again.

Successful colonizers

Jellyfish have colonised almost every part of the ocean throughout their 500 millions of years of evolution! Among the 400 different species that exist there are amazing life forms showing adaptations to every possible condition occurring within the vast ocean. Microscopic or enormous in size, some harmless and others life threatening, some defeat predators by glowing in the dark while others balance predation by producing 45,000 eggs per night!

Next time you cross your way with a jellyfish remember the amazing secrets hidden within their life history.