By Obiabin Onukwugha
Jellyfish, also known as sea jellies are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles.
Although a few are anchored to the seabed by stalks rather than being mobile, jellyfish are found all over the world, from surface waters to the deep sea.
The bell can pulsate to provide propulsion for efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators.
When conditions are favourable, jellyfish can form vast swarms, which can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea.
They feed mainly on zooplankton, small crustaceans, and in some cases, small fish and other jellyfish also form part of their diet.
Also, known predators to jellyfish include: the ocean sunfish, grey triggerfish, turtles, some seabirds such as the fulmars, the whale shark, some crabs (such some whales (such as the humpbacks
Jellyfish have a complex life cycle. The medusa is normally the sexual phase, which produces planula larvae. These then disperse widely and enter a sedentary polyp phase which may include asexual budding before reaching sexual maturity.
The medusae of most species are fast-growing, and mature within a few months then die soon after breeding, but the polyp stage, attached to the seabed, may be much more long-lived.
It is reported that jellyfish have been in existence for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal group.
Jellyfish are eaten by humans in certain cultures. They are considered a delicacy in some Asian countries, where species in the Rhizostomeae order are pressed and salted to remove excess water. Australian researchers have described them as a “perfect food”: sustainable and protein-rich but relatively low in food energy.
However, the stinging cells used by jellyfish to subdue their prey can injure humans. Thousands of swimmers worldwide are stung every year, with effects ranging from mild discomfort to serious injury or even death.
They are also used in cell and molecular biology research, especially the green fluorescent protein used by some species for bioluminescence.
Jellyfish help with nutrient cycling in the ocean – as they drift through different layers of the water column, they help to transport nutrients, such as nitrogen and phosphorous through the sea. These nutrients can then be recycled and used by other marine organisms for growth and survival.
How the Jellyfish lost its bones
Once upon a time, it was said that the jellyfish was a very handsome fellow. Its appearance was beautiful and round as the full moon. He had glittering scales and fins and a tail as other fishes have, but he had more than these. He had little feet as well, so that he could walk upon the land as well as swim in the sea.
Jelly was the most beloved and trusted servant of the Dragon King who ruled the sea from his underground palace.
The magnificent dragon king had recently married a beautiful dragoness, and he was madly in love with her. But unfortunately, one day, the young dragon queen fell ill.
The dragon king was fearfully worried for his wife – and when he saw the doctors shaking their heads in dismay, he became even more worried.
Fetch me the liver of a monkey. When I eat it, I know I will feel quite better. It’s a cure my grandmother told me about years ago, said the Dragon queen.”
“But, Light of my Eyes” said the dragon king, “Our kingdom is undersea and monkeys live on land in the forest. How can I find a monkey’s liver?” Tears ran down the lovely face of his young wife, as she implored.
“If you love me as much as you say you do, you’ll find a way to give me monkey liver, or else I shall surely die and it will all be your fault!”
“My sweet, my sweet, I shall find a way, I promise!” declared the dragon king.
So the King called out to Jelly fish to find a monkey and bring to him. The jelly fish set out and saw a monkey on a tree by the riverside.
The jelly fish tricked the monkey to come attend a banquet with him. When the monkey said he could not smim, jelly offered he was going to carry him on the back.
As they journeyed halfway, jellyfish revealed his real mission to the monkey.
“Ah, said the monkey, I left my liver on the tree where you found me.” “Let’s go get it then,” said jelly fish. So they journeyed back. As monkey climbed back to the tree he told jelly fish that he could not find his heart, that someone must have taken it.
After waiting for several hours, jelly fish went back to tell the “If you love me as much as you say you do, you’ll find a way to give me monkey liver, or else I shall surely die and it will all be your fault!”
“My sweet, my sweet, I shall find a way, I promise!” declared the dragon king.
He immediately went to his court where he summoned his trusted adviser, the Jellyfish.
“You must fetch me the liver of a monkey” he declared, “My wife’s life depends on it. If she does not eat monkey liver soon, she shall die.”
“My lord,” said the Jellyfish, “Where am I to find a monkey liver? I don’t believe I have seen such a thing.”
“They say that monkeys live in the tall trees of the forest,” said the Dragon King to the Jellyfish, “Go and fetch me one if you honour me as much as you say you do.”
“My Lord, your wish is, of course, my command,” replied the Jellyfish, not at all happy with his impossible mission.
The jellyfish set out on a long journey. He swam and he swam to the edge of the wide blue sea. And then he was in luck! He found a place where the forest came right down to the edge of the sea and the branches of the trees hung over the waves. And low and behold, sitting on a branch, he saw a monkey. king all that had happened. Furious, the Dragon king other the other servants to beat jelly fish to a pulp.
That was how his bones crushed. Since then, jelly lives without bones.