Jellyfish is a creature that has become the nightmare of people who swim in the sea, especially in summer. Jellyfish can sometimes appear as small transparent spots in the sea, and sometimes as animals with octopus-like tentacles.
Are you ready to learn what you don't know about the mysterious lives of these creatures?
What is Jellyfish? What are its features?
Jellyfish is a species of creature that lives in salty waters all over the world. Paleontological records show that jellyfish have lived on Earth since 650 million years ago. So they existed even before the dinosaurs.
Jellyfish, which continue their lives today, move in water with currents and tidal movements, regardless of the ground. Jellyfish, also known as 'medusa', are invertebrates and do not have organs such as heart, brain, eyes, bones and scales. Jellyfish arouse everyone's curiosity with their seemingly vulnerable structures. This creature, which can be very dangerous in some cases, lives in the sea with other creatures.
Their bodies are umbrella or bell shaped. Some have tentacles, while others have whip-shaped appendages. These animals, whose bodies are generally transparent, can also be off-white, blue, purple and brown. Jellyfish are members of the Cnidaria clade, along with hydras and corals. The reason for this is the poison cells called "cnidoblasts" located in various places on their bodies.
Jellyfish are made up of 95 percent water, the remaining 5 percent salt and protein. Jellyfish do not have a brain, but have a developed nervous system. It is very sensitive to light and odor. They move slowly and are not aggressive. The body structure of jellyfish consists of mouth, tentacles, oral arm, trunk, stomach and ovary. Jellyfish were known before, but were first studied by scientists in the early 1940s. Before that, there was not enough information about their lives and they were called 'uncertain creatures'.
Are Jellyfish Poisonous?
Jellyfish tentacles and whips are full of tiny venomous vesicles. These vesicles contain a toxin substance called “nematocyst”. Many species of jellyfish are poisonous, but most are mildly venomous. They use this venom to paralyze or kill their prey. For example, some rare species such as the box jellyfish are among the most poisonous and dangerous creatures in the world.
In contact with another creature, sometimes even when the jellyfish is dead, the poison can exert its effect. With any contact, the cell explodes and the poison passes to the living thing. The effect of the poison depends on the contact area and the size of the contact. For this reason, the right thing to do in case of contact with a jellyfish is; to prevent the opening of the sacs and to pull the jellyfish from the surface.
Jellyfish are carnivores. They feed on small sea creatures, plankton, larvae and eggs that come across in the sea. Some larger species can even prey on small fish.
What Happens When You Contact a Jellyfish?
When a jellyfish touches your skin, the first thing you will feel is a burning sensation. Although not always, the burning may be accompanied by redness and itching.
Light-Emitting Jellyfish
Some species living in the depths of the sea have the feature of emitting bright lights. The Atollo jellyfish is the most well-known species with this feature. When this creature encounters an enemy, it cuts off the light emanating from its body and continues to emit light from its tentacles. Thus, he can avoid death by distracting the enemy. Another name for the Atollo jellyfish is the alarm jellyfish. This is because when it encounters an enemy, it spreads its light, attracting the attention of a larger sea creature and getting rid of its enemy.
The other known luminous jellyfish is the crystal jellyfish in Turkish, known as Aequorea Victoria or Hidromedusa. Crystal jellyfish are most common on the west coast of North America.
Biggest Jellyfish
The largest of the jellyfish species is the lion's mane jellyfish. It is mostly seen in the North Atlantic and North Pacific oceans. The largest lion's mane jellyfish ever recorded is the 2.29-meter-diameter, 37-meter-long tentacle jellyfish that washed ashore in Massachusetts Bay in 1870. It mostly likes the open seas and at the end of its 1-year lifespan it will head towards shallow and sheltered bays. The lion's mane feeds on jellyfish, other small sea creatures and jellyfish.
How Do Jellyfish Reproduce?
Jellyfish can reproduce both by budding, which is a form of asexual reproduction, and by sexual reproduction. In sexual reproduction, female egg cells and male sperm cells in the gonads are shed and fertilized in water. The egg passes through the larva and polyp stages, respectively, and after a while turns into a jellyfish.
The Effect of Jellyfish According to Cultures
In most parts of the world, the jellyfish is a creature that people shy away from and act cautiously. However, in the Far East countries, there are jellyfish that are fed in aquariums at home as pets, as well as those that are consumed as food. Especially in countries such as China, Japan and Korea, it is included in the tables as food.
Ways to Avoid Jellyfish
Protective clothing should be worn in areas with jellyfish.
It should not be forgotten that jellyfish secrete toxins even if they are dead.
Precautions should be taken against jellyfish poisoning, necessary drugs for first aid should be carried.
In case of contact with jellyfish, no hard moves should be made to separate the jellyfish from the skin. You should wash that area with sea water and scrape it with a sharp-edged tool. It is wrong to rub and scratch the skin. Applying vinegar to the skin can neutralize toxins.
If there are symptoms such as difficulty in breathing and swallowing, pain in the chest area, a doctor should be consulted immediately.
Interesting Facts About Jellyfish
When they are removed from the water, they evaporate with the effect of the sun.
They change the area they live in according to the temperature of the water.
There are many varieties in different sizes.
They can sense light and smell and emit light.
The largest jellyfish is the species called Stygiomedusa. It has been seen only 17 times in the last century. It can kill thousands of fish at once.
Increase in Jellyfish Numbers
In recent years, there has been a great increase in the number of jellyfish, especially in Southeast Asia, the North Sea and the Gulf of Mexico. While investigating the reasons for this increase, scientists focus on the possibilities such as global warming increasing seawater temperature, eutrophication, pollution caused by excess elements such as phosphorus and nitrogen, overfishing and biological invasion. The increase in sea water temperature and elements such as phosphorus and nitrogen leads to an increase in the number of plankton. In this case, the feeding problem of jellyfish disappears. Overfishing causes a decrease in the number of fish that feed on jellyfish and consume the same food as jellyfish. Jellyfish feeding on fish larvae cause a decrease in fish numbers. Biological invasion, that is, jellyfish that are transported from one region to another by ships, having no natural enemies in the new region they come from, causes the jellyfish to become dominant and cause great damage to the ecosystem. The best example of this situation is the scalloped jellyfish, which comes from the Atlantic to the Black Sea. The high ecological tolerance of jellyfish, that is, their ability to live in harsh conditions, is another reason for the increase in their numbers. The common point of the factors that cause this situation is that they are all human-induced.
