You can find jellyfish in every ocean in the world. There are around 2,000 known jellyfish species in the oceans, but there could still be up to 300,000 more undiscovered species of jellyfish. Jellyfish aren't actually fish.
The largest, known as the Lion's Mane jellyfish (Cyanea capillata), has an umbrella over 2 metres in diameter and tentacles up to 50 metres long. It can weigh several hundred kilos! Jellyfish are everywhere, in every sea, warm or cold, from the surface to the deep sea, and there are even jellyfish living in freshwater.
Jellyfish inhabit all the world's oceans and can withstand a wide range of temperatures and salinities. Most live in shallow coastal waters, but a few inhabit depths of 12,000 feet.
There are thousands of species of jellyfish ranging widely in size, shape, and habitat, and the vast majority of them are not endangered. However, there are a few species of jellyfish that are endangered. For instance, the peach blossom jellyfish is a tiny jellyfish, sometimes measuring less than a centimeter long.
Jellyfish stings are fairly common problems for people swimming, wading or diving in oceans. The long tentacles trailing from the jellyfish can inject venom from thousands of microscopic barbed stingers. Most often jellyfish stings cause instant pain and inflamed marks on the skin.
Stay out of the water when jellyfish numbers are high. Don't dive. To avoid stings on the face, don't dive into waters that may have jellyfish. Use protective lotions.
Among the predators of the jellyfish, the following have been identified: ocean sunfish, grey triggerfish, turtles (especially the leatherback sea turtle), some seabirds (such as the fulmars), the whale shark, some crabs (such as the arrow and hermit crabs), some whales (such as the humpbacks).
Turritopsis dohrnii is called the immortal jellyfish because it can potentially live forever. Jellyfish start life as larvae before establishing themselves on the seafloor and transforming into polyps. These polyps then produce free-swimming medusas, or jellyfish.
Do jellyfish feel pain? Jellyfish do not have organs or bones and only have a "basic network of neurons," according to Ocean Conservancy, an environmental non-profit. As a result, the animals don't feel pain in the same way humans do.
While some species of jellyfish are endangered, environmental stressors including changes in climate, pollution, overharvesting of fish, and dams have actually led to the proliferation of most jellyfish. Jellyfish populations are increasing around the world as jellyfish predators are disappearing.
However, there are times when the animals appear more frequently. Jellyfish Season usually lasts from May to October, and peaks in August or September. Recently, marine biologists have registered an increase in the jellyfish population.
Minor stings: Severe burning pain will lessen within 1-2 hours. Red blotches and lines often improve in 24 hours. Red lines may last 1-2 weeks. More severe stings: Blisters appear within 6 hours.
Most people dislike jellyfish. They fear their venomous sting, hate their jelly-like consistency and see little merit in their continued existence. Like wasps, many people believe we would be better off without them.
Although jellyfish are slow swimmers and not aggressive by nature, they often sting people who accidentally bump into them. Jellyfish stings can be painful, but most are not emergencies. If your child is stung, try to remain calm and reassure your child that they will be okay.
Not true. Any contact with jellyfish is incidental. Humans are not on their menu, but when we are in their environment we can get in the way of their tentacles.
Though jellyfish do not have a brain, they are incredibly smart and adaptable. For more than 500 million years, they've been bobbing around almost all the world's oceans, both close to the water surface as well as in depths of up 700 meters. The jellyfish is the world's oldest animal.
Some box jellies even have courtship and mating behavior. Do these behaviors mean jellyfish are self-aware? They don't have any type of 'centralized' nervous system. As far as anyone knows the two nerve nets and rhopalia do all the heavy lifting as far as 'thinking' goes.
Jellyfish stings cause intense pain and burning right away. The pain can last for several hours. Raised, red welts form along the site of the sting. It may look like you've been hit with a whip. The welts may last for 1 to 2 weeks, and itchy skin rashes may appear 1 to 4 weeks after the sting.
Glass sponges are considered the oldest animals on Earth—and it's by a long shot. Scientists estimate that they can live for more than 10,000 years, possibly 15,000 years maximum.
Tiny jellyfish (about 1mm across) “bud” off from the tips of the polyp and, like miniature umbrellas with tentacles, float through the ocean. After 2-4 weeks, they become sexually mature males or females. They're about 5mm across, with a bright red stomach visible through their transparent body.
The hydrozoan Turritopsis dohrnii, an animal about 4.5 millimetres wide and tall (likely making it smaller than the nail on your little finger), can actually reverse its life cycle. It has been dubbed the immortal jellyfish.
Dehydrated and pickled jellyfish is considered a delicacy in several Asian countries, including China, Korea, Vietnam, and Japan. Dehydrated jellyfish can be prepared for eating by soaking it in water for several hours to rehydrate it, and then parboiling, rinsing and slicing it.
It's a lot like what happens in our own tummies after a meal. Any waste – that's poop – then comes back through the mouth. That's because jellyfish only have one opening into their stomach, so waste comes out the same opening as food goes in.
