The numbers of different types of jellyfish seems to vary according to different sources, from a few hundred to over a thousand. In reality, there are literally thousands of different types of jellyfish in the world’s oceans and seas.
There are many interesting facts about jellyfish
The jellyfish is made up of no less than 95% water. Jellyfish are heartless, spineless creatures. In fact, they are also boneless. Instead of a brain, according to the South Carolina Department of Natural Resources, jellyfish have an “elementary nerve system,” with receptors which enables then to be able to sense things like odor, light and other stimuli. Jellyfish cannot swim but merely drift along in all the oceans and some other bodies of water in the world. The box jellyfish is the exception, perhaps being more intelligent than other jellyfish, in that it has several clusters of eyes and also can swim.
Depending on the species of jellyfish, some prefer shallow waters while others are known to be found at depths of 12,000 feet. Jellyfish live for a very short time, with some species surviving only a few months.
Jellyfish are not in danger of being declared endangered or extinct, however, as was recently demonstrated by a U.K. Daily Mail report of swarms of jellyfish being responsible for having recently caused the shutdown of nuclear power plants and were also responsible for stinging nearly 2,000 people on Florida beaches over the July 4th holiday. The same two types of jellyfish, the cannonball and moon, are suspected of being the culprits.
Cannonball jellyfish do not like being disturbed
The cannonball jellyfish gets its distinctive name from its shape. It ranges from milky brown to having reddish or orange tint and has no tentacles. They prefer warmer waters, including the southeast United States during the summer months. Cannonball jellyfish secretes toxins which is effective at driving most predators away. A person stung by the cannonball jellyfish may suffer heart complications.
Moon jellyfish are perhaps the most common jellyfish
The other culprit in recent disruptions is the moon jellyfish, which “Types of Jellyfish” describes as “the most common jellyfish seen in aquariums around the world.” The different types of moon jellyfish are not as venomous as other jellyfish.
The mangrove jellyfish is commonly referred to as the “upside-down jellyfish” because it actually floats through the water upside down. It prefers shallow waters and rests on the bottom with its tentacles pointing upwards towards the sun.
Box jellyfish are among the smallest and largest jellyfish
Box jellyfish are among the deadliest creatures known. The smallest of box jellyfish, the Irukandji, is no bigger than a thumbnail, yet is poisonous enough to be deadly. Within three minutes after being stung by the larger box jellyfish, the Chironex fleckeri, or sea wasp, cardiac arrest and death can occur. The box jellyfish, unlike other types, can swim, making it easier to avoid predators and catch prey. It can grow to as much as 25 centimeters across with tentacles averaging 3 meters.
Lion’s mane and Nomura’s jellyfish are the largest
The lion’s mane is usually recognized as the world’s largest jellyfish, with the largest one ever caught having a diameter of seven and a half feet, with tentacles of one-hundred twenty feet long. The Nomura, commonly found off the waters of Japan and China has been measured at six feet, seven inches long, according to “Jellyfish Size.”
New types of jellyfish are still being discovered
The true number of different types of jellyfish is still not known. In September, 2009, Discovery Online reported that a new type of jellyfish was discovered off the Canadian Basin of the Arctic. The small blue jellyfish has distinct features such as folding its tentacles over its bell or body while it swims. Although previously unknown, this member of the Narcomedusae group was the third most common type of jellyfish found by researchers on the dive.
Although there are many common types of jellyfish, the number of different types of jellyfish varies widely among sources. As evidenced by the recent find in the Arctic, new types of jellyfish are still being discovered, making it still impossible to accurately state the true number or types of jellyfish that exists.
