The Box Jellyfish

Description

 

 Size relative to a 6-ft (2-m) man

The Box Jellyfish is an invertebrate also known as a Sea Wasp, and a Marine Stinger, It is part of the Phylum Cnidaria, Class Cubozoa, and the Order Cubomedusae. Due to the understudied state of the order Cubomedusae little is really known about the Order. The class Cubozoa has many different species that all have a cuboid or box like umbrella.

Box Jellyfish are actually transparent pale blue complex predators, in both anatomy and behavior, they  measure up to 25 cm along each side of the cube or bell, the Box Jellyfish has up to as many as 15 tentacles on each corner which can be 3 metres in length with up to 5,000 nematocysts (stinging cells) , which are triggered not by touch but by the presence of a chemical on the outer layer of its prey. The Box Jellyfish shoots itself along up to speeds of 4 knots in a jet-like motion and weighs up to 4.4 lbs. It has an average life span of just under a year and its diet is that of a carnivore, the Box Jellyfish has a venom that is toxic and even fatal to humans.

Anatomy

The box jellyfish has a nervous system is also more developed than that of many other jellyfish. Tests have shown that they have a limited memory, and have a limited ability to learn. Box Jellyfish also possess a nerve ring around the base of the umbrella that coordinates their pulsing movements, the only other species that has this complex design is the crown Jellyfish.

The eyes of box jellyfish are located on cup-like structures that hang from their cube-shaped bodies. Whereas we have one set of multi-purpose eyes that sense color, size, shape and light intensity, box jellyfish have four different types of special-purpose eyes. The most primitive set detects only light levels, but one set of eyes is more sophisticated and can detect the color and size of objects. Another special feature of cubozoans is being sighted. These animals have 24 eyes grouped into sets of six and arranged on four faces that make up the siphon of the box jellyfish.

In at least some species the lobe containing the eyes has a heavy crystal at the bottom which always pulls it down. This means that whichever way the jelly is swimming, one eye always points up and the other down. Researchers have done behavioral experiments on one species that suggest for them the upper eye is designed to look up out of the water at landmarks while the other eye can watch out for collisions.

The dangerous part of the jellyfish is the long tentacles they are extremely long, for larger species they can be many meters. The tiny irukandji jellies are only about the size of your fingernail but can have tentacles a meter long with the stinging cells. These are specialized cells like tiny harpoons that shoot into anything they contact and pump in poison. They are designed to catch fish for the jellies to eat but will react to anything, including humans.

No-one is sure why they have such a strong poison, but it is thought it is to provide quick kills. As jellyfish they are fragile and can’t chase injured prey, killing the fish instantly means they can catch it or stop an enemy. If people are stung the intense pain can stop them being able to swim to shore. Vinegar will deactivate any stinging cells that have not been shot and stop further stings but unfortunately it won’t do anything about the venom already inside.

Behavior

The Box Jellyfish has been given the nickname of the Sucker Punch Jellyfish. This is due to the fact that you won’t see them coming. You won’t know that they are upon you until it is too late. The instant pain from the sting is going to be too much for you to ignore. Getting someone out of the water quickly that has been stung by one is very important. People can suffer from shock and fear and not be able to get out on their own.

The body design of the Box Jellyfish offers it a great benefit that other species don’t have. They are able to move around on their own and not use great amounts of energy to do so. They can use the currents of the water or the wind to move then in the direction they want to go. However, they can also move on their own and not have to follow such guides if they choose not to.

This means that they aren’t going to be floating into harm's way of predators without any recourse. It also means that they have a better chance of survival because they can get to their food sources. When there are adverse currents they won’t end up dying due to those types of movements. One species has been tracked patrolling back and forth along a beach in the zone where fish swim. Another that hunts in mangroves will quickly head back towards the nearest trees if it is moved into the open.

Habitat and distribution

The Tropical Indo Pacific region is where you will find the Box Jellyfish. However, there are species found in locations all over the world. Along the oceans of Japan, the Mediterranean and California are very common too. In the South the Box Jellyfish has been found residing in the ocean waters of New Zealand and South Africa.

There are large species found in Australia though that have been known to bite humans. There are some deaths in that area that have occurred due to such stings. There has been a huge increase in the number of Box Jellyfish that are found in Australia. It is believed that this is due to the climate changes as well as the depletion of fish in that area. Since fish are a common predator of the Box Jellyfish more of them are able to reach maturity and reproduce.

The Box Jellyfish seem to move towards the shore in calm waters when tide is rising and gather near the mouths of rivers, streams and creeks following the rain. The Box Jellyfish season starts with the onset of the wet across the top of northern Australia, usually around October and lasts until April. Further south along the northern Queensland or northern Western Australia coast the season is usually from November to March. They sometimes appear further south a few weeks beyond the close of the season.

Feeding habits

The feeding habits of the Box Jellyfish are one of the few species that are able to go hunt for their food resources. They don’t just float along in the water and take what comes along. Still, they are opportunistic so they will eat heavily when there is plenty of food around for them to do so.

Their diet consists of fish, plankton, and crustaceans. They will also consume larvae from various species of Jellyfish and even fish eggs when they find them. Their stomach is very large and allows them to eat plenty at once. They use their tentacles to get the prey and then immobilize it with their toxins.

They swallow their prey whole and then will quickly move on to find more of it. There can be times of the year when they don’t get enough food. That is why they will consume all they can when it is readily available.

Reproduction

Box Jellyfish have the ability to reproduce both sexually and asexually. They are either male or female based on their DNA profile. However, they have the ability to offer both eggs and sperm independently. Once the eggs have been offered then sperm mixes with them to create larvae.

This stage can take a long time, even more than a year. The polyps will continue to grow and to branch out. There can be hundreds of them connected through very thin feeding tubes. As food supplies come along then the nutrients are distributed to all of the polyps through those feeding tubes.

Over time the polyps will start to breach off from each other. This is when there will be the actual Box Jelly fish. Before it can breach off though a mouth has to form, eyes form, and more tentacles form so that it will be able to swim away and care for itself. The average life span in the wild is less than 1 year.

In Hawaii, box jellyfish numbers peak approximately 7 to 10 days after a full moon, when they come near the shore to spawn. Sometimes the influx is so severe that lifeguards have closed infested beaches, such as Hanauma Bay, until the numbers subside.

Predators

predators, which include the butterfish, batfish, rabbitfish, crabs (Blue Swimmer Crab) and various species of sea turtles (hawksbill turtle, flatback turtle). Sea turtles, however, are apparently unaffected by the sting and eat box jellies.

Even though the Box Jellyfish is a very aggressive type of species there are still some predators it has to contend with. Turtles are the biggest problem for them due to their shell protecting them from the toxins. They also have protection over the eyes. Turtles and various species of fish will consume the Box Jellyfish to survive.

Due to the severity of the sting from such a Jellyfish humans are prime predators of the Box Jellyfish. They tend to want to remove its presence from beach areas. They know that people can’t come and enjoy those locations when there is a risk of being stung by one of them. They also know that tourist dollars will stop coming along due to the risks if the problem isn’t kept under control.

Venom / Fist aid Response

Never use methylated spirit or alcohol.

Domestic vinegars should be poured liberally over the tentacles to inactivate stinging cells as soon as possible. The tentacles may then be removed. Artificial respiration and cardiac massage may be required. Where antivenom is unavailable, pressure-immobilisation may be used on limbs after inactivation of stinging cells, while the patient is being transported to the nearest medical centre.

You have virtually no chance of surviving the venomous sting. The pain is so excruciating and overwhelming that you would most likely go into shock and drown before reaching the shore. So don't go swimming alone!

Their venom is considered to be among the most deadly in the world, containing toxins that attack the heart, nervous system, and skin cells. It is so overpoweringly painful, human victims have been known to go into shock and drown or die of heart failure before even reaching shore. Survivors can experience considerable pain for weeks and often have significant scarring where the tentacles made contact.

In 2011, University of Hawaii Assistant Research Professor Angel Yanagihara announced that she had developed an anti-venom by "deconstructing" the venom contained in the box jellyfish tentacles.  Its effectiveness was demonstrated in the PBS NOVA documentary Venom: Nature's Killer, originally shown on North American television in February 2012.

Irukandji

Most of the deaths in Australia have probably been caused by the larger species of box jellyfish. This can be stopped by nets and some beaches are protected. However there is another deadly type of jellyfish here, the two tiny species of Irukandji.

These cause Irukandji syndrome, which was actually described and named a decade before the jellyfish themselves were found. It was named after the Aboriginal people in an area where it is common.

Irukandji have a slightly different type of stinging cell that means in humans the effects are delayed for minutes or hours. However once it begins there is severe pain, cramps, high blood pressure, nausea and psychological symptoms

In Australia, C. fleckeri has caused at least 64 deaths since the first report in 1883,  but even in this species most encounters appear to only result in mild envenoming.  Most recent deaths in Australia have been in children, which is linked to their smaller body mass. In parts of the Malay Archipelago, the number of lethal cases is far higher (in the Philippines alone, an estimated 20-40 die annually from Chirodropid stings), likely due to limited access to medical facilities and antivenom, and the fact that many Australian beaches are enclosed in nets and have vinegar placed in prominent positions allowing for rapid first aid. Vinegar is also used as treatment by locals in the Philippines.

Once a tentacle of the box jellyfish adheres to skin, it pumps nematocysts with venom into the skin, causing the sting and agonizing pain. Successful use of Chironex antivenom by members of the Queensland Ambulance Transport Brigade showed that acetic acid, found in vinegar, disables the box jelly's nematocysts that have not yet discharged into the bloodstream (though it will not alleviate the pain). Common practice is to apply generous amounts of vinegar prior to and after the stinging tentacle is removed. Removal of additional tentacles is usually done with a towel or gloved hand, to prevent secondary stinging. Tentacles will still sting if separated from the bell, or after the creature is dead. Removal of tentacles without prior application of vinegar may cause unfired nematocysts to come into contact with the skin and fire, resulting in a greater degree of envenomation.

References

http://animals.nationalgeographic.com/animals/invertebrates/box-jellyfish

http://www.livescience.com/7243-jellyfish-human-eyes.html

http://jellieszone.com/cubozoa.htm

http://en.wikipedia.org/wiki/Box_jellyfish

http://www.barrierreefaustralia.com/the-great-barrier-reef/jellyfish.htm

http://www.geocities.ws/mundodosinvertebrados/cubozoarios.html

http://science-at-home.org/box-jellyfish/

http://bioexpedition.com/box-jellyfish/