Lifestyles for Better Living

The Blue Jellyfish

Cyanea Lamarckii, or the Blue jellyfish, is also known as the bluefire jellyfish. It is commonly found around British waters, although they have been spotted in other parts of Europe as well.. Normally congregating in the waters off of the Scottish and Irish coasts and the North Sea, they have also been seen on the west and east coasts of the UK.

This species of jellyfish range from ten to twenty centimetres in size although they have been known to reach thirty centimetres and are generally blue or yellow-tinged in colour. They have four large mouth arms and arranged around the lip of the medusa are eight horseshoe or square shaped areas, each containing upwards of forty tentacles. The tentacles can reach over a metre in length.

The reproductive cycle of the Blue jellyfish starts in the winter months. The cycle is similar to that of the moon fish in that, once the eggs are dropped into the sea and fertilized, they will hatch into planula and drift for many miles on the current before coming to rest at the bottom of the sea. The planula develop into small jellyfish, usually colourless and will reach sexual maturity in the spring and summer months. Again, due to lack of food and exhaustion they will start to die off in the autumn and winter months.

This species of jellyfish has a diet similar to that of most jellyfish species. They live mainly on plankton, small crustaceans, eggs, worms, larva and small fish but will eat anything that becomes entangled in their tentacles. The prey is paralysed by a toxin that is released by the jellyfish as soon as anything comes into contact with its tentacles. Once the prey is caught it is passed up to the mouth arms and into the stomach area of the jellyfish where it is digested. Any waste products are then passed out through the membrane into the water. As well as being predators the Blue Jellyfish is also prey to a number of creatures including the leatherback turtle, large species of fish such as the Sunfish and sea birds. Because they spend a great deal of time near the surface they are a target for birds which, if they don't eat the jellyfish will do an enormous amount of damage in the attack causing death anyway.

The venom of the Blue jellyfish is reported as being toxic. A sting from one of these can cause the following symptoms:- intense pain, followed by sickness, diarrhoea, back pain, stomach pain, chills, fever. In fact, apart from the pain the symptoms seem to closely resemble an acute case of the flu. In the event of an allergic reaction to a sting, difficulty breathing can occur and, in very rare cases, death. Whilst medical attention should be sought straight away a sting from a Blue Jellyfish can be treated on the spot to ease the pain. This is done by washing the area in sea water and allowing to dry off. It is important to keep the area cool. If a tentacle has been left in the skin it should be removed very carefully with a pair tweezers - never pull or rub as this will cause the venom to spread more quickly through the blood and exacerbating the effects.

The lifespan of a Blue jellyfish is typically around a year, from one breeding season to the next. However, they can be kept in captivity successfully and, provided the conditions are right and the correct, expert care and nutrition is provided, the Blue jellyfish can and will live for several years.

For more information, pick up the Nook version of “Jellyfish As Pets“ at Barns and Noble.
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