Photos

Blue Bottle Jellyfish (Portuguese Man of War) (Physalia utriculus)

We were walking around one end of Mana Island in Fiji, where we were having a holiday. The sun was so hot and the beautiful white sand was so soft it was hard to walk on. One of the local Fijian lads called us over to him and he was carrying this blue bottle jellyfish on a large pile of sand. He knew how dangerous they are. He placed it carefully in the water to allow us to see it and for me to photograph it. It was very small, its body was about 4-5 centimetres in width, and its 2 tentacles were about 20cm and 30 cm long. You can only see one in the photo as they seem to have joined together.

We do know about these dangerous jellyfish, that they are able to sting even when lying dead on the beach! But I was surprised to see how small this one was. I expected a BIG jellyfish, not one this small. Apparently the blue bottles colour can range from a blue to a pink hue, with a translucent body. And the body of the blue bottle can measure between 3 to 15 cms. The tentacles can range in length from 15 cms up to 10 metres!

In Australia and New Zealand, this jellyfish is known as the Blue Bottle, due to its colour and shape when strewn on a beach. Elsewhere in the world it is known as the"Portuguese Man o’ War" as it is said to look like a Portuguese battleship with a sail.

This jellyfish is actually made up of zooids. The blue bottle is not a single organism, but made up of a number of zooids. Each zooid has a specific role and together they function as if it were an animal. For example a number of zooids will make up the stinging tentacles, others will make up the feeding tentacles, etcetera.

The blue bottle feeds on small fish and other small ocean creatures. They envelope their prey with their tentacles, where a poison is released thus paralysing its prey before being consumed. Nice one, eh? The tentacles stick extremely well to their prey. If a tentacle is put under the microscope you will see that it looks like a long string of barbed hooks, which explains the ability of the tentacle to attach.

If a tentacle attaches itself to a human, it releases a poison (through the use of nematocysts), and if you continue to rub the skin after the tentacle has been removed more poison or venom will be released. If you are stung, it is best to wash the area without touching. A cold pack should be used to relieve the pain. If stung, please consult a doctor immediately.

I am pleased we hadn’t had a swim at that part of the beach – but we had swum about 100 metres further along the beach, 20 minutes earlier!

www.australianfauna.com/bluebottlejellyfish.php