What type of jellyfish are there in British waters? Are any of them dangerous? And is it true that some more dangerous species are coming closer to the UK because of warmer waters?

I ask because I have always loved the seaside and swiming in the sea, but friends I have won't go near it because of fear of being stung by jellyfish or other ocean fiends!

I would like to prove to them that British waters are some of the safest in the world when it comes to animals.

There are jellyfish which occur in British waters which can sting--notably, the Lion's Mane. But in general I would think that UK waters are safer than just about anywhere in the world (except for here where I live because conditions are so similar ) because the water is cold enough that most people don't expose enough skin to get stung badly!

It seems that the most common jellyfish is the Moon Jellyfish. I've seen it many times featured in public aquariums, such as the local Seattle Aquarium.

I think that almost all jellyfish can sting (it's how they capture their food), but some stings are worse than others.

Jellyfish don't swim--they drift. That's how some of the more dangerous jellies have come to be in the UK, they've drifted in on warmer waters. So it's possible that Portugese Man o'Wars could become more common than they've been in the past. Yes, those are dangerous jellyfish.

Kingfisher

I've only ever seen them washed up on the beach. I used to swim in the sea as a kid but now steer clear. I would say you are more likely to be caught in a dangerous current than be stung by a jelly fish although when they do come ashore I have seen pics of them in masses.

I remember looking over the side of the ferry in Dover harbour and seeing jellyfish swimming around the ship.

It's not true that jellyfish don't swim, they have an action to propel themselves that looks rather like an umbrella going up and down, difficult to describe, but it moves them through the water effectively. I believe it's Portugese Men of War that drift, but my only encounter with them was at junior school in the early 1950s (showing my age now!) when the Sussex coast where I lived was infested with them and we had someone come to the school with a dead one in a box to warn us of the dangers, we didn't do much swimming that summer!

As for being dangerous, as has been said, they all sting and I suppose it depends on allegic reaction in many cases as to how dangerous they are.

Good point, wild canon. I should have said rather that jellyfish don't swim the way other fish do, and it appears that the motion is limited to up and down. Or so I've read at the local aquarium! They are fascinating to watch at the aquarium, though.

Kingfisher

It's true taht most if not all jellyfish can sting, but as has been said British waters are some of the safest in the world, and you would have to be extremely unlucky to even get stung, and if you keep an eye out for anything moving, it is unlikely you would ever get stung.

This post was last modified: 26-09-2007 12:55 PM by Xeract.

They are great to watch, they look so serene and like they haven't got a care in the world! They must all drift though, do the PMOW have control over the direction they are travelling then?

The PMOW have no control over the direction. By the way, the PMOW is a colony composed of medusoid and polypoid zooids that are morphologically and functionally specialized. The animals in the colony are so specialised that they cannot exist apart from the creature known as the Portugese Man o' War. The PMOW is not considered a jellyfish, either! The PMOW does have an airbladder, and a sail, but essentially it drifts with the currents.

Kingfisher

Very interesting, thank you! I had no idea they weren't considered jellyfish. You lost me slightly with the "medusoid and polypoid zooids that are morphologically and functionally specialized" though

This post was last modified: 02-10-2007 09:24 AM by riana.

hehehe,
The PMOW is composed of little animals, who essentially have lost the ability to live alone. One set acts as a stomach, one set acts as stingers, etc. They have to interact with each other, or they can't exist.

Kind of a 'no man is an island'...

Kingfisher

That's amazing, I didn't know that and assumed that they were jellyfish.

Thanks for the other comments too. I have referred my friends to this thread so hopefully they will come to their senses.

Jellyfish appeared in the oceans about 650 million years ago, before the dinosaurs. Jellyfish are incredible creatures - it's amazing that they are living things, their bodies are made up of 95% water, they have no bones or cartilage, no heart or blood, and no brain! (Talk about a real no-brainer). They have instead sensory organs known as rhopalia and the jellyfish use them to identify light and smell. The largest jellyfish is the arctic lion’s mane. It body can grow to 2.5m and have tentacles 35m long. The collective noun for a group of jellyfish is a ‘smuck or smack’.

The box jellyfish kills more people than any other marine creature.

This is a very good site for info

http://www.extremescience.com/index.html

This post was last modified: 15-11-2007 08:29 AM by treetops.

Now, I could see a 'squish' of jellyfish, or a 'float' of jellyfish, but 'smuck' and 'smack'?

Kingfisher

I don't like jellyfish. They are very...erm...strange creatures

They can be quite beautiful. I have seen some displays of moon jellyfish, and they are quite lovely.

I don't know that I would much enjoy a swarm of them in the water where I'm swimming, though.

Kingfisher