Jellyfish

albertw

Hi,

I went snorkelling today around Sandycove (near Dun Laoghaire, Co. Dublin) and was surprised to see a lot of jellyfish around. I've never snorkelled here before (I only started snorkelling on a diving course in Oz earlier in the year), so I've nothing to really compare against, it seemed a lot to me.

Visibility was probably 6m at best, but there were easily about 10 jellyfish visible around me, a few were large with bells about 25cm in diameter, but there were also some with bells only a couple of cm across. This was about 40m out at low tide. From a quick look at the jellyfish ID card on www.turtle.ie several were common jellyfish, the four rings were easily visible, but there were other types that I didn't pay enough attention to to identify. ok I'll admit I didn't get too close to them!

So I was wondering if its typical to see a lot of jellyfish, or is it just this particular time of year?

Also how bad a sting could I expect to get from jellyfish in Irish waters? I had a wetsuit on but no gloves or hood.

Thanks

Chris Peak

They are very common around the Sandycove area.

I used to do life-saving out there, and we'd often come accross smarms of them.

For most people, the sting is harmless. It's just like a nettle rash.

If you do get stung, the best thing is not to panic, and spray some white vinegar on it; DON'T RUB!

That said one of our guys went into anaphylactic shock, and had to be rushed to hospital. But that’s incredibly rare.

seadeuce

The common jellyfish - Aurelia Aurita, is a non-stinger, as you probably know.

At the moment there are many jellies around with purple bells, Cyanea Lamarckii, that do sting.
As the previous poster said, the sting would be akin to nettle burns unless one had an allergic reaction.

The Compass Jellyfish, or Chrysoara Hyposcella, is common around our shores. These are known by the brown "compass points" around the base of the bell. These can sting, and are to be avoided.

The third stinger, not very common, is Pelagia Noctiluca. This can be identified by its warty bell, like a toadstool.
These jellies can leave welts across any area that they come in contact with.

Other stinging jellies encountered are extremely rare - Lion's Mane/Portuguese Man of War/Rhizostoma.

When you next see the jellies, lightly tap the top of their bell. More than likely a small fish will dart out. These are either Pilot fish or Whiting, that take refuge within the jelly's bell.
The bell will not sting you.

The very small jellies you see are probably Comb Jellies, or Ctenaphores. Non-stinging, these have minute hairs - called Cilia - that run up and down their bodies allowing them to move through the water column.
The ones with the two strands hanging use same to lasso their prey. They do eat their own.
Others are more tubular in shape and are very often called Salps. They can be quite colourful even though they seem transparent. Watch for the flowing cilia with the irridescent sheen.

The above comes from many hours of safety and deco stops over the years, and quiet observation of what the sea holds for us.

6m vis? We had 25m+ down in Kerry the weekend!


Stay wet

Seadeuce

Pigeon Reaper

There have been lots of swarms in the past week around Dublin bay. Mostly common mixed with compass. Lions mane are common in the waters around Dublin and are best avoided. Very hot water can help with stings as can vinegar. you'll most often see dense swarms around tidelines in the middle of the bay where the currents meet. On Thursday evening I sailed through a dense swarm stretching around 400m long by 15m wide and going down at least 6m with many thousands of jellyfish in it mostly common but with enough lions mane and compass to make me avoid swimming in the area. This was 1/2 NM N of Poolbeg lighthouse. Try to avoid swimming behind the bell if you can.

It would be nice to have 25m in the bay too.

Fratton Fred

I noticed the same thing on Saturday, in fact all I could see was kelp and jellyfish! I didn't have the heart to tell the people swimming off the 40 foot

there are times I have walked on Sandycove beach and seen literally dozens of jellyfish washed up there, usually the purple bell ones.

I also saw what looked like a huge Lions main off Maidens rock, It was caught in the tide and hurtling straight towards us, I know they say don't panic but......:D