A St John's stalked jellyfish - Calvadosia cruxmelitensis - in the Looe and Whitsand Marine Conservation Zone

On a stalked jellyfish mission…

 

My local area is special and it’s partly down to some fabulous little jellies we find here.

Looe and Whitsand Bay was one of the first to be designated a Marine Conservation Zone (MCZ) three years ago. Apparently Ocean quahog (a clam shell), pink sea fans, pink sea fan anemones and a stalked jellyfish species (Haliclystus sp.) can all be found here.

As you'd expect, stalked jellyfish have a stalk which attaches to seaweed so they don't float around like other jellies. They have eight arms with tentacles on the end.
As you’d expect, stalked jellyfish have a stalk which attaches to seaweed so they don’t float around like other jellies. They have eight arms with tentacles on the end.

I’m hoping we can add more species to that list. There have been some local records of giant gobies, which are one of the MCZ ‘feature’ species and we’ve found three other species of stalked jellyfish on our beaches.

The problem with stalked jellyfish is that they’re tiny and seaweed coloured. In theory, the winter die-back of seaweed makes them easier to see, but Cornish winters don’t often provide the calm conditions you need to spot stalked jellies. Consequently not many people see them and even fewer people record their discoveries on ORKS – so please, please do share your finds!

In a quest to add more evidence that these species are present in significant numbers, I take Cornish Rock Pools Junior for a wander through the pools at a quiet local bay.

Grey herons like fishing in this quiet bay - Plaidy beach, East Looe
Grey herons like fishing in this quiet bay – Plaidy beach, East Looe

I find it’s best to focus on nothing else if I’m going to find stalked jellies. The problem is, as anyone who’s seen me in the vicinity of a chocolate hobnob will know, that I have no willpower. So, I spend the first half hour snapping this gorgeous strawberry anemone as it stretches its tentacles towards the last of the autumn sunshine.

Strawberry anemone basking in a brief moment of November sunshine
Strawberry anemone basking in a brief moment of November sunshine

And this common hermit crab unfurling from its shell and pushing its eye stalks out to stare at me.

A common hermit crab (Pagurus bernhardus) - or 'Bernard the Hermit' as Junior calls it, emerging from a topshell.
A common hermit crab (Pagurus bernhardus) – or ‘Bernard the Hermit’ as Junior calls it, emerging from a topshell.

I can’t help wondering if any of these pools might be harbouring a St Piran’s hermit crab and am rummaging among the seaweed when I spot a stalked jellyfish.

My first find of the day - a Haliclystus octoradiaus stalked jellyfish
My first find of the day – a Haliclystus octoradiaus stalked jellyfish

This one is a Haliclystus octoradiatus, easily distinguished from the other stalked jellies we commonly see by the oval blob between each of its tentacle arms. These primary tentacles can help the jellyfish to stick onto surfaces and move around by somersaulting.

The stalked jellyfish (Haliclystus octoradiatus) retracts when I touch it, showing its primary tentacles (the white blobs around its edge) between its tentacle arms.
The stalked jellyfish (Haliclystus octoradiatus) retracts when I touch it, showing its primary tentacles (the white blobs around its edge) between its tentacle arms.

This species is one of the features already protected by the Looe and Whitsand Bay Marine Conservation Zone, so it’s great to see it thriving and to gather records to chart where it’s found. What I really want, though, are records of other species of stalked jelly.

Surprisingly, because I can often stare for hours at the seaweed without seeing any of the things, it only takes another few minutes to come across another species. This is a Calvadosia cruxmelitensis, the most colourful and pretty of the UK species.

Calvadosia cruxmelitensis, the St John's stalked jellyfish. The pattern of white nematocysts (stinging cells) along the edges of its arms are clearly visible.
Calvadosia cruxmelitensis, the St John’s stalked jellyfish. The pattern of white nematocysts (stinging cells) along the edges of its arms are clearly visible.

These little jellies are almost always a deep pinky-mauve colour and are sprinkled all over with white spots, which are especially concentrated around the outline of their eight arms. This creates a pattern supposed to resemble a Maltese cross, which lends the jellyfish its common name: The St John’s Stalked Jellyfish (as voted for in a 2010 competition run by Natural England).

Brownie/ swot points to any avid rockpoolers out there who’ve noticed that this species was until very recently called Lucernariopsis cruxmelitensis. As if it wasn’t already hard enough learning the Latin names, scientists keep changing them as they learn more about genetics. Sigh!

Of course, my camera chooses this moment to steam up, but a combination of holding it up to the sun and wiping off the water with tissues saves the day.

After an hour and a half with my bum in the air sifting through seaweed, I’ve clocked up eight stalked jellies, a personal best. Six of the jellyfish are the better-recorded Haliclystus octoradiatus species, including the tiniest one I’ve ever seen which has me and junior squealing over how cute it is.

A tiny Haliclystus octoradiatus stalked jellyfish - you can see how small it is against my (unkempt) thumb nail!
A tiny Haliclystus octoradiatus stalked jellyfish – you can see how small it is against my (unkempt) thumb nail!

But I do find one more Calvadosia cruxmelitensis, much to my delight.

A St John's stalked jellyfish - Calvadosia cruxmelitensis - in the Looe and Whitsand Marine Conservation Zone
A St John’s stalked jellyfish – Calvadosia cruxmelitensis – in the Looe and Whitsand Marine Conservation Zone

Cornish Rockpools Junior is convinced we’ve ‘saved the Marine Conservation Zone’. A nice thought.

I’m not sure that the MCZ designation is making much difference to our marine wildlife as there’s no sign of any resources going into it, but it’s worth making the effort to record species here. All this information could help this stunning little stalked jellyfish to be recognised and protected as a feature of the Marine Conservation Zone in future and there’s no harm in that.

If you’d like to know more about stalked jellyfish, the fabulously talented marine biologist, David Fenwick, has recently set up this dedicated website – it’s brilliant for identifying species you might come across. Let me know if you see any!

Cornish rock pools junior found this beautiful little baby strawberry jellyfish under a rock (and carried it over the rocks to show me).
Cornish rock pools junior found this beautiful little baby strawberry jellyfish under a rock (and carried it over the rocks to show me).
Star ascidian sea squirt (Botryllus schlosseri). Not rare - just lovely.
Star ascidian sea squirt (Botryllus schlosseri). Not rare – just lovely.
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7 thoughts on “On a stalked jellyfish mission…”

    1. Hi Lesley, Thanks, it’s great to know you enjoyed my blog. Yes, stalked jellies really are very small and well hidden. They’re also very often well-covered by water in areas that have quite a bit of current so it’s not at all easy to focus on them as they’re swaying about! I have an Olympus ‘tough’ camera TG3 (I think). It’s a waterproof camera so doesn’t need a housing. It doesn’t get great treatment with all the sand, salt & rocks, which is probably why it’s started steaming up! It’s very good on macro and fairly small which is ideal for taking photos in tight spaces between rocks. I wouldn’t dare take anything much more expensive on the shore as I’m way too clumsy! All the best, Heather

      Liked by 1 person

      1. Many thanks Heather that helps., just considering photo gear for the future rock pool forays! I had to laugh as I can well imagine myself in similar situation being distracted to other ‘things’ than what I should be recording! thanks again 🙂

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