Category Archives: Anemones and Jellyfish

Full Moon in the Cornish Rock Pools

Ever since we discovered gem anemones in the pools at Plaidy last week, Junior has been planning a night-time trip to see them fluorescing under ultraviolet light. Lots of anemones glow in UV due to special proteins they contain that absorb the ultraviolet light before re-transmitting it at a longer, visible wavelength.

Snakelocks anemones are well-known in rockpooling circles for glowing a vivid, eerie green in UV and we have seen those many times, but we’re intrigued to see if gem anemones are as spectacular by night as they are by day.

Gem anemone by day
Gem anemone by day

Other-Half joins our after-dark ramble. We wrap up and walk through the deserted lanes. In the light of the rising full moon, there’s no need for torches. The stars have been out for a while already and the Eddystone lighthouse is flashing away at the horizon.

It took us quite a while to spot the gem anemones by daylight. Despite their pretty colours, they are tiny and well camouflaged among the pink encrusting seaweed that lines the pools.

We cross the sand and the heap of seaweed that the tide has brought in to the far rocks and take our UV torch out. Junior scans it over the pool and within seconds we’ve found them. They seem to light up in patterns of green and orange.

Under UV the gem anemones are easy to spot
Under UV the gem anemones are easy to spot

We kneel down and look closely at the starburst of orange that radiates out from the turquoise and pink mouth at the anemone’s centre. The green fringes to the tentacles that are sometimes visible by day are unmissable now.

Gem anemone under UV light
Gem anemone under UV light

Junior is keen to look at the sponges and seaweeds to see what they do under UV and leads me on a precarious climb towards an overhang he knows. The rocks here glow insanely orange and though it’s hard to tell what is causing this effect in the dark, it feels like either a dense red seaweed or a sponge.

Junior's orange-glowing sponge or seaweed
Junior’s orange-glowing sponge or seaweed

As we scramble over the rocks, we find more fluorescing plants and animals. A brown seaweed glows green, possibly due to micro-algae that is growing on its fronds.

Brown seaweed glowing green in places - presumably coated in a microalgae
Brown seaweed glowing green in places – presumably coated in a microalgae

Grey topshells are easy to spot because the tip of their shell glows pink.

Grey topshell in UV light
Grey topshell in UV light

We are intrigued by thin bright-blue streaks among the seaweed. It takes a while for us to realise that these are man-made threads. They feel coarse and may well be fibres from a fishing net. Many seaweeds on the shore are so tangled in them that it is almost impossible to clear the plastic fibres without damaging the seaweed.

One of many plastic fibres found tangled in the seaweed
One of many plastic fibres we find tangled in the seaweed

In a shallow, rocky pool lined with sediment more anemones are glowing. These look nothing like the gem, snakelocks or daisy anemones I’ve seen so far.

Another anemone species that fluoresces - Sagartia troglodytes.
Another anemone species that fluoresces – Sagartia troglodytes.

I turn my normal torch on them to see what species they are and I can’t see them at all. By switching back between UV and normal light I manage to pinpoint them. They are at least as small as the gem anemone, but are flecked with a marble of brown, white and orange that blends perfectly into the sand and rock around them.

Under the camera I can make out dark ‘B’ shaped markings at the base of the tentacles and realise this is Sagartia troglodytes. I don’t remember seeing this anemone before, probably because it would be almost impossible to spot in daylight.

The same Sagartia troglodytes anemone under normal torchlight is much harder to see among the sediment.
The same Sagartia troglodytes anemone under normal torchlight is much harder to see among the sediment.

I touch one of the anemones gently with a finger and it retracts in a puff of sediment, disappearing without trace.

I take photos while Junior and Other Half climb onto a high rock to watch the stars. On nights like this it is hard to tell whether the sea or the sky is shining more brightly. With a last sweep of the torch over the glowing anemones we turn away and head home for hot drinks.

Gem anemone under UV
Gem anemone under UV
This daisy anemone glowed red under UV but was a dull brown under normal light.
This daisy anemone glows red under UV but is a dull brown under normal light.
Anemones weren't the only animals out in the moonlight - this green shore crab glowed blue under the UV torch.
Anemones aren’t the only animals out in the moonlight – this green shore crab glows blue under the UV torch.

Gem anemone hunt

We weren’t really rock pooling, just going for a walk to the beach, or so we said. Junior packed his hammer and chisel in case there were fossils and I packed my camera, because you never know.

On my last wander at our local beach I had hoped to find some gem anemones to photograph, but didn’t succeed. It was worth another look for these tiny creatures, which have stripy tentacles and bright colours around their mouths when they are open, but at low tide most of them are retracted into white-striped blobs.

When retracted gem anemones look rather like an urchin test with a warty surface and white stripes down their sides.
When retracted ,gem anemones look rather like an urchin test with a warty surface and white stripes down their sides.

I left the sounds of hammering and splitting rocks behind me at the edge of the shore, where Junior was happily amusing himself on a fossil hunt, and headed towards an unseasonably glassy sea, pausing to look for anemones in the small pools on the way.

At the water’s edge, I reached a large pool too deep for gem anemones, but in the middle of the pool a submerged boulder was covered in Irish moss seaweed, providing the perfect habitat for stalked jellyfish. I looked so closely among the tangles of weed, hunting for tiny jellies, that I almost missed the huge stalked jellyfish right under my nose.

Haliclystus octoradiatus stalked jelly near Looe, Cornwall
Haliclystus octoradiatus stalked jelly near Looe, Cornwall

This was an unusually large Haliclystus octoradiatus stalked jellyfish, easily distinguished from the other species we see in Cornwall by the presence of blob-shaped primary tentacles in between its arms.

Most stalked jellyfish of this species have just one primary tentacle blob between each pair of arms, but this one had far more blobs than usual. The jelly can use these primary tentacles as anchors to grip onto the seaweed if it chooses to move, using a looping, cartwheeling motion.

I've sometimes seen a stalked jelly with one extra primary tentacle blob between its arms, but this one had lots of extras.
I’ve sometimes seen a stalked jelly with one extra primary tentacle blob between its arms, but this one had lots of extras.

In another nearby pool I spotted this colourful Calvadosia cruxmelitensis stalked jellyfish, well decorated with white nematocysts, which are its stinging cells.

Calvadosia cruxmelitensis stalked jellyfish
Calvadosia cruxmelitensis stalked jellyfish

Junior joined me at this point, wanting to show me a blenny he’d found. We scrambled nearly to the top of a high rocky outcrop in which some small pools had formed. There was no sign of his little fish, and there were no gem anemones, but there was this daisy anemone.

Daisy anemones have many layered tentacles, like daisy petals and come in all sorts of colours.
Daisy anemones have many layered tentacles, like daisy petals and come in all sorts of colours.

We carried on our expedition through a gap in the rocks to the adjoining beach where clear, shallow pools lined with pink encrusting seaweed nestled under a towering overhang carved out by the sea into the shape of a breaking wave.

Strawberry anemone
Strawberry anemone

These pools were full of anemones too and we stopped to take photos of clusters of snakelocks anemones and a rather flattened-looking strawberry anemone before I noticed the first gem anemone. It was closed up, forming a diminutive pink blob that blended perfectly into the colours of the pool. Close to it was another.

As we moved among the chain of pools we found dozens, but not a single one was open. Junior stared determinedly into every cranny, excited that the pools he had found were proving so interesting.

“There are some open anemones here,” he called out, “maybe Dahlia anemones? What do gem anemones look like when they’re open?”

I knelt on the rock beside him. At the far edge of the pool, tucked under a small ledge, I could see the white stripes of the gem anemone tentacles. Much cheering and hugging ensued.

The open gem anemones Junior found near Looe
The open gem anemones Junior found near Looe

Soon I was able to show Junior my up-close photos of the anemones so he could see why I was so obsessed with finding them. Each one had a vivid, almost fluorescent green mouth tinged with bright pink spots at its corners. The anemone’s mouths were framed in deep red and grey rays that stretched to the base of the zebra striped tentacles, some of which had flashes of green at their bases.

The mouth of the gem anemone
The mouth of the gem anemone

Truly one of our most spectacular anemones, people rarely notice the gem anemone because it is only a few centimetres across even when fully grown.

Gem anemone near Looe, Cornwall
Gem anemone near Looe, Cornwall

Junior is already planning a night time return to these pools to investigate whether these anemones will glow under the light of our ultra-violet torch. Watch this space!

Gem anemone -winter colour in the Cornish rock pools
Gem anemone -winter colour in the Cornish rock pools

From Cornwall to Cornouailles – a dabble in the Breton rock pools

Once the busy summer season of rock pooling events is over, we like to jump on the ferry and get away for a few weeks. We have friends to visit and lots to do, but somehow we always end up on the beach. It’s fascinating to discover the difference it makes to be a few hundred kilometres further south.

Although there are plenty of familiar species here, there are some that are around their northern limit here in Brittany, but might put in appearance in Cornwall one day, especially as the seas warm up.

On a sheltered shore in the lee of the Quiberon peninsula, the beach where our friend Mylene spent her childhood holidays, I find a Pachygrapsus marmoratus crab, a species I saw nearby last year when I didn’t have my camera.

Pachygrapsus marmoratus crab
Pachygrapsus marmoratus crab

The rippled pattern on its carapace and the wide flat edge between its eyes make it unlike any of our native crabs. Originally found further south on the Atlantic coast, it has been working its way northwards in recent years and seems to be firmly established in Brittany now.

The three teeth along each side of the carapace distinguish this species from other rock crabs
The three teeth along each side of the carapace distinguish this species from other rock crabs

Something I didn’t notice last year is how fabulously green its knee joints are, matching its emerald eyes. It’s not afraid to use those leg-joints, scuttling away at high speed at every opportunity to hide among the dense aggregations of the invasive Pacific oyster. I nearly lose it several times before it decides to settle in the corner of a pool, allowing me photograph those hairy legs and green knees.

The fabulous green knees of Pachygrapsus marmoratus!
The wonderful green knees of Pachygrapsus marmoratus!

Junior calls out that he’s found a slug. He thinks. He’s not sure. There are so many living blobs on the shore that it can be hard to tell.

The blob is a plump yellow thing, perhaps four or five centimetres long and from the speed it’s crawling across the rock, it is most definitely a slug. Initially, I assume it’s a sea lemon, but it doesn’t quite look right. It has a more squidgy, unicoloured look and instead of the citrussy bumps of the sea lemon’s skin, this slug has rounded protrusions of varying sizes all over its back. I can’t place it so we call it a ‘Doris might be a sea lemon, species’ and I take plenty of photos to help identify it for sure later.

Doris verrucosa - the 'warty Doris' - exploring a bed of Pacific oysters
Doris verrucosa – the ‘warty Doris’ – exploring a bed of Pacific oysters

It’s over a month after we return from holiday that I remember the photos and transfer them to my computer. On screen it’s obvious that this Doris slug looks nothing like any sea lemon I’ve ever seen. With the help of some extremely geeky books, websites and a forum of fellow nudibranch aficionados, I manage to confirm that it is a Doris verrucosa. The “warty Doris”… not the most charming name, but Junior is rightly thrilled that he found it. This isn’t a species we’ve ever seen in the UK.

Each rhinophore on the slug's head is framed by two pairs of prominent protrusions and the gills are framed by a crown of tall protrusions.
Each rhinophore on the slug’s head is framed by two pairs of prominent protrusions and the gills are framed by a crown of tall protrusions.

We revisit a beach that is the polar opposite of the sheltered shore of Quiberon. Ste Anne de Palud is a west-facing windswept expanse of muddy sand framed by a north-facing rocky headland and pools, which provide an incredible habitat for all sorts of clam shells and colourful anemones as well as a perfect set of conditions for the honeycomb reef worm, which builds its huge beehive-like structures all around the rocks.

A honeycomb worm reef overhanging a pool at Ste Anne la Palud, Brittany
A honeycomb worm reef overhanging a pool at Ste Anne la Palud, Brittany

The anemones are fabulous, but so well tucked under steep overhangs of rock or so well buried in sediment that they are tricky to see, let alone identify.

Sagartia elegans anemone, Ste Anne la Palud
Sagartia elegans anemone, Ste Anne la Palud
Strawberry amemone showing its blue beadlet fighting tentacles
Strawberry amemone showing its blue beadlet fighting tentacles
Another colour variation of Sagartia elegans
Another colour variation of Sagartia elegans

Junior is digging holes in the sand and discovers just how packed with life the sand is as he uncovers dozens of thin tellin shells, which burrow their way back down as he watches. The tideline is strewn with evidence of the diversity of life beneath our feet, with spiny cockles, sea potato urchins, the delicate tubes of the worm Pectinaria belgica and necklace shells.

Spiny cockles and their relatives are common here
Spiny cockles and their relatives are common here
Pectinaria belgica worm tube
Pectinaria belgica worm tube
Necklace shell. Euspina catena
Necklace shell. Euspina catena

There’s a good chance that some of the less familiar animals we’ve seen will show up on the Cornish coast at some point. The St Piran’s hermit crab has already successfully made the crossing and I saw them first here.

A trip to Brittany feels like the perfect way to familiarise myself with creatures that I might need to identify in future. It’s also a good excuse to eat lots of pancakes and put my feet up. Both make me happy!

The vast, rich sands of Ste Anne la Palud
The vast, rich sands of Ste Anne la Palud
A juvenile sea hare
A juvenile sea hare

A summer of snorkels, jellyfish and wrasse

On a summer’s day when the sea and the sky are a matching blue and the whole world sparkles, there’s nothing as inviting as donning a snorkel and taking a swim across the bay. This summer, for the first time, Junior joined me in my forays over the rocky reefs.

While he built up experience, we floated shoulder to shoulder and sculled our way over the waving seaweed to the deeper gullies.

On our third snorkel outing, I was enjoying the sun on my back and the gentle roll of the waves when Junior screamed down his snorkel. I grabbed his arm in case he was hurt, but he was frantically pointing and making the “fish’”sign with his hand. He had just seen his first ballan wrasse.

The fish was a full-sized adult, maybe 40 or 50cm long with a thick body and a criss-cross patterns of lines interspersed with pale blue spots. An impressive fish. Undeterred by Junior’s shriek of excitement, it carried on its slow, hovering path through the kelp-lined gully for a while before darting away as we neared.

Juvenile ballan wrasse can be bright green like this one, but they grow up to around 50cm long when they're mature.
Juvenile ballan wrasse can be bright green like this one, but they grow up to around 50cm long when they’re mature.

On the same venture, we spotted barnacles feeding with their feathery legs, shore crabs strolling along the sea floor, a shanny surveying its territory from the top of a rock and great glistening shoals of sand eels rolling by. On other days, we came across groups of corkwing wrasse with pouting lips and turquoise-striped faces, spider crabs lurching through the kelp, and tangled snakelocks anemones spreading their green tentacles.

Snakelocks anemone
Snakelocks anemone

Nearby, crowds of tourists paddled and swam, oblivious to the beauty below them (or the pinching claws and stinging tentacles near their feet).

This summer has seen waves of jellyfish drifting through, from comb jellies to the harmless moon jelly, the less harmless blue and compass jellies and the enormous barrel jellies. Some days the sea was thick with jellyfish, but this didn’t stop Junior from mastering the art of catching waves on his bodyboard or wiping out headfirst into the blue-jelly-soup. He swam for the shore in a hurry on one of our snorkel safaris though, when a compass jelly brushed over my face and stung my back.

Compass jellies have striking markings and also pack a nettle-like sting
Compass jellies have striking markings and also pack a nettle-like sting

I have almost no photos of our snorkelling expeditions this year. Next year, when Junior is more confident, I’ll be able to carry a camera, but this season we just revelled in the perfect days and soaked up the sun . As we knew it would, the summer ended abruptly, dissipating like a mirage from one day to the next and the water is no longer so inviting.

For now, we are hanging up our snorkels and returning to the rock pools, exchanging beach shoes for wellies as the autumn chill moves in, but there is everything to look forward to. A week of Shoresearch surveys starts tomorrow in Looe, which is guaranteed to bring new finds and lots of species records for Cornwall Wildlife Trust.

The empty beaches make this a wonderful time of year to explore the rock pools and before we know it, the first of the autumn storms will blast in, washing who knows what onto our shores. Watch this space!

Between the snorkel trips, I did squeeze in some rock pooling. Here are some of my favourite photos from the summer.

Xantho hydrophilus crab
Xantho hydrophilus crab
Candy striped flatworm grazing on bryozoans in Looe
Candy striped flatworm grazing on bryozoans in Looe
A variegated scallop with irridescent shining eyes
A variegated scallop with irridescent shining eyes
A green shore urchin with its tentacle feet extended
A green shore urchin with its tentacle feet extended
Doris ocelligera sea slug - I recorded these for the first time a couple of months ago and have found them regularly in the same spot this summer.
Doris ocelligera sea slug – I recorded these for the first time a couple of months ago and have found them regularly in the same spot this summer.
St Piran's hermit crab - now a common find on all our local beaches.
St Piran’s hermit crab – now a common find on all our local beaches.

Wading through jelly – Comb Jellies  in Looe

I should be at home, cracking on with some work, but I’ve heard there are comb jellies about and I could do with some photos for my jellyfish course for ERCCIS.

Any excuse.

I cut through overgrown vegetation, down the cliff path to a favourite cove. In the ten minutes it’s taken me to walk here, the grey clouds have lifted and the sea’s looking good enough to dive into.

My progress through the rocky gully is slow. The warm weather has brought an explosion of slippery sea lettuce which blocks my view of my feet as they feel for underwater rocks. Tangles of pink spaghetti, the eggs of sea hares, are wrapped around many of the green fronds and a close inspection reveals that dozens of stalked jellyfish (Haliclystus octoradiatus) have already made their homes here.

As I move into deeper water, something catches my eye, floating below the surface. It’s so transparent it’s barely there, but it shimmers intermittently. With some difficulty, the current swishing the jelly back and forth, I scoop it up and carry it in cupped hands to a sheltered overhang. For a moment I think I’ve dropped it, then it swims out.

Barely there - a transparent Beroe cucumis comb jelly in my hand
Barely there – a transparent Beroe cucumis comb jelly in my hand

I’m treated to a fabulous display of iridescence as the comb jelly beats its tiny combs, sending a trail of light and colour up the lines on its tiny body.

Between the current washing into the pool and the jelly’s own surprisingly speedy swimming efforts, it slips away each time I come close to getting it under the camera. To add to the fun, my camera can’t see it. I take a whole series of photos of nothing. The perfect transparency of the animal means I can only focus on the seaweed below.

The Beroe cucumis comb jelly has a characteristic sack shape.
The Beroe cucumis comb jelly has a characteristic sack shape.

When another comb jelly washes into the pool, I’m sure there will be lots more opportunities to attempt photos. Stepping out into the open water, I take some time to accustom my eyes, staring past the surface reflection into the water. Soon, I notice comb jellies everywhere.

The irridescent combs of Beroe cucumis
The irridescent combs of Beroe cucumis

There are dozens, hundreds even, and some are large enough to fill the palm of my hand. Even the large jellies pose a challenge to my camera, but amongst the many seaweed shots, I start to take a few that show off the jellies’ light display.

While most are the large species, Beroe cucumis, with their characteristic sack shape, there are a few smaller ones amongst them. These are sea gooseberries, Pleurobrachia pileus. They are barely a couple of centimetres long, spherical, with two trailing tentacles.

A sea gooseberry with trailing tentacles. Its combs are arranged in lines up its sides.
A sea gooseberry with trailing tentacles. Its combs are arranged in lines up its sides.

Despite their tiny size, they are just as mesmerising as the B. Cucumis, the lines down their sides flickering every colour of the rainbow.

Sparkles of irridescence from a passing Sea gooseberry
Sparkles of irridescence from a passing Sea gooseberry

Among all the comb jellies I spot an even smaller interloper, a hydroid medusa. Hydroids are related to jellyfish, but their adult form usually lives attached to seaweeds, stones or shells. This minute creature is a baby hydroid, looking very much like a jellyfish as it actively swims past, beating its bell fringed with short tentacles.

Hydroid medusa - probably Clytia hemisphaerica swimming by
Hydroid medusa – probably Clytia hemisphaerica swimming by

The pattern of the cross on top of it and the fringe of dark spots around the edge of the bell suggest that it is a young Clytia hemispherica.

Hydroid medusa showing its delicate pattern and short tentacles.
Hydroid medusa showing its delicate pattern and short tentacles.

The glare of sunlight on my screen combined with the transparency of all the animals I’m trying to photograph make it impossible to tell how I am doing. I give up taking photos and simply enjoy the spectacle until the tide calls time and forces me back up the beach.

Comb jellies are supposed to phosphoresce, which would be amazing to see. I’m wondering if I can sneak in a little night time rockpooling this weekend. Although the jellies are here in huge numbers today, they may disappear as quickly as they arrived. I should be working, but some things are just too exciting.

A Night Out in the Rock Pools

Nights out tend to become a distant memory when you’re a parent. For the most part I don’t miss them. I have, however, been looking forward to Junior being old enough to join me for night time rock pooling. Towards the end of last year, we tried it for the first time and, although the conditions weren’t ideal, he’s been asking to go again ever since.

The best low tides always happen around the middle of the day, and the middle of the night, but we compromise for this first family expedition of the year, choosing a reasonable low tide at around 10.30pm. The warm, calm weather provides good opportunities for seeing nocturnal activity and tonight I’m trying out my ultraviolet (UV) torch.

It doesn’t disappoint.

Head torch at the ready - night time rock pooling is a perfect adventure
Head torch at the ready – night time rock pooling is a perfect adventure

I’ve always known that certain species glow under UV light, but I had no idea how much. We’ve barely taken ten paces out across the rocks when we see our first snakelocks anemone, shining from the darkness like an eerie green beacon. The colour is wonderfully alien.

Snakelocks anemone at night under UV light - a true alien of the Cornish rock pools
Snakelocks anemone at night under UV light – a true alien of the Cornish rock pools

This fluorescence is caused by certain proteins within the animals that take in light of one colour and emit it as another. Some deeper water species can use these properties to appear red, even though red light is filtered out as it passes through the water, meaning the only light available to underwater creatures is UV or blue.

It’s not clear why snakelocks anemones and other sea creatures might want to fluoresce in this way. It seems there may be some benefit in it for their symbiotic algae or it might give them sun protection. It may just be a by-product of a protein that’s useful in other ways. Whatever the reasons, it produces an incredible glow. Junior is already talking of coming back at Halloween.

A spooky night time rock pooling walk is definitely on the programme for this Halloweeen!
A spooky night-time rock pooling walk is definitely on the programme for this Halloweeen!

It’s not just the anemones that take our breath away. If you’re used to rock pooling in daylight when most animals are hiding away under rocks and seaweed, the sheer level of activity in after dark takes you by surprise.

A scratching, crackling sound stops us in our tracks. It’s coming from the rocks. I lift the seaweed to show Junior a group of limpets. Some are feeding, their strong radulas scouring seaweed off the rock and chipping bits of rock. Others are setting into their home scars, grinding their shells into their grooves to create a perfect fit. Close-up, their activities make a surprising amount of noise.

Limpets on their way home as the tide retreats
Limpets on their way home as the tide retreats

Most rockpool animals are largely nocturnal. Pools that seem empty in daytime become bustling cities of activity. We watch hermit crabs milling around in large numbers, crabs marauding through the pool and across the rocks, fish floating in plain sight. Prawns come towards the light and watch us before shooting away backwards.

A green shore crab looking blue in the UV light
A green shore crab looking blue in the UV light
Hermit crabs are more active at night, every pool is teeming with them
Hermit crabs are more active at night, every pool is teeming with them

Other Half spots a small species of spider crab (Macropodia sp.) decorated with long fronds of seaweed edging sideways across the pool. It’s moving too fast to take a clear photo in the poor light. The blurring makes it look even more alien.

A blurry small spider crab (Macropodia sp) moving across sand.
A blurry small spider crab (Macropodia sp) moving across sand.

A scorpion fish lies still on the sand, watching out for prey.

A scorpion fish (Taurus bubalis) hiding in plain sight.
A scorpion fish (Taurus bubalis) hiding in plain sight.

One surprise is the stunning colours of the seaweeds under the UV light. Some of the dark red seaweeds take on a far more intense, bright colour, glowing red, pink and orange. Where the top shells have worn spires, their tips glow pink.

A grey topshell on a red seaweed under UV light
A grey topshell on a red seaweed under UV light

After an hour, tiredness and cold begin to set in. We switch off our torches and take a moment to gaze at the stars before we head home to bed. Junior is already asking if we can come again the next night, and the next.

It looks like I’ll be having a few more nights out this summer.

Chilly autumn rockpooling

I’m not a fan of winter. Even though I go rock pooling all year round and love the way the wildlife varies with the seasons, the November to February period is a challenge for me. The thought of sticking my hands in icy-cold water makes me want to hibernate. Right on cue, a fierce northerly wind blows in for the spring tides. I layer up and wear my fluffiest, most comforting jumper to bring you this week’s blog post.

Obelia geniculata - a hydroid known as 'sea fir'.
Obelia geniculata – a hydroid known as ‘Kelp fir’. Recognisable by its zig-zag ‘stems’.

I’m trying to photograph hydroids at the moment. These relatives of the jellyfish and anemones are generally translucent and no more than a few centimetres long, making them hard to spot. At this time of year when the seaweeds die back and the waves roll in, it’s especially tricky. My camera doesn’t like focussing on them and they won’t stay still in the current, but their nodding tentacles and curious structures are mesmerising.

Another hydroid - Coryne pusilla. This one can't retract its tentacles into little cups. It has a ringed stem (visible in the bottom-left of the photo).
Another hydroid – Coryne pusilla. This one can’t retract its tentacles into little cups. It has a ringed stem (visible in the bottom-left of the photo).

As always there are strange creatures galore. This Sea gherkin is unusually large and gnarled.

A Sea gherkin (Pawsonia saxicola) - this is a type of sea cucumber and clings onto the rock with its tentacle feet.
A Sea gherkin (Pawsonia saxicola) – this is a type of sea cucumber and clings onto the rock with its tentacle feet.

Among the sponges and brittle stars I come across this invasive species from the South Pacific, the Orange-tipped sea squirt, Corella eumyota.

The invasive Orange-tipped sea squirt
The invasive Orange-tipped sea squirt

The twisted gut is very prominent in this species and you can see the orange colouration at the top. It’s thought this species may compete with native squirts and other invertebrates, but we will only find out by monitoring its spread. This is the first one I’ve recorded here.

Nearby I find the native sea squirt Ascidia mentula with lovely red flecks in its almost transparent test.

Ascidia mentula - a tunicate sea squirt. The red streaks reminded me of fireworks.
Ascidia mentula – a tunicate sea squirt. The red streaks reminded me of fireworks.

This sponge also catches my eye. It’s hard to identify many sponges with any certainty without examining their spicules under a microscope, but this one has the appearance of Myxilla rosacea.

A striking sponge with its fine structures and deep pores. Possibly Myxilla rosacea.
A striking pink sponge with fine structures and deep pores. Possibly Myxilla rosacea.

On the next tide we make a successful return visit to the beach where Cornish Rock Pools Junior achieved finding a world record haul of stalked jellyfish last year. We come close to matching the numbers we found last time. I lose count at 25 because Junior makes it clear he doesn’t want his record broken.

Many of the stalked jellyfish are juveniles, only a few millimetres long and it tests my eyes to pick them out among the swirling seaweed. Then I spot this 1mm pinprick of a jelly blob and take a photo in case it turns out to be a stalked jelly.

My eyes must still be good - a 1mm baby stalked jellyfish. It's not possible to say for sure what species.
My eyes must still be good – a 1mm baby stalked jellyfish. It’s not possible to say for sure what species.

On my screen at home its column is clearly visible although the tentacles are either retracted or haven’t yet grown. Little is known about the very early stages of development of these creatures and how to separate the species by sight, but David Fenwick who runs the amazing Stauromedusae UK website confirms that it is definitely a stalked jelly.

It’s great to be able to show a friend from Natural England how abundant these species are in the Looe and Whitsand Bay Marine Conservation Zone, which aims to give them protection from developments and disturbance.

Haliclystus octoradiatus - the blobs between the arms are primary tentacles, which easily identify this species from most others we see.
Haliclystus octoradiatus – the blobs between the arms are primary tentacles, which easily identify this species from most others we see.

One of her sons does an impressive job of finding stalked jellies and even finds one that is in the middle of eating an amphipod. The current is too strong to get a great photo, but you can clearly see the unfortunate creature’s head sticking out of the stalked jellyfish’s mouth here.

A stalked jellyfish (Haliclystus octoradiatus) eating an amphipod.
A stalked jellyfish (Haliclystus octoradiatus) eating an amphipod.

I’ll be submitting all my stalked jellyfish records to help reinforce the evidence that will hopefully keep these protected species from harm.

A juvenile Calvadosia cruxmelitensis stalked jellyfish. We found 3 species of stalked jellyfish on the site.
A juvenile Calvadosia cruxmelitensis stalked jellyfish. We found 3 species of stalked jellyfish on the site.

I can’t help taking a look at some other things while I’m here. But before long the cold is hurting my fingers and chilling my insides in the sort of way that can only be fixed by a steaming mug of hot chocolate.

That’s the bit of winter I look forward to!

Rayed trough shell
Rayed trough shell
Aslia lefevrei - the brown sea cucumber. This sea cucumber lives in crevices in the rock with just its tip poking out.
Aslia lefevrei – the brown sea cucumber. This sea cucumber lives in crevices in the rock with just its dark tip poking out.
Dysidea fragilis - or the hedgehog sponge as I call it.
Dysidea fragilis – or the hedgehog sponge as I call it.
3-spot cowrie hanging on an overhang
3-spot cowrie hanging on an overhang

 

Happy rockpooling!