Category Archives: Wildlife

A Shore In Recovery on St Piran’s Day

We tread extra-carefully around the pool, even though we’ve already guessed the St Piran’s hermit crabs won’t be here. The trail of destruction left by the powerful easterly gales is evident: boulders have been lifted by the waves and tossed far from their usual positions, the rich coatings of sponges, squirts and hydroids on their undersides gone. Life is still going on but not as before.

Junior finds a rock goby and some pipefish, but the pool feels like a shadow of its former self. The signs are not good for the nursery of young St Piran’s hermit crabs* (Clibanarius erythropus) that we have been monitoring for the last year.

One thing we have learned from watching these starry eyed, red-whiskered, bristly-legged hermit crabs is that they tend to huddle together. Unlike our common ‘Bernard’ hermits, we usually find the St Piran’s crabs congregated in just two pools on the beach. In this particular pool, there is a central rocky island where all the tiny young crabs like to hang out under a sponge-coated rock, scuttling around like a bunch of kids at the soft play, while the adults are normally found quietly feeding in an adjacent pool.

The St Piran’s hermit crab nursery last year. Every shell has a juvenile St Piran’s crab in it.

We haven’t seen a single St Piran’s hermit crab in the adult pool. They are easily distinguished from the common hermit by their equal-sized claws and bright red antennae, which are visible at a quick glance, even if most of the crab is well-hidden in the shell.

A fully grown St Piran’s crab with the distinctive red antennae, equal sized claws, black and white-spotted eyes and blue-striped leg tips.

As we approach the nursery area I almost don’t want to look. I see a common periwinkle shell sprout legs and my heart jumps. I kneel on a rock to look closely, but it is a common hermit crab, using its oversized right pincer to explore the coral weed, searching for food.

The common ‘Bernard’ hermit crab has yellow-green eyes, a right claw that is bigger than the left and pale antennae.

Among the nursery rocks, there is nothing.

Last time we were here, before the storms hit, every little shell had a St Piran’s hermit crab inside. Now, apart from a broad clawed porcelain crab clinging to the underside of a stone, the area is eerily quiet.

Cornwall’s shores are no strangers to fierce weather and, in places, there are signs of a recovery already, with new seaweed growth and newly-forming sea squirts. St Piran’s hermit crabs, on the other hand, are already at the northern limit of their range here, so they may not cope well with cold winter gales and dips in the sea temperature.

At the far end of the pool I find a chiton on the rock and stop to take a photo. These animals are molluscs but look more like woodlice than snails with their plate-armour shells. Unlike their crustacean look-alikes they have no legs and live firmly attached to the rock.

The colours of the chiton (Lepidochitona cinerea) blend in with the rock.

A flat periwinkle shell on the sand behind the chiton catches my eye. It’s not an unusual shell, but the living shells are usually found feeding on the seaweed and most of the loose shells have been swept away by the storm. There are other small shells close by and they are likely to all be hermit crabs.

My instincts are good. Just as I turn the flat periwinkle shell and glimpse the red antennae deep inside, Junior crouches next to me and shouts that he thinks he can see a St Piran’s crab.

Our first glimpse of a your St Piran’s hermit crab in the pool.

We soon discover that every little shell in this part of the pool is a St Piran’s. Our nursery crabs are still here and have upgraded to bigger shells. There are dozens of them.

Our St Piran’s crab emerges to check us out. It still has some growing to do but is far bigger than last year. It now has the classic colours of the adult crab.
We soon discover lots more shells, all with St Piran’s hermit crabs inside.

It is still early days for this hermit crab that returned to Cornwall’s shores relatively recently after a long absence. In the past it was only an intermittent resident but warming seas may enable these hermit crabs to breed successfully here. On the other hand, an increase in storm events or a weakening of the Gulf Stream could have the opposite effect. A changing climate risks heavier rain bringing more pollution from our rivers and changes in marine oxygen levels and in the plankton on which the food chain depends.

The marine ecosystem is sensitive to our changing climate and so complex that it is extremely hard to predict the exact impacts of changes. (If you’re interested to find out more, check out the Marine Climate Change Impacts Partnership 2020 Report Card).

Further down the shore we find slightly less storm damage and some of the rock pool residents in their usual places. A young topknot flatfish demonstrates its ability to sucker onto the rocks and glide across the seabed, moulding its body to every contour.

Topknot flatfish suckering onto the rock.

In what feels like a reward for our persistence, we find a fabulous Geitodoris planata slug on the lower shore. This time of year, lots of slugs are beginning to spawn.

Geitodoris planata (formerly known by the wonderful name Discodoris planata). The white patches on its back are acid glands used as a defence against predators.

We find a second G. planata in another pool. I am tempted to do some matchmaking, but we leave the slugs where we found them and let nature take its course.

The second Geitodoris planata, looking especially flat and starry.
A close-up of those acid glands (the white stars).

The sun is shining, the St Piran’s crabs are still here, we have seen our favourite nudibranch slug and we have every reason to think that the shore will recover well from the impact of the storms as the spring arrives.

All that is left to do is to head home to prepare our pasties and saffron buns for St Piran’s Day. I would share photos of them, but they were gone too fast!

Gool Peran Lowen!

* I understand that some our lovely neighbours in Devon aren’t so keen on the use of the common name ‘St Piran’s’ for the Clibanarius erythropus hermit crab, which has returned to parts of West Devon as well as to Cornwall. I am completely biased, but the name seems a good fit and it saves me from attempting to pronounce the scientific name. The legend of St Piran says that he was thrown into the sea in his native Ireland with a millstone tied to him, but floated across the sea to Cornwall. The hermit crabs also arrived floating in the plankton from somewhere, most likely Brittany, which also has connections with St Piran. The hermit crab’s striking black and white eyes match the colours of the Cornish flag. I’ve heard plenty of other common names for this crab and anyone can invent their own. In other parts of Europe Clibanarius erythropus has names meaning ‘Little Hermit Crab’, ‘Devil’s Hand Crab’ and ‘Antisocial Crab’, among others.

A Year of Cornish Marine Life

Like everything else about 2020, this is a strange New Year’s Eve. Many have lost loved ones this year, and most of us have spent the festive season apart from friends and family. Whatever the year ahead brings, it will be made better by connecting with the natural world and doing the small (or large) things that we can to build a better society and environment.

On the eve of 2021, I am struggling personally to come to terms with losing EU citizenship and all of the opportunity, discovery and connections it has brought me. International cooperation is essential to tackling the global issues that face our wildlife and we will have to work harder than ever to build understanding and find solutions to problems that cannot wait.

Life will go on and I am super-excited about my new children’s book, Beach Explorer, due to be published in the spring. As ever, I will continue to bring you the very best of the Cornish rock pools straight to your computer through my blog.

To bring a little cheer to myself and to you, here are a few of my favourite rock pool wildlife photos from my encounters this year. I hope you will be inspired to get outside and meet your own local wildlife, and to join all of us who are working to protect and restore nature.

A Happy and Healthy New Year to All! Bonne Année 2021!

A painted top shell – January 2020

Xantho pilipes crab – February 2020.
Pagurus cuanensis, the hairy hermit crab. March 2020
Bright coloured sponge (Prob Oscarella sp.) April 2020.
“Cedric the spider crab”. Photo by Cornish Rock Pools Junior. May 2020.
Juvenile masked crab moult. June 2020.
Cladonema radiatum – an athecate hydroid medusa. July 2020.
Calma glaucoides sea slug with its spawn. August 2020.
Star ascidian growing on seaweed. September 2020.
Dahlia anemone. October 2020.
Facelina auriculata – October 2020.
My first ever Xaiva biguttata crab! October 2020.

Migrating Prawns and Blue-Rayed Limpets

Junior normally keeps a low profile on this blog, but for several years now, he has been taking his own photos and videos of marine life. He recently put together this lovely video for Cornwall Wildlife Trust’s Your Shore Beach Rangers project. It showcased alongside other amazing videos by local young people last weekend at the virtual See You at the Sea Festival and he would love to share it with all our Cornish Rock Pools friends.

My favourite part of the video shows something Junior discovered in Looe a couple of months ago: a prawn migration. I was crawling around in waders with my head under a rocky overhang at the time, so I only saw the tail end of the procession as it advanced with the incoming tide. Fortunately, Junior managed to capture some fantastic footage of hundreds of prawns galloping along the seabed, all heading in the same direction in their hunt for food.

Junior’s photo of a common prawn (not migrating!).

Also featured in the video are Junior’s top photographic subjects – the blue-rayed limpet and sea slugs. He’s even coded an animation showing a day in the life of a corkwing wrasse family. We hope you enjoy his work.

Blue-rayed limpets by Cornish Rock Pools Junior

Junior’s friend, Rowen, has also created a video for the festival showing her beautiful marine artwork and how she creates it, all accompanied by incredible facts about the animals she draws and paints. She would love you to take a look.

All of the videos are available to view on the Cornwall Wildlife Trust Marine channel on YouTube. The three with the most likes and views and that catch the judges eye will win prizes this weekend!

I have been writing my new children’s book this year (due to publish spring 2021), but with that nearly ready, I’m looking forward to sharing lots of the fabulous creatures I’ve been seeing in the rock pools over the last few months. Watch this space!

Meeting up and staying apart in the rock pools

When I’m sitting here writing my blog in the evening, with the cat snoring gently beside me, I find it hard to imagine that people anywhere in the world might be reading about my finds the next day. So, it’s always lovely to receive messages from people who follow the blog and share my passion for our rock pool wildlife. It’s especially surprising to me that these include many people I’ve never met and that some of my readers even live beyond the Tamar!

With the days beginning to draw in and with all normal group activities off due to Covid, making connections with others is more important than ever. When I heard from a couple of keen naturalists and Shoresearchers planning a trip to Cornwall, I thought it could be fun to head out on the shore together with my family. I couldn’t have been more right!

You know someone is a good person when they like finding slugs. Within minutes of meeting our new friends on Millendreath beach near Looe, we had established that slugs were top of their wishlist of things to find. I led the way to “slug alley”, a deep gully between the rocks where I often find sea slugs feeding on the sponges, squirts, bryozoans and hydroids that line the dripping overhangs.

We advance in our family groups, keeping several metres apart, pointing at interesting creatures, giving directions then backing away. By this stage in the pandemic, we’re all confident in these new dance steps.

Botryllus leachii colonial sea squirts

Large patches of colonial sea squirts smooth over the rocky surfaces, providing not just striking colours and patterns but food for many animals that predate them. We find both the European three-spot cowrie and the Arctic cowrie happily gorging themselves on this beautiful feast.

A cowrie on the search for sea squirts to eat.

A brown spot among the squirts and barnacles catches my eye. Although the colours blend in perfectly, it looks different from its surrounds. I gently touch it and it comes away. In a seawater-filled petri dish it rapidly transforms itself, puffing up, elongating and sprouting feathery gills and tall rhinophores. There’s no doubt about it, we have our first slug. My excitement is as great as that of our new friends – this is a species I have never seen before.

Goniodoris castanea exploring the petri dish.

We take turns to examine the slug and take photos. As soon as it is under my camera, which shows far more detail than I can make out with the naked eye, I recognise it from my books (yes, I browse slug books for fun). It’s my first Goniodoris castanea. Castanea means chestnut and the slug’s autumnal mottling of red, brown and white hues make seems a perfect fit with the oncoming season.

Goniodoris castanea showing off its beautiful autumnal colours.
Goniodoris castanea

While our friends marvel at the slug, Junior makes another exciting find. He knows what it is just by the purplish tips of the arms protruding from under the rock. “Spiny starfish!” he calls. We carefully move it out to take a look and it’s a monster. Our starfish has clearly found plenty to eat in this area. Although we regularly see them on the shore here, spiny starfish aren’t found in rockpools in some other parts of the country and this is another new species for our visitors.

I forgot to take photos of the spiny starfish due to my excitement over the slugs – but here’s a pic of one we found on an earlier expedition to Millendreath.

We edge ever outwards with the tide. Although we can hear the shouts of holidaymakers playing in the waves on the beach beyond the rocks, no one else ventures into our magical gully where startled sand eels zip across the surface of the water like skimming stones and velvet swimming crabs scuttle across the seabed then bury themselves in the sand, leaving only their red eyes visible.

A lurking velvet swimming crab.

Some of the rocks are fringed with a dense covering of brown seaweeds. Toothed wrack and kelp compete for space here and clinging to this forest, mossy bryozoans and delicate hydroids thrive, creating a perfect habitat for isopods and slugs. Some of the seaweeds have crescents of white jelly scattered among their fronds. These are sea slug eggs but it takes me some time to find the slug itself, which is smaller than its spawn and decorated with bright yellow and black which somehow make it hard to see.

Sea slug spawn…. now to find the slugs.

These pretty little slugs were, until very recently, known as Polycera quadrilineata. Scientists have now discovered that there are two separate species and the ones we see here, which sometimes have black lines and spots, are now called Polycera norvegica.

Polycera norvegica feeding on bryozoans.

In the moving seaweed, it’s hard to take clear photos and the tide is, of course, coming in just as I’m trying to position the camera in water that’s already waist deep, but we are all content just to be here, together but apart, sharing this experience of encountering incredible creatures.

Polycera norvegica.
Pair of Polycera norvegica sea slugs with the edge of a fingernail in shot showing just how tiny these stunning little creatures are!

These are strange times for everyone, but finding ways to come together and enjoy nature is what makes the world go round (for me at least). Thanks to our new friends for making it a fabulous day. Happy rock pooling!

This time of year, the kelp is studded with blue-rayed limpets – always a joy to see.
Brown sea cucumber – Aslia lefevrei.

Introducing the Rock Pool Project and the ‘Rocket Jelly’

After a whirlwind of book promotion, including my debut on Woman’s Hour, in which I introduced the nation to barnacle reproduction, it was a relief to return to the rock pools. Thursday was the sort of mizzly day that only sea creatures and marine life fanatics appreciate, so I had no doubt that Dr Ben Holt would turn up as planned for some distanced exploration of one of my favourite local rocky shores near Looe.

Who could resist a day out in the drizzle?

Ben may have started his career researching fish in the Caribbean, but he soon realised that Cornwall was the best place in the world and moved to Falmouth, where he founded the fabulous Rock Pool Project.

The Rock Pool Project is a not-for-profit social enterprise, offering not just rockpooling and marine conservation themed activities on Cornish beaches for the public and school children, but also brings the rock pools indoors with the help of its mobile rock pool. So far, the team of experts has visited schools, care homes and community events to give people the chance to learn about our rock pool wildlife and how we can look after it. Now they are looking to expand their range of citizen science projects that everyone can join in, as well as reaching out more widely, once social distancing restrictions allow.

Socially distanced photo with Dr Ben Holt of the Rock Pool Project. (Photo by Cornish Rock Pools Junior).

This month Junior and I helped to test out the crustacean survey method and had great fun seeing how many different species of barnacle, prawn and crab we could find within our allotted time. Anyone will be able to sign up to survey a local beach, regardless of previous knowledge and experience. It’s a great way to get out with the family, learn together and discover your local beach in a new way, and barnacles are lovely if you catch them feeding as the tide’s going out!

Chthamalus sp. barnacles showing a flash of blue as they open to feed.

Back to our rainy day and Ben, Junior and I soon discovered that trying to point out tiny creatures is a challenge when you’re social distancing. I found a stalked jelly but by the time I’d moved a few metres away, the seaweed had shifted and it took a while for Ben to relocate it. Despite the challenges, we made the most of having the beach to ourselves.

One of the largest Haliclystus octoradiatus stalked jellyfish we found.

The dense seaweed made it hard to see into the water, but we found crabs, urchins and ascidians as we clambered ever further out across the rocks. We had a half-mile long stretch of beach all to ourselves and everything had fallen silent under the misty cloud.

Star ascidian colonial sea squirt on an overhang.
Arctic cowrie looking for sea squirts to eat, its shell almost entirely covered by its mantle.

Junior discovered a clump of seaweed with lots of stalked jellies on it: Halyclistus octoradiatus and Calvadosia campanulata. Most were too small to photograph in the moving water, but we delighted in losing and re-finding them among the swirling weed.

Calvadosia campanulata stalked jellyfish.

As the tide moved in, Ben was intent on finding a stalked jellyfish for himself. After a few minutes of filming the stunningly pink entrance to a worm burrow that Junior had found, I joined Ben’s search.

With the tide rising up my boots I was about to give up on the stalked jellies, when I saw a tiny shape float past me. It looked like a stalked jellyfish that had become detached from the seaweed, drifing with the tide. I made a quick grab and scooped it into a bucket.

The whole animal was only a few millimetres long and for a moment I wondered if it was just a blob of seaweed. Junior and I peered into the bucket, heads touching. The blob had arms but wasn’t a stalked jelly. It looked more like a miniature space rocket pointed skyward, with trailing tentacles spread around its base. As we watched it launched, zipping across the bucket at surprising speed.

The tiny jelly was tricky to photograph and kept zooming away across the petri dish.

Under my camera it was weirder than ever. The rocket shape was enclosed in a jelly dome and the tentacles had a knobbly appearance, rather like the sucker arms of an octopus. At the base of each tentacle was a black spot: a primitive eye. This was a jellyfish-like medusa of an athecate hydroid, Cladonema radiatum, a species I’ve only seen once before. We decided to call it the rocket jelly, although I’ve also heard it called the root-arm jelly, presumably due to those twisting tentacles. Although it isn’t a true jellyfish, the tentacles do pack a fair sting.

Cladonema radiatum – the ‘rocket jelly’. An athecate hydroid medusa.

 We took turns watching and trying to photograph the minute animal as it zipped around a petri dish. The tide was rising steadily so after a few minutes, Junior waded out and released the medusa, repeating the process several times as it kept swimming back to the petri dish.

Cladonema radiatus swimming upside-down for a moment.
Cladonema radiatum showing the dark eye spots at the base of the tentacle arms.

It may be a while before we are able to resume events and before I can meet again with Ben and his team, but lots is going on behind the scenes both at The Rock Pool Project and at Cornish Rock Pools HQ where the first draft of my new children’s activity book is nearing completion. Watch this space!

Junior’s pink worm burrow.

Summer is acome unto day… May Rock Pool Gallery

Summer arrives early in Cornwall, with festivals around the county singing in the new season on the first of May every year.  Except, this year the Padstow Obby Osses have stayed in their stables, the Calstock Giant hasn’t set sail down the Tamar to re-join his love, and there has been none of the usual dancing through the streets of Helston.

Oblivious to all of this, the natural world is carrying on. Swifts are screaming past the window,  the herring gulls are nestled on their mossy rooftop nests and in rockpools everywhere, there will be tangles of new-growing seaweed, father fish guarding their eggs and all manner of colourful creatures going about their usual business.

Scroll through the gallery below for a glimpse of what will be happening right now beneath the waves in rock pools around Cornwall. And if you’d like to find out more about our amazing marine life, explore my blog, or take a look at the fantastic video workshops that Cornwall Wildlife Trust has been busy creating. Happy virtual rockpooling!

  • Our brown Geitodoris planata and its much paler yellow mate getting friendly in the Cornish rock pools!
  • This small species of spider crab (Inachus sp.) was so completely covered in sponges that I couldn't see her shell at all.
  • Another species of stalked jellyfish - Haliclystus octoradiatus - near Penzance
  • Facelina auriculata sea slug
  • Polycera quadrilineata sea slug at Gyllingvase, Falmouth

Bottoms-up! Wildlife Recording on the Last Spring Tides Before Lockdown

There’s no collective noun, as far as I am aware, for a group of rock poolers, but if there was it would refer to bottoms in the air as that’s our standard position – head down, bottom up, searching for marine life. On the best tides it’s not unusual to find other rock pool fanatics on my local shore, drawn by the promise of rarely accessible habitats. So, during the spring tides of early March, I found myself in the company of the bottoms-up brigade at Hannafore, exploring one of our favourite shores.

Junior and his friends were with me, enjoying one of the endless field trips that usually make up our home educating life. Around us, life was churning along as usual despite the first Coronavirus cases being recorded in Cornwall a day or two before. With so many of good friends living elsewhere in Europe, we were only too aware of how quickly the situation might deteriorate, but while we were already starting to avoid indoor events and gatherings as far as we could, the open shore felt as good a place to be as any.

A beautifully marked Xantho pillipes crab – one of many lovely finds at Hannafore.

While the kids were building stone citadels and warring rocky villages at the top of the beach, I gave them vague instructions to come and find me soon and set off down the shore, following the receding tide over slippery rocks and frothing seaweed. I was joined by a friend from north Devon making a special guest appearance at Hannafore.

Among the boulders we discovered a tiny Montagu’s sea snail; a small tadpole-like fish with tiny eyes that tends to curl its tail round its head, looking more like a sleeping cat to me than a snail. These fish were soon turning up everywhere, with more than half-a dozen down a single gully.

A Montagu’s sea snail (fish) in its classic curled-up position. The fish suckers onto rocks.

Further along, a topknot flatfish was clinging to the rock with its sucker-fin, so perfectly blended with the colours of the stones and weed that only its fluttering gills and swivelling eyes gave it away.

Topknots sucker onto rocks and stay still to avoid being seen. Like many other intertidal fish, they can change colour to match their surroundings.

A head popped up from a neighbouring gully, another marine biologist friend from the Marine Biological Association  (MBA) was busy exploring, and across the lagoon, other friends from Bude Marine Group were approaching. Junior and his friends also abandoned their construction works and set out to explore the exposed reef armed with cameras to capture their adventures.

A dahlia anemone. These anemones have a sticky column and are often covered in gravel.

Despite a brisk, cold wind that was welding my fingers to my camera, the excitement of the finds stopped me from worrying about anything except what was in front of me. Sea slugs, quirky hydroids, and beautiful clingfish kept me occupied and there was still a little time before the tide would turn.

A small clingfish, possibly a two-spot. These fish also have a sucker to help them stick to rocks.

The egg cases of the larger of our two catshark species were plentiful on the rainbow wrack and a shout from my MBA friend brought the children running back – a newly-hatched baby Greater spotted catshark (Scyliorhinus stellaris).

Greater spotted catshark egg cases, often called mermaid’s purses.

Baby Greater spotted cat shark (Scyliorhinus stellaris).

Time always feels desperately short to explore this fabulous environment, but every second is full of wonder. Finding a hairy hermit crab made my day, if it wasn’t already made by just being there with so many fantastic and knowledgeable people.

Hairy hermit crab. It’s easy to see how it gets its name!

The hairy hermit crab isn’t a common find on our local shores and this particular crab was exceptionally co-operative, emerging from its hiding place without hesitation which meant I could take photos and video of its incredibly hairy claws, its pale blue eyes and its stunning violet antennae.

Hairy hermit crab.

This week I published the paperback of my book and shared the celebrations through video interviews and a recorded book reading.

Like all children, my son is doing his best to adapt to keeping in touch with friends and family from a distance and my other half is working from home. Some friends have been desperately ill and others still are putting their lives on the line every day as nurses and critical workers. Writing has felt pointless at times, impossible at other time and yet it seems important to share the beautiful things, because these will return.

Stalked jellyfish, Calvadosia cruxmelitensis.

The happy moments shared with my bottoms-up brigade of rock poolers, the exploration and the freedom may just be a memory at the moment, but I am reassured to know that life carries out there beneath the waves as it will here above. The wild creatures that make me catch my breath will still be there when all this is over. Friendships remain and my little community is showing strength, compassion and ingenuity to make sure we carry each other through.

European 3-spot cowrie (Trivia monacha) on star ascidian (Botryllus schlosseri).

Stay safe and watch this space for more colourful creatures to brighten your days, whatever they may bring.

Spot the spider crab! (Macropodia sp.)
Spider crab (Macropodia sp.)
A well-decorated spider crab (Macropodia sp.) in the water. This crab deliberately covers itself in seaweed as camouflage.
Aeolidia filomena – The great grey sea slug or ‘sheep’ slug. These common sea slugs feed on sea anemones.

The Surprising Mini-World of Rock Pool Insects

If my blog posts have seemed a bit thin on the ground the last few months, it’s fair to put the blame on Atiyah, Brendan, Ciara and Dennis.

Even on the good days the lighting and conditions have been less than ideal so, to make the best of a mediocre tide, I enlisted the help of Other Half. Together, we could look under the sort of rock I usually see but leave alone, knowing it weighs far more than I do.

This short video shows you some of the animals living there…. read on to find out more.

Other Half was pleased with the strawberry anemones, which were enormously plump with all their tentacles retracted.

Strawberry anemone
Strawberry anemone

Under a carefully constructed shelter made of small stones and pieces of kelp we could also see the purple-tipped spines of a green shore urchin. Among its many disc-topped tube feet, a long polychaete worm was exploring.

Green shore urchin
Green shore urchin

What drew my eye most, though, were the holes in the rock. These were scattered across the surface of the rock and about the circumference of a pencil. I caught the tiniest glimpse of movement as I looked into one of them.

Piddock holes underneath the boulder.

If I were the BBC Natural History Unit, I’d have filmed inside with an endoscope or transported the rock to deeper water so I could photograph the gaping shells emerging to feed.  Instead, you will have to take my word for it that there were piddocks in those holes!

Piddocks are bivalve molluscs (clam shells), which burrow into the rock and spend their entire lives in their holes.

A rock with this many cracks and holes in it is bound to contain some good hiding places for other animals and also some air pockets, which enable some of our most unlikely rock pool wildlife to survive being submerged twice a day. Some insects and other arthropods that breathe air live here, but you have to be patient to see them.

I settled down with my camera and before long, the first waggling antennae of a springtail poked over the rim.

The end of a piddock protruding from a hole. (Taken on another occasion).

I often see rafts of blue-grey Anurida maritima springtails floating on the surface tension of pools in the summer, but these were smaller still and so pale they looked almost transparent. They are clearly visible in the video but I could only take very blurred still photos.

The fabulous Essential Guide to Rock Pooling by Steve Trewhella and Julie Hatcher was my first port of call in trying to identify them. The book has great photos and plenty of clear information on what to look for. Steve kindly identified these springtails as Axelsonia littorlis – a new species to me. It’s amazing what you find when you stop to look.

The best shots I could get were of a larger bug called Aepophilus bonnairei, a beetle-like creature with red eyes and a spiky coat of hairs around its back and legs. These hairs trap air bubbles, which help the insect to breathe when it is submerged.

Aeopophilus bonnairei bug on a rock
Aepophilus bonnairei bug on a rock
A juvenile Aepophilus bonnarirei.

Time was short as the tide was already turning and the waves were pounding in. I tried to photograph as many species as I could so that I could put records together afterwards. Some, like the painted top shells and the various crabs, are easy to identify.

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Painted top shell.

One of the most striking sponges I see on the shore is the vivid blue Terpios gelatinosus. Many other sponges are harder to identify confidently.

Blue sponge - Terpios gelatinosus with keel worm
Blue sponge – Terpios gelatinosus – with keel worm

It seemed that no part of this valuable habitat was left unoccupied. To avoid any of these creatures coming to harm, we gently manoeuvred the rock back in place well before the surging waves reached us.

Different coloured patches of star ascidian among spirorbid worms, keel worms and other life on the boulder.

As always, I was left in utter awe of the fragile little creatures we saw.

It is remarkable that these animals will cling onto life here no matter how much the wind howls and the sea roars around them, while we head home to bring the plant pots in out of the wind, check the fences and put the kettle on.

Broad-clawed porcelain crab
A grey and windy day on the shore. It’s incredible that anything can survive in these pools, especially insects.

A Quick Winter Walk

Though there is much to love about December, I know I’m not the only one who’s flagging well before the end of the month. The spring tides arrive at the perfect time to boost my energy levels, ready for all the rockpooling and writing adventures that await me in 2020.

No-one in the family is sure what day it is, and the gloomy weather isn’t doing anything for our timekeeping. By the time we reach Plaidy, we only have half an hour left before it will begin to get dark. Fortunately, that’s plenty of time to find some winter colour.

This beach is ideal for strawberry anemones, a species that seems to like some wave energy. While I try to take photos of a stunning open anemone, its bright tentacles tucked too far under a dark overhang for my camera to capture well, the waves surge in behind me, finding a hole somewhere in my left welly.

Strawberry anemone

Undeterred by the steady seep of chilly water down my ankle, I take a close look at the tough seaweeds that have clung on at the edges of the pools through the winter storms. There are tufty pink fringes of coral weed, the frayed remains of last summer’s kelp, and, sprouting from the rocks at the pool’s entrance, there are dark clusters of wiry-looking Irish moss. Among these seaweeds are dozens of mauve stalked jellyfish dancing like fairy lights.

Stalked jellyfish – Calvadosia cruxmelitensis.

In every rocky crack and crevice alongside the pools there are crabs lurking, waiting for the returning tide. A velvet swimming crab watches me through red eyes like glowing coals.

Velvet swimming crab

Nearby, the sculpted pink spire of a painted top-shell brightens up a shady overhang that is also home to several cushion stars and bright sponges.

Painted top shell.

Everywhere I look there are colourful sea squirts, shells, fish and seaweeds. These may be the darkest days of the year, and I can feel a cold coming on, but the brightness of the shore always reminds me that spring is around the corner.

Breadcrumb sponge.

In fact, new life is beginning already in the rock pools. Before I leave I come across this 2mm long baby sea hare grazing on the seaweed. By the summer, if it survives, this tiny slug will have developed a striking brown leopard-spot colouration and will have grown large enough to fill my palm. Perhaps we will meet again?

Juvenile sea hare – Aplysia punctata

Happy New Year! May 2020 bring you health, happiness, and many, many beach adventures.

Happy New Year from Bernard the hermit! (Pagurus bernhardus).

Starfish and Blue-Rayed Limpets on a gloomy day

The clocks have gone back, endless bands of rain are pushing in from the grey sea and the UK government has announced there will be a general election during the festive season. It might be easier to hide under a duvet and attempt hibernation, but Junior and I have other plans. We grab a camera each and race to the rock pools in search of brightness and sparkle.

To the rock pools!

Millendreath beach near Looe is cold enough to warrant silly winter hats – mine has big ear flaps and Junior’s is a Christmas pudding – we don’t care what we look like as long as we’re comfortable. We head out onto a rocky outcrop that gives us some shelter from the north-easterly winds and begin our search. When I find a spiny starfish twice the size of my hand in the first pool we come to, we know it’s going to be a good day.

Junior takes a look at the tube feet on the underside of the spiny starfish.

Moving towards the sea, the gullies are full of leathery kelp and Junior knows just what to look for. The iridescent blue dashed lines on the shells of blue-rayed limpets are his favourite thing to photograph and at this time of year, some of the kelp is studded with these miniature jewels.

Blue rayed limpets on kelp – photo by Cornish Rock Pools Junior.

While Junior gets to work trying to capture these colours, I edge along the slippery rocks towards a tall overhang. Sponges and sea squirts coat the rocks in a huge range of hues from pinks and yellows to blues and greens. Among them are cowries, which feed on the sea squirts. One has abseiled down from the rock and is hanging by its mucous thread.

This Arctic cowrie has abseiled from the top of the rock and is still holding on to its thread of mucus.
A pair of Arctic cowries with their shells partly covered by their dark-striped mantles.

Nearby, a common starfish is trying to hide in a crevice but its bright orange colour gives it away. In the dark behind it, a Xantho hydrophilus crab is doing a better job of blending in.

A bright star on a gloomy day – common starfish at Millendreath.
Xantho hydrophilus crab hiding in a crevice.

For some reason the painted top shells here are paler than on those on our other local beaches and some are almost white. Another feature of this beach is the high population of sea cucumbers. We spot both the sea gherkin and the brown sea cucumber, but they are closed up today, hiding their frilly tentacles.

A pale and beautifully marked painted top shell.
Brown sea cucumber (centre) mostly hidden in a crevice, surrounded by sponges and other encrusting animals.

Just before we move out of this isolated gully, Junior shouts in delight. He has taken his best ever photo of a blue-rayed limpet. All the practice and patience has paid off.

Junior’s best blue-rayed limpet photo.
He’s also captured me at work in my natural habitat!

As the tide turns we take a quick look for stalked jellyfish. At this time of year, the seaweed is dying back making it easier to spot them, but the rushing currents from the stormy sea and the large amount of sediment that has been stirred up by the waves aren’t aiding our search. There are probably scores of stalked jellies here as the location is perfect for them, but we only see half a dozen. Among them are three different species: Calvadosia cruxmenlitensis, Haliclystus octoradiatus and a rather sorry-looking closed up specimen of Calvadosia campanulata.

This Calvadosia campanulata stalked jellyfish has (hopefully) seen better days!
The only Haliclystus octoradiatus stalked jellyfish we find is being thrown around in the current, but the white blobs of its primary tentacles can be clearly seen in this photo.
Most of the stalked jellyfish we see today are the ‘Maltese cross’ stalked jelly – Calvadosia cruxmelitensis.
Calvadosia cruxmelitensis stalked jelly with lots of white spots – these spots are clusters of the stinging cells (nematocysts).

Junior spends a happy half hour watching the cracking cliffs of sand that have formed around the edges of the rain-swollen stream, until the incoming tide begins to send waves up the river, flooding the sand around us and forcing us back.

The first spots of drizzle spatter down and will soon be followed by yet more heavy rain. There’s nothing we can do to prevent the arrival of even shorter days or colder weather, but whenever we need to find colour and inspiration during the dark winter, we will know where to find it.

Berthella plumula sea slug
A breadcrumb sponge with microalgae growing inside the green parts.
Star ascidian
A tortoiseshell limpet surrounded by pink encrusting seaweed.

Happy rock pooling!

Huge thanks to everyone who has shared their finds and photos with me. I love hearing about your rock pooling adventures through my contact page.