Tag Archives: cup coral

Rock Pool Bingo – Searching for Southerly Species (Part 2 – North Coast)

With our bingo cards of southerly species part-filled after an exciting day on the south coast, our visitors from Wales still had quite a wish list left to accomplish. To find cup corals and Celtic sea slugs, a trip to a more exposed coast would be needed. Naturally, I suggested my favourite beach: Porth Mear.

A flock of geese joined us on the shore at low tide.

The weather was on our side, taking a break between the endless storms that have characterised the summer holidays. So, with swimmers and beach shoes at the ready, we walked down a valley alive with tortoiseshell butterflies to where the bluest sky met the bluest sea. Even the pools at the top of the beach churned with trapped young mullet, scurrying shore crabs and bright anemones. While one of our friends stayed looking at the upper shore pools and gathering shells, Junior and I led our other friend on a long slip and slide across the rocks to reach our goal.

With two hours to go until low tide, we could safely allow ourselves a few distractions on the way. I couldn’t resist stopping to take photos of this wonderful Montagu’s blenny, which let me creep ever closer with my camera as it sheltered under a limpet shell. Blennies are able to move their eyes independently and this one kept an eye on me while scanning the surface of the pool with the other.

Montagu’s blenny looking two ways at once. This blenny has a single head tentacle.

My friend was delighted. Although it hadn’t appeared on our bingo card, the Montagu’s blenny is another southerly species which he had never seen in North Wales. This was too easy!

We had met some St Piran’s hermit crabs at Hannafore the previous day, but the colony here was well worth a look too. We found scores of these crabs in and around the pools along a couple of rocky overhangs, living in a range of sizes of shell. This species is doing well here, towards the northerly limit of its known range.

The painted top shells on this beach are always especially pink and beautiful, perhaps because in this more exposed location, they tend to accumulate less silt and micro-algae on their shells. We stopped to take plenty of photos.

A typically bright pink painted top shell at Porth Mear.

Although it can be hard to find stalked jellyfish in the summer when the beach is thick with the seaweeds they attach to, we were determined to tick one or two off the list, especially Haliclystus octoradiatus. This may not be a particularly southerly species, but it occurs frequently around Cornish coasts. After much searching we found a very small blob that was probably a juvenile, but I could only confirm that by looking at photos afterwards.

This tiny juvenile Haliclystus octoradiatus stalked jellyfish was only a few milimetres long, but in the photos, its primary tentacles are visible.

As the tide dropped further, we picked up our pace and clambered towards a wave-battered gully. This area is only accessible on the lowest tides and, even then, is often out-of-bounds due to the huge swells that pound these rocks for much of the year. Today, the calm conditions were perfect and we could explore in relative safety while keeping an eye on the time.

Junior made straight for the high rocks, where he quickly found the first Celtic sea slug, out in the open among the barnacles and mussels.

Celtic sea slug

These strange black lumps always remind me of armoured cars. This is mainly a very southerly species which is found widely around exposed Cornish coasts, but it has been recorded as far north as the Farne Islands and Scotland.

Celtic sea slugs may not be the most classically pretty slugs, but they are incredible animals. They are able to survive on these rough shores in terrifying conditions and they don’t even have gills. They breathe air and hide away in cracks in the rock when the tide comes in, staying alive by keeping an air pocket sealed inside their bodies and breathing through their skin when needed.

If there is one Celtic sea slug, there is usually a whole colony and we found dozens more on the rocks all along the gully.

Celtic sea slug foraging on tiny micro-algae and other micro-organisms.

Our next stop was a deep overhang with a pool at its base where we knew we would be able tick off another species from our bingo card, the scarlet and gold cup coral.

We had to kneel and lie at strange angles on rocks encrusted with sharp barnacles, but we were soon rewarded with the brilliant glow of many corals.

Scarlet and gold cup corals

These tiny orange and yellow corals open their transluscent tentacles in the water here and always astound me. Their delicate soft bodies encase a spongy, fragile exoskeleton, none of which looks like it could stand up to a gust of wind, let alone the fierce, pounding seas that rage through this gully on a daily basis. Despite their soft appearance, scarlet and gold cup corals, like the Celtic sea slugs, thrive in these wild places.

It was a good thing we had left ourselves plenty of time to explore this rock pooler’s paradise. Between deep pools packed with enormous snakelocks anemones and prawns as big as my hand, we scrambled and stared at the huge diversity of species in front of us. Arctic and three-spot cowries moved across the damp surfaces encrusted with pink seaweeds and colourful sea squirts. Groups of light-bulb sea squirts seemed to shine out from the dark water and so much life abounded on every surface that we moved with great caution for fear of accidentally treading on creatures.

3-spot cowrie

The underside of a large boulder at the head of the gully was coated in a red sponge. A quick inspection revealed a small white coil of sea slug sponge. It took me longer to find the slug, which matched its background flawlessly. Rostanga rubra are a common find on these sponges but this was another first for my friend who is almost as obsessed with slugs as I am. He was so delighted with this little find that he took some persuading to move away from the gully before the tide turned.

Rostanga rubra sea slug
Rostanga rubra sea slugs feed on orange and red sponges such as Ophlitaspongia papilla. As they feed they take in the colour from the sponge, which makes them perfectly camouflaged.

On our way out of the gully, we waded through a pool, up to our waists in the water and no longer caring how wet we were. Hidden at the back of the pool we discovered a deep hole in the rock that harboured dozens of scarlet and gold cup corals and many large snakelocks anemones. I spotted a leg sticking out from underneath this one and uncovered this Leach’s spider crab (Inachus phalangium) sheltering there.

Inachus phalangium living in the shelter of a snakelocks anemone’s stinging tentacles. This crab also grows sponge on its carapace for camouflage.

A shallow pool nearby was dotted with tufts of rainbow weed. To our surprise, these harboured many Asterina phylactica – a small species of starfish. A nearby clump of codium seaweed was also home to several Elysia viridis sea slugs.

Asterina phylactica – a small species of cushion star.

On our way back across the beach, my friend found a clump of seaweed with half a dozen stalked jellyfish growing on it. This time, the blobs of the primary tentacles between the arms were easy to spot and we could be sure that these were Haliclystus octoradiatus.

A white Haliclystus octoradiatus stalked jellyfish

With most of our bingo card of southerly species complete and with another day of rock pooling to try to find the remaining species, my friend set off up the beach to rest and enjoy a well-earned picnic.

Junior and I lingered in the sunny pools, exploring further into the slippery masses of thong weed and kelp until the tide turned.

To celebrate the rare August sunshine, we finished the day with a visit to the vast rock pool where I used to swim as a child. Plunging into the cool waters, I experienced the familiar feelings of wonder and trepidation at the thought of what might lurk in the depths.

We splashed and floated between the rocky walls, finding starfish, prawns, star ascidians and sponges as we swam, side by side. Time might move on, but this beach never loses its magic.

Sea hare, Aplysia punctata, at Porth Mear
A blue-rayed limpet on kelp at Porth Mear
A yellow form of the Scarlet and gold cup coral.
A huge prawn checks out my camera!
A shanny (common blenny) hiding in a crevice waiting for the tide to come in at Porth Mear.
Light bulb sea squirts at Porth Mear.
The walk to and from Porth Mear is always a wonderful part of the adventure – Junior spotted lots of cinnabar moth caterpillars on our way back.

Scarlet and Gold Cup Corals -A Treasure Quest

The sea, viewed from the top of the steep valley, is a distant pool of blue decorated with a scattering of rocky islets. Here ‘my people’ (as my other half puts it) gather, unperturbed by the intense hail shower that sweeps over us. We pull on our wellies and waterproofs in the shelter of our car boots until the storm slinks away, uncovering a cleansed sky.

A few years back I hosted a Coastwise North Devon field trip to the south Cornish coast. Today I’ve been invited back for a north Cornwall foray with this dedicated group of marine naturalists. There could be no more serious band of rockpoolers. Should there be any unusual species on this shore, they are about to be discovered.

The walk down the valley to Porth Mear beach never disappoints, even in the muddy aftermath of a hail storm. Our party is accompanied by the trills of the first skylarks of summer and the first swallows dancing over the marshes.

Porth Mear beach at low tide.
Porth Mear beach at low tide.

My main objective today is to photograph the corals. Like so much of our colourful marine life, the scarlet and gold cup coral (Balanophyllia regia) is barely the size of my fingernail and prefers to live in the most awkward spots possible.

When I last found corals here, I crawled into a damp overhang on my belly, discovered the space was too small for my camera’s waterproof casing and removed it so I could hold my camera at arm’s length into the dripping cave (it died soon afterwards). The resulting photos showed blurred bloblets. The colours were lovely but beyond that you had to use your imagination. I suspect my new camera can do better.

Scarlet and gold star coral
My very best blurred bloblet photos from last year…. can I do better?

The water is slow to run out today. A swell is building in advance of a storm and waves are rushing into the gullies that I was hoping to explore; the ones where I last saw the cup corals. Despite that, it’s one of the best tides of the year, and with so many expert eyes on the case it’s not long before a shout goes up and people gather round. 

In a shallow pool at the back of a rocky grotto are dozens of scarlet and gold cup corals, spots of colour as bright as a sunset. Each one has a central disc of fiery orange fringed in rays of saffron yellow tentacles. I can only see this by lying down and pulling myself over the rocks until my head is wedged in the overhang  so deeply that salt water dribbles down my forehead. I have a small head, small enough to wear my child’s bike helmet; just occasionally that’s useful.

Scarlet and gold cup corals growing all along the base of the overhang.
Scarlet and gold cup corals growing all along the base of the overhang.

This time my camera fits easily through the slit in the rocks and after a fair amount of wriggling I find a way to position it in the water and focus. A clear shot of the cup coral, translucent spotted tentacles and all, appears on my screen. I bang my head on the rock in my excitement, then take fifty more photos – just in case.

Scarlet and gold cup coral at Porth Mear
Scarlet and gold cup coral at Porth Mear

I could spend all day here, except that the spray is already breaking over my back from the waves pounding the seaward rocks. Soon the tide will swallow this gully once more. The cup corals need these fierce currents to bring them food, but I wouldn’t last two minutes in them.

More scarlet and gold cup corals
More scarlet and gold cup corals

We carry on our explorations, making more discoveries and enjoying the sunshine, so unexpected after the morning’s hail.

There may be places where the sea shows its treasures more willingly, where large, colourful wildlife swims all around you without having to clamber over slippery rocks, lift boulders or traipse back up a steep hill at the end of the day. But I prefer this. Just as adventure stories would be dull if the quest were over on page one, finding marine treasure would be less fulfilling if you didn’t have to work at it; or so I tell myself.

Finding and managing a decent photo of a scarlet and gold cup coral has taken me nearly forty years. Even now, I’ve only managed it thanks to having ‘my people’ around me, sharing my fascination with these creatures. I couldn’t ask for more.

Scarlet and gold cup coral in a Cornish rock pool
Scarlet and gold cup coral in a Cornish rock pool