Category Archives: Molluscs

Home from Home: Quiberon in Brittany

Things have been quiet on this page the last couple of months. Cornish Rock Pools Junior, Other Half and I took an extended holiday to visit the towns and beaches of Brittany. As always our travels had a bit of a marine theme…

Est-ce que c’est un anémone?” the eager child in the dark-rimmed spectacles asks. We explain what a ‘stalked jellyfish’ is to the class of seven-year-olds. “Jellyfish!” they chant.

 

Stalked jellyfish - a Lucernariopsis cruxmelitensis.
Stalked jellyfish – a Lucernariopsis cruxmelitensis.

Between fascinating excursions to the fire station and the sardine factory, we are giving impromptu English lessons to a class of primary school students during our twinning visit to Quiberon in Brittany.

 

We have covered the words goby, crab, jellyfish and shark so far and there’s still a sea of raised hands. The children seem desperate to tell us about their finds around the shores of Quiberon. Continue reading Home from Home: Quiberon in Brittany

Hatchlings in the rock pools at Port Nadler

A sunny bank holiday weekend followed by a sunny half-term week is nothing short of a miracle. That the second weekend also coincided with some big spring tides is more amazing still.

I’ve seen some wonderful photos this week of rockpooling finds all around Cornwall. Some fabulous creatures. And if you haven’t been able to explore the shore yourself, Springwatch tonight (8th June) are going to be showing footage of the remarkable comeback of the Clybanarius ethryropus (nope, still can’t pronounce it) hermit crab, filmed with Cornwall Wildlife Trust at Castle Beach, Falmouth.

The stars of my pretty perfect day of wading through pools in the blazing sunshine at Port Nadler, near Looe, were the baby fish.

There are plenty of young fish around at the moment but the new hatchlings can hard to spot. I took this photo of clingfish eggs to capture the eyes staring out of each eggs and the little spotty tails curled round them.

Clingfish eggs hatching in a Cornish rock pool.
Clingfish eggs hatching in a Cornish rock pool.

It was only when I uploaded photo to my laptop that I realised I’d managed to capture my first hatchling (in the centre of the picture). I can’t get enough of those golden eyes.

A recently hatched Cornish clingfish among its egg-bound siblings
A recently hatched Cornish clingfish among its egg-bound siblings

Fish often stick around to guard their eggs and sure enough there was a proud parent next to this rock.

An adult Cornish clingfish showing the typical beaky nose, antenna by the eyes and blue patches on the head.
An adult Cornish clingfish showing the typical beaky nose, antenna by the eyes and blue patches on the head.

I was up to my waist between rocks leading to the open sea when I saw this pale creature, about 4cm long, wriggling amongst the darker kelp. From its elongated, looping form I expected a worm.

A recently-hatched Greater pipefish baby.
A recently-hatched Greater pipefish baby.

On closer inspection the large eyes and fins were clear. This is the first time I’ve ever seen a baby pipefish.

A baby Greater pipefish with yolk sac still attached. The large eyes and long snout are reminiscent of its cousins, the seahorses.
A baby Greater pipefish with yolk sac still attached. The large eyes and long snout are reminiscent of its cousins, the seahorses.

Judging by the yolk sac still attached to its belly, this little fish hatched very recently. I saw several more in the water, their curling movements reminding me of their cousins the seahorses. I wondered if the dad was close by – like seahorses, the male pipefish looks after the gestating eggs in his pouch until they hatch – but he’d be too well camouflaged to spot in this seaweed.

 The rocks were crawling with crabs and the pools were busy with the fry of larger fish that use these sheltered waters as nurseries. My camera battery was low, but this Limacia clavigera sea slug was worth draining my battery for.

A Limacia clavigera sea slug on the move.
A Limacia clavigera sea slug on the move.

 The water was so warm after a week of sun that I put on my snorkel for the first time this year and enjoyed a leisurely float across the bay, watching wrasse skirting the rocks and snakelocks anemones waving in the current. 

If this weather carries on, I can see myself returning to Port Nadler regularly this summer to watch the baby fish growing up.

Cornish Rock Pools junior drying off in the sunshine at Port Nadler, near Looe.
Cornish Rock Pools junior drying off in the sunshine at Port Nadler, near Looe.

Rockpooling at Hannafore – Video

A variegated scallop opens up showing its multiple eyes then snaps shut. A topknot flatfish skimming along the sand. Just some of the creatures I saw in the rockpools at Hannafore, Looe today on the low spring tide.

I was a too busy taking kids ‘shark hunting’ to take more video today. It was a successful mission; we found more than twenty live egg cases of the Nursehound (Scyliorhinus stellaris) and one live Smallspotted catshark (Scyliorhinus canicula) egg case. There were all sorts of other treasures too.

I’m already looking forward to doing it all again tomorrow.

 

Worms, slugs and jelly

As anyone who spends time around children knows, they generally delight in things that adults find yucky. So, what better for a day out with Cornish Rock Pools Junior than a visit to a sheltered, silty shore? It’s the perfect environment for all things slimy.

It didn’t take us long to find one of the strangest – and stinkiest – animals on the shore, the bootlace worm. We turned a stone and on one side was the head and part of the tangled body of the brown worm. The rest of the body spanned across to the next boulder like a rope bridge.

The thin, long body of a bootlace worm stretched between two rocks.
The long, thin body of a bootlace worm stretched between two rocks.

The bootlace worm is massively long – the longest recorded apparently came in at 55 metres, making it the longest animal in the Guinness Book of Records. This one would probably have spanned at least 7 metres. Given the difficulties of unravelling the tangled body without breaking it coupled with the fact it exudes acrid-smelling, toxic mucus, we decided against measuring it.

On another rock we found a prettier creature, the candy-stripe flat worm. This one had moulded its paper-thin body to the contours of the rock. When they’re not oozing along like this, they’re reasonable swimmers, albeit with a technique that resembles a tissue blowing along the pavement.

A small candy stripe flatworm oozing along its way.
A small candy stripe flatworm oozing along its way.

We started the search for jellies. The sheltered clumps of seaweed seemed a likely spot for stalked jellies, although Junior’s fascination with kicking up ‘pyroclastic flows’ of silt did hamper visibility a little. For a while we found nothing but ‘snotworm’ eggs, the green eggclumps of the green leaf worm.

When we did find our first jelly blob, it turned out to be another kiddy favourite, a slug. Out of the water, it was a shapeless splodge of yellow. In the water, it stretched out its white body to display yellow stripes and various yellow appendages and antennae.

Sea slug - Polycera quadrilineata
Sea slug – Polycera quadrilineata

As we watched the Polycera quadrilineata slug’s slow progress along the seaweed, we noticed another, more flowery jelly-blob behind it. This was the first of several Lucernariopsis cruxmelitensis stalked jellyfish we found.

Stalked jellyfish - a Lucernariopsis cruxmelitensis.
Stalked jellyfish – a Lucernariopsis cruxmelitensis.

The incoming current was throwing up a cloud of silt, but we managed to find eight stalked jellies among this small area of the shore. Not a bad haul of squidgy, slimy, child-pleasing creatures.

Stalked jellies have stinging tentacles like their cousins, the jellyfish, but live attached to seaweed rather than floating in the ocean.
Stalked jellies have stinging tentacles like their cousins, the jellyfish, but live attached to seaweed rather than floating in the ocean.

 Here are some of our other favourites from this expedition:

A sea spider. These delicate little creatures are perfectly camouflaged among the seaweed.
A sea spider. These delicate little creatures are perfectly camouflaged among the seaweed.
Tubulanus annulatus. This strikingly coloured worm was a first for me and is more commonly seen offshore.
Tubulanus annulatus. This strikingly coloured worm was a first for me and is more commonly seen offshore.
I was right at the depth-limit for my wellies when I found this topknot flat fish scooting along the bottom of a pool. Junior loves their asymmetrical faces.
I was right at the depth-limit for my wellies when I found this topknot flat fish scooting along the bottom of a pool. Junior loves their asymmetrical faces.
More slime! Cowries are able to dangle from the rocks using their strong mucus trails.
More slime! Cowries are able to dangle from the rocks using their strong mucus trails. This one’s in typical abseiling position.

Rockpooling Heaven (And a downpour)

The sun is shining and, for the first time in months, I can feel the warmth on my face. With calm seas, the tide has run out even further than I hoped, rockpooling conditions here in Looe are near-perfect. There are ominous clouds looming over the hills behind me, but I choose not to look at them.

Perfect - this sheltered gully has weathered the storms.
Perfect – this sheltered gully has weathered the storms.

After the fierce storms, I half expect to find the rockpools empty, scoured of life, but I couldn’t be more wrong. I explore an area of my local shore in Looe that I don’t often visit and within minutes I have found my new favourite rockpooling spot, a gully that’s visibly wriggling with life. Continue reading Rockpooling Heaven (And a downpour)

Colourful and Endearing – Video: Meet the Flat Periwinkle

If you’ve ever collected shells on the shore, you’ve probably homed in on the bright yellow, orange, white and even chequerboard colours of the flat periwinkle. Their shells look like a miniature version of the garden snail, but smaller, tougher and much, much brighter.

Flat periwinkle in a Cornish rock pool
A flat periwinkle on the mid-shore seaweed

This time of year, when the seas are rough and the lower shore is hard to reach, I love to search among the seaweeds of the mid and upper shore. The flat periwinkles’ vivid colours shine out like jewels among the tangle of brown seaweeds.

On a damp day at my local beach, it doesn’t take me long to find dozens of them. They’re in no danger of drying out today so they’re busy grazing, tentacles waving from side to side, black eyes on the lookout for crabs and other predators.

An orange-banded flat periwinkle on the move - showing its eye and tentacles.
An orange-banded flat periwinkle on the move – showing its eye and tentacles.

Close-up they’re endearing little things, a herd of gentle grazers feeling their way through the swathes of seaweed. In this video you can see how they search out food with their tentacles. Watch them reaching out their proboscis mouth, pink radula pulsing as they rasp away at the seaweed.

In a patch of seaweed around five metres square, I find a huge variety of colours. These variations probably offer some protection from predators, as does the covering of microalgae on many flat periwinkles, which gives them a green colour.

Some flat periwinkles are white or cream coloured
Some flat periwinkles are white or cream coloured

Whatever the reasons for their varied colours, they make the flat periwinkle one of the most striking shells on the shore. (Note: If you collect shells, please always remember to check they’re empty before you take them home.)

Some flat periwinkles are black or brown. The variety probably provides protection from predators.
Some flat periwinkles are black or brown. The variety probably provides protection from predators.

It’s so easy to get close to these animals and watch them in action. Look out for them next time you’re at the beach.

 About flat periwinkles…

There are two species of flat periwinkle, Littorina obtusata and Littorina mariae. In theory L. mariae has a flatter profile and is the smaller of the two with a thicker shell, but on the shore they vary and mix so it is hard to distinguish between the two species.

Generally, you find Littorina obtusata on the mid-upper shore, especially on egg wrack and Littorina mariae on the lower shore, especially on serrated wrack. The main difference is that L. obtusata tucks into the seaweeds it lives on, whereas L. mariae likes to graze on organisms that live on the its preferred seaweeds. Each one prefers to live on the seaweeds mainly found on its own zone of the shore.

The animals in these pictures are almost certainly Littorina obtusata given their location and diet. However, as far as I know the only way to be certain is to examine the animal’s penis – not something I intend to do. The Field Studies Council have a great paper on the habits and identification of the two flat periwinkle species (including penis shapes) here: http://fsj.field-studies-council.org/media/342551/vol7.3_202.pdf. Take a look if you’d like to know more.

A tiny yellow flat periwinkle grazing among the Cornish rock pools.
A tiny yellow flat periwinkle grazing among the Cornish rock pools.

 

 

A Variegated Scallop Takes a Little Swim

Here’s something I’ve never seen before. While I was rockpooling, I lifted a stone and found this little variegated scallop, which is a smaller cousin of the scallops people eat. As I watched it began to open and I guessed it might take a little swim so I took this short video.

All scallops can swim but they don’t do it very often because it takes a lot of energy. I think this one was thought I might be a predator and wanted to swim back to the safety of a rock. It was surprisingly speedy.

Filmed at Hannafore Beach, West Looe, Cornwall on 31 August 2015 during a very low spring tide.

Lazy Sunday rockpooling

This time of year when the roads are busy and the beaches packed, the summer can feel anything but relaxing. It’s Sunday today and we’re taking it easy, so what could be better than a stroll to a local cove that’s a bit off the beaten track for a spot of quiet rockpooling. Starfish, sea slugs, fish and stalked jellyfish await me. 

Going slowly and looking at the seaweed can reveal some beautiful encrustations of sea squirts and bryozoans
Going slowly and looking at the seaweed can reveal some beautiful encrustations of sea squirts and bryozoans

It’s always a good idea to move slowly in the rockpools and today I have nothing to rush for. By staring at the seaweed for a very long time, I begin to notice more details and my eye is drawn to a stalked jellyfish. The blobs between the arms are primary tentacles, suckers that the jelly can use to move around.

Stalked jelly Haliclystus ocroradiatus showing its primary tentacles (blobs between the arms)
Stalked jelly Haliclystus ocroradiatus showing its primary tentacles (blobs between the arms)

A little further on I find another species. This one doesn’t have the blobs between the arms and is flecked with pale spots, which contain stinging cells. Continue reading Lazy Sunday rockpooling

Giant birthday surprises – a rare sea hare and a greater pipefish

There are lots of benefits to having a summer birthday; the sun usually shines, the rock pools shimmer and it’s just about warm enough to put my snorkel on and jump in. The beach has lots of presents in store for me today, including a huge greater pipefish, a cousin of the sea horse, and a rare sea slug. No unwrapping required.

A juvenile Aplysia depilans - a rare sea hare in UK waters.
A juvenile Aplysia depilans – a rare sea hare in UK waters.

It’s holiday season , but a little planning and some walking is all that is needed to find a peaceful cove. We set off to Port Nadler in perfect, calm conditions loaded with wetsuits, buckets and an ample picnic.

A typical rock pool at Port Nadler near Looe
A typical rock pool at Port Nadler near Looe

Under a rock I spot what I think is a very large anemone, but it looks odd. I’m still trying to puzzle it out when it crawls away, unfurling long ear-like tentacles from its head. It’s a sea hare but more bulky than the ones I normally see (Aplysia punctata).

I think I've found a strange anemone
I think I’ve found a strange anemone
Surprise! It turns into a sea hare.
Surprise! It turns into a sea hare.

As it oozes towards me across the rock I’m struck by its face, more like a hippo than a hare with wide flapping ears and a broad snout. Very occasionally larger sea hares, Aplysia depilans, have been found around the southern shores of the UK, and I begin to wonder.

Aplysia depilans - looking more like a sea hippo than a sea hare
Aplysia depilans – looking more like a sea hippo than a sea hare

I contact experts who have seen them before and they confirm it is a juvenile Aplysia deplians – a rare find and a species I’ve never seen before. Happy birthday to me!

It’s still cold for snorkelling and I only last about a quarter of an hour before my teeth start to chatter, but it’s worth it. After several minutes of seeing nothing but kelp, silt and the occasional two-spot goby, a long snake-like body catches my eye. It’s the unmistakeable shape of a greater pipefish (Syngnathus acus).

The greater pipefish looks out from the weeds
The greater pipefish looks out from the weeds

These fish grow to about arm length and have a hexagonal cross-section. This one hardly moves, relying on camouflage for defence, its long nose stretching out over the sand.

Greater pipefish - a cousin of the seahorse
Greater pipefish – a cousin of the seahorse

I drift back into shore, and find a compass jellyfish (Chrysaora hysoscella) stranded in the shallows. It takes its name from the beautiful markings on its back, but I don’t go too close – sea nettle is its other common name.

Compass jellyfish - showing its distinctive markings
Compass jellyfish – showing its distinctive markings

Back on the shore, I huddle on the sand, wrapped in jumpers and towels, shivering and eating cake. Birthdays don’t get any better than this.

This snakelocks anemone looks like it's had a fright - the tentacles were being picked up by the current
This snakelocks anemone looks like it’s had a fright – the tentacles were being picked up by the current

 

Up close to a red-eyed velvet swimming crab (Necora puber)
Up close to a red-eyed velvet swimming crab (Necora puber)

 

Cornish clingfish eggs - little eyes and noses visible inside
Cornish clingfish eggs – little eyes and noses visible inside
A snorkel-scape. Thong weed at Port Nadler near Looe
A snorkel-scape. Thong weed at Port Nadler near Looe

Practice Run – Rockpooling just before the big tides

This weekend will be a rockpool marathon. I’ll be out in my splendidly flattering waders crawling among kelp and tearing my fingers apart on barnacles and keel worms, making the most of the exceptional spring tides.

In preparation I take a leisurely pootle to my local beach, Plaidy. High pressure and calm seas mean this is already a great tide – it will drop another half-metre by Saturday.

Baby sand eel
Baby sand eel

Cornish Rockpools junior is digging sea defences, rescuing the baby Continue reading Practice Run – Rockpooling just before the big tides