All posts by Heather Buttivant

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!

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Identifying my mystery creatures

The rock pools are full of weird creatures. I come away from most rockpooling trips with photos of strange blobs and odd leggy things that I mean to identify. Some are new to me, some I can’t remember the names of and some are things that look so much like other things they’re worth checking.

While I wait for the return of the spring tides this weekend, it seems a good time to put names to things I’ve tagged ‘to identify’.

First up is a minute shell that Cornish Rock Pools Junior thrust into my hand one day. At around half a centimetre long, it was too much of a challenge to identify in the field, so we took a photo and promptly forgot about it.

Fortunately on-screen in a warm living room it’s much easier to figure out how many whorls it’s got, that the opening has a short canal and that there are three rows of tubercles on each whorl. It has a distinctly unmemorable name: Cerithiopsis tubercularis. These shells live on sponges like the breadcrumb sponge, which is where we found this one.

Cerithiopsis tubercularis
Cerithiopsis tubercularis

The next photo is one end of a scale worm – it’s not entirely clear which end, but hopefully the worm knows. After a lot of staring at the arrangement of the bristles and the shape of the scales I’m satisfied that this is Lepidonotus clava.

Lepidonotus clava - a scale worm
Lepidonotus clava – a scale worm

Among my photos there are others like this Syllid worm that I’m unable to identify to species level. I was taking a photo of the Candelabrum cocksi and by the time I realised it was there it was slithering off down the far side of the boulder.

A syllid worm - orange at the far end and white at the near end between two Candelanbrum cocksi.
A syllid worm – orange at the far end and white at the near end between two Candelanbrum cocksi.

Sea spiders always need a close look as there are some very similar species. This is a Nymphon gracile. The egg sac it’s carrying looks huge under its spindly, delicate body.

Nymphon gracile sea spider
Nymphon gracile sea spider

This isopod was hard to photograph as it was especially small and kept walking about on the rock. It had amazingly long antennae, longer than its whole body, making it easy to identify as a Janira maculosa.

Janira maculosa - a marine isopod
Janira maculosa – a marine isopod

Chitons aren’t easy to tell apart with the naked eye, so I usually take a photo of the edges (the girdle) to check the details. This one is a Lepidochitona cineraria with sand-like grains fringed with lots of little spines around the edge. The shell also has a grainy texture.

Lepidochitona cineraria - a chiton
Lepidochitona cineraria – a chiton

I still have a pile of photos to go through and I’m half-buried under identification books, but it’s been a great learning exercise. Here are a few more photos that I (think) I’ve identified today.  I’ll be back soon with whatever turns up in the rockpools this weekend!

Morchellium argus sea squirt
Morchellium argus sea squirt
Didemnum maculosum sea squirt
Didemnum maculosum sea squirt
A Common dragonet - Callionymus lyra
A Common dragonet – Callionymus lyra
Sargatia troglodytes anemone
Sargatia troglodytes anemone
I've no idea what the leechy worm is, but the bryozoan it's on is Membranipora membranacea, which is recognisable from the rectangular shape of the zooids.
I’ve no idea what the leechy worm is, but the bryozoan it’s on is Membranipora membranacea, which is recognisable from the rectangular shape of the zooids.

Spooky Rock Pool Spells

Cornish Rock Pools Junior loves Harry Potter. A while back he noticed that a lot of rock pool creatures have scientific names that sound like spells straight from a Hogwarts classroom.

Rock pool animals have many amazing (and disgusting) tricks up their sleeves. Some are simply fearsome looking like the Devil crab in the photo above. Others have weapons and disguises.

What better way to learn their names than by chanting them spell-style to unleash their freaky abilities?

So, wands at the ready – swish and flick – here are some top spooky rock pool spells.

Sepia officinalis – Invisibility spell

A cuttlefish shows off its camouflage skills in the IFREMER visitor centre, Concarneau, Brittany.
A cuttlefish shows off its camouflage skills in the IFREMER visitor centre, Concarneau, Brittany.

Nothing can hide better than a Common cuttlefish. Sepia officianalis can change colour and texture in an instant to make it invisible to both its predators and its prey.

Marthasterias glacialis – Regrow-an-arm spell

This Spiny starfish (Marthasterias glacialis) is regrowing two of its arms.
This Spiny starfish (Marthasterias glacialis) is regrowing two of its arms.

Many sea creatures like crabs and starfish can re-grow a lost limb. Starfish like this Spiny starfish can regenerate several arms at once, so it’s not uncommon to find one with just a couple of arms and three stumps.

Here’s a spooky story for you… Some say that fishermen in the North Sea used to hack starfish in half when they found them in their nets. Starfish attacked their catch so they were determined to get rid of them. They slaughtered all the starfish they could get their hands on, certain they were reducing the population. Instead, each half of the severed starfish began to regenerate, slowly regrowing its arms. So, every time the fishermen cut one in half, they created two starfish. Soon the area was swarming with starfish.

I’m not convinced this story’s true, but it makes a great Halloween tale!

Berthella plumula – Acid squirting spell

More dangerous than it looks - the Berthella plumula sea slug
More dangerous than it looks – the Berthella plumula sea slug

Lots of sea slugs use poisons from their prey to defend themselves and some produce acid. The Berthella plumula can squirt out sulphuric acid from a special gland when it’s attacked. If you pick one up, it’ll make your skin blister and fall off (so best not to!).

Anemonia viridis – Harpoon stinging spell

The tentacles of the Snakelocks anemone are packed with harpoon-like stinging cells
The tentacles of the Snakelocks anemone are packed with harpoon-like stinging cells

Use this spell to unleash a secret weapon – the nematocysts. All jellyfish, anemones and other related animals have special stinging cells called nematocysts. Inside each cell is a coiled harpoon, which is fired out into anything that touches the tentacles.

Here’s a video of a pool full of Anemonia viridis eating an unfortunate fly.

Lineus longissimus – Smelly slime spell

Part of a Bootlace worm on a rock - if you pick it up you'll get stinky slime on your hands.
A Bootlace worm on a rock – if you pick it up you’ll get stinky slime on your hands.

The bootlace worm is in the Guinness Book of Records as the world’s longest animal. When fully unravelled it often stretches 7 or 8 metres but the longest ever recorded was an incredible 55 metres long. More importantly, though, its special power is giving out a stinky slime. A perfect spell to use against your enemies!

Elysia viridis – Energy-making spell

The photosynthesising sea slug - Elysia viridis, grazing on Codium tomentosum seaweed.
The photosynthesising sea slug – Elysia viridis, grazing on Codium tomentosum seaweed.

Feeling worn out? Try the Elysia viridis spell instead of over-doing the trick-or-treat sweets. This amazing little sea slug retains energy-making chloroplasts from the seaweed it eats. The chloroplasts carry on making food for the slug through photosynthesis, giving the slug an ideal energy boost.

Aplysia punctata – Smoke screen spell

We must have accidentally disturbed a sea hare (Aplysia punctata), making it release a cloud of purple ink.
We must have accidentally disturbed a sea hare (Aplysia punctata), making it release a cloud of purple ink.

Werewolves, zombies and vampires on your tail? Don’t panic – use the smoke screen spell!

Sea hares (Aplysia punctata) may look like dull brown blobs, but they are as strange as rock pool creatures get. Not only do they lay eggs in the form of pink silly-string, but they have the ability to shoot out a cloud of purple ink when attacked, providing a perfect smoke screen.

These are just a few of the bizarre things our rock-pool creatures can do. There’s plenty more rock pool magic to learn.

If you’d like to know more about the gruesome habits of the animals on our shore, have a read of my guide to revolting rockpools. You can also take part in organised events to meet the creatures for yourself. Happy Halloween!

Citizen Science in action with Shoresearch

Every year, the Cornwall Wildlife Trust’s Shoresearch project undertakes the ultimate rockpooling challenge with a week of beach surveys. I’d love to survey all five locations, but Junior has other plans, including a midnight rockpooling session. Watching hermit crabs bombing about the pools at 1am is great fun, but isn’t conducive to being the other side of the county bright and early.

Night-pooling at Hannafore. Many rock pool animals are more active at night.
Night-pooling at Hannafore. Many rock pool animals are more active at night.

We catch up with the indefatigable Matt and Adele from the Cornwall Wildlife Trust on days three and four of their Shoresearch survey marathon. Together with a team of enthusiastic volunteers, we complete a randomised quadrant transect and a general search at Readymoney Cove in Fowey and Hannafore beach in Looe.

Shoresearch crew in action at Readymoney
Shoresearch crew in action at Readymoney

It’s lovely to hang out with like-minded people and whether you’re experienced or completely new to rockpooling, there are always new things to find and learn by exploring the shore in a group.

At Readymoney Cove, we soon discover that there are lots of Common starfish about. These are the classic orange five-armed sea stars that are always represented on children’s seaside books, but are more common in deeper water than on the shore.

Common starfish are less common on the shore than Spiny starfish and Cushion stars.
Common starfish are less common on the shore than Spiny starfish and Cushion stars.

In fact, it’s an echinoderm-rich sort of day, with loads of representatives of this family of animals on the shore. There’s a whole collection of echinoderms together on one rock: a green shore urchin; sea gherkin (a type of sea cucumber); brittle stars and cushion stars.

Sea gherkin - these small sea cucumbers are often found on rocks on the shore. They're related to starfish and urchins.
Sea gherkin – these small sea cucumbers are often found on rocks on the shore. They’re related to starfish and urchins.
A spiny starfish
A spiny starfish

It feels like interrupting a family meeting so I replace the stone and leave them to it.

Later in the day we find another echinoderm, the Kaleidoscope starfish (Asterina phylactica) which is very small and lives among the pink coral weeds in sheltered pools. Its back is covered in colourful circles of orange and white, forming a dark star in its centre. The dots are made by the little pincers (pedicillerae) which the starfish uses to keep its back clean, as you can see in the photo.

Asterina phylactica - the kaleidoscope starfish in a rock pool at Readymoney, Fowey.
Asterina phylactica – the kaleidoscope starfish in a rock pool at Readymoney, Fowey.

Other great finds were numerous Devonshire cup corals.

Devonshire cup coral at Readymoney. This species has a squashed oval shape to the cup and is a pale creamy-yellow colour.
Devonshire cup coral at Readymoney. This species has a squashed oval shape to the cup and is a pale creamy-yellow colour.

When these are underwater they extend their translucent tentacles, but on the shore you tend to only see the calcerous cup shapes.

There were several Devonshire cup corals in this dark overhang
There are several Devonshire cup corals in this dark overhang
This coral was submerged and you can just see some of its tentacles coming out at the bottom. As is often the case it was in an awkward position so I couldn't see to focus!
This coral is submerged and you can just see some of its tentacles coming out at the bottom. As is often the case it is in an awkward position so I can’t focus!

There are several Calvadosia campanulata stalked jellyfish in the pools. They seem to grow large this time of year and are easier to spot as the seaweed begins to die back.

Trying to take a photo of a Calvadosia campanulata stalked jelly, but being photo-bombed by a common prawn!
Trying to take a photo of a Calvadosia campanulata stalked jelly, but being photo-bombed by a common prawn!

After a lot of looking, I finally turn up some sea slugs too. There are several Sea lemons under one rock and next to a coil of spawn I also find a Jorunna tomentosa slug.

Jorunna tomentosa sea slug
Jorunna tomentosa sea slug

On the next day we survey Hannafore, which has a vast are of rocky shore. We spread out looking for interesting creatures and have no problem finding them.

The bizarre-looking echiuran worm Thalassema thalassemum
The bizarre-looking echiuran worm Thalassema thalassemum
Exterminate! Junior loved the shape of this Lamellaria perspicua mollusc - the hollow syphon does look like a gun!
Exterminate! Junior loves the shape of this Lamellaria perspicua mollusc – the hollow syphon does look like a gun!

We spend a lot of time failing to re-find the very rare Lucernaria quadricornis stalked jellyfish which was recorded on this beach a few months back. We do, however, find many other fabulous creatures while we are looking.

Close-up of a Sea lemon sea slug
Close-up of a Sea lemon sea slug
An interesting creature congregation: A Scyon ciliatum sponge (left) and a Candelabrum cocksii (right), which is a hyrozoan animal related to jellyfish and anemones.
An interesting creature congregation: A Scyon ciliatum sponge (left) and a Candelabrum cocksii (right), which is a hyrozoan animal related to jellyfish and anemones.

Junior and I decide to leave a bit early as he’s been wading in deep water and is completely sodden, so we miss the find of the day, a Giant goby.

Shoresearch has been going for a good few years now and is a perfect opportunity to learn about wildlife, contribute to conservation and connect with others. I’m hoping I’ll get to do all five days of Shoresearch Week next year as well as other surveys and events during the year. Perhaps I’ll see you there?

In the meantime here are some more of the week’s finds…

A tortoiseshell limpet (Tectura virginea) living on kelp, Hannafore
A tortoiseshell limpet (Tectura virginea) living on kelp, Hannafore
Tethya aurantium - a 'golf ball' sponge at Hannafore
Tethya aurantium – a ‘golf ball’ sponge at Hannafore
A white Painted top shell (Calliostoma zizyphinum) - usually pink
A white Painted top shell (Calliostoma zizyphinum) – usually pink
Scorpion fish (Taurulus bubalis) - the white barbel at the corner of the mouth is a good way to identify this species.
Scorpion fish (Taurulus bubalis) – the white barbel at the corner of the mouth is a good way to identify this species.

Finally! Portuguese Man O’ War in Looe

I’m always pleased to hear about interesting things other people have found around Cornwall especially from readers of this blog. I’ve been more than a touch jealous these last few weeks, however, of all the people finding Portuguese man o’war. They turn up occasionally in Cornwall but I’ve never seen one before and I feel like I’m missing my chance.

According to other people’s messages, Portuguese man o’war are everywhere and have been for weeks, covering strand lines, floating in pools, strewn on rocks everywhere from Penzance to Wales. And for weeks I’ve been searching and searching my local beaches and finding none. Until today.

It’s low tide and there are posts bouncing around social media saying that there are Portuguese man o’war around Looe. I have a house to clean, scones to make and blogs to write, so of course I drop everything and drag my other half and Junior to Hannafore beach.

I know they’ll be lifted off with each tide and battered and probably blown away with the next storm, so I’m not going to let this opportunity pass. Junior thinks I’ve gone mad though. He knows how powerful their sting is and insists, at first, that he’s not going near one.

His reluctance evaporates within a minute of arriving at the beach, when I find the first one. We all huddle round. The colours take me by surprise. In photos they always look a striking blue, but in real life they’re iridescent and seem to glow in the sun.

My first Portuguese man o'war
My first Portuguese man o’war

Continue reading Finally! Portuguese Man O’ War in Looe

A close (enough) encounter with Weever fish.

We’re on a stomp about the beaches between Looe and Seaton, enjoying a patch of sunshine.  “Watch out for Portuguese Man O’War jellies,” I warn Junior as we cross the muddy sand at Millendreath. I know there have been reports of them washing up all around the south west coast over the last few weeks, but there are none today. Inevitably, it’s something else that nearly gets me.

In a sandy pool at the sea’s edge, a flicker of movement catches my eye. It happens so quickly I can’t be sure there’s anything there but the sand is settling, suggesting something has just buried itself.

I call Junior over to look and I crouch low, reaching a hand to the water’s surface. If I can scoop the sand up from underneath I might be able to gently lift out the creature. Having seen plenty of well-camouflaged dragonets scooting about the pools today, I expect this to be another one. I stop short and stare into the shimmering pool.

Dragonets, especially the females, are perfectly camouflaged on sand.
Dragonets, especially the females, are perfectly camouflaged on sand.

It’s a good call. You never know what might be lurking in the rock pools. Near where I saw the movement is a sandy coloured lump. I think I recognise the shape, but it’s only when I lower my camera into the water and zoom right in that I can be sure. A Lesser weever-fish is staring down my lens, its frog-mouth gaping slightly, the rest of its body buried in the sand. Before I can take a shot it’s gone. Continue reading A close (enough) encounter with Weever fish.

Giants of the Cornish rock pools

Last week I shared with you the miniature world of the sea slugs, so this week I’ll super-size things and bring you some big fish. Silly-season reports of Great-white sharks often hit the headlines in Cornwall, but I prefer rock-pool giants; they’re not made up, and you can get close to them without having your leg bitten off!

Cornwall is brilliant in all sorts of ways, our network of local, grassroots marine conservation groups being just one of them. The public launch, last week, of the new Three Bays Wildlife Group brought experts and volunteers together and gave me a chance to explore some new beaches in the St Austell area.

Judging by the squeals of excitement from the children and adults alike, the crabs, pipefish, prawns and anemones we found at the main rockpool ramble on Portmellon beach near Mevagissey went down well. By the end of the day, the local group had recruited lots of potential new volunteers.

Green shore urchin at Portmellon beach - adorned in seaweed
Green shore urchin adorned in seaweed. Portmellon beach.

Continue reading Giants of the Cornish rock pools