Category Archives: Rock pooling tips

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!

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Top 5 Fierce(ish) Rockpool Creatures

As you might imagine, we’re fans of nature documentaries in this house and we’re all looking forward to watching Steve Backshall’s new series, Fierce. It’s got me and Cornish Rockpools Junior thinking about opportunities to meet ‘fierce’ wild creatures closer to home.

Of course, these animals aren’t exactly fierce, they’re just equipped to survive the evolutionary arms race with attitudes, weapons and chemicals that aren’t very human-friendly.

You don’t need a plane, a film crew and a ton of equipment to seek out an encounter with a well-armed rockpool ninja. This weekend’s massive low tides are the perfect opportunity to head out onto the shore and check out our top 5 fierce(ish) rockpool creatures.

So, check the tide times, grab a bucket, put on your wellies and take a look…

5. Small spotted catshark

Scyliorhinus canicula - small spotted catshark or dogfish stranded in a Cornish rock pool
Scyliorhinus canicula – small spotted catshark, also known as dogfish – stranded in a Cornish rock pool

These small sharks, often known as dogfish, sometimes become stranded in pools during the very lowest of tides. They’re not at all aggressive, but it’ll sound impressive that you’ve met one. They have incredibly rough skin that used to be used as sandpaper. In some places you can also find their egg cases and those of their larger cousin, the nursehound, attached to seaweed. They take around 7-9 months to hatch out so never detach the egg case from the weed.

The developing greater spotted catshark can be seen at the bottom of the eggcase
The developing greater spotted catshark can be seen at the bottom of this eggcase

4. Snakelocks anemone

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 are being picked up by the current

This anemone is common in rockpools all around Cornwall. It’s easy to see how it gets its name from its long snake-like tentacles, which are usually green with purple tips, but sometimes a dull-brown. They’re from the same family as jellyfish and have stinging cells which shoot poisonous harpoons into anything that touches their tentacles. It’s best not to touch this anemone as some people have a reaction to the sting. If you do touch one be sure not to rub your eyes because stinging cells can attach to your skin – wash your hands as soon as you can.

Cornish Rock Pools Junior is convinced snakelocks anemones can eat your foot. That’s unlikely, but watch what they do to this fly…

3. Worms

Worms are often buried in sand and mud burrows - if disturbed they can shoot out their jaws and give a nasty nip.
Worms like this ragworm are often buried in sand and mud burrows – if disturbed they can shoot out their jaws and give a nasty nip.

An unlikely contender, but there are several species of worm on the shore that can be pretty fearsome, especially the larger ragworms. These animals have an extendible jaw that can shoot out and deliver a painful bite. Others, like the bootlace worm secrete a toxic mucus. Handle with care!

Other finds... a bootlace worm. These worms are many metres long when fully extended, but are usually found in a tangled ball like this.
A bootlace worm. These worms are many metres long when fully extended, but are usually found in a tangled ball like this.

2. Compass jellyfish

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

Like the anemone, this jellyfish is armed with lots of nematocysts (stinging cells), but far more powerful. These jellies with their distinctive V-shape compass markings can give you a painful sting. Jellyfish don’t live in the rockpools but are often washed in by the winds and tides, especially in the summer and autumn months. They’re beautiful creatures and well worth a look, but remember not to get close or to put your hands in the water – their tentacles can be hard to see, very long and can become detatched from the main jellyfish, so it’s not worth the risk (yes, that’s talking from experience… I’m a slow learner). There are lots of different species of jellyfish and some, including the massive barrel jellyfish, are harmless, but if you’re not sure, stay clear!

Jellyfish tentacles can be hard to see, so be careful not to put your hands in a pool that has a jellyfish in it (e.g. to take underwater photos of tentacles like this one!)
Jellyfish tentacles can be hard to see. It’s best not to put your hands in a pool that has a jellyfish in it (e.g. to take underwater photos of tentacles like this one!)

1. Devil crab (Velvet Swimming Crab)

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A velvet swimming crab (devil crab) shows off its red eyes.

The top fierce creature award, as voted by Cornish Rock Pools Junior who will not go near them, is [insert fanfare of your choice here]… the velvet swimming crab. This crab, known by Junior and many others who’ve met it as the ‘devil crab’, is afraid of nothing and is always quick to use its pincers. Their dark shells and gleaming red eyes give these crabs a sinister look to match their temperament. They’re brilliantly suited to hunting in the rockpools and shallow seas. If you dare to look closely at one (see ‘How to pick up a crab’), you’ll see that their stripy back legs are flattened into paddles, making them excellent swimmers. Watch out for them lurking buried in the sand, with only those red eyes showing.

As soon as you approach a velvet swimming crab will stand on its back legs, its claws raised, ready for action.
As soon as you approach a velvet swimming crab will stand on its back legs, its claws raised, ready for battle.

There are plenty more dangerous creatures, such as the weever fish and the Portuguese man o’ war, that didn’t make our list because we so rarely see them in the rock pools.

It almost goes without saying that by far the most dangerous creature on the shore is us humans. Marine litter, warming seas, pollutants, overfishing and habitat destruction all threaten our amazing marine life. Please do your bit every time you visit the shore:

  • If you turn any rocks replace them gently, the right way up.
  • Avoid using nets that can harm creatures and tread carefully.
  • If you catch any creatures, keep them in plenty of sea water and return them quickly to where you found them.
  • Don’t leave any litter behind and be aware that sun cream isn’t good for wildlife.
  • Every time you visit a beach take 2 minutes to pick up any rubbish you see.

Have fun and please do let me know what creatures you meet (fierce or otherwise) in the Cornish rock pools.

Warm in Waders -a chilly beach adventure

Have I mentioned that I don’t like the cold? Well I don’t, and worse than that I don’t function well in it; my fingers seize up, my brain goes fuzzy and my grumpiness level soars. Not ideal when I’ve agreed to meet up with a small army of children on a freezing, windswept beach. Fortunately I’m prepared and have no shame. 

Full thermals + three layers of jumpers + coat + scarf + green waders equals = a toasty-warm fashion disaster. 

Junior’s still young enough not to notice or care about anything except whether I’ve brought his enormous metal spade. The other kids don’t seem worried either as I waddle over to them. They call me ‘the shark lady’. I think they mean that in a good way. 

It’s amazing how fast children learn. A few minutes after he’s shown his first catshark egg case, a friend’s child is spotting them everywhere, his sharp eyes picking them out faster than me. We’ve soon clocked a couple of dozen of them. The parents find some too.

Mandy's catshark egg case. Hannafore, Looe
Mandy’s Greater spotted catshark egg case. Hannafore, Looe

Continue reading Warm in Waders -a chilly beach adventure

A rockpooling warm-up

You might not think that rockpooling is the sort of activity that requires a warm up, but there’s nothing like practice for getting your ‘eye in’. The more and closer you look, the more you’ll see. What better excuse to get out on Cornwall’s beaches before, during and after this week’s massive tides?

I’ve been out on a few family rambles on the local shores the last couple of weeks to make sure I’m ready for some serious rockpooling this weekend (like most weeks, but they don’t complain).

If you’re wondering what you might see if you head down to the shore in the next few days, here are some of the things I’ve been finding…

Go slowly and look closely - this little ring of jelly contains thousands of eggs from a sea lemon (a type of slug).
Go slowly and look closely – this little ring of jelly contains thousands of eggs from a sea lemon (a type of slug).

Continue reading A rockpooling warm-up

Egg hunting in the Cornish Rock Pools

It may seem too early in the year for rock pooling, but this is an exciting time of year on the shore. Spring has arrived in the Cornish rock pools and the huge clutch of eggs under the tail of a female green shore crab proves it.

Eggs come in all sorts of forms in the rock pools. Why not get out for your own ‘egg hunt’ on the shore this Easter?

Here’s my quick guide to some of the common types of egg you might see. Continue reading Egg hunting in the Cornish Rock Pools

A guided rockpooling tour

We all love spending time with likeminded people, don’t we? So, when a keen diver from Newquay contacts me to request a guided rockpooling tour, I can’t resist. Unusually for a bank holiday weekend, the sun pushes the clouds away and leaves behind a perfect, calm shore ready for us to explore.

We’ve barely known each other a minute before we’re enthusing about the joys of going slowly and taking the time to look for underwater life. We discover our shared love of nudibranchs (sea slugs – read on, they’re lovely, really!). I assure my new friend that we’ll find plenty of wildlife, including some species few divers ever see, and all with minimum kit, no buoyancy control and a limitless supply of air.

The underside of a painted top shell showing the mother-of-pearl lining
The underside of a painted top shell showing the mother-of-pearl lining

Despite being familiar with edible crabs and velvet swimming crabs from diving, there are several species of intertidal crabs that are new to my guest. Continue reading A guided rockpooling tour

Searching for Starfish

We’ve been planning this trip since our visitors first came to Cornwall a year ago. They’re determined to try rock pooling having missed out last time. This week the tides are perfect. They live near the sea back home in Essex, but they tell me it’s not the same and I can well believe it.

They’ve never seen a starfish in the wild before. My mission is clear.

Getting stuck in to Cornish rock pooling
Getting stuck in to Cornish rock pooling

With picnic and buckets in hand, we set out, treading gingerly over seaweed and searching among the rocks. Within minutes, our friends are putting yesterday’s hasty tutorial on crabs into practice as they try picking them up safely. They score top marks on this and on working out whether the crabs are male or female from the shape of their tails. We find several species of crustacean, including this large squat lobster.

A squat lobster - galathea squamifera
A squat lobster – galathea squamifera

While our visitors search the shallow pools, finding anemones, fish, prawns and hermit crabs, Other Half and I walk out through slippery gullies towards the sea with Junior, taking photos and collecting interesting creatures for our visitors to see. I find a small rock with a beautiful covering of star ascidian. Continue reading Searching for Starfish