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).
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 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.
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
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.
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.
Here are some of our other favourites from this expedition:
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.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. This one’s in typical abseiling position.
This week the spring tides are huge, which means perfect rockpooling conditions all around Cornwall. Yesterday’s ‘storm without a name’ passed just in time and today the sun shone, so I dusted off my waders and followed the tide out to see what it would reveal. Answer: lobsters, baby sharks and a whole lot more.
I was hoping to re-discover an overhang packed with jewel anemones at the far end of the beach that I’d come across once before, but couldn’t resist taking a look at the wildlife on the way. You know it’s going to be a good day when the first stone you lift is unexpectedly awesome. This one was hiding a troop of hermit crabs, a rock goby and a beautifully camouflaged scorpion fish.(more…)
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.(more…)
I did my first Facebook challenge this week: #challengeonnaturephotography. One nature photo a day for a week.
I normally operate a ‘just say no/ pretend I haven’t seen it’ policy when it comes to nominations for social media challenges, but this one caught my eye. It was hard to know what to choose, but, of course, I majored on photos of the Cornish rock pools.
Given how much I squirm when I’m nominated for anything, I haven’t tagged anyone to carry on the challenge. But, if you’d like to share photos of wild things and places you love with your friends, please do take it up.
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.
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. (more…)
Rockpooling in stormy winter weather can be a risky business here in Cornwall, so my advice is … don’t. At best you get blown over on the slippery rocks and soaked by rain that seems to come in horizontally and go right up your nose. At worst you could end up in the path of the fierce waves and currents. It’s not worth it.
When there’s a calm moment and a good tide (I’m hoping tomorrow will be such a day), there’s plenty to see in the rockpools. Between times, stick to the strandline, where the sea throws up all sorts of treasures and unexpected visitors.
Mauve stinger jellyfish (Pelagia noctiluca) at Mawgan Porth
One of my favourites this year was the swarm of mauve stinger jellyfish (Pelagia noctiluca). They look small and inoffensive, measuring up to 10cm across their bell. The spotted pattern that gives them their name is distinctive and rather pretty. They can also glow in the dark – noctiluca means night light. (more…)
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.
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.
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
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.
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.
Autumn is a time of great change in the Cornish rock pools, but on the surface this could be mid-summer. The water is warm, the sun is blazing and an immense low tide is beckoning. I accompany a group of under-fives and their parents as they set out to investigate.
On land, the yellow tinge of autumn is only just creeping across the woods, but in the rock pools, the seaweeds have already died back. The invasive Japanese wireweed (Sargassum muticum) that clogs the pools all summer with long tresses like knotted hair all summer has thinned away, making it easier to see into the water.
A daisy anemone in clear water
There are many species that visit the shore in spring and summer to breed and some of these are long gone, but there’s still plenty to see. I was surprised to find a worm pipefish (Nerophys lumbriciformis) with eggs this late in the year. The pipefish are closely related to the seahorses, so it is the male that carries the eggs in a special groove on his belly. (more…)
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.
Privacy & Cookies: This site uses cookies. By continuing to use this website, you agree to their use. To find out more, including how to control cookies, see here: Privacy and Cookies Policy.
Cornish Rock Pools 