A Masked Crab at Studland

A Masked Crab waiting for the tide to come in

I saw a little Masked Crab (Corystes cassivelaunus Pennant) on Knoll Beach at Studland the other day. It was an unusual sighting for that location. The crab was alive – but lucky to be so. It had buried itself in the wet sand to survive the rigours of exposure at low tide. There are not many other places for an animal to hide on this part of the beach.

The small crab, only a couple of inches long, would probably have stayed out of view until the tide came in again – except that this was the afternoon that several schools decided that it was just the right moment for the students to run on the beach while the sun was shining. The youngsters pounded their way along the shore and one of them stepped on the very spot where the crab was sheltering. Being disturbed by this close encounter, it surfaced, all covered in wet sand, as I walked past it and eastwards in the direction of Shell Bay.

I was surprised to see this same little seashore creature again as I made my way back along the water’s edge going westwards. I know it was the same crab because it was almost the only live thing I found, and certainly the most interesting. It was one of those days when there was not much at all newly washed ashore: a few fresh clumps of spindly red seaweed, some brown Sea Oak and strands of kelp, a few pieces of translucent green Sea Lettuce, and some clusters of Slipper Limpets. Lots of empty bivalve shells.

On this second meeting with the Masked Crab, the creature was more active and had got rid of the sand which had been covering it before. It was waiting for the waves. I have seen this activity previously in Masked Crabs on Rhossili Beach on the Gower Peninsula. The animal sits facing the sea, using its legs to brace itself against the oncoming water. Its two fringed antennae can be joined together to form a single tube and this was projecting forwards and upwards – looking very much like an angler holding a fishing rod. It was fascinating to watch the way to crab parted and then joined the antennae, moving them side to side as if using them to gauge the speed and timing of the next wave. The antennae form a breathing tube when the crab is buried.

I took a few photographs of the Masked Crab and some short video clips which you can see below. I hope that you will appreciate that it was a bit difficult to film the crab in action because of its small size and the necessity for recording it in such a low position – plus the imminent drenching of both the crab, the camera, and the photographer.


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Sea Foam & Stormy Sea at Rhossili (3)

Moving natural patterns of sea foam being driven by high winds across a low tide sandy beach at Rhossili on the Gower Peninsula in South Wales during Christmas week 2013.

Sea Foam & Stormy Sea at Rhossili (2)

More sea-foam from Rhossili Beach during Christmas week.

N.B. I did have a folded cloth held tight over the microphone during the filming – so you can imagine just how deafening was the roar of the sea and the wind at the time.

Sea Foam & Stormy Sea at Rhossili

Watching sea foam generated by storm force winds on Rhossili Beach, I had to make a run for it!

Moon Jellyfish Swimming 1

Moon Jellyfish (Aurelia aurita Linnaeus) swimming near the surface in a boat marina at Charlottestown, Prince Edward Island, Canada.

Castor canadensis at Montreal Biodome

Cute crittur!

Mumbles Tidepool Fish

Lots of small iridescent fish in a rock pool

I am not very familiar with fish identification but I think that these pretty little iridescent fish are possibly Sandeels. They were swimming in a shallow rock pool left by the retreating tide on the seashore at Mumbles on the Gower peninsula in South Wales.

I used the most excellent A Field Guide to the Marine Fishes of Wales and Adjacent Waters by Paul Kay and Frances Dipper (2009) produced for The Marine Conservation Society by Marine Wildlife, ISBN 978-0-9562048-0-6.

Lots of small iridescent fish in a rock pool


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View from the Wheat Field

From the path through the ripening wheat, a vista opens across the valley to fields being harvested on the hills of the other side.


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Out on Worms Head Causeway 1

This video clip shows what it is like on the far side of the Worms Head Causeway in Gower at low spring tide on a sunny day, showing tide pools and rock gullies with running water.

Click here for more information about Gullies on Worms Head Causeway


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Live Sea Urchin at Port Eynon: video clip

I have talked about and photographed, the Sea Potato sea urchins – Echinocardium cordatum Pennant – that live on the shores of the Gower Peninsula in earlier postings. This is the first time I have been able to capture one in a short video clip, very much alive and actively moving its spines, with two of the small pink bivalved molluscs (Tellimya ferruginosa Montagu) that live commensally in the burrow of the urchin still in position  among the spines at the rear end of the animal near the anus.

For more information about the Sea Potato and other urchins click the links below to earlier postings on Jessica’s Nature Blog:

Living ‘Sea Potato’ sea urchin from Port Eynon

Sea Potatoes from Gower

Sea Potato sea urchin shell

Live ‘Sea Potato’ sea urchin emerging from its burrow

Tube feet on starfish & sea urchins

Green sea urchin on Worms Head Causeway


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