Nippers

Today's Guardian Country Diary is about the return of marine life to the Durham coast at Dawdon, where coal mining waste was dumped onto the beach until Dawdon colliery was closed in 1991. An underwater survey by divers at that time found half a metre of coal silt on the sea floor at Noses Point (in the background of this photo) and water that was so turbid that it was impossible to see any marine life.

Since then the Turning the Tide campaign has cleaned up the beaches, to the point where this beach was recently described in the Guardian as one of the best lesser-known National Trust beaches in the UK 

Click here for more pictures and information about the restored coastline here.

Meanwhile the waves have done their work offshore, washing away the coal spoil, so now it's a beach where you can go rock-pooling again. We found this shore crab amongst the rocks near Noses Point. The pointed abdomen under its body indicates that it's a male.

Catching a shore crab took me back to childhood rock-pooling days, and learning to pick up an angry crab between finger and thumb on either side of the shell. That armoured carapace protects the crab from predators but prevents it reaching above its shell with those powerful nippers. This method of holding them works well with shore crabs but from painful experience I've learned that this is less successful with velvet swimming crabs whose nippers seem to be better articulated and can reach back to deliver a very strong pinch. 

A spot of rock-pooling

Mid-day low tide so went rock-pooling today at Whitburn rocks, Sunderland. It's not exactly the Great Barrier Reef but you can usually find something interesting.

Who can resist turning over rocks on the seashore? This shanny (?) Lipophrys pholis was under one in the middle shore and wriggled out of the water when disturbed.

Lots of young edible crabs, that adopt this characteristic pose when you pick them up by their crimped-pie-crust carapaces

This one was tiny, smaller than my thumbnail, and judging by its colour had recently moulted.

The rock pools were full of hermit crabs, with their jerky walk that makes them look like automata.

I think this is a very young shore crab, half-hidden in the wet sand under a rock, and .....

....... this is a larger one, very disgruntled and in defensive pose.

This was probably the most interesting find - a grey topshell that had recently spawned - you can see the developing embryos in the jelly, from which they'll hatch and enjoy a brief period as planktonic larvae.

Beachcombing

There are few more pleasant ways to idle away an afternoon than to indulge in a spot of beachcombing, discovering what the falling tide has left behind, and when we arrived at Warkworth beach last Saturday lunchtime the tide had just turned, leaving a trail of marine artefacts, like the crimped pie-crust carapace of this edible crab .....

... and the saw-toothed carapace of a shore crab.

Recent rough seas had scoured the sand and cast up thousands of these sand mason worms, with their tubes constructed from grains of sand ....

... but this dog whelk, with its tough, thick shell may have been rolling around in the surf for weeks.

This is a mollusc that doesn't belong on the shore at all - it's a grove or brown-lipped snail Cepaea nemoralis, which is an air-breathing species that lives amongst the marram grass on the sand dunes behind the beach. Maybe a bird caught it and dropped it on the beach, or it might have been dislodged when a spring tide eroded the edge of the dune. This species comes in a variety of background colours and banding patterns, but many on the dunes here are either pure yellow or sometimes pink.

 

This is the delicate mauve interior of the rayed trough shell, which is decorated with markings ....

..... like the rays of the setting sun on its outer surface.

Banded wedge shells come in a range of colours, including brown and purple, but the pure yellow ones are particularly attractive.  

The star find was this tower or auger shell, Turritella communis. It's common enough around much of Britain, especially on the west coast, but this is the first time that I've found it here in thirty years of walking along this beach.

And finally, a modern archaeological curiosity - a clay pipe. I wonder who lost this, and how long ago - maybe a fisherman who dropped it overboard? Whoever it belonged to, it must have remained buried in the sand until a convergence of rough weather and high tide scoured it out and left it on the tide line.

For more beachcombing on Warkworth beach, visit

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