Quite a large number of these little crabs found around the rocks, along with other types I am more familiar with.
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Lovely shots dl3993.
Amazingly clean - our water is as clean as yours but you must have little muddy sediments. See mine http://www.ispot.org.uk/node/330644
Lat/Lng: 50.61816, -2.24971
OS grid ref: SY824798