collect yer own!
if you get down to the black middens on a very low tide you can get to the big uns, bigger than you\'ll see in the shops. Nobody collects them down there, which is not to suprising, don\'t think I\'d want to eat them.
good crabbing spot while your there
not sure about clammydos, not heard them but they might
be the same as piddocks
http://www.geocities.com/slongrigg/pholas.html
they can be 6\" long and the mollusc in side is fairly tough, so good for the hook.
there\'s
loads on the west coast of scotland, commoner than mussels in places, but I have found them at low tide on druridge bay
bizzarre thing about the piddock is the they are bioluminescent - there\'s a part of the mollusc that glows in the dark!
Tracey pointed these out me years ago - shes an avid shell collector. They seem to work well in cocktails with other baits, and because they are so big, just one can be enough on a hook