To judge by the number of boats landing their catches the floor of the North Sea must be covered in crabs. In ten minutes I saw four boats landing their crates and this one was just coming into harbour.
The main crab caught is the Brown Crab (Cancer Pagurus) the most commercially important species of crab in the U.K.
To catch 'em you'll need some bait, of course, some juicy looking salmon or trout heads will do nicely.
A few of these wouldn't come amiss
Load it up then you're ready to go.