Crabs are one of the deadliest baits for sea fishing but they must be in the right state,during the summer months crabs molt in other words cast off their shells,they have to do this in order to grow,when they,re in this state they,re called peelers and are deadly for catching fish, they just seem to go nuts for them.When looking for peelers look at the back of the crab along the back where a seam can be seen,if its a peeler it,ll look as if the top shell is coming away from the bottom,another way is if you squeeze the crab and if bubbles appear along the seams of the body it usually means the crab is getting ready to molt as they pump water under their shells to aid the casting of the shell.To use them just peel off all of the shell from the crab and you,ll be left with a soft crab full of juices that sends the fish wild and begging to jump on your hook.Sometimes when looking under rocks during the summer you,ll find a crab thats soft to the touch, not hard like a normal crab, these are crabs that have cast their shells and are hidding out of the way waiting until the calcium in their skin to solidify thus making a new hard shell,these are known as softies,they,re not as effective as peelers but do the job anyway.
In Britain it is illegal to use Brown(edible)peeler crabs in certain areas of the country, one guy has already been heavily fined for using Brown peeler in a competition,so steer clear of Browns.
So if your out bushcrafting on the coast and come across a peeler don,t pass it by,use it because its a superior bait to all the others and it just might get you a meal a lot quicker than conventional baits,and its easily gathered thus saving energy.