Yes I try to use crabs all the time is I can for both blue water and creeks. I find that I catch cods, jacks, and bream on ghost and other types of crabs. I like to use ghost crabs in my berley to.
As for the blue water I find they are the best bait for blueys and parrot by a long shot. I know a guy who uses half mud crabs for bait and catches huge fish.
As for rigging them up I put the hook throught the bottom leg and into the carpace where it seems to fit nicely. Or through the bottom of the carpace and out the other side. Some people like to remove all the legs but I prefer to leave them on.
All in all I find they are bloody good bait
Devocean