You could use a milk crate. Stone crabs are not a swimming crab, so you could just pull it up a couple times a day, and if there was any in it, they would just sit there (instead of trying to escape).
I caught a bunch of dungeoness crabs in Washington with this method. You need to put something heavy in the milk crate to sink it (a rock). I would put them in a holding pen (two milk crates ziptied together) until you had enough to deal with. :whistling: