Yes there brown growth when they live in Mud mostly in the creeks and rivers like the Navisink up in red bank. that made for a good read. If you ever get a chance to got to Christville MD its a crab mecca. I was there for a week end and luck out with a tour of one of the Plants, I saw the Boats The Cookers the pickers and machines that finish them off. then what looked like a Jail it was the shredder tables behind barbed wire and locked gates each crabber had their own section, god forbid poaching, The festival they have is a no miss but rooms are in short supply. look up the area about the out Islands a lot of history and all. Bill