Blue Crab Not So Blue

Type: Tidal
Region: Southern
Location: West/Rhode River

Caught this one Tuesday night! Is this a normal thing? Just wondering First time ever catching one looking like that!

DNR Response: The crab in your picture has Chitinoclastic disease which is commonly called Brown Spot or Burn Spot disease due to the unsightly legions on the shell. This condition is fairly common and is caused by a type of bacteria that attacks a compound found in the shell called chitin. There is not known to be any harmful effects to humans from consuming these crabs, although the disease certainly makes them look unappetizing.