As Roy said... Burbot and the common Ling are two different fish. Burbot is also know as a Lawyer.. not sure if that has anything to do with the slim or not (sorry Marty!) Burbot is the only member of it's, Lota, family and is a freshwater fish that is cod LIKE.. not a family member. The Common Ling is a member of the cod family and is an ocean fish.
So kinda like that Walleye/Pickeral deal. We all call them Ling.. but they are really Burbot ! People call them lots of things besides UGLY !! Lota lota or Ling, Eelpout, Loche, Freshwater Cod, Maria, Methy, Lush, Lawyer
Other common names include: American Burbot, Cusk, Dogfish, Eelpout, Freshwater Cod, Freshwater Codfish, Freshwater Crusk, Gudgeon, Lawyer, Ling, Lingcod, Loche, Lush (Alaska), Maria, Methy, Mother Eel, Mud Blower, Spineless Catfish, Lake (Swe)
(google is your friend ! LOL)