Feb 18/15-The Jazz Aviation LP (DBA Air Canada Express) Bombardier CL-600-2B19 (CRJ), C-FDJA, was operating as flight JZA517 from Winnipeg (CYWG) to Edmonton (CYEG). After arrival, the flight crew became aware of the missing left main landing gear door. The crew did not experience any abnormalities during flight. Initial maintenance inspections revealed no further damage to the aircraft. The Yellowknife (CYZF) Airport Authority located what appears to be a CRJ gear door adjacent to a runway. C-FDJA operated through CYZF on 18 February 2015.