This dog was walking by herself. I did not see the owner, s/he most likely walked past me just before but I didn’t notice.

She looks so proud of herself. According to the Vancouver by-laws she must be on the leash. The Vancouver by-law states:

Female dog carrying her own leash when walking on the seawall: Vancouver, BC

Carrying her own leash when walking on the seawall: Vancouver, BC

A person who keeps a dog must not permit, suffer, or allow the dog to be on a street or other public place unless the dog is under the immediate charge and control of a competent person by means of a leash that is not more than 2.5 m long or another by - law allows the dog to be off - leash under certain circumstances.

I would say that she qualifies. She is under control and the leash is under 2.5m/8½ft.