In a dutch oven or large pot, melt butter over medium heat. Add celery, leek, and fennel and cook about 5 minutes or until tender but not browned. Add thyme, bay leaves, salt and fennel seeds and cook, stirring, for another minute.
Add potatoes, stock, and tomato juice and bring to a boil. Reduce heat and simmer until potatoes are tender, about 15 minutes. Remove from heat and stir in salmon (breaking into chunkand cream. Heat on medium low until soup is hot but not boiling. Remove bay leaves.