Melt butter in a Dutch oven over medium heat. Add chopped onion, and sauté for 5 minutes. Sprinkle onion mixture with celery salt. Stir in flour, and cook for 1 minute, stirring constantly. Gradually add clam juice. Bring mixture to a boil, and cook for 1 minute or until thick, stirring constantly. Add potato cubes and carrot slices, and stir in milk. Bring to a boil; reduce heat, and simmer for 10 minutes. Break Maple-Glazed Roasted Salmon into chunks; add salmon, chopped dill, and Worcestershire sauce to pan. Bring chowder to a boil; reduce heat, and simmer for 10 minutes or until potato is tender.