Sprinkle flour over bottom of heavy large pot. Stir flour constantly over medium-low heat until flour turns golden grown (do not allow to burn), about 15 minutes. Pour browned flour into bowl.
Heat oil in same pot over medium heat. Add onion and bell pepper and sautÃ© until tender, about 7 minutes. Add garlic, thyme and bay leaf; stir 1 minute. Add sausages and sautÃ© until brown, breaking up with back of spoon, about 5 minutes, then add browned flour. Add tomatoes with juices, broth and Creole seasoning. Bring to boil. Reduce heat, cover and simmer 20 minutes to blend flavors, stirring frequently.
Add shrimp and whitefish to pot and simmer just until seafood is opaque in center, about 5 minutes. Discard bay leaf. Season with salt and pepper and serve.