In a Dutch oven with a thick bottom, heat olive oil until smoking. Add onion, celery, carrots and garlic and cook until softened and light brown. Add white wine, tomato sauce and bring to a boil. Add fish, cover and bring to a boil. Lower heat and simmer 25 minutes. Check for seasoning with salt and pepper and adjust with water if too thick. Add parsley and stir through. Grill bread and place on bottom of each of 4 bowls. Divide soup among 4 bowls and serve.