Heat oil in a 6 qt. pot over medium-low heat; sauté onion and garlic for 5-6 min. until tender, adjusting heat down as needed to prevent garlic from browning. Add next 10 ingredients through black pepper; bring to a boil. Add mussels and cook until they open wide (about 7 min.). Discard unopened mussels and bay leaf; add fish and shrimp. Reduce heat to a high simmer; cook until fish and shrimp are opaque (about 4 min.), stirring often. Serve with hunks of bread for dipping.