Fish Stew

Ingredients

• 4 cups clam juice or fish stock (or the bones of one large, mild-flavored fish plus 4 cups water)
• 1/2 cup dry white wine
• 1 bay leaf
• 1 fresh thyme sprig
• 1 fresh italian parsley sprig
• 5 whole black peppercorns
• 1 (28-ounce) can whole peeled tomatoes
• 3 tablespoons olive oil
• 2 medium leeks, halved lengthwise and cut into 1/2-inch pieces (white and light green parts only)
• 1 medium fennel bulb, outside layer discarded, cored, and cut into medium dice
• 2 medium garlic cloves, minced
• kosher salt
• freshly ground black pepper
• 1/2 cup dry white wine
• 1 pound littleneck clams, scrubbed and soaked in several changes of cold water
• 2 pounds mixed white mild-flavored fish fillets (such as cod, halibut, or grouper), skin on or off, cut into 2-inch pieces
• 2 tablespoons coarsely chopped fresh chervil or tarragon leaves
• 2 tablespoons coarsely chopped fresh italian parsley leaves
• 1 cup aioli (optional)
• crusty french baguette, for serving