Scrub mussels (or clams), add to stew and simmer covered. Once mussels open up, transfer with tongs or slotted spoon to empty dish (discard any clams unopened after 10 min). Season other seafood, add to stew, and simmer covered until cooked through, approx 5 min. Discard bay leaves and return mussels back to pot.
Stir in basil and lemon juice. Serve with sourdough or foccacia.