The oil spill in the Gulf cast an uncomfortable pall over Jazz Fest last month. As the spill makes landfall and expands, it threatens to cast an even greater shadow over the Louisiana Seafood Festival, a weekend-long event celebrating the fishing communities that collectively produce nearly a third of all American seafood. The event is part of the June weekend known as the Vieux-to-Do, when the U.S. Mint and the French Market host the Creole Tomato Festival and the Louisiana Cajun-Zydeco Fest...