Bustling trade and loudmouthed fisherman used to be fixtures at the South Street Seaport. But in 2005, the Fulton Street Fish Market moved to the Bronx, taking its rough-and-tumble culture with it. This Sunday, New Amsterdam Market hopes to revive the seafood scene in lower Manhattan with its second Gathering of Fisheries event. Fishermen and purveyors will bring in fresh, local seafood and teach people about cutting, cleaning and cooking fish.