PORTLAND, Maine — The harvest of soft-shell clams continues to dwindle in New England, where the shellfish are embedded in the culture as much as the tidal muck.Soft-shell clams are also called "steamers" or "longnecks" and they are one of the northeastern U.S.'s most beloved seafood items. But the nationwide harvest fell to a little less than 2.8 million pounds in 2016, the lowest total since 2000.