Cherrystones, topnecks and chowders are all names for hardshell clams that reflect their size? Topnecks are the third smallest of all hardshell varieties, and are young and tender. Cherrystone clams are five to six years old, while large chowder clams can be as much as 30 years old! Clams are harvested by hydraulic dredges, hand rakes and scissorlike tongs, then sold live in bags. While they can be found from the Gulf of Mexico to the Canadian Maritimes, the majority of the U.S. clam harvest is taken between Florida and Massachusetts.