The Soft-Shell Clam Mya arenaria: Biology, Fisheries, and Mariculture

Chapter 15: Soft-Shell Clam Mya arenaria Mariculture: History and Culture Techniques

Brian F. Beal


This chapter focuses on the history of farming soft-shell clams Mya arenaria as well as methods to rear clams through larval and juvenile stages to adults. Clam farming had its earliest origins in the late 1800s, when selectmen in Essex, Massachusetts leased intertidal parcels up to an acre in size to individuals who transplanted wild clams too small to sell from high-density areas onto their lease. While that and subsequent attempts at private clam mariculture in the northeast USA were thwarted for nearly a century by the lack of any legal resolve to curb poaching, it did not stop commissioners in states such as Rhode Island (Inland Fisheries), Massachusetts (Fisheries and Game), and Maine (Sea and Shore Fisheries) from trying. Each recognized that clam farming was a means to counter declines of wild stocks due to a combination of overharvesting and the vagaries associated with successful annual sets of 0-year-class clams. Without scientific investigation, however, the practice could not flourish. The commissioners understood that most biological and ecological criteria for success (e.g., site-, tidal height-, season-, and habitat-specific growth and survival rates of various size clams; seed collection and transplanting techniques; reproductive cycle) were unknown, and each directed resources to address these gaps in knowledge. A flurry of activity during the early 1900s, especially in Rhode Island and Massachusetts, resulted in Herculean efforts by the earliest shellfish biologists, recognized today as pioneers of soft-shell clam mariculture, such as James L. Kellogg, Albert D. Mead, Ernest W. Barnes, and David L. Belding.

The idea of private soft-shell clam farming was stronger than its actual success. Its practice in coastal towns such as Newburyport, Rowley, Plymouth, and Barnstable (Massachusetts) and Lamoine, Wells, and York (Maine) was fleeting, with little regular activities from 1915 until the late 1940s. At that time, clam landings began to decline, coinciding with a period of about 5–8 years in both states of historic increases in seawater temperatures in the Gulf of Maine followed by a population explosion of the invasive green crab Carcinus maenas. The federal government stepped in, and, from 1949 to 1953, scientists at the Bureau of Commercial Fisheries (Boothbay Harbor, Maine; Newburyport, Massachusetts; and Kingston, Rhode Island) conducted collaborative research with shellfish biologists in each state, with several efforts directed in Maine and Massachusetts to determine if clam farming could be a viable economic venture to combat the effects of green crabs and other predators. It was not viable; however, by the late 1950s through the 1960s seawater temperatures in the Gulf of Maine cooled, predation subsided, and clam landings increased to levels not seen since the years immediately following the end of World War II.