Ipswich Soft Shell Clam Farm

History of Ipswich Clam Farm

The soft shell clam industry in years past has been a major market for interstate commerce for the coastal town of Ipswich, Massachusetts.  The supply of these tasty little bivalves seems to follow an 8-10 year cycle.  This cycle follows a specific trend which sees frequent years when an over whelming number of commercial harvesters land thousands of tons of clams, followed by many years when few clams are available and very few commercial harvesters are working the clam beds.  Many generations of clammers have relied on Mother Nature to bring back the depleted clam stocks.  Some have tried transplanting clams from productive beds to barren flats, hoping the clams would stay and thrive, only to see their efforts eaten up by the multitude of predators along the coastline.  Currently, the local markets now have to import clams for outside this once productive area.  In order to bring back the once abundant clams, some type of animal husbandry needs to be implemented to manage the depleting clam stocks, and what better way than by introducing shellfish farming to an area already know for its extraordinary shellfish product.

            In 2001, Massachusetts Department of Food and Agriculture and NEMAC (North East Massachusetts Aquaculture Center) supplied a grant in the amount of $6500 to initiate a shellfish farm north of Boston in the town Ipswich.  The gear purchased would be able to cover and farm approximately 1.39 acres of an inter-tidal clam flat.  The grant purchased three different rolls of predator exclusion netting, floats for the netting, buoys to mark the boundary area, cinder blocks, rope and lumber for signs.  Many different challenges were faced during the first year of operation.  Such as how long to cut the nets, how many buoys were needed to be attached to the nets, and where to place the nets?  Three different types of netting were purchased to find out which one would be the best fit for predator exclusion and juvenile clam capture.  The three different types of netting are: 1/6 inch woven mesh at 8ft wide and 30ft lengths, ¼ inch polypropylene light mesh at 16ft wide and cut at 50ft lengths, and lastly a ¼ inch polypropylene extra duty mesh at 14ft wide also cut at 50ft lengths.  The small mesh size was chosen primarily to exclude out all types of crabs.

            Results show that the woven mesh caught too much fouling and caused excess sediment buildup.  The next choice for netting is the light ¼ inch mesh.  It is versatile for many reasons: lowest price, least fouling and very little sediment buildup.  A 50ft section of this netting captured a good amount of juvenile clams and covered more than twice the area of a woven mesh net.  The extra duty ¼ inch polypropylene mesh, a higher price per foot, also worked great for capturing juvenile clams and had very little fowling and sediment buildup.  The light mesh will last an entire growing season before ripping up but the extra duty will last several growing season costing less over the 2-3 year period.  A major lesson learned with regards to seed capture and the type of netting is that capturing too many juvenile clams is not a good thing.  Over populating the flat could lead to a disastrous lose in clams or result in stunting the clam’s growth.  Much care was taken to observe the settling densities of the juvenile clams.  Nets which captured large amount of seed were removed and the seed was sifted out of the mud.  This seed can be relocated to another part of the clam farm and recovered with netting.

            Observations also proved the importance of the predator exclusion netting with regards to survival of the juvenile clams.  During the late fall season when all signs of predators are no longer visible, you can clearly observe very few juvenile clams outside the netted areas while under the netting clam densities reached well over 100 per square ft.  The winter months proved to be the harshest conditions throughout the year.  All netting must be removed before the ice forms if not the ice will freeze to the flat and lift the nets and carry them out to see causing potential danger to birds, marine fish and mammals.  Seed capture and grow out proved to be the best economical method for farming soft shell clams but in areas that don’t capture as well, juvenile clams must be bought from a state certified hatchery and grown under the ¼ inch predator exclusion netting.