Shellfish aquaculture production at the hundreds of farms in Massachusetts is roughly 95% oyster sold by the piece. There has been much interest in diversifying but many challenges. Previous work has shown that Atlantic surf clams have potential as an emerging aquaculture species in the Northeastern US. While clam growth has been relatively rapid in all studies, survival has been challenged by warm waters and intertidal conditions typical of many aquaculture areas in MA. Most aquaculture work in the region has been done with the more common and well-known Atlantic surf clam, Spisula solidissima solidissima, though the Southern surf clam, Spisula solidissima similis also populates the mouth of many estuaries on the southern side of Cape Cod. The natural history of Southern surf clams is poorly understood in the New England region, but aquaculture potential has been suggested for other parts of the species range.
To determine and compare the aquaculture potential of the two species, seed from both species were obtained using local parent stock in summer of 2020 and verified for genetic identity. The seed of both species were planted at nine different shellfish aquaculture sites representing a range of conditions including subtidal and intertidal. Seven of the sites were monitored closely for growth and survival comparison between the two species using mesh-covered trays buried in the sediment and sampled at roughly bimonthly intervals. Data are being collected into fall of 2021, but early results suggest some clear advantages in survival and sometimes with growth using Southern surf clams, Spisula solidissima similis, over Atlantic surf clams, with the most pronounced differences in intertidal conditions.