on the North American east coast from Canada to Georgia. They are ecologically as well as commercially important in many benthic ecosystems. Natural populations of soft-shell clams have persisted in Virginia, and soft-shell clams have been cultured for many years in Maine. They have a wide environmental tolerance for temperature (-2 – 28 °C) and salinity (4 – 35 psu), which allows them to grow in many locations. Mya arenaria is a broadcast spawner with high fecundity and planktonic larvae that allow wide dispersal, but postsettlement mortalities are typically high. Population abundances in Virginia are currently low, which has led to recent efforts and discussions regarding conservation and restoration to raise populations to an alternative stable state.
We have been able to spawn Mya in VA, and there is potential capacity to grow them to seed size for transplanting for restoration if we can overcome temperature extremes and predation. Growth is quick in VA, as soft-shell clams can add >1 mm shell length/week when grown on-bottom from the fall to spring seasons. In Virginia, substantial mortality of Mya occurs when summer temperatures rise above the clam’s thermal tolerance of 28oC. Predation is also a key determinant of Mya survival. Current populations of soft-shell clams in Virginia have been kept at a low stable state through predation, mainly from blue crabs. In addition, clams persist only in structured habitats, and sources of Mya broodstock likely reside in habitats such as seagrass beds and shelly habitats. Restoration of this species would need to focus on saturating structured habitats with high densities of seed in early fall to allow grow-out to sexual maturity (> 40 mm) and spawning before high temperatures hit in the summer. Experiments to determine the feasibility of restoration are underway and are showing promising results.