Filter feeders that consume phytoplankton and zooplankton.

SPAWNING:

Spawning is related to water temperature. M. mercenaria can be conditioned to spawn by slowly raising the temperature of the water to 18-20 degrees Celsius. Similarly, placing into cold water can prevent spawning. Release of gametes is initiated by increasing water temperature to 28-30 degrees Celsius. then lowering it again to 22 degrees Celsius. This is repeated every 30 minutes until spawning. Eggs and sperm are mixed and zygotes are transferred to warmed larval rearing tanks where they develop into velegers. They are reared on cultured phytoplankton for one to two weeks. Newly metamorphosed clams are held in containers of stagnant water (water changed often) and fed a rich phytoplankton diet. After 4-5 weeks the clams are moved to a nursery facility, tanks with freshly pumped seawater and grown out to seed clams (7 mm).

GROWTH:

Littlenecks, 5-6 cm across; cherrystones, 7-8 cm across, chowder clams, > 8 cm across.

USES:

Popular food items used in soups and sauces or eaten baked or raw.

CULTURE:

Growout methods for M. Mercenaria can differ. Generally seed is transferred to the field to areas having firm sand or mud. Densities of 500 seed clams/ m² are desirable for production of 5-6 cm clams. Seeding sites are selected, seed deposited and generally placed into bags, or protected in some manner from predators ( i.e. crabs, gastropods, starfish, and rays).

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