– Hatchery –
Soft-Shell Clams
To purchase clams that are ready to be seeded (larger than 2mm), you should order cultured soft-shell clam (Mya arenaria) juveniles in the late winter for planting in the following spring (15 months in advance). This is the only way we can be sure to have an adequate supply of seed on hand for you.
If you are interested in ordering small clams up to 2 mm (for growing in an upweller or floating nursery trays), these can be shipped to you between May and June the same year you order them. Due to winter mortality, we advise against planting clams in the fall and recommend they be overwintered in flow-through seawater until planting the following spring.
Seed clam prices are based on size, as larger clams require more care and handling by DEI staff.
Contact Keane at 207-259-5084 or e-mail: knunan@downeastinstitute.org with questions or to place an order.
For Delivery Inside Maine
| Size (mm) | Size (in) | Price per 1,000 |
|---|---|---|
| 1 mm | 0.04 in | $5.30 |
| 1.5 mm | 0.06 in | $8.00 |
| 2 mm | 0.07 in | $10.15 |
| 5-7.9 | .20-.31 | $19.00 |
| >8 mm | >.32 | $25.00 |
For Delivery Outside Maine
| Size (mm) | Size (in) | Price per 1,000 |
|---|---|---|
| 1 mm | 0.04 in | $5.30 |
| 1.5 mm | 0.06 in | $8.00 |
| 2 mm | 0.07 in | $10.15 |
| 5-7.9 | .20-.31 | $24.00 |
| >8 mm | >.32 | $30.00 |
*Size is shell-length.
Clam Pick Up and Planting
You are encouraged to pick up your clams sometime in April, but prior to May 1. After May 1 we cannot guarantee that your order will be filled. Planting clams during April or May ensures that the animals will reach their maximum shell length by the time growth ceases in the fall.
For more information on increasing clam survival in the clam flats and hatchery culture, check out DEI’s Manual on the Culture and Grow-Out of Soft-Shell Clams: A Practical Guide for Growing Clams in the Intertidal.
Transplant Permit Required in Maine
For Maine communities and individuals ordering DEI soft-shell clam seed, remember that you will need to obtain a transplant permit from the Maine Department of Marine Resources. Please follow this link to find a transplant/relay permit application and instructions, as well as contact information for the area biologists in your region.
Growing seed clams is a labor-intensive process that begins in January when we collect soft-shell clam broodstock from local flats. Hatchery staff grow algae (single-celled plants, or phytoplankton) to feed clam broodstock for approximately two months before inducing them to spawn. The newly born larval clams swim in the water and are microscopic. For their first two weeks of life, the larval clams live in conical tanks where they grow from 1/600th of an inch to 1/50th of an inch, or a little bit smaller than a grain of sand.
A variety of microalgae is also used to feed clam larvae and juveniles.
The tiny clams are then transferred to trays with fine mesh screening which float in large rectangular “set” tanks filled with seawater. From that point on, the animals feed on the cultured algae grown in the hatchery.
Cleanliness is critical to the survival of tiny clams, and hatchery workers drain, clean, and refill the set tanks every other day, spraying off the clams and moving them to increasingly larger screens as they grow. When the clams grow to two millimeters in length, hatchery staff use a graduated cylinder to measure out 15,000 to 20,000 animals and place them in trays constructed of wood and window screening. Each tray receives a handful of periwinkles to prevent fouling before being moved to a nearby ocean nursery site. Alternately, clams may be moved to an upweller during their nursery phase.
The trays float on the surface of the water until November, which is the end of the clams’ natural growth cycle. By the end of the growing season, the juvenile clams are 1/4 (6.35 mm) to 1/2-inch (12.7 mm) in length.
Although the clams are large enough to seed, staff return them to our facility rather than expose them to winter mortality on the flats. The seed clams are transferred from the trays into mesh bags, which are stacked into modified lobster traps and submerged in circulating seawater until spring.
The following spring, clams are stocked onto flats in communities that are interested in enhancing their flats with cultured clam seed.
All proceeds from shellfish seed sales helps support DEI’s nonprofit mission.
