The use of mesh bags for rearing northern quahog (hard clam), Mercenaria mercenaria, seed

Seed clams are a major cost for shellfish planters. Buying small hatchery seed and conducting the nursery in the estuary could reduce seed costs. We designed experiments to examine the biological and economic feasibility of growing seed clams to planting size (10 mm) in polyethylene (poly) and nylon mesh bags under commercial conditions. An initial study examined stocking densities ranging from 2000 to 6000 5 mm seed per poly bag (0.5-1.4 clam per cm super(2)) in on- and off-bottom configurations. We then examined two types of mesh bags (poly and tented soft nylon) at two sites. There were significant differences in size and total volume of clams recovered between sites. Within a site there were no significant differences in seed size with bag type or position. Economic analysis indicates that on-bottom poly mesh bags are a viable alternative for a hard clam seed nursery, but careful attention to seed cost, bag maintenance (to assure adequate growth and survival), and measurement of resulting production will be essential to profitability.