SPECIAL REPORT: Clams
Aquaculture is the wave of the future for NJ’s iconic bivalve.
Hard Clam Aquaculture 101
- Broodstock: Hard clam breeding season is triggered by temperature. As clams awaken from hibernation, they feed vigorously, building stores of sperm or eggs. Aquaculturists manipulate this in the hatchery, replicating nature on an accelerated timeline. The first step is to gather breeders, bring them in, and offer an algae diet.
- Spawn: As the breeders eat, their tank temperature is slowly raised. At around 68 degrees Fahrenheit, a female mercenaria mercenaria will release millions of eggs. Normally, this happens around April. In the hatchery, it can begin as early as February.
- Larvae: Under a microscope, larval clams are a riot of activity. Infants have cilia that flutter like eyelashes.They swim in furious circles and draw in food, their well-fed stomachs appearing like tiny, dark dots.
- Nursery: Initially, larvae are housed in hatchery downwellers. Around 10-15 days, they lose their cilia, grow their foot and begin to form a denser shell, causing them to sink. At this stage, they are transferred to nursery upwellers through which fresh bay water is pumped, and then it’s on to raceways to finish grow-out.
- Planting: Once clams reach pencil-eraser size, 8-12 millimeters, they're bay planted on 14 x 20-foot plots with 100,000 or so siblings. Farmers may allow clams to grow overwinter without screens, covering them in the spring. Clams continue to receive care from their farmer until they reach littleneck size. The wait is typically three years.
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