Genetic Tools for Virginia’s Hard Clam Industry

Nestled beneath the muddy bottom of Virginia’s Eastern Shore lies a powerhouse of the U.S. aquaculture industry: the hard clam (Mercenaria mercenaria). This bivalve supports the largest hard clam industry in the U.S. and the economies of Virginia’s Eastern Shore and lower Chesapeake Bay regions.

Like many marine organisms, hard clams face increasing environmental stress from fluctuating temperatures and emerging diseases. Ensuring their resilience is a priority for sustaining this vital industry.

A healthy hard clam begins with a dependable spawning stock– a subset of mature clams that hatcheries use for reproduction. Spawning stocks vary between hatchery operators who use their own breeding strategies and observations of field performance to assess the productivity of the spawning stock. The genetic diversity of a spawning stock is crucial to producing offspring that can withstand environmental stress. However, many hatcheries lack access to the genetic tools available for managing genetic diversity, until now.

To bridge this gap, shellfish extension specialists from Virginia Sea Grant and VIMS Marine Advisory Program partnered with hard clam hatcheries to connect the industry with available genetic tools for supporting sustainable management decisions within their operations. A small-scale study was conducted comparing the genetic diversity of cultured versus wild hard clams collected along the East Coast. These results were compiled into a report and shared at a highly focused workshop gathering Virginia’s hard clam hatcheries and VIMS’ geneticists to discuss applications of the genetic tool.

“The format encouraged in-depth discussion around the practical implementation of these tools, including cost and complexity,” says Karen Hudson, shellfish aquaculture specialist in VIMS Marine Advisory Program. “While the group was small, the insights were directly relevant to advancing applied solutions.”