Bay scallops continue to rebound

Pictured: Rebecca Turner Smith and Darian Kelley holding scallop seed.

By Linda Cicoira

Results of an annual population survey led by the Eastern Shore’s Virginia Institute of Marine Science laboratory show Bay Scallops continue to rebound.

Once protected behind the barrier islands in lush underwater grass, the scallops became extinct locally due to eelgrass wasting disease that destroyed its habitat. VIMS has been working on scallop restoration for a dozen years. The density has grown in southern coastal bays to nearly .07 scallops per square meter.

Scientists say this may not be enough to support a recreational fishery, but it’s close. In Florida, a minimum population density of .10 scallops per square meter is used.

In 2001, Robert Orth, former director of the Submerged Aquatic Vegetation Program at VIMS began a seagrass restoration project after a small patch of eelgrass was discovered in South Bay near Wreck Island. The program was continued by the current director, Christopher Patrick. And is now the largest restoration of seagrass in the world.

“Most seagrass restoration efforts fail because the underlying issues affecting the environment haven’t been addressed,” said Patrick. “Underwater grasses can recover relatively quickly in a healthy environment,” he said.

By 2010, VIMS, The Nature Conservancy, UVA, and other partners, restored approximately 6,000 acres of underwater meadows. The current figure is about 10,000 acres.

The ultimate goal is to re-establish grass beds from Fisherman’s Island to Chincoteague, which will require continued and expanded funding.

The Eastern Shore lab has a long history specializing in shellfish aquaculture. Its founding director, Mike Castagna, helped establish Virginia’s hard clam industry – now the largest in the U.S. – with research in the 1960s.

In 2010, former VIMS director and Associate Dean for Research and Advisory Services Mark Luckenbach brought wild scallops from North Carolina to Castagna Shellfish Research Hatchery. In 2012, they began releasing bay scallop larvae, juveniles, and adults into the restored grass beds. The survey commenced in 2013.

During the three-day survey, scientists, staff, and volunteers split up approximately 240 stations across the Eastern Shore’s southern coastal bays. With a minimum of five people per boat, they place a one-square-meter quadrat in water up to four feet deep. Then the participants use their hands to feel for scallops hiding in the grass within the quadrat.

As a group, they repeat this process 50 times at each station, ultimately searching more than 12,000 square meters of seagrass meadow. Scallops are counted and measured, and a small subset is brought back to the local lab for DNA sampling and to use as brood stock for future generations. The rest are released back into the wild.

“It’s a multi-institution, multi-personnel, all-hands-on-deck activity, and something we look forward to every year with dread and excitement,” said Richard Snyder, director of the VIMS lab and professor at William & Mary’s Batten School of Coastal & Marine Sciences. “It’s a lot of work, but it’s also extremely exciting and rewarding,” he added. The researchers also record similar data about Ark clams at each station.

The first several years of scallop restoration efforts were tumultuous, the VIMS website states. Initial hopes were dashed when populations crashed in subsequent years. This boom-bust trend continued for the first five years, prompting the team to consider genetic diversity of the species.

“Around 2018, we brought wild bay scallops from different locations … and began breeding them in the hatchery,” said Nursery Manager Darian Kelly. “We began incorporating larvae from these brood stocks into our restoration efforts and started to see population increases in subsequent years.”

It’s unclear whether the increased genetic diversity was the reason for the turnaround or if the population had finally reached a threshold required for sustained growth, the website stated.

“We’re trying to figure out what the Virginia scallop looks like genetically,” said Snyder. “We really don’t know what the genetics were originally since they were lost so long ago, but we suspect they were a blend of characteristics from scallops that live in cooler, northern climates and more heat-tolerant, southern variants,” said Snyder.

DNA analyses on scallops collected from the annual surveys are used for aquaculture farming. The local team is also working to isolate DNA from scallop shells located at commercial sites from the early 1900s.

“At some point, we’ll need to pull back our support to determine whether the population can continue to expand on its own,” said Snyder.

VIMS provides small juveniles as “seed” to local farmers to test in commercial operations.

“We’re hoping to prove that the bay scallop can be easily added to an aquaculture farm without having to significantly change operations,” said hatchery manager Rebecca T. Smith. “It’s been really rewarding to see a lot of interest pick up from the local growers. We had more people requesting test seed this year than ever before.”

“We’ve isolated a genetic line that produces some very distinct orange scallops, and there are other variations that include reds, browns, and stripes,” said Smith. “We hope to swap our orange scallops for a yellow line that has been isolated in North Carolina so we can start breeding pure-color lines,” she continued. “This isn’t something that we’d want to do for a restoration project for wild scallops, but we can make a more visually appealing product for aquaculture farms.”