During Virginia Oyster month in November–and all year long–Virginia Tech seafood researchers help oyster farmers adapt to water quality issues

Over the last three decades, Maryland and Virginia have suffered more than $4 billion in cumulative annual losses because of the decline of industries related to oyster harvesting. Likewise, harvests have fallen to less than one percent of historic levels.

As Virginia Oyster month kicks off in November, Virginia Tech experts are available to talk about erratic water quality and other environmental factors that make delivering oysters to the dinner table more challenging these days. About 95 percent of oysters consumed worldwide are cultivated, and while aquaculture has helped the industry meet growing consumer demand, climate pressures impacting water quality have complicated oyster and bivalve production.

In Virginia coastal waters, rising temperatures, more frequent rain events carrying pollutants into the water, and changes in salinity and dissolved oxygen are some factors leading to increased mortality in shellfish hatcheries, particularly by mid-summer going into the fall.

Researchers at the Virginia Seafood Agricultural Research and Extension Center are working with research and industry partners to adapt recirculating aquaculture systems for oyster culture.

Chesapeake Bay summer water temperatures are increasing by nearly a half degree Fahrenheit per decade and rising nearly twice as fast as global surface ocean water temperatures, according to a study by researchers at the Virginia Institute of Marine Science.

“Anything and everything that we’re seeing in the coastal waters really impacts all types of coastal aquaculture,” said Michael Schwarz, Virginia Seafood Agricultural Research and Extension Center director.

Virginia is a leading producer of oysters and clams on the Atlantic Coast, so for the local economy, for the watermen, and for Virginia consumers, the stakes are high for the development of resilience measures in the face of the vexing challenges posed by a changing climate. 

“Hatcheries are experiencing losses or are having to shut down production earlier in the year because the conditions in the environment aren’t suitable,” said Jonathan van Senten, assistant professor in the Department of Agricultural and Applied Economics and assistant director of the Virginia Seafood Agricultural Research and Extension Center. “What was needed is a shift in approach.”


Michael Schwarz is the director of the Virginia Seafood Agricultural Research and Extension Center (Seafood AREC) in Hampton, Virginia. Schwarz is a leader in aquaculture production and has worked around the globe to share that knowledge with nations and industries looking to increase sustainable food production. He has been with the College of Agriculture and Life Sciences since 1997 with a joint appointment in the College of Natural Resources and Environment’s Department of Fish and Wildlife Conservation. He is also a Virginia Cooperative Extension aquaculture specialist. Schwarz is associate director for the Center for Coastal Studies and is working to expand Virginia Tech research capacity on the coast via the Virginia Tech Coastal Collaborator.

Jonathan van Senten is an assistant professor in the Department of Agricultural and Applied Economics and assistant director of the Virginia Seafood Agricultural Research and Extension Center in Hampton, Virginia. His work focuses primarily on aquaculture, aimed at understanding and quantifying the costs and impacts of the regulatory environment at the farm level. To date, he has evaluated three sectors of U.S. aquaculture (baitfish, trout, and west coast shellfish) with colleagues. He will be working on tilapia, hybrid striped bass, catfish, and east coast shellfish over the course of the next two years. In addition, he’s also involved with assessing the viability of emerging species, commercial aquaponics, evaluating new diet formulations for aquaculture, financial benchmarking, and economic impact assessment.