December 2, 2014
Contact: Shelley Dawicki
Bay Scallop Culture and the Tank Farm
Bay scallops donated and distributed in recent weeks were raised at the Milford Lab’s own hatcheries. To allow growth to a larger pre-winter size so that the probability of overwintering survival is increased, bay scallops are conditioned in the lab to spawn out of season, in March or April, using warm water and feeding. The process takes three to eight weeks, depending on temperature and available food.
After spawning, the fertilized eggs are moved to conicals or tanks containing 400 liters (105 gallons) of aerated seawater, and the developing larvae feed for about 7-14 days. Once the scallop larvae develop an eyespot and a foot, indicating they have reached the juvenile stage, they are ready to “set” (or attach to the substrate with a byssal thread) and are moved to trays with running water. When the juvenile scallops reach about 5 mm in size (0.2 inches), they are transferred to raceway tanks for “grow-out” to their adult stage. Adult bay scallops can reach 100 mm (4 inches) in size.
The Milford Lab’s “tank farm” includes 45 outdoor and 14 indoor raceways and 12 circular tanks. The building portion is heated for year-round use and operates with running seawater for a variety of aquaculture projects involving oysters, clams, scallops, crabs, lobsters, and finfish. Shellfish genetics is just one of the research programs underway at the Lab, which houses the NEFSC’s Aquaculture and Enhancement research division.
The tank farm, covering about 24,000 square feet, simulates nature using raw seawater under semi-natural conditions and serves as a mini-ecosystem for environmental and experimental studies. Bay scallops usually spawn in warmer summer months, but through conditioning can grow fairly large, to 50 mm (about two inches) or more. Sheila Stiles, a geneticist at the Milford Laboratory, and colleagues Joseph Choromanski and Dorothy Jeffress work with the various recipients of donated animals to determine which sizes and genetic lines are best for each particular project.
Selective breeding for desirable traits, such as maximum growth and survival and resistance to diseases, enables scallop stocks to survive in nature. Environmental factors like water temperature, currents, and habitat location affect the success of the animals, as do whether the scallops are in nets and cages or left unprotected on the bottom and subject to predation.
“We cannot control all of these factors, so monitoring the habitat sites is key to the success of any of the efforts,” Stiles said, noting that the groups involved monitor the field sites and work closely with laboratory staff on genetic studies.
In 2008, Stiles, Choromanski, and Jeffress published a Connecticut Sea Grant manual, “Genetic Approaches for the Culture and Restoration of Bay Scallops,” that provides information on techniques and technology for developing genetic lines and genetic strategies for improving culture, stock enhancement and restoration. Although the bay scallop is the focus, the information has genetic implications for bivalves and other organisms in general.
The Milford Lab’s aquaculture research follows NOAA’s National Shellfish Initiative, established in 2011 to increase populations of bivalve shellfish – including oysters, clams, abalone, and mussels – in U.S. coastal waters through both sustainable commercial production and restoration activities. The National Strategic Plan for Federal Aquaculture Research (2014-2019), a framework for collaboration and coordination among federal agencies, has nine strategic goals, including employing genetics to increase productivity and protect natural populations.
Stiles and her colleagues have shared their work on genetic applications for shellfish restoration at various national and international meetings and conferences. Their most recent research explores the effects of environmental conditions such as increasing acidification of coastal and marine waters on shellfish genetics. In January 2015, the team will present more research findings at the joint Milford Aquaculture Seminar/Northeast Aquaculture Conference and Exposition to be held in Portland, Maine.
# # #
NOAA Fisheries Service is dedicated to protecting and preserving our nation's living marine resources and their habitat through scientific research, management and enforcement. NOAA Fisheries Service provides effective stewardship of these resources for the benefit of the nation, supporting coastal communities that depend upon them, and helping to provide safe and healthy seafood to consumers and recreational opportunities for the American public. Join NOAA Fisheries on Facebook, Twitter and our other social media channels.
NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Twitter, Facebook, Instagram, and our other social media channels.