DV-17-12 Field testing a new genetic marker on spawning scallop populations

Peter Countway
Bigelow Laboratory for Ocean Sciences

Skylar Bayer
School of Marine Sciences
University of Maine

Richard Wahle
School of Marine Sciences
University of Maine

The giant sea scallop (Placopecten magellanicus) is a highly valuable seafood species harvested in the Gulf of Maine. Fishermen and managers responded to declining populations by instituting a series of closures to protect scallop beds; these closures occur both in the federal fishery offshore near Georges Bank and the coastal fishery in Maine. As a result, landings have increased and the fishery has been sustained in recent years. However, managers don’t know the actual productivity (spawning and reproduction) of individual scallop beds. The scallop is a “broadcast spawner”: females and males release their eggs and sperm into the water. Monitoring such spawning events would inform predictions of future scallop stocks, however detecting such events in real time is extremely difficult.

In a 2016 Program Development project, Countway, Bayer, and colleagues developed a technique to measure gamete concentrations of giant sea scallops in the water column using quantitative genetics (qPCR). This second grant supported field-testing of the method. The researchers collected water and plankton samples from around scallops hung in lantern nets from the dock at Bigelow Lab, and analyzed them for scallop gamete concentration using the new DNA probe. They also examined scallops to assess reproductive status. They were able to detect increases in scallop DNA during the spawning season, thus indicating spawning events. The technique could be expanded to other species and habitats, be used to monitor wild scallop beds, and provide aquaculture operations with a way to track reproduction.

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Sea Grant funds $3,758