Contact: Ariele Baker
Research Surveys Measure Scallop Abundance
Scallops are a highly productive fishery in waters from the Gulf of Maine through the Mid-Atlantic Bight. Information about scallops is collected from commercial fisheries sources and through research surveys. Surveys create a picture of the population in time and space that is separate from fishing.
Federal scallop surveys are conducted by dredge (right) and HabCam (left) aboard the R/V Hugh Sharp annually for five weeks beginning in mid-May. The dredge collects sea scallops that are brought onboard for biological sampling. The HabCam has sensors and cameras that continuously collect environmental data and photograph the ocean bottom. The photographs provide a way to measure scallop abundance separately from the dredge survey. HabCam images also tell a lot about the ecosystem, habitat, and other animals that occur with sea scallops.
HabCam provides a glimpse of the seafloor through imaging. The HabCam vehicle is towed over the ocean floor continuously on a series of predetermined tracks. It takes six images a second that create a continuous image stream in space and time. The Habcam has been incorporated into the stock assessments since 2012, and is a noninvasive way to measure the scallop population. For more information about HabCam, read this press release.
The HabCam can show areas of high and low scallop density on the ocean floor.
When the HabCam is not being deployed, dredging is conducted at randomly selected locations within specified survey areas. Survey areas, or "strata", are delineated by latitude and depth.
The dredge net has 2-inch steel rings and a 1.5-inch liner, and captures sea scallops of different sizes--very small to very large.
On deck, scallops are sorted, weighed, and then measured. Knowing how many scallops are available, where they are located, and how large they are gives stock assessment scientist a measure of the population in space and time.
Scallops in the Mid-Atlantic Bight are sampled by our partner, the Virginia Institute of Marine Science.
Researchers at VIMS count, weigh, and measure scallops just as researchers from NEFSC do aboard the Sharp.
Sharing survey results across the region allows us to sample more areas in order to estimate more precisely within stock assessments.