2025 Sea Scallop Dredge Survey Completed
Annual dredge survey completed 84 percent of the planned stations aboard the commercial fishing vessel Selje. This year included improvements to the survey and saw a very large catch of young scallops at one of the fixed stations.
Our Atlantic sea scallop dredge survey collects data on abundance, spatial distribution, and life history for Atlantic sea scallops from Georges Bank to Delmarva. We use a standardized 8-foot-wide New Bedford sea scallop dredge to collect sea scallops and associated bycatch for biological analyses. Sensors on the dredge also record tilt, roll, bottom contact, temperature, and depth.
Dates and Legs
The 2025 Dredge Survey began on July 10 and completed operations on July 19 aboard the F/V Selje. This year’s dredge survey occurred in 1 leg, moving from Closed Area 1 North, up the Northern Flank to Closed Area 2, then back down to Closed area 1 and the Great South Channel. This allowed us to optimize sampling in the highest priority areas.
Location
This survey monitors sea scallop stock abundance and distribution on the Northwest Atlantic Ocean from Georges Bank to the Mid-Atlantic. This year sampling targeted Georges Bank.
Completion Rates
The survey team:
- Conducted fishery resource survey dredge tows at 174 of 206 planned random stations (84 percent completion)
- Completed three of three planned fixed stations
Despite challenges during the planning phase, the 2025 survey is considered a fully representative survey. We had excellent weather and the efficiency and hard work of the crew and scientific staff ensured the survey’s success.
We planned additional stations this year, up from 190 stations in 2024. We provided good coverage of all strata and high priority areas.
Data Collection and Use
Data collected are primarily used to track scallop abundance, distribution, ages, lengths, weights, sex, maturity, and disease presence. We count fish and lobster and record lengths for skates, monkfish, and certain other fish. We also count key scallop predators like sea stars, crabs in the Cancer genus, and waved whelks at all stations, unless stations were within 4 nautical miles of each other. We estimate the composition of substrate (mud, rocks, etc.) and other bycatch by volume.
Each dredge has a sensor that records tilt along three axes to make sure the dredge has good contact with the bottom. The sensor also records temperature and depth every second to help link organism distribution to physical oceanographic conditions.
Survey Improvements
The dredge survey uses a stratified random sampling design. From 1975 through 2024, survey strata boundaries were based primarily on depth and secondarily by latitude. While depth is generally related to scallop abundance, the strata were not specifically designed for sea scallops. After a review by a subpanel of the New England Fishery Management Council Scientific and Statistical Committee, we implemented a spatially balanced random sampling design this year. It uses a Generalized Random Tessellation Stratified (GRTS) sampling design to select stations for sampling. We also switched to using Scallop Area Management Simulator (SAMS) areas as survey strata. This survey design is more efficient, is consistent with long-term management boundaries, and is a more flexible way to track changing distributions of scallops. Some of our stations were outside the management simulator area boundaries to maintain coverage from the historical survey footprint.
Preliminary Results
We observed the largest catches of scallops in the western portion of Closed Area 1 and the northern edge of Closed Area 2. We collected a very large catch of 2- to 4-year-old scallops at a fixed station in the Nantucket Lightship area. We estimated that catch to contain 48,000 individuals.
We release survey data annually after the survey is complete. When available, the data can be found on our survey page.
Completed Dredge Survey Stations
Survey Mission
The Dredge Survey first began in 1979, and the Habitat Camera Survey (HabCam) was incorporated into the Dredge Survey in 2012. Beginning in 2024, these surveys were split into two distinct surveys.
The Dredge Survey has developed into a collaborative survey between our science center and the scallop industry using an industry vessel.