Virginia Institute of Marine Science
Marine Advisory Program (MAP)
Marine Resource Report No. 2020-3
The sea scallop fishery is typically supported by several primary survey methods (i.e., dredge and optical surveys), which provide multiple, spatially explicit biomass estimates on an annual basis. Since 2015, significant divergence in area-specific biomass estimates between the optical and dredge survey methods has been noted. The divergent estimates are associated with areas of high scallop densities within the Nantucket Lightship Access Area (NL) and the Elephant Truck Access Area (ET). In 2018 and 2019, the disparity in biomass estimates between the different survey methods in the ET was reduced, but in the NL, the issue has continued. Evidence suggests gear saturation is occurring for the survey dredge upon the examination of the 2016 and 2017 survey results for these areas of high scallop density (NEFSC, 2018). This effect is currently the main explanation for the difference in biomass estimates between survey methods. While several independent sources of biomass estimates are beneficial for successful management of the resource, divergent area-specific estimates can contribute to uncertainty when setting annual specifications. Understanding all sources of uncertainty in survey dredge gear performance should be investigated to fully comprehend how and why survey dredge estimates differ from optical survey estimates.
Sea scallop fishery
Award Number: NA18NMF4540012
Rudders, D. B., Roman, S. A., & Mohr, E. (2020) Understanding Dredge Performance for a Lined versus Unlined NMFS Sea Scallop Dredge: Final Report. Marine Resource Report No. 2020-3. Virginia Institute of Marine Science, William & Mary. https://scholarworks.wm.edu/reports/2097