EK500 Water Column Sonar Data Collected During DE9809

NEFSC 1998 Atlantic Herring Acoustic/Midwater Trawl Survey (DE9809, EK500). The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic and New England regions. The survey is conducted in the fall on pre-spawning and spawning herring primarily in the Georges Bank region, but with other historical sites in the Gulf of Maine surveyed. The survey is a systematic design with parallel transects oriented perpendicular to bathymetric features. Midwater trawl sites are selected on an ad hoc basis to sample acoustic backscatter attributed to Atlantic herring as well as backscatter by other organisms. The primary gear is multifrequency Simrad echosounders, but midwater trawl, CTD, and a host of other scientific sensor data are collected ancillary to the acoustic data.