A converted ferryboat is used in the Potomac River by the Virginia Institute of
Marine Science to test the efficiency of a midwater trawl in catching alewives
as they migrate upstream to spawn.
Image ID: fish7977, NOAA's Historic Fisheries Collection Location: Virginia, Potomac River Credit: NOAA Central Library Historical Fisheries Collection; P. 108 of "Our Changing Fisheries" 1970 Centenary NMFS centenary volume
