A tracing made by an echo sounder shows concentrations of Pacific ocean perch
on the sea floor, as well as the otter trawl of another vessel sweeping over the
bottom toward the fish.
Image ID: fish7975, NOAA's Historic Fisheries Collection Location: Eastern Pacific Ocean Credit: NOAA Central Library Historical Fisheries Collection; P. 420 of "Our Changing Fisheries" 1970 Centenary NMFS centenary volume
