Midwater trawl comparison study for acoustic surveys of walleye pollock (Gadus chalcogrammus) in Alaska

Midwater trawling is a critical component of acoustic-trawl fisheries surveys, and it is used to determine the species and size composition of acoustically sampled fish schools. Changes in midwater trawl gear can influence the catch, and therefore potentially bias the survey data. The Alaska Fisheries Science Center conducts acoustic-trawl surveys of walleye pollock (Gadus chalcogrammus) in Alaska waters and recently switched to a new midwater LFS1421 trawl (LFS) from an older Aleutian Wing Trawl (AWT).