This file documents aerial survey routes of Pacific herring Clupea pallasii aerial surveys in the Prince William Sound Area, Alaska, 1997-2021. The Prince William Sound Area (Registration Area E) is described in regulation (5 AAC 27.300) as follows: The Prince William Sound Area has as its western boundary a line extending south from Cape Fairfield, as its eastern boundary a line extending south from Cape Suckling and as its southern boundary 59 degrees N. lat. Aerial surveys are generally conducted between late March and mid-May as this brackets the majority of spring spawning events. Generally a single observer was on surveys prior to 2006. Since 2006 two observers were on most surveys, except in 2020 and 2021. Route maps were not drawn prior to 1997. Between 1997 and 2008, survey routes were drawn on a paper map during the survey and digitized later. From 2008-2020, a bluetooth GPS with an integrated ArcPad application and a backup Garmin GPS have been used to document survey routes. In 2021, ArcPad and computer were replaced with ESRI Field Maps on an iPad Pro using external bluetooth GPS and a backup Garmin GPS. Since 2008, one observer collected data on an ESRI Arcpad application, and the second observer collected data on paper maps and photographed spawn, herring schools; and marine mammal or sea bird observations. Almost all of these aerial survey data were collected digitally at the time of observation. A few surveys since 2008 were only collected on paper maps and digitized later.