Acoustic Juvenile Herring Abundance Data, Prince William Sound, 2012-2015, EVOS Herring Program

These data are part of the Herring Program of the Exxon Valdez Oil Spill Trustee Council, project numbers 12120111-F, 13120111-F, 14120111-F, and 16120111-F, which is a multi-faceted study to determine why herring populations in Prince William Sound remain depressed since the early 1990s.

Specifically, these data provide a measure of juvenile herring abundance in Prince William Sound to predict future additions to the spawning stock. Hydroacoustic (sonar) surveys were conducted each November from 2012 to 2016 in eight bays around Prince William Sound to estimate the abundance of juvenile herring (focusing on age-0 fish). This effort is a continuation of similar juvenile herring acoustic surveys conducted in twelve locations within Prince William Sound during fall (November) and winters (March), 2007 to 2012. Surveys were conducted during the night, when herring are known to come near the surface (which makes them more accessible to hydroacoustic methods), using a BioSonics 124 kHz digital split-beam transducer mounted down-looking on an aluminum towfin. The dataset consists of intermediary files (in CSV format) of acoustic backscatter outputted by the Echoview program in the form of the area backscatter coefficient (sa, m2 m-2) from raw acoustic source data files (in *.DT4 format). While the time series of acoustic data dates back to 2007, this dataset represents only years 2012-2015 for which full acoustic analysis has been completed. The analysis excludes Windy Bay due to low catches of herring. Subsurface trawls were used to collect fish to determine the mix of fish present during each hydroacoustic survey. The length, weight, and age estimation of captured fish are included in a related dataset entitled: Validation of Acoustic Surveys for Pacific Herring, 2010-2016: EVOS Herring Program.