Data were processed in Echoview 11.1.34 (Echoview Software Pty Ltd). Exported survey data were merged into four master survey files based on frequency (38/120kHZ) and collection mode (CW/FM). Files included are “cw38_2020_repos.csv”, “cw120_2020_repos.csv”, “fm38_2020_repos.csv”, and “fm120_2020_repos.csv”.

CW processing: Bottom and surface exclusion regions were first applied to remove bad data. Impulsive noise and background noise removal algorithms were then used to remove interference produced by the boat and electrical systems based on the techniques presented by Ryan et al. (2015) and De Robertis & Higginbottom (2007). The default Echoview settings were used. Impulse noise was evaluated based using three consecutive pings, and ten samples in the vertical domain. Data were removed if an adjacent region was >10dB greater or less than the reference region. Background noise was evaluated based on 20 consecutive pings, and five samples in the vertical domain. The maximum noise threshold was set to -125dB and the signal-to-noise ratio was set to 10.0. Those samples that did not mee the criteria were excluded. Data were then divided into 5m vertical by 5m horizontal cells and exported as .csv files.

FM processing: Bottom and surface exclusion regions were first applied to remove bad data. Data were then divided into 5m vertical by 5m horizontal cells. No further processing was completed.

Additional dataset description: Each row represents a 5m vertical x 5m horizontal cell along the transect. Individual cells can be identified by interval and layer. “_M” indicates mean for the respective variable. For example, “Time_M” is the mean time within interval “x”, and “Lat_M” is the mean latitude within interval “x”.

BCO-DMO processing notes:

merged all 4 datasets into 1 file
converted data to ISO_DateTime_UTC

hydroacoustics_all.csv