De Robertis et al, 2017 - Chukchi shelf acoustic-trawl survey (corrected)

Abundance estimates of fishes from Acoustic-trawl surveys of the US sector of the Chukchi Sea continental shelf conducted in 2012 and 2013.

These surveys are described in

De Robertis, A., Taylor, K., Wilson, C., and Farley, E. 2017a. Abundance and Distribution of Arctic cod (Boreogadus saida) and other Pelagic Fishes over the U.S. Continental Shelf of the Northern Bering and Chukchi Seas Deep-Sea Research II, 135: 51-65. http://dx.doi.org/10.1016/j.dsr2.2016.03.002

De Robertis et al. 2017a applied calculations used selectivity relationships from

De Robertis, A., Taylor, K., Williams, K., and Wilson, C. D. 2017b. Species and size selectivity of two midwater trawls used in an acoustic survey of the Alaska Arctic. Deep Sea Research II, 135: 40-50.
http://dx.doi.org/10.1016/j.dsr2.2015.11.014

An error was discovered in a parameter these selectivity calculations, and a correction publication was prepared

De Robertis, A., Taylor, K., Wilson, C., and Williams, K. 2021. Corrigendum to: “Species and size selectivity of two midwater trawls used in an acoustic survey of the Alaska Arctic” (Deep-Sea Res. II 135 (2017) 40-50). Deep Sea Research II https://doi.org/10.1016/j.dsr2.2021.104997.

These files contain abundance data from De Robertis et al., 2017a reprocessed to use the corrected selectivity values given in table 1 of De Robertis et al., 2021.

The abundance change to only a small degree (see De Robertis et al., 2021). These revised data should be used in future studies.

We have also provided estimates of walleye pollock abundance that were not included in the original publication - these were computed with the methods described in De Robertis et al., 2017a,.

Changes in second version posted to Mendeley data ( files marked v4)
increased numerical precision of positions in csv files
Added UTC time

data are summarized in 0.5 nautical mile along-track intervals

*along_track_summary*.csv - overall summary for all species
Latitude - degrees N
Longitude - degrees W
Bottom_depth - average bottom depth
Time_UTC - date/time
Fish_38_kHz_sA - nautical area backscattering coefficient (m^2 / nmi^2) attributed to fish at 38 kHz
Zooplankton_120_kHz_sA- nautical area backscattering coefficient (m^2 / nmi^2) attributed to zooplankton at 120 kHz
Arctic_cod_No_m_sq - number of fish per meter squared of sea surface
Saffron_cod_No_m_sq - number of fish per meter squared of sea surface
Capelin_No_m_sq - number of fish per meter squared of sea surface
herring_No_m_sq - number of fish per meter squared of sea surface
pollock_No_m_sq- number of fish per meter squared of sea surface

* by_length_alongrack_per_m_squared*.csv - abundance by length in 1 cm bins for a single species
Latitude - degrees N
Longitude - degrees W
Bottom_depth - average bottom depth
Time_UTC - date/time
len_1_cm - number of fish per m^2 in the 0.5 to 1.5 cm size class
len_2_cm - number of fish per m^2 in the 1.5 to 2.5 cm size class
additional size classes follow the same format