The dataset is composed of raw files (.raw) recorded with a SIMRAD EK60 three-frequency (38, 120, 200 kHz) split-beam echosounder that was operated continuously during the ArcticNet cruise aboard the CCGS Amundsen from 2006 to 2016 (no data were collected in 2012 due to the CCGS Amundsen being in dry dock). All three 7° transducers were hull-mounted and calibrated prior to departure. The acoustic signal was recorded continuously on a PC using ER60 software version 2.0.0. Ping rate varied from 1 to 2 seconds depending on maximum depth, and the pulse length was set at 1.024 milliseconds. The files can be read with the open source programming software R, other proprietary programming software like MATLAB or with specific proprietary software for hydro-acoustic analysis such as Echoview (https://www.echoview.com/​).

The dataset is composed of raw files (.raw) recorded with a SIMRAD EK60 three-frequency (38, 120, 200 kHz) split-beam echosounder that was operated continuously during the ArcticNet cruise aboard the CCGS Amundsen from 2017 to 2019. To ground-truth the hydroacoustic signal, various sampling techniques were applied throughout the cruise track such as midwater and bottom trawling as well as plankton net deployments.

The dataset is composed of Ichthyoplankton and zooplankton captured during the ArcticNet cruise aboard the CCGS Amundsen from 2017 to 2019. Three samplers fitted with 200 µm to 500 µm mesh nets were used for zooplankton collection . One was a metallic structure with 4 nets of 1 square meter opening each (2x2 multiple net sampler) for water column integrated sampling pulled vertically over from 10 m above the bottom to the surface to catch mesozooplankton. The other sampler was 2 nets of 1 square meter opening each towed at 10 m depth for 20 minutes at 2 knots to catch ichthyoplankton and macrozooplankton. Finally, a 0.5 square meter opening multinet Hydrobios for stratified sampling into nine layer also hauled vertically from 10 m above the sea bottom to the surface. Zooplankton samples were preserved in a 10% buffered formalin seawater solution and were sieved through 1000 µm and 200 µm sieves for analysis. Ichthyoplankton was identified to the lowest taxonomic level possible, a sub-sample was measured and all larvea were kept in ethanol.

The dataset is composed of adult fish species captured during the ArcticNet cruise aboard the CCGS Amundsen from 2017 to 2019. Pelagic fish were caught with an Isaacs-Kidd Midwater Trawl (IKMT, 9-m2 rectangular mouth aperture with mesh sizes of 11 mm in the first section and 5 mm in the last section). It was deployed from the surface to depths targeting possible aggregation of fish as recorded by the acoustic echosounder from the ship. Demersal and benthic fish were sampled with a bottom beam trawl (3-m2 rectangular aperture with a headline and a footrope of 4.27 m and a cod-end mesh of 9.5 mm) deployed on the seafloor. The pelagic and bottom trawls were towed at ~3 knots for 10 to 20 min. All fish collected by the trawls were measured and identified at least to the family level before freezing at -20°C.

Ocean Mapping Group acoustic data generated from the 2003 multibeam sonar survey on the 2003 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

Ocean Mapping Group acoustic data generated from the 2007 multibeam sonar survey on the 2007 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

Ocean Mapping Group acoustic data generated from the 2006 multibeam sonar survey on the 2006 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

Ocean Mapping Group acoustic data generated from the 2010 multibeam sonar survey on the 2010 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

The datasets present new data from microscopic counts and selected nutrient and physical data assembled from the following missions. Aboard the CCGS Louis St-Laurent: IPY Canada's Three Oceans 2007. Aboard the CCGS Amundsen: International Polar Year (IPY) Circumpolar Flaw Lead Study 2008; ArcticNet 2008. Temporal coverage is July-September. Cell density of the three sub-clades MAST-1A, MAST-1B and MAST-1C was measured by cell-counts using fluorescent in situ hybridization with taxa-specific probe. Biomass of phototrophic organisms, of different size classes, was obtained by counts of DAPI-stained cells under epifluorescence microscopy. Samples for total chlorophyll a (chl a) were filtered onto GF/F filters, extracted in either ethanol or acetone and analysed by spectrofluorometry. Chl a was also measured for the < 3 µm size fraction, and chl a in the < 3 µm size fraction was calculate by simple substraction. CCGS Amundsen data: Temperature, salinity, transmissivity, oxygen, and photosynthetically active radiation were provided by Dr. Y. Gratton (Institut National de la Recherche Scientifique, Québec). Nitrate and Phosphate concentrations were provided by Dr. J.-É. Tremblay (Université Laval, Québec). CCGS Louis St-Laurent data were supplied by Drs. E.C. Carmack and J. Nelson (Institute of Ocean Sciences, Sidney, B.C.). Distance to ice edge was obtained from the Canadian Ice Services (http://ice-glaces.ec.gc.ca).

Ocean Mapping Group acoustic data generated from the 2004 multibeam sonar survey on the 2004 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.