This dataset provides comprehensive records of species identified and their daily abundance in three deep-sites (Upper Slope -400m, Wall -900m, and Axis -1000m) of the Barkley Canyon (British Columbia, Canada) from 2012 to 2015.The data was collected through video recordings from the Ocean Network Canada observatory, which are publicly accessible using their SeaTube website.The dataset includes:- a detailed list of species = "species_list_match.csv"- a corresponding table of species names = "Species_details.csv"- daily abundance counts for each sites = "Abundance_SiteName.csv"- a file that outlines the methodology used for identification and counting = "ReadMe.txt"----------Method:- During each daily sampling, all 5-minute recordings made between 08:00 and 08:05 were viewed using VLC 2.0.1 © software to count and identify individuals at the lowest possible taxonomic level. All videos (2 minutes fixed + 3 minutes of scanning) were utilized. Videos were deemed unusable if viewing conditions were poor or particle counts were too high. When identification was not feasible, OTUs were defined.    On the three sites mentioned, a camera mounted on a tripod recorded continuously at 5-minute intervals each day of the year. During these recordings, the background was illuminated using two spotlights. The camera recorded fixedly for the initial two minutes and could rotate from 0° (stationary, upper slope, pod2) to 360° (full rotation, canyon axis pod1, except between August 2014 and January 2015) and 180° (canyon wall, pod4). The illumination and zoom parameters, adjustable via the ONC site, were not consistent across all sites and sampling periods, affecting the observed surface area, ranging from 0.5 m² (upper slope, pod2 between May 2013 and May 2014) to a maximum of 9 m² (canyon axis, pod1 between mid-2013 and February 2014). The surface area was calculated each time the camera settings were changed (usually during annual maintenance missions) using a scaling grid developed from the camera’s two lasers, fixing a width of 10 cm on the ground as measured in the camera's field of view. Image captures were taken at intervals to cover the entire surface swept by the camera during rotation, estimating the sampled surface by overlaying the scaling grid on each image.          - For more details on the methodology and to understand the context in which the data were collected (scientific questions, hypotheses, and studies conducted), you can refer to Pauline Chauvet's thesis (available in open access).

During the 2014 BICOSE cruise of RV Pourquoi Pas ? (Cambon-Bonavita 2014, https://doi.org/10.17600/14000100), biomass-dominant fauna was sampled in two deep-sea hydrothermal vent fields: Snake Pit and TAG (Mid-Atlantic Ridge). Stable isotope ratios and elemental contents of carbon and nitrogen of 137 samples belonging to 21 taxa were measured. Samples were identified and frozen at -80°C on board, then brought back to the laboratory for processing. They were prepared for analysis at the LEP (Laboratoire Environnement Profond, Ifremer, Centre de Bretagne, France; https://wwz.ifremer.fr/deep_eng/). Analytical measurements were performed at the LIENSs stable isotope facility (University of La Rochelle, France; https://lienss.univ-larochelle.fr/isotopic-spectrometry).The dataset consists of two files: one containing the data itself, and one describing all used terms (measurements or metadata).