Carbon and nitrogen stable isotope compositions of thirteen deep-pelagic invertebrate species (Malacostraca, Cephalopoda, and Scyphozoa) sampled between 2017 and 2022 in the Bay of Biscay, Northeast Atlantic

The dataset contains carbon and nitrogen stable isotope compositions (δ13C and δ15N values, respectively) measured on a total of 730 individuals (corresponding to 127 analytical samples) belonging to 13 deep-pelagic invertebrates species (Systellaspis debilis, Ephyrina figueirai, Acanthephyra pelagica, Pasiphaea sivado, Pasiphaea multidentata, Meganyctiphanes norvegica, Sergia robusta, Haliphron atlanticus, Teuthowenia megalops, Histioteuthis reversa, Todarodes sagittatus, Atolla vanhoeffeni and Periphylla periphylla) collected on the Bay of Biscay slope, Northeast Atlantic. Organisms sampling was carried out by pelagic trawl in canyons of the continental slope of the Bay of Biscay during EVHOE scientific cruises ("Evaluation Halieutique de l'Ouest de l'Europe"; https://doi.org/10.18142/8), in autumn between 2017 and 2022. Trawls were conducted at night between 370 and 2000 m depth. Each haul was conducted at a selected depth. The average vertical mouth opening was about 24 m and the horizontal opening was about 58 m. Subsamples for stable isotope analysis were taken from the white dorsal muscle for Cephalopoda and Malacostraca, and from the whole organism for Scyphozoa. Small individuals of the same size sampled during the same trawling operation were grouped to have sufficient material for isotopic analyses. Analyses were performed using an isotope ratio mass spectrometer (Delta V Advantage with a Conflo IV interface, Thermo Scientific) coupled to an elemental analyser (Flash EA, 2000; Thermo Scientific). Results are presented in the usual δ notation relative to the deviation from international standards (PDB for δ13C values, atmospheric nitrogen for δ15N values), in parts per thousand (‰). Based on repeated measurements of USGS-61 and USGS-62, used as internal laboratory standards, the experimental analytical precision was <0.15‰ for both δ13C and δ15N values.