Stable isotope data for benthic, demersal and pelagic fauna off western and southern Mallorca (Western Mediterranean) at two seasons (December and July) and three depth strata (250, 650 and 850 m)

Natural abundance values of stable isotopes (δ13C and δ15N) were measured in three pooled size-based groups of zooplankton (50–200, 200–500, and >500 µm) and 78 species or genera from the hyperbenthic and pelagic domains. The taxonomic records include 23 decapod crustaceans, 21 cephalopods, 1 gastropod, 17 osteichthyes, 2 chondrichthyes, 7 peracarids, 1 echinoderm, 2 thaliaceans and 1 brachyopod. This dataset comprises 815 records, including δ13C, δ15N, %C and %N, which were obtained, depending on the species size, from bulk tissues, whole or pooled individuals. It also provides the count and size (in mm) of sampled organisms from the dominant species in the area, representing 70% of the total catch in terms of total biomass or numerical abundance (Quetglas et al. 2014; Olivar et al. 2012; Simao et al. 2014).