Prey_StableIsotopes_Data_Hyrenbach

This file summarizes the stable isotope (delC13 and delN15) of prey items recovered from the stomach contents of skipjack tuna (from 40 to 84 cm fork length, FL) captured northeast of Oʻahu (21.477° N, 157.757° W) between May 20 and September 2 of 2020. The dataset involves 53 fish, 14 squids, and 47 crustaceans. White muscle was sampled from fish, the mantle was sampled from the squids, and entire crustaceans were analyzed. Due to the influence of inorganic carbon in crustacean exoskeletons, their samples were analyzed twice: one for delN15, and once for delC13. Before the samples for analyzed for delC13, they were acidified to remove the inorganic calcium carbonate. The samples were analyzed for carbon and nitrogen bulk stable isotopic composition at the University of Hawaiʻi at Manoa Biogeochemical Stable Isotope facility using a Costech ECS 4010 Elemental Combustion System, with a Zero Blank Autosampler, a ThermoFinnigan MAT Conflo IV, and a ThermoFinnigan DeltaXP.​​ Each sample yielded mass of carbon (mg) and nitrogen (mg), and the isotopic values for δ13C (‰) and δ15N (‰).The δ values were calculated using the following equation: δX = [(Rsample/Rstandard)-1] * 1000,where X is 13C and 15N and R is the ratio of heavy isotope to light isotope, for carbon (13C/12C) and nitrogen (15N/14N), respectively.