Regional patterns of δ(13)C and δ(15)N for European common cuttlefish (Sepia officinalis) throughout the Northeast Atlantic Ocean and Mediterranean Sea

Stable isotope compositions of carbon and nitrogen (expressed as δ(13)C and δ(15)N) from the European common cuttlefish (Sepia officinalis) were measured in order to evaluate the utility of using these natural tracers throughout the Northeast Atlantic Ocean and Mediterranean Sea (NEAO-MS). Mantle tissue was obtained from S. officinalis collected from 11 sampling locations spanning a wide geographical coverage in the NEAO-MS. Significant differences of both δ(13)C and δ(15)N values were found among S. officinalis samples relative to sampling location. δ(13)C values did not show any discernable spatial trends; however, a distinct pattern of lower δ(15)N values in the Mediterranean Sea relative to the NEAO existed. Mean δ(15)N values of S. officinalis in the Mediterranean Sea averaged 2.5‰ lower than conspecifics collected in the NEAO and showed a decreasing eastward trend within the Mediterranean Sea with the lowest values in the most eastern sampling locations. Results suggest δ(15)N may serve as a useful natural tracer for studies on the population structure of S. officinalis as well as other marine organisms throughout the NEAO-MS.