Data from: Stable isotope-based location in a shelf sea setting: accuracy and precision are comparable to light-based location methods

Retrospective determination of location for marine animals would
facilitate investigations of migration, connectivity and food provenance.
Predictable spatial variations in carbon and nitrogen isotopes in primary
production across shelf seas provide a basis for stable isotope-based
location. Here, we assess the accuracy and precision that can be obtained
through dietary-isotope-based location methods. We build isoscapes from
jellyfish tissues and use these to assign scallops of fixed and known
individual location, and herring with well-understood population-level
distributions in the North Sea. Accuracy and precision for retrospective
isotope-based location in the North Sea were of a similar order to
light-based location devices, with 75% of individual scallops assigned
correctly to areas representing c. 30% of the North Sea, with a mean
linear error on the order of 102 km. Applying assignment methods to an
alternative migratory species (herring) resulted in ecologically realistic
assignments consistent with fisheries survey data. Location methods based
on dietary isotopes such as carbon and nitrogen recover the spatial origin
of nutrients assimilated into tissues, and this may not correspond
directly to the physical location if either the test animal or its prey is
highly migratory. Stable isotope-based location can be applied to any
marine-feeding organism or derived food product, but the ecological
meaning of any assigned area will be more difficult to interpret for
large, high trophic level, migratory animals with relatively slow isotopic
assimilation rates.