MEPS 613:211-216 (2019)  -  DOI: https://doi.org/10.3354/meps12893

ABSTRACT: Stable isotope analysis (SIA) has become a useful tool to investigate food web structures in Arctic marine ecosystems. This method requires assumptions about how isotopes are assimilated from food into tissues. Few controlled lab experiments have determined the appropriate trophic discrimination factors (TDFs) for Arctic marine species, thus many studies have resorted to using global averages or values determined from species in different habitats or taxa. We examined the trophic niche space for prey resources predicted from the isotopic ratios of fish collected in the coastal Beaufort and Chukchi Seas using several published Arctic marine TDFs. The different predictions were compared to highlight the implications of selecting appropriate TDFs in Arctic marine food web models. Predicted trophic niche space of prey resources differed greatly depending on the TDFs used, and the most appropriate TDFs from those that are currently available were identified for modeling Arctic nearshore lower trophic levels.

KEY WORDS: Trophic · Enrichment · Fractionation · Carbon · Nitrogen · Fish · Plankton