Stable isotope analysis versus TROPH a comparison

Authors: Felipe Amezcua Víctor MuroTorres Martín F SotoJiménez

Publish Date: 2015/04/29

Volume: 49, Issue: 2, Pages: 235-250

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Abstract

Ecosystembased fishery management programs require a reliable estimate of the trophic positions of aquatic resources Both stable isotope analysis SIA and stomach content analysis SCA have been used to estimate the trophic positions TP of aquatic systems but few studies have compared results from both methods To determine whether the two methods produced similar results we used SIA δ15N and δ13C SCA estimated with the TROPH routine and data from FishBase to estimate the TP of 66 fish species in a subtropical estuarine system of the Gulf of California SIA values ranged from 26 to 56 with 56  of the species having a SIA value above 45 and 14  of the species having a SIA value below 4 The SCA values ranged from 26 to 48 with 76  of the species having a SCA value of 3–4 Overall SCA results underestimated TP including FishBase data while SIA yielded better results particularly if both δ15N and δ13C are used The TROPH routine has oversimplified assumptions such as the same TP for all organisms in the same taxon but if SIA is unavailable SCA could be used accompanied by knowledge of the TP of the most important prey itemsThe authors thank all of the students who helped us with the SIA and SCA and E Jaffer for the English editing We thank the editor and anonymous reviewers for their constructive comments which helped us to improve the manuscript This work was supported by the research project PAPIITIN2174083 and IN208613

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