Acid treatment of Atlantic salmon (Salmo salar) scales prior to analysis has negligible effects on δ13C and δ15N isotope ratios

Abstract

There is debate in the literature as to whether scales of fishes require acidification to remove inorganic carbonates prior to stable isotope analysis. Acid-treated and untreated scales from 208 Atlantic salmon from nine locations on both sides of the Atlantic were analysed for δ¹³C and δ¹⁵N. Linear mixed-effect models determined the effect of acid treatment to be statistically significant. However, the mean difference was small (δ¹³C 0.1 ± 0.2‰, δ¹⁵N -0.1 ± 0.2‰) and not of biological relevance. This study concludes that Atlantic salmon scales do not need to be acidified prior to stable isotope analysis.

Keywords: Atlantic salmon; Salmo salar; acidification; decalcification; fish scales; stable isotope analysis.