Effects of skeletal element identity, delipidation and demineralization on the analysis of stable isotope ratios of C and N in fish bone

Abstract

Stable isotope ratios of C and N in the bone tissue of three different skeletal elements (angular, cleithrum and vertebra) of three fish species from different evolutionary lineages (Clupeiformes, Atheriniformes and Notothenioidei) were determined before (δ¹³ C_bulk and δ¹⁵ N_bulk ) and after demineralization and delipidation (δ¹³ C_dml and δ¹⁵ N_dml ). One of the species had cellular bone and the other two had acellular bone. Results revealed that δ¹⁵ N and δ¹³ C values from different skeletal elements were interchangeable in species with acellular bone, but caution was needed in species with cellular bone, as δ¹⁵ N values varied among skeletal elements. Furthermore, δ¹⁵ N_bulk values were significantly lower than δ¹⁵ N_dml values in the three species, thus suggesting that they are not comparable. This difference is probably because δ¹⁵ N_bulk refers to total bone protein and δ¹⁵ N_dml to collagen only.

Keywords: Eleginops maclovinus; Odontesthes nigricans; Sprattus fuegensis; acidification; zooarchaeology.