Stable isotope measurements as analytical tools for the traceability of crocodile–derived products

Abstract

In this preliminary study we examined the application of dual stable isotope analysis (δ13C and δ15N) to identify the origin of skins and meat derived from wild and farmed crocodiles. Traceability protocols can benefit from analytical techniques that are able to distinguish farmed or wild organisms. Scutes and muscle samples were obtained from wild and farmed crocodiles Crocodylus acutus (n = 14) and C. moreletii (n = 9). Isotopic values in scutes differed significantly between wild and farmed organisms, this difference being higher for δ15N than for δ13C values. When both isotopic values were integrated using a discriminant analysis, we observed a significant categorization. The isotopic values of muscle samples were very similar to those measured in scutes from the same individuals. In addition, two specimens of C. acutus were kept on a constant diet for 97 days to obtain reference isotopic values and tissues were compared. We also estimated the isotopic discrimination factors between tissues and the supplied diet.