Identification of the geographical origin of wild rice field eel (Monopterus albus) in China by stable isotopes

Abstract

The mislabeling of wild rice field eel (Monopterus albus) origin disrupts market order and hinders ecological research and conservation. To address this, 100 wild eel samples were collected from five regions across three major river basins in China. For the first time, stable isotope ratio analysis (δ¹³C, δ¹⁵N, δ²H, and δ¹⁸O) was used to assess geographic variation. Results showed significant regional differences: samples from Shanghai had lower δ¹³C and higher δ¹⁵N ratios, while those from Nanning exhibited significantly higher δ²H and δ¹⁸O ratios (p < 0.05). These differences reflect environmental and trophic distinctions among habitats. Partial least squares discriminant analysis (PLS-DA), validated through leave-one-out cross-validation, achieved an overall classification accuracy of 92 %, with identification rates exceeding 90 % for each region. This study demonstrates that stable isotope analysis is a reliable tool for tracing the geographic origin of wild eels in China, improving product traceability, supporting conservation, and enhancing consumer trust.