Geographical Traceability of Anguilla japonica from Different Habitats Successfully Achieved Using Muscle Elemental Fingerprint Analysis

Anguilla japonica is a catadromous fish widely distributed in coastal areas, rivers, and adjacent water bodies in China, North Korea, Japan, and other regions. The Yangtze River Estuary serves as a crucial passage for A. japonica migrating downstream to the sea. The peak migration period occurs from late September to early November each year, during which a large number of adult A. japonica appear on the market. However, during market supervision and law enforcement, it is difficult to determine their origin and whether they come from prohibited fishing areas. Therefore, there is an urgent need to trace the origin of A. japonica from different water bodies. This study used muscle elemental fingerprint analysis (EFA) to determine the geographical origin of A. japonica from different water bodies. The results showed that A. japonica from different habitats had distinct elemental compositions in their muscles. Specifically, A. japonica from estuary waters (EW) were characterized by significantly higher levels of V and Hg compared to other water bodies. Na was identified as a key discriminant element among different habitats, with its content significantly increasing in river waters (RW), EW, and offshore waters (OW), respectively. Discriminant analysis selected four discriminant elements (V, Hg, Na and Cu) from 21 elemental compositions, among which V, Hg and Na were the three key distinguishing elements. Based on the composition of these four discriminant elements in the muscles of A. japonica from different habitats, hierarchical cluster analysis (HCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and linear discriminant analysis (LDA) were applied and validated, successfully achieving rapid and accurate origin tracing and verification for new samples. Therefore, the application of muscle EFA can achieve geographical traceability of A. japonica from different habitats. The analytical method and verification process for origin tracing established in this study can be successfully applied to market supervision for tracing the origin of samples with unknown sources.