Geographical discrimination of swimming crabs (Portunus trituberculatus) using stable isotope and multi-element analyses

Abstract

Reliable identification of the origin of economically important animal species is essential to preventing fraud. We investigated the efficacy of stable isotope and multi-element analyses in claw meat, abdominal meat, gills, and the hepatopancreas of swimming crabs (Portunus trituberculatus) using specimens from three discrete production areas in China and developed an origin discrimination model using stepwise discriminant analysis. Stable isotope ratios (δ13C, δ15N) and the contents of 14 elements (Na, Mg, Al, K, Mn, Fe, Co, Cu, Zn, As, Se, Rb, Ag, and Ba) varied significantly by tissue and by sampling location (P < 0.01). Obvious isotopic fractionation effect was observed among different tissues, the muscle tissue and gills isotope ratios were more effective geographical origin indicators than hepatopancreas. Although the accumulation effects of the elements differed between tissues, the discriminatory correctness was generally consistent across tissues. By combining stable isotopes and elemental contents., stepwise discriminant analysis of these indicators was continued at the 0.01 level of significance, and the correct extent of discrimination was improved for all tissues. The correct extent of discrimination of claw meat, abdominal meat, gills, and hepatopancreas were 100%100 %, 100 %, 100 % and 94.7 %, respectively, indicating that all crab tissues can distinguish the origin of P. trituberculatus to some extent. This method supports the geographical traceability and origin identification of P. trituberculatus.