Large yellow croaker (Larimichthys crocea), as an important marine economic fish in China, is currently facing the problem of declining quality under large-scale aquaculture mode. Stable isotope analysis of carbon and nitrogen (¹³C, ¹⁵N) provides an effective means for studying the nutritional intake, growth status, and health level of large yellow croaker. This study analyzed the carbon and nitrogen stable isotope composition of different tissues (muscles, scales, and mucus) in large yellow croaker, revealing the heterogeneity distribution characteristics of stable isotopes in large yellow croaker and establishing quantitative relationships between tissues. The results indicate that the heterogeneity of carbon and nitrogen stable isotopes in large yellow croaker mainly stems from the differences in isotopic fractionation and mixing among different components. There is a significant linear relationship between the stable isotope composition of carbon and nitrogen in scales and muscles, while the correlation with mucus is a bit lower. In addition, this study established a non-lethal sampling method for the determination of carbon and nitrogen stable isotopes in large yellow croaker. Non lethal samples (scales and mucus) from the surface of large yellow croaker were used as effective substitutes for muscle isotope quantitative analysis, which can provide reference for nutritional study and traceability identification of large yellow croaker.

large yellow croaker, stable isotopes, heterogeneity, non-lethal sampling, quantitative relationships