Nonlethal sampling for stable isotope analysis of juvenile Chinese sturgeon (Acipenser sinensis): Comparing δ13C and δ15N signatures in muscle and fin tissues

We compared C-13 and N-15 values of muscle with fin from juvenile Chinese sturgeon (Acipenser sinensis), to evaluate the feasibility of using nonlethal (fin) as an alternative to lethal (muscle) sampling. Size and lipid effect on the relationship between fin and muscle were also investigated. Dorsal muscle (DM) and fin clip (FC) were collected from A.sinensis with different body length (120-373mm) in the Yangtze Estuary for isotope analysis. The result showed that (1) muscle isotope values could estimated by the values of fin, from either use the regression model (C-13(DM)=0.939xFC-2.577; N-15(DM)=0.737xFC+4.638) or constants factors (C-13(DM)=C-13(FC)-1.27; N-15(DM)=N-15(FC)+0.59); (2) no size-based relationships with C-13 and N-15 from either fin or muscle; (3) lipid extraction significantly improving the fin and muscle regression model fit for both C-13 and N-15 values. Therefore, this study support the use of nonlethal fin tissues for isotope analysis of juvenile A.sinensis, and will allow trophic studies to avoid the effect of lipid accumulation from muscle.