Nonlethal sampling for stable isotope analysis of juvenile Chinese sturgeon (Acipenser sinensis ): Comparing δ13 C and δ15 N signatures in muscle and fin tissues

Abstract

We compared δ13C and δ15N 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 (120–373 mm) 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 (δ13CDM = 0.939 × FC − 2.577; δ15NDM = 0.737 × FC + 4.638) or constants factors (δ13CDM = δ13CFC − 1.27; δ15NDM = δ15NFC + 0.59); (2) no size-based relationships with δ13C and δ15N from either fin or muscle; (3) lipid extraction significantly improving the fin and muscle regression model fit for both δ13C and δ15N 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.