Carbon and nitrogen isotopic values of muscle and mantle in Mediterranean endemic bivalve Pinna nobilis individuals have been analyzed to study tissue fractionation. Muscle tissue is enriched in both δ13C and δ15N compared to mantle on average 1.11 ‰ and 0.71 ‰, respectively. Analyses of mantle tissue do not involve sacrifice of individuals and are therefore proposed as a conservation tool in the study of P. nobilis
