What about the delta (ẟ13C)? A case for brackish fish in Mediterranean palaeodietary isotopic baselines

• Seventeen new ẟ 13 C and ẟ 15 N values reported from freshwater and estuarine fishes from the Levant. • Demonstration of the wide range (-27.97‰ to -10.87‰) of ẟ 13 C values encountered in ancient Mediterranean aquatic ecosystems. • Improved data available for constructing isotopic baselines and interpreting human palaeodiet. While a lot of paleodietary studies in the Mediterranean region have reported ẟ 13 C and ẟ 15 N values for humans, similar data for aquatic resources is much more limited. The aim of our paper is to make relevant data available for isotopic faunal baselines and future paleodietary research in the eastern Mediterranean. We analysed the collagen extracted from the bones of freshwater and brackish fish from two coastal archaeological sites in the Levant, Kinet Höyük (n = 21) (1550 BCE − 14th c. AD, present day Turkey) and Tell el-Burak (n = 8) (975–332 BCE, present day Lebanon). From the original 29 bones sampled, 17 (59 %) produced collagen which met quality control criteria and we present the corresponding ẟ 13 C and ẟ 15 N values here. Whereas freshwater and marine ecosystems in an area typically have distinctive ẟ 13 C values, paleodietary interpretations regarding aquatic resource consumption can be challenging when isotopic values reflecting the range of exploitable aquatic environments are not available. Bearing this in mind, our data set is used to demonstrate the potential range of ẟ 13 C values (−27.97 ‰ to −10.87 ‰) of freshwater and brackish environments along the Levantine coast, encouraging future palaeodietary studies in the region to consider this more robust isoscape for aquatic resources.