Neolithic cod (Gadus morhua) and herring (Clupea harengus) fisheries in the Baltic Sea, in the light of fine-mesh sieving: a comparative study of subfossil fishbone from the late Stone Age sites at Ajvide, Gotland, Sweden and Jettbole, Aland, Finland

During the Late Stone Age, the sites of Ajvide and Jettbole were located on the seashore but in quite different marine environments. Ajvide on Gotland had direct access to the open sea of the central Baltic, while Jettbole in the Aland archipelago was surrounded by islands and skerries in the northern part of the Baltic Sea. Continuous excavations at Ajvide revealed large amounts of Cod (Gadus morhua) while herring (Clupea harengus) was found in small numbers. At Jettbole, as well, cod bones have been observed in large numbers while the skeletal remains of herring were few. In this study, soil samples of fishbone materials from Ajvide and Jettbole were sieved through screens of different mesh-sizes and then osteologically analysed. The finer screens aided the recovery of small herring bones that usually are lost when sieving through a common standard mesh-size of 4 mm. The results of the study confirmed the importance of fine-mesh sieving for the retrieval of the fishbone materials. Additionally, the achieved osteometric data indicated a difference in cod and herring size between the sites. Other factors that form our base for the understanding of Neolithic fishing strategies are: a general knowledge of the behaviour of the retrieved fish species, a reconstruction of the ancient marine environment and the abundance of fish species at each site.