A Zooarchaeological and Paleoclimate Analysis of Gadus Morhua Otoliths Recovered from the Sandwick South Site, Shetland Islands, United Kingdom

The Shetland Islands are an archipelago 240 km northeast of the northern tip of mainland Scotland and 360 km west of Bergen, Norway (Figure 1.1). The Gulf Stream, which flows from the Gulf of Mexico to the coast of Norway, passes along the western side of the Shetland Islands, leading to a warmer climate than would be predicted by their latitude. On the eastern side lay the colder waters of the North Sea, which also impact the climate of the islands. During the period in which the Sandwick South site was inhabited, 1100-1350 AD, paleoclimate reconstructions show a transition from a warmer period, the Medieval Climatic Optimum, to a distinctly cooler period, the Little Ice Age (Mann 2009). This transition has not been heavily studied in the Shetland Islands, as the acidic, non-arable soils of the Shetland environment makes many paleotemperature proxies difficult to reassemble. One paleotemperature record that can be used in the Shetland Islands is the otolith record, in which the 18O values of aragonite from inner ear bones of fish are utilized to reconstruct paleotemperature at the time the fish lived. These inner ear bones are collected from midden units within settlements. In addition to paleotemperature data, otoliths can also reveal information about the fishing methods of the inhabitants of the islands and ecological impact that the fishing had on the fish population. Refining our knowledge of paleoclimate records can not only help to understand the potential future shifting of climate systems, but can also be a valuable tool in determining the effect that climate has on people living in the environment. Fish otoliths are an especially important source of information for a society heavily dependent on fishing for its livelihood, as they can provide a high resolution record throughout the inhabitation of a site