Human exploitation may not be the cause for the declining size of Patella vulgata (Common limpet): A comparison between the Late Norse and the modern populations of Patella vulgata at Sandwick Bay, Unst, Shetland Islands, UK
Date of Graduation
Bachelor of Science
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Zooarchaeological artefacts like shells are a source of information on the exploitation of prehisotric the rocky intertidal zone. In this study the size and density of Patella vulgata was used to investigate the exploitation of rocky intertidal resources during the Late Norse occupation (1100-1350 AD) of Sandwick, Unst, Shetland, UK. The Patella vulgata collected by the Late Norse at Sandwick were compared to the modern population currently at Sandwick Bay. There was a 7% decline in the mean length of P. vulgata from 39.9mm in 1100 AD to 30.5 mm in the 1350 AD, a result that has been explained by the harvesting strategy of the Late Norse to pick the larger shells in the population. Most archaeological studies have not compared prehistoric size trends to modern populations. This study compares the Late Norse population to the modern and finds the modern population mean of 29.5 mm is 8% smaller than the beginning of the Late Norse population and 1% smaller than the population at the end of the Late Norse occupation. The size of the Sandwick modern population suggests the decline in size of the Sandwick population during the Late Norse occupation as well as other prehistoric populations might be a result of ecological factors and not human predation. Competition due to the high density in 2013, 42.5 individuals/m2, and of 74.0 individuals/m2 in 2012 of the modern population may be one of the ecological factors that can explain a decline in Patella vulgata size.
Silverberg, Sarah Mae Brennan, "Human exploitation may not be the cause for the declining size of Patella vulgata (Common limpet): A comparison between the Late Norse and the modern populations of Patella vulgata at Sandwick Bay, Unst, Shetland Islands, UK" (2014). Standard Theses. 36.