A pilot study on the river Hayle, Cornwall: the feasibility of local mink Mustela vison control and water vole Arvicola terrestris establishment

This study investigates mink distribution and activity using the mink raft methodology (Reynolds et al., 2004) along an Bkm section of the River Hayle in Cornwall. Floating rafts were placed in the river channel to monitor the presence and level of mink activity at every kilometre over a period of six weeks. The site was chosen, as the boundary to a larger area where the control of mink numbers has been proposed, and as a line that will defend against any future control within the Penwith peninsula. Results of the mink raft survey are discussed in relation to otter activity along the site. Mink were found to have a strong presence and are coexisting with otter on the River Hayle. This coexistence is thought to be made possible by the availability of alternative habitats, and as a result, prey for mink. There was a significant gap found either side of the site with greatest otter activity, which suggested that otters may be acting as barriers to mink movement along the river section. Mink control will be necessary for the establishment of future water vole populations in Cornwall. The Hayle has no current records for water vole, and yet, depending on its potential habitat suitability could be selected as an area for future water vole establishment. The suitability of the site to water vole establishment is explored and then interpreted using a decision model based on findings in the literature and relating to conditions required for water vole persistence. The tool developed in this study may have practical applications in comparing sites for establishing water voles in areas from which they are absent.Faculty of Science, Cornwall Wildlife Trus