Dear MARMAMers, Last year, the following PhD thesis was completed investigating harbour porpoises habitat preferences and distribution using six years of visual and acoustic line-transect survey data west of Scotland. Habitat preferences and distribution were assessed at a range of temporal and spatial scales. In addition the PhD looks at the prevalence and received levels of Airmar seal scarers deployed and the potential for these sounds to impact porpoises via cumulative exposures. It is now publicly available for download from: http://research-repository.st-andrews.ac.uk/handle/10023/1701 Thesis citation: Booth, 2010. Variation in habitat preference and distribution of harbour porpoises west of Scotland. PhD Thesis. Scottish Oceans Institute. University of St Andrews. pp264. Abstract: “The waters off the west coast of Scotland have one of the highest densities of harbour porpoise (*Phocoena phocoena*) in Europe. Harbour porpoise are listed under Annex II of the EU Habitats Directive, requiring the designation of Special Areas of Conservation (SACs) for the species’ protection and conservation. The main aim of this thesis is to identify habitat preferences for harbour porpoise, and key regions that embody these preferences, which could therefore be suitable as SACs; and to determine how harbour porpoise use these regions over time and space. Designed visual and acoustic line-transect surveys were conducted between 2003 and 2008. GAMs with Generalised Estimating Equations (GEEs) were used to determine relationships between the relative density of harbour porpoise and temporally and spatially variable oceanographic covariates. Predictive models showed that depth, slope, distance to land and spring tidal range were all important in explaining porpoise distribution. There were also significant temporal variations in habitat use. However, whilst some variation was observed among years and months, consistent preferences for water depths between 50 and 150 m and highly sloped regions were observed across the temporal models. Predicted surfaces revealed a consistent inshore distribution for the species throughout the west coast of Scotland. Regional models revealed similar habitat preferences to the full-extent models, and indicated that the Small Isles and Sound of Jura were the most consistently important regions for harbour porpoise, and that given this consistency; these regions could be suitable as SACs. The received levels and impacts of Airmar seal scarers on distribution and habitat use of porpoises were also investigated, and there were indications that these devices have the potential to displace harbour porpoise and that the potential for auditory injury should be considered in response to cumulative exposures. These results can be considered in the assessment of sites for SAC designation, and in implementing appropriate conservation measures for harbour porpoise.” Please contact me on cgb8@st-andrews.ac.uk if you have any questions or would like to discuss the work in more detail. Best regards, Cormac Booth