2014, SMRU Marine, Skerries, Marine Mammal Monitoring series https://portal.medin.org.uk/portal/start.php?tpc=015_5a388a4b-9921-42c9-8461-aa4f43379351 There is a range of monitoring methodologies available for monitoring marine mammals at marine renewable energy sites (Macleod et al. 2011; Sparling et al. 2011). However, the location and scale of the Anglesey Skerries Tidal Array Project site presents a particular set of challenges with respect to collecting marine mammal data. Traditional vessel based line transect surveys do not yield data of sufficient spatial and temporal resolution to fully inform questions of risk relating to a project of this scale nor provide a suitable baseline against which to measure change given the resolution of sampling and the likely natural variation. Additionally vessel based line transect surveys are generally not feasible year round given expected weather conditions and wave climate at such an exposed site. Static PAM methods are a challenge in highly noisy and energetic areas such as tidal sites and only appropriate for echolocating cetaceans and are not suitable for monitoring seals. However, since the development area is just under two kilometres from shore it is also not optimal for shore based vantage point surveys. In order to assess whether shore based data collection methods would be suitable for pre-installation monitoring at the Skerries site, a land-based vantage-point (VP) transect survey trial was implemented to determine if recent advances in vantage point methods and analytical approaches could provide sufficient data to meet the monitoring objectives set out in the EMAMP. 20210517T14:06:22