Abstract
Ship based surveys were conducted over two to three days each month from November 2009. Visual data were analysed from November 2009 to October 2011. Acoustic data collection did not start until December 2010. Acoustic data collected between December 2010 and August 2011 have been analysed for this report. Initial exploratory spatial models for harbour porpoise showed significant variation in density with latitude and longitude but with patterns that rather conflicted between visual and acoustic data. These models did not include a time of day term. When time of day was included latitude and longitude were no longer significant in the acoustic model suggesting that apparent spatial variability could be explained by acoustic detection probability.The spatial patterns of grey seal distribution were more pronounced than those for harbour porpoise with highest densities in the NW and lowest in the SE of the survey region. However, grey seals showed little seasonal variation in density. Seasonal variation in density was pronounced for harbour porpoise with lowest numbers in May. The acoustic and visual data gave a broadly consistent picture of seasonal distribution but this was limited by the number of acoustic surveys which only spanned 9 months.