Fine-scale harbour seal at-sea usage mapping around Orkney and the North coast of Scotland

Abstract

The report describes how fine-scale harbour seal usage maps around Orkney and the north coast of Scotland, UK, can be used and interpreted, the caveats and limitations, and methodology used to produce them (Appendix A). 1. Harbour seal movement data from telemetry tagged seals, collected between 2003 and 2015, were combined with terrestrial count data. The most recent year that count data were collected from each onshore location was used, which ranged from 2008 to 2015. Population-level species distribution maps and associated confidence intervals were produced around Orkney and the north coast of Scotland at a resolution of 0.6 km x 0.6 km. 2. At the time of publication, the usage maps are available to download in geo-referenced formats from the Marine Scotland Information website at the following address (http://marine.gov.scot). 3. Seasonal usage was investigated (Appendix B). There were a number of data and numerical constraints that meant robust seasonal usage maps could not be produced. To address these constraints, recommendations of telemetry and terrestrial count data collection and further analysis are made.