Abstract
The Pentland Firth and Orkney waters are important for both grey and harbour seals. Both species are resident, using the area for all aspects of their life cycle. The area is also high in wave and tidal energy and areas in the Pentland Firth and Orkney waters have been leased for both demonstration and commercial renewable energy production projects.
This report aims to assess the potential for overlap between areas around Orkney and the Pentland Firth that are used by seals and those proposed for wave/tidal energy development. In particular, the spatial and temporal overlap between seals and the location of potential renewable energy devices was required.
Main Findings
- In 2008, 37% of Orkney grey seal pups were born at colonies close to or within the Pentland Firth.
- Numbers of grey seals hauling out during the summer have not changed particularly in recent years.
- When foraging, adult grey seals routinely move large distances.
- The main overlap between grey seals and areas of high tidal current/potential development appears to be in the Pentland Firth, particularly the area around Stroma, Swona and the Pentland Skerries (which are heavily used for both breeding and hauling out).
- Harbour seal numbers in Orkney declined by 63% between 2001 and 2008. On the north coast of Scotland, they declined by 41% between 1997 and 2008.
- Harbour seal movements are relatively local, and there is less movement between haulout regions than there is for grey seals.
- Costa Head, the licensed area to the west of Rousay, overlaps a corridor that harbour seals use to move to and from a foraging area to the west of Orkney.
- Both seal species use the whole water column when diving.