Occurrence of killer whales in Scottish inshore waters: temporal and spatial patterns relative to the distribution of declining harbour seal populations

Sightings of killer whales around Shetland were recorded between 1991 and 2006 and for the whole of Scotland for 2007. The data were used to investigate temporal patterns in killer whale occurrence around Shetland and spatial patterns in occurrence around Scotland. 2. There was a strong seasonal peak in sightings around Shetland during June-July, coinciding with the harbour seal pupping season. 3. There was no clear trend in annual sightings around Shetland between 1991 and 2006. 4. Killer whales were sighted most frequently around Shetland and the Pentland Firth as well as around Mull and the Treshnish Isles. 5. These findings are discussed in terms of potential impacts upon local declining harbour seal populations and future research requirements. Copyrightr2009 John Wiley & Sons, Ltd.