Photo-identification of the minke whale Balaenoptera acutorostrata off the Isle of Mull, Scotland

Abstract

Sea Life Surveys, set up by Richard Fairbairns in 1990, conducts research and whale-watching trips in the waters around the Isle of Mull on the West Coast of Scotland. The main focus of this research is the Minke Whale Balaenoptera acutorostrata and since 1990 a photographic database has been collected containing photographs and sightings information. This database was analysed to evaluate the potential of using photo-identification to identify individual minke whales. Twenty-eight minke whales have been identified using distinguishing features such as dorsal fin notches, scars to the body and lateral body pigmentation. Fifteen whales have been seen at least twice, eleven of which have been sighted in more than 1 year. This suggests that some minke whales show site fidelity in returning to the area in successive years. Ten of the identified whales have been sighted at least twice within 1 year, with eight of these sighted in at least two different months of that year. This suggests that some minke whales are seasonally resident in the waters around Mull. There appears to be no evidence of any exclusive ranges as shown by minke whales in the eastern North, Pacific. However the data suggest that the whales tend to move progressively northwards throughout the season. This could be explained by spatial changes in prey abundance or temporal changes in the whales' selection of diet.