Effects of diel and seasonal cycles on the dive duration of the minke whale (Balaenoptera acutorostrata)

Minke whale (Balaenoptera acutorostrata) surfacing intervals were recorded over a period of three years in the coastal waters of Mull, Coll and the Sm all Isles, in the north-west of Scotland. Significant differences in surfac ing intervals were noted both throughout the day and throughout the year. S urfacing intervals were shortest at noon and in the months of June and July Surfacing intervals were longest both mid-morning and mid-afternoon and du ring May and August. Differences in surfacing intervals were interpreted to be the result of ecological changes such as different foraging strategies. Consequently the results of this study have an impact on the methodologies and designs of minke whale sightings surveys.