Abstract

Results of an aerial sightings survey conducted in coastal (within the 600m depth contour) Icelandic waters from 27 June-20 July 1986 are presented. The survey followed a predetermined random grid, stratified according to assumed densities of minke whales in the different areas. The total surveyed track was 5,300 n.miles (9,817km) flown in approx. 58 hours at an altitude of 750 ft (228.6 m) and an average speed of about 92 miles/hour {165 km/hr). A total (average school size in parenthesis) of 24 fin (1.7), 2 blue (1.0), 54 humpback (2.3), 211 minke (1.1), 12 sperm (1.0), 14 killer (2.3), 119 pilot (14.7) and 3 northern bottlenose (3.0) whales was observed in addition to 1,122 white-beaked dolphins (7.2), 89 Atlantic white-sided dolphins (6.4) and 126 harbour porpoises (1.7). The influence of environmental conditions, position of observers in the plane and between-observer differences on sightability is discussed. It is found that sightability is better from the 61cm plexiglass bubble window in the rear than from the blister nose window, particularly at short distances and beneath the plane. Although no minke whale population estimate is produced due to the need for further information on correction factors, it is concluded that aerial surveys, particularly if utilising the ‘cue-counting’ technique, are suitable for estimating the minke whale population size in Icelandic coastal waters.