Abstract
The summer range of belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) in Prince Regent Inlet, Barrow Strait and Peel Sound in the Canadian High Arctic was surveyed from 31 July to 3 August 1996 with a visual aerial survey of offshore areas and photographic aerial surveys of concentration areas. The visual survey estimate based on the number of belugas visible to the observers using systematic line transect methods was 10,347 (cv = 0.28). This included corrections for whales that were missed by the observers, observations without distance measurements and an estimate of 1,949 (cv=0.22) belugas from a photographic survey in southern Peel Sound. Using data from belugas tagged with satellite-linked time-depth recorders, the estimate was adjusted for individuals that were diving during the survey which resulted in an estimate of 18,930 belugas (cv = 0.28). Finally, counts of belugas in estuaries, corrected for estuarine surface time, were added to provide a complete estimate of 21,213 belugas (95% CI 10,985 to 32,619). The estimated number of narwhals corrected for sightings that were missed by observers was 16,364 (cv = 0.24). Adjusting this for sightings without distance information and correcting for whales that were submerged produced an estimate of 45,358 narwhals (95% CI 23,397 to 87,932).
Highlights
Belugas (Delphinapterus leucas) that summer near Somerset Island in the Canadian High Arctic migrate during the early fall to wintering areas in the North Water and off the west coast of Greenland (Fig.1)
Visual surveys of offshore areas Previous surveys and tagging studies show that the distribution of belugas during late July and early August is centred around Somerset Island in the waters of western Lancaster Sound, Barrow Strait, Peel Sound, Prince Regent Inlet, Wellington Channel and McDougall Sound (Fig. 2; Sergeant and Brodie 1975, Smith et al 1985, Martin et al 1993, Smith and Martin 1994, Koski et al 2002)
Distribution of belugas and narwhals The belugas were concentrated in the central parts of Prince Regent Inlet and in Peel Sound with only few sightings in Barrow Strait (Fig. 5)
Summary
Belugas (Delphinapterus leucas) that summer near Somerset Island in the Canadian High Arctic migrate during the early fall to wintering areas in the North Water and off the west coast of Greenland (Fig. 1). Koski et al (2002) estimated 10,250 to 12,000 belugas migrated at the surface along the south coast of Devon Island (see Fig. 2) from aerial counts in September 1979. Smith et al (1985) estimated there were 9,586 belugas (95% confidence interval (CI) = 2,699 – 16,471) in Lancaster Sound, Barrow Strait, and Prince Regent Inlet in July and August 1981. This estimate was based on strip transect surveys, offtransect sightings, and surveys of concentration areas. No correction factors were available for the number of belugas at the surface but missed by observers, as well as those that were below the surface when the survey airplane flew over-head
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