. The Canadian field-naturalist. 236 The Canadian Field-Naturalist Vol. 92. Figure 1. Aerial survey tracklines, November-April 1975-1977. Results and Discussion Figures 1 and 3 show aerial tracklines flown during the winter (November-April) and summer (May-October) months, respectively. Figures 2 and 4 depict Beluga sightings for corresponding time periods. Most trackhnes in Figures 1 and 3 were covered more than once during each 6-mo period: consequently these illustrations portray minimum survey range and intensity for each half-year. Specific months during which surveys were conducted are d
. The Canadian field-naturalist. 236 The Canadian Field-Naturalist Vol. 92. Figure 1. Aerial survey tracklines, November-April 1975-1977. Results and Discussion Figures 1 and 3 show aerial tracklines flown during the winter (November-April) and summer (May-October) months, respectively. Figures 2 and 4 depict Beluga sightings for corresponding time periods. Most trackhnes in Figures 1 and 3 were covered more than once during each 6-mo period: consequently these illustrations portray minimum survey range and intensity for each half-year. Specific months during which surveys were conducted are discussed below. Table 1 lists chronologically all Beluga sightings for these surveys and includes relevant environmental data. We observed 99 animals on 29 occasions for a mean animals/observation. In no instance did we encounter large groups of hundreds or thousands such as those reported in Hudson Bay or the Mackenzie Delta, Canada (Sergeant and Brodie 1975). Our relatively low mean herd size is probably a result of the fact that we may not have censused prime migratory routes during migration, nor did we survey calving grounds. Further, Beluga apparently are not as numerous in Alaska as in Canada (Sergeant and Hoek 1974). Numbers of observed Beluga are minimum estimates since Cetacea spend considerable time at depths which do not allow visual detection: nevertheless patterns of geographical and habitat usage emerge from these surveys. Western Beaufort Sea Surveys in this region were conducted during July and August and the region contained 6000 km of trackline. Beluga pass through these. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
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