. The Canadian field-naturalist. . Figure 2. Distribution of the Blue Whale, Balaenoptera nmsculus, in Canadian waters. General Biology Most of the detailed accounts of Blue Whale biol- ogy result from studies carried out in the Antarctic (Mackintoshand Wheeler 1929; Nishiwakiand Haya- shi 1950; Nishiwaki and Oye 1951; Ruud, Jonsgard, and Ottestad 1950). The work has been well summarized in several more generalized accounts, particularly those of Ruud (1937, 1956). Perhaps the most important considera- tion of the Blue Whale's biology is its mode of feeding. Like most baleen whales it consumes
. The Canadian field-naturalist. . Figure 2. Distribution of the Blue Whale, Balaenoptera nmsculus, in Canadian waters. General Biology Most of the detailed accounts of Blue Whale biol- ogy result from studies carried out in the Antarctic (Mackintoshand Wheeler 1929; Nishiwakiand Haya- shi 1950; Nishiwaki and Oye 1951; Ruud, Jonsgard, and Ottestad 1950). The work has been well summarized in several more generalized accounts, particularly those of Ruud (1937, 1956). Perhaps the most important considera- tion of the Blue Whale's biology is its mode of feeding. Like most baleen whales it consumes plankton, but it is markedly stenophagous, its diet being restricted to euphausids (Beamish and Mitchell 1971; Gaskin 1976). Limiting Factors Commercial whaling has been the predominant cause of population decline, but the stocks are now protected from exploitation and should begin to increase. Whether or not they will reach pre- exploitation levels will depend on the extent to which they are affected by man's increasing activities in the marine environment, specifically in hydrocarbon developments. In this regard, whales do not migrate in large herds, but rather in twos or threes. Further, unlike Bowhead Whales {Balaena mysticetus) which skim their invertebrate food from the surface layers, Blue Whales generally feed below the surface. Special Significance of the Species The Blue Whale is the largest cetacean and also the largest mammal that has lived on earth. It was avidly sought after by the early pelagic whaling fleets, almost to the exclusion of other species, and as a consequence. 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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