. The Canadian field-naturalist. 418 The Canadian Field-Naturalist Vol. 99 SHAPE OF BLOW DORSAL FIN FLUKES ON DIVE i. Figure \. The Blue Whale, Balaenoplera musculus. Population Size and Trend Atlantic: Quantitative information on the North- western Atlantic population is sparse, but Sergeant (1966) estimated a virgin stock of about 1500 from the cumulative catch in the early whaling period (1898- 1915). Present estimates, based upon strip censuses, are in the very low hundreds (Mitchell 1974). There may be 60-100 Blue Whales in the Gulf of St. Law- rence (D. E. Sergeant personal communication
. The Canadian field-naturalist. 418 The Canadian Field-Naturalist Vol. 99 SHAPE OF BLOW DORSAL FIN FLUKES ON DIVE i. Figure \. The Blue Whale, Balaenoplera musculus. Population Size and Trend Atlantic: Quantitative information on the North- western Atlantic population is sparse, but Sergeant (1966) estimated a virgin stock of about 1500 from the cumulative catch in the early whaling period (1898- 1915). Present estimates, based upon strip censuses, are in the very low hundreds (Mitchell 1974). There may be 60-100 Blue Whales in the Gulf of St. Law- rence (D. E. Sergeant personal communication), but there are no current studies on the populations south of Newfoundland and off Nova Scotia, and on their relationship to the animals in the Gulf. The relation- ships of present populations to past abundance are unknown, except that the areas of occurrence are the same (D. E. Sergeant personal communication). A series of recent strandings in southwestern Newfound- land (Mitchell 1974, 1978, 1979; D. E. Sergeant, per- sonal communication) suggests that the numbers may be increasing in the Gulf of St. Lawrence. North Pacific: During the period 1913-1965, Blue Whale catches from land stations in British Columbia averaged about 14 per year, with a maximum of 62 in 1923 (Pike and MacAskie 1969). The population was estimated to be 600 in 1952, and 1400 by 1964 (Inter- national Whaling Commission 1967). From total catches in the eastern North Pacific in the period 1924-1929, Rice (1974) estimated the stock at that time to be about 6 000. His data suggested "that Blue Whales were never very abundant in the eastern North Pacific and their population has not decreased very ; Gamble (1976) reports that the exploita- ble portion of the stock numbered 4 900 prior to whal- ing and 1 600 after. The total population is perhaps times larger than the exploitable population. Habitat According to Pike and MacAskie (1970), Blue Whales off the west coast of Canada sel
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