. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 298 DISCOVERY REPORTS 7 days later 525 miles to the north (27' S., 153° 26' E.) having maintained an average speed of 3-6 knots in its northward migration. If the migrating near-term fin whales travel at 4-6 knots they will take 21-31 days to cover the distance from the Antarctic to sub-tropical breeding areas. We may therefore assume that about a month will elapse between the time of leaving the Antarctic whaling grounds and giving birth to the calf. 40 0 > /^~\ ^30 / \ 111 / \ D 0 / ^ A ui
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 298 DISCOVERY REPORTS 7 days later 525 miles to the north (27' S., 153° 26' E.) having maintained an average speed of 3-6 knots in its northward migration. If the migrating near-term fin whales travel at 4-6 knots they will take 21-31 days to cover the distance from the Antarctic to sub-tropical breeding areas. We may therefore assume that about a month will elapse between the time of leaving the Antarctic whaling grounds and giving birth to the calf. 40 0 > /^~\ ^30 / \ 111 / \ D 0 / ^ A ui a / / \\ u. / / \\ UJ / / \ \ •i 20 - 1 1 \\ H 1 V—.^\ Z / Dx^''"^ \t\ Ul 0 / / ^-^'''\ \^^ a. 1 / y^ \ \ ^'^^v UJ / /J / \ \ NX a / / / \ V-'^^'^vX Z-^^^*"^ ^^"^"\ 10 // /^A'^v-'^x^ ^^^\r\ /^^^i^^\\ ^^\^^\\ y^ \ \ x^^-^.r^\;>-^ 10 so 60 20 30 40 LENGTH IN METRES Text-fig. 10. Monthly foetal length frequencies of southern hemisphere fin whales, Balaenoptera physalus, smoothed and converted into D J F MONTHS Text-fig. II. Diagram to show expected changes in the shapes of the monthly foetal length frequencies for the fin whale. See text for explanation. Referring now to the average foetal growth curve for fin whales, this means that foetuses above about 475 m. in length should be under-represented in the Antarctic samples. The probable eflFect of this on the shape of the monthly length frequency curves is indicated in Text-fig. 11 bv the broken lines. The February sample should be only slightly affected, but from March onwards the eflFect on the frequency distribution should be considerable. Thus the model frequency curve for March becomes skewed in the reverse direction to those for December and January. This is precisely what the actual length frequencies of the monthly samples show (Text-fig. 10).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
