. 6 01 ' o^ 10 20 x> 10 to ° PREGNANT (FOETAL LENGTH)] LACTATION [ RESTING j PREGNANT ' J 'j/a's'o'n'd'j 'f'm'a'm'j 'Jv'a's'o'n'd'J ' f'ma'm'JJy A S Text-fig. 4. Follicular activity at different stages of 2-year cycle. Above, percentage of follicles over 3 cm. in diameter; below, size of largest follicle (mean ± 2 , and range; near-term values from humpback whale). of pregnancy. If allowance is made for this there is an even greater decline in follicle size during the second half of pregnancy in individual females, which gives a closer agreement with the findings for late-pregnancy hump
. 6 01 ' o^ 10 20 x> 10 to ° PREGNANT (FOETAL LENGTH)] LACTATION [ RESTING j PREGNANT ' J 'j/a's'o'n'd'j 'f'm'a'm'j 'Jv'a's'o'n'd'J ' f'ma'm'JJy A S Text-fig. 4. Follicular activity at different stages of 2-year cycle. Above, percentage of follicles over 3 cm. in diameter; below, size of largest follicle (mean ± 2 , and range; near-term values from humpback whale). of pregnancy. If allowance is made for this there is an even greater decline in follicle size during the second half of pregnancy in individual females, which gives a closer agreement with the findings for late-pregnancy humpback whales. Lactating females Owing to the regulations prohibiting the taking of lactating whales and the small numbers entering antarctic waters, follicle records from only 56 lactating fin whales are available. The majority of these females would be in late lactation (see p. 446). They show a mean maximum follicle diameter of 1 -93 ±0-34 cm. and a range from 0-5 to 5-0 cm. Chittleborough (1954) gives the range of maximum follicle diameter for 60 humpback whales in late lactation as 1-0-5-0 cm., which is in very close agreement, especially since some of the fin-whale records may be from females in mid- or early lactation. (It is not possible to estimate the stage of lactation of individuals.) For three humpback whales in mid-lactation the largest follicles are i-i, 1-5 and i-8 cm. and for three in early lactation the maximum follicle sizes were o-6, o-8 and 2-6 cm. respectively. These were probably in very early
Size: 1971px × 2536px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
