Fróðskaparrit - 01.01.1992, Blaðsíða 19

THE INTERNATIONAL RESEARCH . . .
23
and elevated testis weights and testosterone
levels were still observable in males in
autumn and winter, a non-negligible pro-
portion of adult individuals were capable of
reproducing outside the main breeding sea-
son.
The average breakdown for the female
sample in 23 schools gave 31% immature,
16% pregnant, 5% simultaneously preg-
nant and lactating, 34% lactating and 15%
resting.
Estimation of reproductive parameters is
continuing. Variations of hormones in-
volved in reproduction are being analysed
in relation to life-history data and seasonal-
ity. Future work will examine in detail the
evidence for the existence of a post/non-
reproductive stage, on the basis of system-
atic histological examination of ovaries,
mammary gland and reproductive tract of
females. Emphasis will also be given to
variations between schools, and their
potential explanation, and to school struc-
ture and its social and behavioural signifi-
cance.
Bloch, D., Lockyer, C. and Zachariassen, M. In press. Age
and growth parameters of the long-finned pilot whale
off the Faroe Islands. Rep.int.Whal.Commn (Special
Issue 14).
Desportes, G. In prep. Ovarian activity and seasonality in
female long-fmned pilot whales off the Faroe Islands.
Desportes, G. In press. Symmetry in testicular development
in long-finned pilot whales. Marine Mammal Science.
Desportes, G., Mauget, R. and Lacroix, A. in prep.
Secretion pattem of oestrogens and progesterone in
female long-fmned pilot whales in relation to life-histo-
ry parameters and seasonality.
Desportes, G. and Mouritsen, R. In press. Some results on
the diet of long-finned pilot whales around the Faroe
Islands. Rep. int. Whal. Commn (Special Issue 14).
Desportes, G. and Lacroix, A. 1987. Preliminary study of
the male reproductive cycle in the pilot whale
(Globicephala melaena) off the Faroe Islands, using
testes examination and testosterone assay. Paper
SC/39/SM WP2 presented to the IWC Scientific
Committee, May 1987 (unpublished). 1-21.
Desportes, G., Saboureau, M. and Lacroix, A. 1989.
Preliminary study on the male reproductive cycle of
Globicephala melas off the Faroe Islands, using testes
examination and testosterone assay. Paper SC/41/SM11
presented to the IWC Scientific Committee, May 1989
(unpublished). 1-18.
Desportes, G. Saboureau, M. and Lacroix, A. In press.
Reproductive maturity and seasonality of male
long-finned pilot whales off the Faroe Islands.
Rep.int.Whal.Commn (Special Issue 14).
Desportes, G. Saboureau, M. and Lacroix, A. In prep.
Growth-related changes in testicular weight and plasma
testosterone concentrations in long-fmned pilot whales,
Globicephala melas. Submitted to J.Reprod.Fert.
Martin, A. R. and Desportes, G. 1987. Preliminary studies
of pilot whales from Faroese waters since 1986: repro-
duction and foetal growth. Paper SC/39/SM15 prese-
nted to the IWC Scientific Committee, May 1987 (u-
npublished). 1-8.
Martin, A.R. and Rothery, P. In press. Reproductive para-
meters of female long-finned pilot whales
(Globicephala melas) around the Faroe Islands.
Rep.int.Whal.Commn (Special Issue 14).
Sex identification and variation in sex ratio
through life
Sex chromatin allowed sex identification in
foetuses too small to be sex-identified
macroscopically or histologically. The
method can also be used in post-natal indi-
viduals, but is more difficult to handle. The
sex of post-natal individuals can be identi-
fied with higher confidence by means of a
human Y-specific DNA probe.
The overall sex ratio is skewed towards
females, with 1.6 females per male. There
is an average of 4.4 mature females per
mature male but only 0.8 mating females
per mating males.