Fróðskaparrit - 01.01.1991, Page 53

STUDIES ON THE LONG-FINNED PILOT WHALE
57
the findings for short-finned pilot whales
(Kasuya and Matsui, 1984) and sperm
whales (Ralls, Brownell and Ballou, 1980).
There was no connection between the ma-
ture female/male frequency in relation to
either school size or the time of year. But we
have to keep in mind that some of the
schools are only a part of a greater school,
for instance Klaksvík, September 4, 1984,
and January 29, 1985, with both schools
containing only 4.2% mature males. Fewer
males than females in the schools are other-
wise not surprising in a social animal like the
pilot whales, for which it was shown that
more males than females died in the lifespan
(Fig. 3), despite equality at birth (Table 5).
The occurrence of fighting marks in com-
parison with a closer study of the school
structure could be one explanation for the
higher natural mortality rate in males than
females in the schools.
This study has clearly shown what a
unique oppurtunity the Faroese whale drive
provides to examine entire schools of this
small cetacean, making it possible to com-
pare ages classes, sexes, and reproductive
states. It has also become apparent that if
comprehensive samples are to be taken from
all animals in the landed schools, then it is
necessary to have a large team of people to
sample, who are ready to leave as soon as the
»grind message« has been received.
Moreover, this study draws attention to
the value of the old Faroese whale statistics,
which contain a great deal of material about
the composition of the schools and the pat-
tern in the occurrence of the long-finned pi-
lot whale around the Faroe Islands.
Acknowledgements
I want to thank Rógvi Mouritsen, The Fishery Labora-
tory, Tórshavn and the students at the University of the
Faroe Islands for practical help in the sampling.
My best thanks to J. S. Joensen, Director of the Fish-
eries Laboratory, Tórshavn, for allowing me to use the
material on pilot whales sampled at the Fisheries
Laboratory. Furthermore I also wish to thank J. S.
Joensen for encouraging the examinations at all times.
For computer help I wish to thank Dr. Bogi Hansen,
Árni Nicolajsen and Martin Zachariassen at the Fisher-
ies Laboratory, and Petur Zachariassen from the
University of the Faroe Islands.
Also thanks to M. Clarke, MBA, Plymouth for deter-
mination of the squid beaks, and to V. de Buffrenil,
Museum of Natural History, Paris, for reading some of
the teeth.
C. Lockyer very kindly helped me with an attempt to
reexamine the age of the whales and took part in the
readings of the ovaries, not to mention taking part in
our many stimulating discussions.
Thanks to Kjartan Hoydal, Director of Fisheries,
Faroe Islands and Bertel Møhl, University of Aarhus for
commenting on a further edition of this manuscript, to
Kate Sandersson for proofreading this edition, and to
Marianne Debes Dahl for translating the summary in
Faroese.
And finally, to Genevieve Desportes, who took part
in the sampling in 1984, my greatest thanks for the
histological examinations of the testes, and not least for
all the discussion and many constructive comments on
the manuscript.
References
Andersen, A., Julshamn, K., Ringdal, O. and Mørkøre,
J. 1987. Trace elements intake in the Faroe Islands.
II. Intake of mercury and other elements by con-
sumption of pilot whales (Globicephalus melae-
nus). The Sci. of the Total Environment 65: 63-68.
Andersen, L. W. in print. Further studies on the popu-
lation structure of Globicephala melas off the Faroe
Islands. Rep. int. Whal. Commn (Special Issue 14).
Amos, W., Barrett, J. and Dover, G. A. 1991. Breeding
system and social structure in the Faroese pilot
whale as revealed by DNA fingerprinting. Rep. int.
Whal. Commn (Special Issue 13): 255-68.