Fróðskaparrit - 01.01.1992, Síða 21

THE INTERNATIONAL RESEARCH . . .
25
Morphological characters
Dorsal saddles were observed more fre-
quently than eye blazes. Both pattems
occurred beyond a certain body length and
age, and became more common with
increasing body length and age. The saddle
pattem had the same occurrence in males
and females, while the eye blaze occurred
significantly more in males and was not so
strongly related to body length or age. The
length of the dorsal fin and the shape of the
flukes were linearly correlated to blubber
thickness. This explained the seasonal dif-
ferences found between schools and was
related to the seasonal variation of the blub-
ber thickness. Sexual dimorphism was
apparent in flippers and flukes, males had
longer flippers and longer and wider flukes
than females at similar body lengths.
Immature males and females had signifi-
cantly shorter flippers and flukes in propor-
tion to body length than mature individuals.
The ratio of flipper length to body length
was greater than that previously found
(Sergeant, 1962b), and 2.7% of individuals
showed a ratio within the range encoun-
tered in the short-finned pilot whales (Bree,
1971; Nores and Perez, 1988; Yonekura et
al., 1980).
Bloch, D., Zachariassen, M. and Zachariassen, P. 1989. The
possibility of using morphological characteristics of the
long-finned pilot whale (Globicephala melas Traill) in
school identification. Paper SC/41/SM9 presented to the
IWC Scientific Committee, May 1989 (unpublished). 1-
15.
Bloch, D., Zachariassen, M. and Zachariassen, P. In press.
Some extemal characters of the long-finned pilot whale
off the Faroe Islands and a comparison with the
short-finned pilot whale. Rep.int.Whal.Commn (Special
Issue 14).
Feeding ecology
A minimum of 13 genera of cephalopods,
14 genera of fish and 3 species of crustacea,
plus miscellaneous other items were identi-
fied. Pilot whales ate mainly squid around
the Faroes. Two squid species, Todarodes
sagittatus followed by Gonatus sp., were
by far the most dominant prey in the diet,
both in frequency of occurrence and in
quantity. No species of commercial interest
were important in the diet.
Around the Faroes, pilot whales fed
almost exclusively on Todarodes sagittatus
whenever this prey was available, other-
wise the diet was diversified and supple-
mented with a large range of items includ-
ing fish and shrimps. In the summers of
1986 to 1989 when virtually no T. sagitta-
tus were landed in the Faroes, pilot whales
did not appear to have fed upon densely
occurring species of fish (e.g. cod, blue
whiting, saithe...) in waters around the
Faroes, but to have preyed further offshore,
maybe on the slope of the Faroe plateau, on
another squid species Gonatus sp. This
indicates that while the type of prey taken
reflects to some extent local availability,
some degree of choice is exercised by the
pilot whales between squid and fish and
among squid species. Seasonal variations
are observed, with a greater diversity of
prey in winter when more fish is consumed,
though squid remain the major part of the
diet.
Further work is being carried out to
analyse the apparent differences in feeding
pattems according to age and sexual status.
Future studies will in particular try to esti-
mate the actual choice made by the preda-