Fróðskaparrit - 01.01.1991, Page 41

STUDIES ON THE LONG-FINNED PILOT WHALE
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into two populations with different life
parameters (Kasuya, Miyashita and Kasa-
matsu, 1988a; Wada, 1988; Kasuya, in print;
Kasuya and Tai, in print, a; in print, b).
The length frequency distribution shows
groups of both the immature and the mature
whales of both sexes (Fig. 6, a and b). The
immature animals have a peak at 352.0 t
6.4 cm for the males, and 297.5 í 5.5 cm for
the females. For the mature whales the peaks
were at 551.8 X 4.4 cm for males, and 437.4
t 1.8 cm for females. Males grow longer on
average than females, with 54.5 cm for the
immatures, and 114.4 cm for the matures.
Since the length at birth is nearly the same
(see below), this would point to a higher
growth rate for the males, especially in rela-
tion to their shorter life span.
Weight. The 7 whales weighed before parti-
tion showed a correlation between age,
length, skinn and weight. The weighed
animals consisted of a newborn, the largest
male, and 5 in between (Table 2). The weight-
length relationship is close and exponential
as is normal for animal growth and follows
the formula:
2. W = 0.00023 x L2501
where W = total body weight in kg, L = to-
tal body length in cm. A single equation was
found to be satisfactory for both sexes of all
ages and throughout all months of the year
(Lockyer, in print, b).
At birth, the animals are estimated to
weigh about 100 kg (Sergeant, 1962; Des-
portes, 1983; Martin et al, 1987;), while large
males of 24 skinn probably weigh close to
2.5 tonnes. This examination showed, how-
ever, that Miiller (1882; 1884) was wrong
when he said that a 20 skinn whale weighed
2,000 pounds; it will weigh twice that, name-
ly about 2 tonnes.
Skinn. The skinn is the standard, traditional
means of evaluating quantities for consump-
tion and as such is a sort of weight measure-
Fig. 7. Skinn value frequency distribution histogram
for long-finned pilot whales in the Faroe Islands in the
period 1978 to 1985. Empty stacks = males, filled =
females. N=944.
I □ 143 imm males; -+- 88 mat males; X 103 imm lemales; m 221 mat temales |
Fig. 8. Skinn value at body length in the long-finned
pilot whales off the Faroe Islands. The formula for the
correlation isincluded. N=555.