EXTERNAL CHARACTERS OF
SOUTHERN MINKE WHALES AND
THE EXISTENCE OF A DIMINUTIVE FORM

PETER B. BEST*ABSTRACTTwo colour phases were found amongst minke whales examined at
the Durban whaling station. The majority of the animals had asymmetrically-coloured baleen, with the right series having a larger number ofwhite plates anteriorly than the left, and with the remaining plates having
a black outer border whose width amongst the longest plates averaged
about 31-34% of the width of the plate. These animals also had plain or
two-tone flippers (Type 1 or 2) on which white patches were never found,and dark pigment on the neck did not descend below the level of the eye.
Whales of the second colour phase were much rarer (-3 to 4% of theminke whales taken). They had all-white baleen or baleen with an
unusually large proportion of white plates (with little or no asymmetry),
in which the largest plates were either completely white or with a narrow
black outer border less than 10% of the width of the plate. The flippers
carried a striking white patch connected to a roughly circular white blazeon the shoulder (Type 3), and dark pigment in the neck region extended
onto the ventral grooves.
Type 3 whales appear to be born smaller and attain a smaller size atsexual maturity than Type 1 or 2 whales. Off Durban they were foundcloser inshore and earlier in the year than Type 1 or 2 whales, and were
not killed from the same groups. Whales with similar coloration to Type 3
animals have also been recorded from Brazil, New Zealand and Australia,
but probably do not occur in higher latitudes of the Antarctic.
INTRODUCTION

Minke whales in the Southern Hemisphere are reported to have either nowhite flipper bands (Ohsumi, Masaki and Kawamura, 1970; Van Utrecht andVan der Spoel, 1962; Williamson, 1959, 1961; Zemsky and Tormosov, 1964)
or flippers with "light" (Taylor, 1957) or white bands (Aguayo, 1974). The
existence of two Southern Hemisphere forms, one with and one without
white flipper bands is suggested by data provided by Baker (1983), Gaskin(1972) and Kasuya and lchihara (1965). The baleen coloration of southern* Mammal Research Institute, University of Pretoria, South Africa.
Postal Address: clo Oceanography Dept. University of Cape Town, Private Bag, Rondebosch 7700
Sci. Rep. Whales Res. Inst.,
No. 36, 1985, 1-33

2

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minke whales has been usually reported as consisting of some anterior allwhite plates and the rest white with dark borders externally, with considerable
individual variation in the proportion of all-white plates, and with asymmetry
in their distribution between left and right sides of the head (Kasuya andIchihara, 1965; Ohsumiet al., 1970; Williamson, 1959, 1961). Some individuals
have been reported with no all-white plates (Ohsumi et al., 1970), even on
both sides of the head (Van Utrecht and Van der Spoel, 1962). Gaskin ( 1972),
Guiler ( 1978) and Baker (1983) are the only authors so far who have describedsouthern minke whales as simply having "yellow or pale ochre'', "yellowish"
or "yellow-grey" baleen with no mention of dark edges.
It is clearly of some interest to establish whether different colour phasesof minke whales do occur in the Southern Hemisphere, and particularly toinvestigate whether these might vary geographically as potential indicators ofstock identity. Systematic observations were therefore made of the colorationof the baleen and flippers (and certain other parts of the body) of minke
whales landed at Durban (ea 30°S, 31°E) and on the factory ship Nisshin Maru
no.3 in the Antarctic. This paper presents analyses of these observations
together with some morphometric data, and includes information fromanimals stranded on the South African coast and elsewhere.
MATERIAL AND METHODSAs part of their routine examination of minke whales on the flensing platform,
the whaling inspectors at Durban were instructed to record variations
in coloration.
The most convenient way of recording flipper patterns was by photography. Photographs of one or both flippers of each minke whale landed
were taken with an Instamatic camera (using flash for night shots). In order
to distinguish between individual whales, a slate bearing the platform numberof the whale was included in each frame.
Photographs were taken in three seasons (1970, 1971 and 1973) for a
total of 299 whales.
Baleen coloration was recorded in several ways. Initially ( 1969) separate
counts were made of the number of all-white plates and the number withblack edges for at least one series of each whale. The plates counted included
all those defined as hairs by Williamson (1973). Because this was so laborious,
a more rapid method of assessing the relative proportions of the two types ofbaleen was used subsequently (1970, 1971 and 1973). One entire side ofbaleen was carefully removed and laid straight and flat (fringe downwards) on
the deck. Its total length and the length of the series of all-white plates werethen measured with a steel or fibreglass tape in a straight line between theanterior and posterior extremities of the series. The relative length of the
all-white section could then be used as a measure of the proportion of white
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

SOUTHERN MINKE WHALES

3

plates in the series. The coloration of baleen was recorded in these two ways
for a total of 488 animals.
In addition, one of the longest baleen plates from one side of each whale
was collected in 1970, 1971, 1973, 1974 and 1975, and fixed in formalin.
These could be recognised as being from the left or right series depending on
their shape, and were used to confirm on which side the measurements orcounts of different-coloured baleen had been made. They were also used toprovide measurements of the relative width of the black border to the outeredge of the plate.
The length and width of the plate were measured as described by Omura
and Fujino (1954), while the width of the black border was measured withvernier calipers at the same level as the width of the plate. Baleen plates from
504 whales were so measured, to the nearest mm.
From 20 January to 17 February 1979, 161 minke whales were examinedaboard the Japanese factory ship Nisshin Maru no.3 while it operated along
the ice edge between the longitudes of 62° and I 07°E. The procedures
followed were almost identical to those described above; the proportions ofblack and white baleen plates were obtained by measurement rather thancounting, while a ruler rather than vernier calipers was used to measure thethickness of the black border.
Throughout this paper a '±' figure following an estimate refers to one
standard error.
COLORATION

Flipper and associated body coloration
From an examination of the photographs, the flipper coloration of minke
whales landed at Durban and in the Antarctic could be classified into three
types.
1. Plain - The outer surface of the flipper was a steely-grey (or slightly
darker) colour, darkening on the trailing edge of the flipper but lightening to almost white on the leading edge. Such changes in coloration were
not sharply differentiated but were diffuse in nature (Fig. la). Thisseemed to be equivalent to the Type 1 flipper coloration as illustrated by
Doroshenko (1979) and Wada and Numachi (1979).
2. Two-tone - The outer surface of the flipper was of two tones of grey
separated by a distinct line running perpendicularly across the width of
the flipper approximately level with the axilla. This line varied frombeing roughly straight to being strongly backet-shaped in conformation,and separated the lighter colour of the distal part of the flipper from thedarker proximal part (Fig. lb). The clarity of this distinction into twotones varied considerably, depending on the degree of contrast between
the colours of the proximal and distal parts of the flipper: the lighter inSci. Rep. Whales Res. Inst.,
No. 36, 1985

4

BEST

S
c
i
.Re
p
. Wh
a
l
e
sR
e
s
.I
n
s
t
.
,
N
o
.3
6
,198
5

SOUTHERN MINKE WHALES

5

tone the distal part, the greater the distinction. Although animals could
be classified as having weakly, moderately or strongly two-toned flippers,
there actually appeared to be a continuous range in variation, with someflippers having such a faint line dividing the two tones that it was difficult to distinguish them from plain flippers, while at the other extreme
the distal portion of the flipper was a bright grey colour (but neverwhite). In all flippers there was a gradual darkening at the extreme trailing edge and a lightening at the leading edge, as described for plain flippers.
This seemed to be equivalent to the Type 2 flipper coloration as
illustrated by Doroshenko ( 1979), and possibly to Types II and III colo ration as illustrated by Wada and Numachi (1979).
3. White - The outer surface of the flipper was glossy white anteriorly andlight grey rapidly deepening to glossy black posteriorly. The dividing
line between the two was irregular in outline but clearly differentiated,
and ran from the axilla to the leading edge of the flipper at about onethird of its length from the tip (Fig. le). The white proximal area of the
flipper was connected (via the entire width of the flipper from anterior
insertion to axilla) with a roughly circular white blaze on the shoulder
immediately above the flipper. This blaze was highly irregular in outline
but well-differentiated from the surrounding pigmented area. While
there was some individual variation in these flipper patterns, and particularly the size and shape of the shoulder blaze, the basic coloration of
the flipper remained proximally white and distally black. This has beentermed "Type 3" flipper coloration in this paper.
Although Wada and Numachi (1979) illustrate a flipper with awhite transverse band as Type IV, it is not clear whether this is similar to
the Type 3 coloration described here, or is simply a representation of theband commonly see in minke whales from the Northern Hemisphere.
Classification of flipper patterns into these three types (particularly the
first two) could be affected by prolonged post-mortem times, which tended todarken lightly-pigmented areas, and by skin damage (particularly to theflipper that lay beneath the whale's body as it was transported from the water
to the flensing platform), which tended to obliterate pigmentation patterns.
Some photographs at Durban were also taken from an inappropriate angle sothat the outer surface of the flipper could not be seen. Some of these photoFig. I. Minke whale coloration patterns
a. Plain (Type I) flipper
b. Two-tone (Type 2) flipper
c. White (Type 3) flipper
d. Throat region of a Type I or 2 whalee. Throat region of a Type 3 whale
f. Baleen coloration of a Type 3 whale

Sci. Rep. Whales Res. Inst.,
No. 36, 1985

6

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graphs could be used, however, to make gross classifications of coloration
type because of a difference between the pigmentation pattern in the neckregion of minke whales with flipper Types I and 2 and those with Type 3. In
the former, the dark pigment of the back did not extend ventrally farther
than a line roughly between the eye and flipper insertion, so that the ventral
grooves appeared almost entirely white in the throat region (Fig. Id). In
whales with Type 3 flippers, however, this dark pigment extended much
farther ventrally (as much as 15 ventral grooves down from the level of theeye to flipper insertion), so that there was a distinct tongue of black extending
onto the throat (Fig. le). This feature could be seen clearly in photographs of
the flippers taken from the ventral side of the whale, when details of the actual outer surface of the flipper were obscured. Consequently it was possible
to deduce from such photographs whether the whale had a flipper belonging
to Type I or 2 or to Type 3, though it was impossible to discriminate between
Types I and 2 from this angle. Similarly the slate was sometimes placed over
the area where the dividing line of Type 2 flippers occurred, so that it was impossible to be certain whether the flipper was Type I or 2. Under both thesecircumstances if it was clear that the animal was not a Type 3 whale it was recorded as "Type I or 2".
TABLE 1.

FLIPPER COLORATION OF MINKE WHALES AT DURBAN FOR WHICH
BOTH FLIPPERS WERE EXAMINEDColour type

Frequency (number of whales)

Both Type 1
One Type 1, one Type 2
Both Type 2
Both Type 3

26

Total

64

17
18
3

Photographs were taken of both flippers of 64 whales at Durban (Table1). In 17 of these animals one flipper was judged to be Type I and the otherType 2. This indicates that there is no phenotypic distinction between the two
flipper patterns, and that Type I is actually one extreme of a range of variation including Type 2. Of these 17 animals, 14 had a Type 2 left flipper andthree a Type I left flipper. These proportions are significantly different fromparity (chi-square test, Yates' correction, P < 0.02, df = 1), indicating that
there may be asymmetry of pigmentation in the flippers of the southernminke whale, as in its baleen. This is confirmed by differences in the intensityof pigmentation between right and left flippers of whales in which both flippers were classified as Type 2. Out of the 18 whales so classified, 11 had bothflippers of the same intensity while seven had the left flipper with a brighterband of pigmentation (i.e. a more striking two-tone coloration) than the right.
None had the reverse condition.
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

7

SOUTHERN MINKE WHALESTABLE 2.

COLORATION OF LEFT AND RIGHT FLIPPERS OF MINKE WHALES
DurbanLeft

Colour type

Antarctic
Left

Right

Right

No.

%

No.

%

No.

%

No.

%

Type I
Type 2aType 2bType 2c
Type I or 2
Type 3

51
31
44
8
46
5

27.6
16.8
23.8
4.3
24.9
2.7

81
36
16

43.8
19.5
8.6
0.5
23.8
3.8

12
28
23
6

17.4
40.6
33.3
8.7

36
28
16
0

45.0
35.0
20.0
0

0

0

0

0

Total

185

44
7
185

69

80

Because of this asymmetry in pigmentation, any analysis of the variationin flipper coloration for southern minke whales must separate data for left
and right sides of the animal. In Table 2 data have been presented separately
for whales whose left or right flippers only were examined, and including relevant data from those whales for which both flippers were examined.
Flippers of the two-tone type have been further classified into weak(2a),moderate (2b) or strong (2c), based on the intensity of the contrast in pigmentation. As might be expected from the asymmetry of coloration, whales whose
left flippers were examined had a greater ratio of Type 2 to Type 1 coloration
than whales whose right flippers were examined, both at Durban (chi-square= 13.44, p < 0.001) and in the Antarctic (chi-square = 12.93, p < 0.001).
Furthermore, in both areas there was a higher proportion of Types 2band 2c relative to Type 2a coloration in the left flippers than the right,
though this was only statistically significant in the Durban data (chi-square =12.10, p < 0.001, Durban; chi-square= 2.12, p > 0.10, Antarctic). The twoareas studied, however, seemed to differ in the intensity of flipper coloration.
The proportion of Type 2 relative to Type 1 flippers was higher in the
Antarctic than Durban, both for left (chi-square = 9.09, p < 0.005) and rightflippers (chi-square = 4.82, p < 0.05). This may reflect the shorter postmortem times in the Antarctic (producing less darkening of pigmentation
after death), or it may represent a real difference between the two populations. There was no significant difference, however, between the proportionof Type 2a relative to Types 2b and c coloration in the Antarctic and Durban(chi-square = 1.92, p > 0.10, left flippers; chi-square= 0.20, p > 0.50, rightflippers).
No asymmetry of pigmentation could be detected in whales whose
flippers were classified as Type 3, and no whale was found with a Type 3
flipper on one side and a different type on the other. This group seemed toform a relatively uncommon but distinct phenotype (see below), and was notencountered in the Antarctic sample.
Data presented by Doroshenko ( 1979) indicate significant differences inSci. Rep. Whales Res. Inst.,
No. 36, 1985

BEST

8
20

RIGHT
10

0

60

50

40

30

20

n= 276
10

>.

u

c:
Cl)

:::>
O'"

~

0

u..
LEFT

10

0
60

50

40

30

20

10

0

0

10

~

20

~

w

M

40

~

50

~

60

~

ro

n

w

~

~

~

~

°lo white plates

Fig. 2. Proportion of all-white baleen plates in each series, from plate counts(hatched) and proportional measurements (open).

Sci. Rep. Whales Res. Inst.,
No. 36, 1985

9

SOUTHERN MINKE WHALES

the proportions of whales with Type 1 and Type 2 flippers between different areas of the Antarctic (Van Beek and Van Biezen, 1982), supporting
the possibility that there may be population differences in this character. In
presenting similar data (but for four flipper types), however, Wada andN umachi ( 1979) conclude that the data " .... include some bias arising fromvariation in the classification criterion among the observers, and that they are
inadequate for stock identification or that the external characters of minke
whales do not reflect stock units. Before this can be determined it is essential
to unify the criterion classification technique of each observer." The apparent
presence of whales with white bands on the flippers (their Type IV) in a small
proportion of their data (0.9%) must therefore be viewed with caution.
Baleen coloration
The two methods of assessing the proportion of all-white plates in thebaleen series did not give consistent results. Counts of individual baleen plates
100

Durban

95

90
85

80
75
70
65
Q)

60

"'O
'iii 55

-

.....

~ 50

.S!"' 45
0

1i 40

.S!

~

~

35

0

.•,._.··!...,.

;)"' 30
25

. .:
.....
: .. ; .
... ·:.. .....·i.'.....·.·· ·:,.
......... ... .. ..·
"'.
:

20
15
10
5
0

•

I

• ::••':-. ; I

5

m

~

m ~

~

~

~

~

~

~

60

°lo white plates right side

~

ro

~

ao e

%

~

Fig. 3a. Comparison between proportions of all-white baleen plates on right andleft sides of same whale at Durban.
Sci. Rep. Whales Res. Inst.,
N-0. 36, 1985

~

10

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100
95

ANTARCTIC

90
85
80
75
70

.
.
.
.

.,,·;; 65
60
55

0

o_

:.c

>

50
45

~

40

35
30

••I

25

•

..:.......:

20. .. ....
·. ·: ! .......
• •,p:.
. ·...
: : ..
. . ....
. .· ": .
·.. ·.

•
~

.·

15
10
0

'\"
10

15

20

25

...... 1: .. :·
30

35

40
'Yo

45

50

white

ptotes

55

60
right

65

70

75

80

85

90

95

100

side

Fig. 3b. Comparison between proportions of all-white baleen plates on right andleft sides of same whale in the Antarctic.

produced on average a higher proportion of all-white plates in the series than
did relative measurements (Fig. 2). This is almost certainly due to the fact thata high proportion of the anterior, all-white section of the series consists of thesmall, closely-spaced structures termed "hairs" by Williamson (1973), andtheir relative contribution will therefore appear greater in counts than inmeasurements. However, the difference between the two methods is relatively
small (the modes in the frequency data differing by 5 to 10%), and for further
analysis the greater quantity of data (from measurements) has been used.
The proportion of all-white plates was measured for both right and leftbaleen series of the same animal in 148 whales from Durban (Fig. 3a) and 157
whales from the Antarctic (Fig. 3b). The asymmetry of the coloration in the
majority of animals is clear. Four animals at Durban, however, seemed exceptional in the pattern of their coloration. Three of these were recorded asSci. Rep. Whales Res. Inst.,
No. 36, 1985

SOUTHERN MINKE WHALES

11

having (on both sides of the head) all-white baleen or white baleen interspersed with a few black plates having a very thin black outer border, estimated at 0.3 cm wide (see Fig. 1£). The latter animals were considered in
effect to have all-white baleen. The fourth whale was recorded as having allwhite baleen on the right-hand side and an unusually high proportion ofwhite plates on the left-hand side. It is possible that this animal also had whitebaleen interspersed with a few plates very thinly edged with black, but thatthe measurement of the white baleen on the left side was taken to the first
black-edged plate (as was done with subsequent whales but with an explanatory
note in the records).
The remaining 144 whales at Durban with asymmetrically-coloured
baleen ranged from individuals with almost no white plates on either side (asrecorded by Van Utrecht and Van der Spoel, 1962), to individuals where as
much as 41 % of the left side and 50% of the right side were white, and included animals with only 2 or 3% white plates on the left side but up to 46%
white plates on the right. Despite this variation, there was no obvious separation of these animals into different groups, and there is clearly a positive correlation between the proportion of white plates on either side of the head ofthese animals (r = 0.5612, p < 0.001). The average proportion of white plates
was 16.6 ± 1.6% for the left series and 36.7 ± 3.2% for the right series.
All but one of the animals in the Antarctic sample had asymmetricallycoloured baleen. The exception was an animal in which all plates on bothsides of the head had black or "dusky" outer edges, though those towards theanterior end of the righthand series were lighter in colour. There was a positive correlation between the proportion of white plates on either side of thehead in the whole sample (r = 0.4966, p < 0.001), and the mean proportionof white plates was 12.0 ± 1.2% for the left series and 34.4 ± 2.8% for theright series. There were no animals in the sample with all-white baleen or
white baleen interspersed with a few black-edged plates.
The mean proportions of white plates on both the left and right sides of
the head differed significantly between Durban and the Antarctic (t = 4.57, p< 0.001, left; t = 2.33, p < 0.025, right), suggesting either a difference between populations or a difference in interpretation of what constitutes a blackedged or a white plate between the two areas (the data being collected by atechnician at Durban but by the author in the Antarctic).
The existence of two groups of whales differing in their baleen coloration is also suggested by the larger body of data from Durban given in Fig. 2.
One large group has a modal proportion of all-white plates on the right sideof the head of 35 to 40% and on the left side of the head of 20 to 25%, while asecond, much smaller group has from 90 or 95 to 100% white plates on eitherside of the head.
On the left side there also appears to be an intermediate group of animals
with a higher-than-normal proportion (mode 50- 55%) of white plates. Someof these may be animals with white baleen irregularly streaked with someSci. Rep. Whales Res. Inst.,
No. 36, 1985

12

BEST

black plates with narrow borders as described above, and in which the contribution of black-edged plates has been exaggerated because of the methodof recording used (see above). It is impossible, however, to be sure on thispoint, consequently it is considered safest to ignore the data shown in Fig. 2
when calculating the relative proportions of the two groups of whales in thecatch.
Correlation between flipper and baleen coloration
There was no significant correlation between increasing flipper pigmentation and the proportion of all-white baleen plates for animals with Types 1
and 2 flippers at Durban. Because of the asymmetry of pigmentation, data
were analysed separately for left and right sides of each animal (Fig. 4). The
correlation coefficients so calculated were -0.01212 (n = 92, p > 0.9) for theleft and 0.07337 (n = 90, p > 0.4) for the right. This lack of correlation
100

90

RIGHT

BO
70
60

50
40

30

c:
Q)
Q)

]
.5

I{!

20
10
0

J;! 100

a.

j! 90

LEFT

:..c

~ BO

~
0

70
60
50
40
30
20
10
0

rr,

IT2

IT3

][

lorlI

flipper coloration typeFig. 4. Relationship between baleen and flipper coloration of same whale.

Sci. Rep. Whales Res. Inst.,
No. 36, 1985

13

SOUTHERN MINKE WHALES

further suggests that whales with Types 1 and 2 flippers and asymmetricallycoloured baleen are one homogeneous group. Whales with Type 3 flippers,
however, differed from Types 1 or 2 in having all-white baleen or baleen withan unusually high proportion of white plates. These whales may therefore
form an uncommon but distinct phenotype from the "normal" southernminke whale.
Width of black outer border of baleen
The width of the black outer edge (or border) of one of the longest
plates of the baleen series was measured as a percentage of the total width ofthe plate. Some plates had a secondary black stripe on the lingual side of theblack border: such plates were omitted from subsequent analysis. At Durban
the frequency distribution of the relative width of the black border on the
60
ANTARCTIC50{o•159)

40

30
20
10

60
DURBAN, RIGHT

50

i"' 228)

40

30
20
10

70

DURBAN , LEFT{o o 240)

60
50
40

30
20
10

10

~

w

~

w

~

~

~

Width of block stripe as

m

~

~

'Yo of width

~

ro

~

w

~

~

~

of baleenFig. 5. Width of black border on one of longest baleen plates as a proportion of thetotal width of the plate at Durban, and in the Antarctic.

Sci. Rep. Whales Res. Inst.,
No. 36, 1985

~

14

BEST

right side of the head shows a bimodality, with one group of animals having amode around 25 - 35% and a second, much smaller, group having a mode ofless than 5%; on the left side there is not such a pronounced bimodality but
animals were still encountered with a black border less than 10% of the widthof the plate (Fig. 5). Amongst such animals eight (or 50%) in fact had no blackborder at all. All whales with Type 3 flippers fell into this group, i.e. theyeither had all-white baleen or baleen with some plates having a very thin blackouter border (less than 10% of the width of the plate). If only animals with astripe 10% or more of the plate width (i.e. presumably Type 1 and 2 animals)
are considered, the relative width of the border was greater on the left (34.9± 0.7%) than on the right (32.7 ± 0.6%) side of the whale (t = 2.47, p < 0.02,
450 df, the samples being independent as the left and right plates examined
were from different animals). This difference in the coloration of the largest
plates of the baleen series probably reflects the asymmetry of baleen pigmentation as a whole. Williamson (1961) has pointed out that the width of theborder increases towards the back of the mouth, so that presumably the moreanterior white plates in a series there are, the thinner the border will be on
the largest plates. As there are (in asymmetrically-coloured animals) invariably
more white plates on the right side of the head, it is to be expected that thewidth of the black border will be somewhat less in the largest plates of theright side.
In 159 animals examined in the Antarctic, the black border ranged from
14.7% to 58.5% of the width of the plate (right and left sides combined), witha mean of 33.4 ± 0.7% (Fig. 5).
Wada and Numachi (1979) classified baleen plates into six Types, depending on the width of the black border, with Type 0 representing plateswith no black stripe and Type 5 representing all-black plates. The majority ofanimals (78%) were Types 2 and 3 (stripe one-third to one-half width ofplate), which would be similar to the results obtained above for the Antarctic,
but all six Types were recorded, although Types 0 and 5 only infrequently(0.1 % and 0.2% respectively). However, Wada and Numachi (1979) express
reservations about the reliability of this data (as described for flipper coloration - see above), and the inferred presence of minke whales in the Antarctic
with no black border to the largest baleen plate must be viewed with caution.
Body coloration
Certain other features of body coloration were noted systematically in alimited number of animals examined at Durban, and in a larger sample ofanimals from the Antarctic in 1978/79.
(i) Tongue of dark pigment extending onto the ventral grooves between the eye and theflipper insertion

In 58 whales examined at Durban or in the Antarctic for which photoSci. Rep. Whales Res. Inst.,
No. 36, 1985

15

SOUTHERN MINKE WHALESTABLE 3.

DETAILS OF STRANDED (OR ENTRAPPED) MINKE WHALES WITH
TYPE 3 PIGMENTATION

Field Length Sex Date(m)no.
stranded
72/8

1.92

N438

3.49

80/14

2.54

3.85
4.04

M

Locality

15.5.72 Kommetjie, S.A.
(34°07'S l8°2l'E)
F
5.8.74 Nahoon Beach, S.A.
(32°59'S 27°57'E)
M 21.7.80 Cordons Bay, S.A.
(34°09'S l8°5l'E)- 26.6. 76 N. of Rio Grande,Brazil (-32°S 52°W)-.6.54 Plimmerton, NZ(-41°05'S 174°52'E)
M 17 .8.80 Dargaville, NZ(-36°S 173°47'E)
F 27.8.82 Wonga Beach, Aus.
(l6°28'S 145°23'E)
F 18.9.82* Hook Reef, Aus.
(l9°50'S 149°13'E)

FlippercolourPigment on % whitegrooves?
baleen(L) Type 3(R)Type 3(R) Type 3

Yes
Yes
Yes

100
100

(L) Type 3(R) Type 3
(L) -

Yes
Yes
Yes

100
100

(R) Type 3

Yes

100

(R) Type 3

Yes

100

(L) Type 3

Yes

100?

(L) Type 3(R) Type 3

Yes
Yes

SourceSFRI files
G.J.B. Ross
(pers. commn)
SFRI files

C.R. Williamson(pers. commn)
Gaskin (1968)
Baker (1983)
M.W. Cawthorn(pers. commn)
H. Marsh(pers. commn)
H. Marsh(pers. commn)* Entrapped in coral reef.

graphs exist showing simultaneously both the pigmentation of the flipper andthe region between the eye and the flipper insertion, all 53 with no such tongue had Type 1 or 2 flippers, while the remaining five animals with a tongueof dark pigmentation all had Type 3 flippers. Some of the animals with Type
1 or 2 flippers had dark pigment in the folds between the ventral grooves inthis region, but this was only conspicuous when the throat region was relaxed,and none had the continuous dark pigmentation characteristic of Type 3 animals. This tongue of dark pigmentation was also present in eight strandedminke whales with Type 3 pigmentation (Table 3). When present this feature
seemed to be symmetrical in extent between left and right sides of the same
animal.
(ii) Blowhole streaks
A typical feature of the minke whales examined was a pair of grey
streaks extending posteriorly for about 0.6 m from the blowholes, one fromeach opening (Fig. 6a). These streaks were irregular in course but bothtended to veer towards the left side of the body posteriorly. They were present in all animals examined for this feature (12 at Durban and 149 in the Antarctic), all of which had Type 1 or 2 flippers. A similar marking was seen in ajuvenile stranded minke whale from the South African coast that had Type 3
flippers (80/ 14), so it is possibly a universal feature of all southern minke
whales. It can be seen in some of the photographs of ice-trapped animals
published by Kellogg (1940) and Taylor (1957), and in a photograph of a calf
stranded in New Zealand (Lillie, 1915). Photographs sent to me by M.W.
Cawthorn of another animal stranded in New Zealand also show this characSci. Rep. Whales Res. Inst.,
No. 36, 1985

1
6

BEST

Fi
g.6.Fea
t
u
r
e
sofmi
n
k
ewhal
ebodyco
l
o
r
a
t
i
on c
. chev
r
onmar
k
s f
.t
h
o
r
a
xbl
a
z
eandf
l
ankp
a
t
ch
a
.s
t
r
e
a
k
sfromblowholed. dorsalf
in f
l
ar
e g.f
lankp
a
t
c
hvi
s
i
b
l
ea
ts
白
b
.c
r
e
s
c
e
n
t
‑
s
hapeds
t
r
e
a
k
smeet
i
n
gmid
‑
dor
s
a
l
l
ye
.s
peck
l
ing

S
c
i
.Re
p
.Whal
e
sRe
s
.I
n
s
t
.
,
No.3
6
,1985

SOUTHERN MINKE WHALES

17

ter. However, it was not mentioned by Williamson (1959, 1961), Van Utrecht
and Van der Spoel (1962), or Kasuya and Ichihara (1965).
(iii) Grey streak up side
In nearly all the animals examined, a crescent-shaped grey streak extended up each side of the whale above the flipper insertion towards the dorsal
midline, where the streaks from either side met (Fig. 6b). This streak appears
to be homologous to the pale streak originating near the anterior insertion of
the flipper and extending towards the shoulder which was described and figured by Kasuya and Ichihara (1965), although the continuation of the streak
as far as the mid-dorsum was not figured by those authors. This feature wasseen in all 11 whales inspected at Durban, and in 96.3% of 134 whales
examined in the Antarctic. It should be pointed out that this marking (as (ii)above) is most conspicuous in the living or freshly-dead animal, and rapidly
fades after death, particularly when the animal is exposed to direct sunlight.
Thus although it was not mentioned by Williamson (1959, 1961) or Van
Utrecht and Van der Spoel (1962), the lack of previous descriptions of suchfeatures may in part represent an unfamiliarity with fresh material. Alternatively the markings may have been overlooked or considered unimportant:photographs of Williamson's (1959) whale no. 2 taken by the present author
at the time the whale was flensed clearly show both the blowhole streaks andthe crescent-shaped streaks meeting mid-dorsally. No minke whale with Type3 flippers was examined for this feature at Durban. However a juvenile whalewith Type 3 coloration stranded on the South African coast (80/ l 4) shows asimilar (but somewhat broader) crescent-shaped mark running from above
the flipper towards the mid-dorsum, and there are indications of a similar
marking in a whale with Type 3 body coloration stranded in New Zealand(Baker 1983). Consequently it is possible that this feature is common to all ornearly all southern minke whales.
(iv) Caudal chevrons
On most minke whales examined, the dark dorsal pigmentation extended ventrally as a pair of curved "chevrons" (pointing anteriorly), situatedeither side of the base of the tail on the caudal peduncle (Fig. 6c). Such markings were present in 80.3 % of the 142 whales examined in the Antarctic forthis character, all of which had Type 1 or 2 flipper coloration. No whales were
inspected for this character at Durban. There were indications of possible
chevron markings in a stranded minke whale from the South African coastthat had Type 3 flippers (80/ l 4), but the skin in the peduncle region wasbadly damaged.
(v) Dorsal fin flare

Some southern minke whales had a grey flare on the posterior half ofthe dorsal fin (Fig. 6d), as seen in some Lagenorhynchus species (see Fraser,
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

18

BEST

1966). This was very variable in intensity, and could be detected in only
55.4% of 74 minke whales examined in the Antarctic for this feature. It could
not be detected in the only three whales with Type 3 flipper coloration thatwere examined, all of which were juveniles stranded on the South African
coast, but because of the variability in this feature it is impossible to say
whether such flares are only found in whales with Types 1 and 2 coloration.
(vi) Speckling
In some minke whales examined, small dark, irregularly-shaped speckles
were present mid-laterally, usually at the border between the dark grey dorsal
and the white ventral coloration (Fig. 6e). They were very variable in number,most often occurring in the region between the eye and the flipper insertion,
but sometimes extending past the tip of the flipper and as far back as the levelof the anus. Such speckling was seen in 63.6% of 11 whales landed at Durban
but in only 30.7% of 114 whales examined in the Antarctic: all the whales
examined in both localities had Type 1 or 2 flipper coloration. Such acharacter was not seen in two Type 3 coloration minke whales examined that'stranded on the South African coast (72/8, 80/14), but because of its great
variability in Type 1 and 2 animals it is impossible from this small sample size
to determine whether Type 3 animals do or do not exhibit this feature.
Although it was not the subject of systematic recording, a conspicuous
feature of the body pigmentation of most southern minke whales with Type 1
and 2 coloration at Durban and in the Antarctic was a light grey flank patch.
Starting at the angle of the gape and progressing posteriorly, the border between the dark pigmentation of the back and the white of the belly initiallyran between the angle of the gape and the anterior insertion of the flipper.
Between the axillary region of the flipper and the caudal peduncle, however,this border extended dorsally twice (Fig. 6£). The first extension (or "thorax
blaze") ran diagonally up from the axilla and then diagonally back again toabout the same level, forming a roughly triangular invasion of light grey pigment dorsally. The second dorsal extension commenced only a short distanceposterior to the completion of the first. The anterior border of this extension
was nearly vertical and continued much farther dorsally than the "thorax
blaze". Its posterior border sloped down gradually towards the midline, where
it merged with the white of the ventral surface of the caudal peduncle.
Both Williamson (1959; 1975) and Kasuya and Ichihara (1965) havesketched these two dorsal extensions of light pigment on the side of southernminke whales (and Ohsumi et al. 1970 referred to "slight waves" in the transitional zone between dorsal and ventral pigmentation along the side of thebody), but only in the illustration provided by Williamson (1975) was theprominence of the more posterior (flank) patch sufficiently stressed. This
patch can be clearly seen at sea if the whale rounds its back before submerging (Fig. 6g): a photograph in Kellogg (1940) shows the flank patch andSci. Rep. Whales Res, Inst.,
No. 36, 1985

SOUTHERN MINKE WHALES

19

thorax blaze in the living animals particularly well. Presumably it was also
the flank patch that was referred to in Lillie ( 1915) as "a characteristic triangular patch of lighter colour ... on either side of the back, in the region of thedorsal fin." A sketch accompanying this description shows the patches in dorsal view. The flank patches can in fact be most conspicuous from the air (pers.
obs.), when in dorsal view they are seen extending up either side in front of
the dorsal fin, which is therefore situated in a comparatively narrow strip ofdark pigment extending along the middle of the back of the posterior half of
the whale.
The thorax and flank patches seemed to be present in the majority ofminke whales landed at Durban and in all minke whales examined in the Antarctic. In the three stranded animals with Type 3 flipper coloration
examined on the South African coast, both thorax and flank patches could bediscerned, although the latter was faint. Their position also appeared further
anterior than in minke whales with Type 1 or 2 coloration, the thorax blaze
terminating just posterior to the tip of the flipper and the flank patch about
the level of the dorsal fin. A third, tongue-like dorsal extension of lighter pigment could be detected in all three animals between the dorsal fin and the
fluke insertion, here termed the peduncle patch. This was not noted in animals with Type 1 or 2 flipper coloration, and may be typical of Type 3 animals. Baker (1983) refers to two or three deep scallops of pale pigment along
the flanks in minke whales with Type 3 body coloration, whereas a photograph of a minke whale stranded at Dargaville, New Zealand, with Type 3
body coloration and all-white baleen clearly shows a third, peduncle patch(photograph supplied by M.W. Cawthorn).
MORPHOMETRICS

Total Length
Southern minke whales in general are estimated to reach sexual maturity
at 7.19 m (23.6 ft) or 7.59 m (24.9 ft) in males (Ohsumi and Masaki, 1975;
Best, 1982), and 8.0 to 8.1 m (26.2 to 26.6 ft) in females (Best, 1982; daRocha, 1980; Doroshenko, Kuzmin, Nikolsky and Patsenko, 1974; Ohsumi
and Masaki, 1975). Asymptotic lengths are 8.5 to 8.6 m (27.9 to 28.2 ft) inmales and 8.93 to 8.99 m (29.3 to 29.5 ft) in females (Best, 1982; Ohsumi and
Masaki, 1975).
In Table 4 details oflength, sex and maturity are provided for 13 minke
whales landed at Durban between 1970 and 1973 which are considered (onthe basis of exhibiting at least two of the pigmentation characteristics) to beType 3 animals. Four males, ranging from 6.71 to 6.83 m in total length, wereclassified as sexually mature based on a histological examination of theirtestes, and the weight of their larger testis was from 0.64 to 1.10 kg (mean0.875 ± 0.114 kg), about four times heavier than the average for their size
(Best, 1982). The largest male examined was 7.62 m long, but this animal was
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

Vi

~

"'

;

'O ~
Co -

.._ .....

. °'. ~\;.} ::;i

;:i

<; ~

~

~

::;i

?.

Date
killedFlippercolour

6.83

1248

6.76

M 28 June 1973 (L) Type 3

F 26June 1973

M 19 June 1973 (R) Type 3

F 19June 1973 (R)Type3

M 19June 1973

* Measured to nearest foot (0.3 m)

1319

7.32

6.40

1247

1295

6.71

1246

6.15
F 26 May 1971
7.62* M 19 May 1973 (L) Type 3
6.81
M 23 May 1973 (R) Type 3

1214
981
1037

-

6.40

1634

F 19June 1973

7.77

891

7.37

6.68

874

1245

6.96

837

F 25 May 1970 (L) Type 3(R) Type 3
M 26 May 1970 (L) Type 3(R) Type 3
F 28 May 1970 (L) Type 3(R) Type 3
F 10 Aug. 1970 (R) Type 3

Plath
Lengt
form
Sex
(m)
no.

TABLE 4.

(L) 91.7(L) 68.2(R) 100

Yes

-

4.3

(R) 70.5

Yes

2.4

7

2.6

6

(L) 54.2

-

0
0

0

-

0

(L) 54.9(R) 100(L) 100(R) 100(L) 100(R) 100(L) 100(R) 100(R) 100(L) 55.7(?) 68.2(R) 100

-

-

Yes

-

-

Yes

Yes

-

19

13

-

13 ?

27? +

10?
21

30?

17?

14?

Width of
Pigment%h.
black stripe
Age
on
w 1te
% plate (=GLGs)
grooves? baleen
width

Mature640,
580

Mature1100, Mature
880

720,
540

1040, Mature
880

450,
435

70,
55

45

105,
95

55,
40

-

Testes
Wt
Wt
Maturity
(g)
(g)

2.03
0

0

0
0

4.0
0

-

2.6
0.95

0

2.5,1.45,1.05
0

0
2.2

-

-

Ovaries
Diameter
Diameterc. luteumc. albicans
(cm)
(cm)

PIGMENTATION, AGE AND REPRODUCTIVE DETAILS OF MINKE WHALESLANDED AT DURBAN WITH TYPE 3 CHARACTERS

2,2.255,3.75

6.25,5

3,4

7,8

7,8

One
ovary lost

Lactating

Uterusdiameter Remarks
(cm)

t'l

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t:tl

0

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22

BEST

.
)
4
1
/
0
PBB8
a(
c
i
r
f
uthA
,So
y
tCordonsBaealeminkewha
l
i
n
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v
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.8
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i
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6
.3
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N

SOUTHERN MINKE WHALES

23

not measured as accurately as the others; the largest reliably-measured malewas 6.83 m. Three females, ranging from 6.40 to 7.37 m in length, were classified as mature based on the presence of one or more corpora lutea or albicantia in the ovaries. The largest of these had three ovarian corpora, but
was 0.5 m smaller than the smallest mature female with Type 1 or 2 coloration examined at Durban. The largest female examined was 7.77 m long.
The three whales with a 'white spot' on the flipper from Brazil mentioned by da Rocha and Braga (1982) also matured at an unusually small size.
Two males 6.92 and 7.13 m in length were mature, each with a larger(?) testis
weighing 1OOO g, while a female 7 .62 m long had eight ovarian corpora.
It seems clear that whales of this colour phase are significantly smaller
than normally-pigmented southern minke whales, but with the small sample
size available it is impossible to say how much smaller.
Further evidence of their diminutive nature comes from two juveniles
stranded on the South African coast. A male minke whale 1.92 m long founddead on the beach at Kommetjie (Table 3) had a raw and completely unhealed umbilicus, while the lungs were air-filled, indicating a very recent live
birth. The typical Type 3 flipper and associated body coloration was visible(Fig. 7). A male minke whale 2.54 m long seen swimming very slowly in Cordons Bay harbour, where it died later the same day (Table 3), had some severe lacerations to the posterior half of the body that were attributed tosharks. Its umbilicus was completely healed, both baleen series were fully
erupted and there was heavy lungworm infestation in all bronchi, indicating
an animal that had been alive for some time. The typical Type 3 flipper andassociated body coloration was also visible on this animal (Fig. 8), and the baleen plates were all white.
The normal length at birth for southern minke whales is not well established, but most estimates lie in the range 2.7 to 2.9 m (Best, 1982; lvashin
and Mikhalev, 1978; Ohsumi and Masaki, 1975). While there may be considerable variation in this parameter, and strandlings may not be typical of normal newborn calves, the Kommetjie animal was only 68.5% of the estimatedmean birth length, while the Cordons Bay animal was 74.1 % of the length of
the next smallest calf recorded with a healed umbilicus (Best, 1982). These
examples suggest that whales of the Type 3 colour phase are born at a significantly smaller size than normally pigmented southern minke whales.
Body Proportions
Body measurements other than total length are available for only two
whales with Type 3 coloration, the stranded juveniles 72/8 and 80/ 14. These,
expressed as proportions of total length, are compared in Table 5 with similar
measurements for six other juvenile minke whales (< 4 m long) stranded on
the South African coast, and with measurements of 12 adult Antarctic minke
whales (from Ohsumi et al., 1970). In only two measurements did the values
for both Type 3 animals fail to fall within the range for the six other juveniles,
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

'""~

Oo -

\0 ~

............

,?'- ~'""::0

~~

~

~

::0

~-

[/)

1 Measured half-way and then doubled

3 Obtained by adding two measurements

4.6
1.3
19.2
12.6
5.3
5.6
8.3
24.2
8.3
1.7

4.0
2.3
1.5

-

1.0

28.5

-

192
72.5
64.9
71.5
63.6
54.3
51.5
31.5
25.2
18.2
19.2
13.2

72/8
(M)
254
72.8
65.6
71.3
64.6
52.4
48.6
28.9
24.2
17.9
18.3
14.0
46.5
47.4
27.0
17.7
7.3
1.0
6.1
10.8
3.9
2.2
1.4
0.3
4.8
1.4
16.5
11.7
4.0
4.8
8.9
23.0
7.5
1.2

80/14
(M)

Type3

4.7
1.8
17.6
12.3
4.1
5.0
8.8
24.3
6.7
1.5

341
72.7
64.5
73.6
66.9
51.9
49.3
30.5
24.9
18.0
18.6
14.5
47.5 147.5 129.9 1
20.5 1
8.7
0.9
6.5
11.1
4.0
2.8
1.3

80/28
(M)

16.9
11.1
4.1
3.4
6.1
19.5
7.3
l.;l

-

1.2

0.4
5.8
11.4
3.1,3.4-

28.6 1

343
73.8
70.6
72.9
66.5
52.5
51.3
30.0
25.l
21.6
17.8
13.4
44.9 1

76/26
(F)
345
71.3
68.4
74.8
67.8
53.0
48.4
28.7
24.6
18.3
18.8
13.9
52.2 152.2 1
29.3
19.6
8.4
0.4
5.8
10.4
4.5
1.9
1.7
0.5
9.3
0.7
18.0
12.8
3.5
3.6
6.5
24.6
7.5
0.9

81/15
(F)

9.9
3.1
1.4
2.0
0.6
3.4
0.7
15.6
12.0
3.7
3.3
8.5
20.l
4.5
1.1

20.l
19.3
13.0
44.8
44.8
28.6
19.8
9.6
1.3

-

353
72.2
62.9
74.8
67.4
49.9
46.7
28.9

78/23
(M)

0.7
5.8
10.5
3.1
1.6
1.3
0.2
6.1
0.5
16.2
10.6
3.4
3.6
6.1
24.1
8.0
0.9

377
70.7
67.6
73.l
67.l
51.5
48.0
27.7
23.6
17.2
18.2
13.3
46.7 149.3 131.0 175111(F)

2 To posterior emargination of dorsal fin, not tip
4 Obtained by subtracting two measurements

-0.8
6.6
12.0
3.5
2.2
1.5
0.4
5.3
0.2
19.9
12.l
4.2
5.1
11.3
23.3 1
8.0
0.8

-

301
70.4
68.1
76.1
68.1
52.8
49.5
30.2
27.2
20.6
20.6
15.0
53.2 1
53.2 1

73/12(F)

Field no. & sex
Type 1 or 2

53.7
48.0
29.3 4
25.13
18.7
20.0
14.3

47.5-62.4
43.5-54.8
24.0-32.0
23.4-27.0
17.1-20.5
18.3- 22.0
12.2- 16.0

2.8-4.1
3.0-4.2
3.7-7.7
25.1- 35.8

12.5 - 17.5

4.7-5.7

3.7
3.7
5.5
29.0

15.8

5.1

73.0
66.5
71.5) 2710-930
68.7-76.4
64.4-70.9(70.0-74.0

-

Mean

Ohsumi et al. (1970)
Range

BODY PROPORTIONS (AS % TOTAL LENGTH) FOR SOUTHERN MINKE WHALES

Total length (cm)
Tip of snout to centre of anus (%)
Tip of snout to centre of genital aperture
Tip of snout to tip of dorsal fin
Tip of snout to ant. insertion dorsal fin
Tip of snout to centre of umbilicus
Tip of snout to post. extremity ventral grooves
Tip of snout to ant. insertion flipper
Tip of snout to external auditory meatus
Tip of snout to angle of gape
Tip of snout to centre of eye
Tip of snout to centre of blow hole
Girth, at axilla
Girth, maximum
Girth, at anus
Girth, midway anus to notch in flukes
Height of body at same locality
Projection of lower jaw beyond upper
Centre of eye to external auditory meatus
Centre of eye to blowhole
Blowhole length
Blowhole width
Eye length
Eye height
Length of genital slit
Length of anal opening
Flipper, length, ant. insertion to tip
Flipper, length, axilla to tip
Flipper, maximum width
Dorsal fin, height
Dorsal fin, length of fin base
Flukes, width tip to tip
Flukes, nearest point on ant. margin to notch
Flukes, depth of notch

Measurement

TABLE 5.

....

en
...,

t"tj

o:i

Nl

SOUTHERN MINKE WHALES

25

these being measurements concerning the position of the dorsal fin, which
was apparently situated further forward in the Type 3 animals. Unfortunately
the relevant measurements for the Antarctic minke whales are not comparable, being recorded to the posterior emargination of the dorsal fin rather
than its tip or anterior insertion. Furthermore, Doroshenko ( 1979) reported
small differences in the relative position of the dorsal fin between populationsof southern minke whales, so the significance of the presenr{inding remains
uncertain until larger samples of Type 3 animals from different localities
have been compared.
Both Type 3 animals measured differed from the sample of Antarctic
adults in measurements concerning the size of the dorsal fin and the width of
the tail flukes. The height of the dorsal fin was greater and the width of thetail flukes less in the Type 3 animals, but as the other juveniles examined appeared to be closer to the Type 3 animals in these measurements the differences may simply represent ontogenetic change. The length of the dorsal finbase is a particularly subjective measurement, and the differences shown here
may arise mainly from differences in interpretation between Japanese andSouth African researchers.
Number of Ventral Grooves
These were normally counted (as recommended by Williamson, 1973) inthe region between the eye and the flipper insertion, starting with the mostdorsal (and smallest) groove and continuing to the mid-ventral groove (identified by tracing its path from the tip of the lower jaw). The counts are therefore essentially half-counts of the maximum number of grooves.
In the two stranded Type 3 animals these numbered 38 (72/8) and 27(80/14) respectively, while in another five juveniles examined with Type 1 or
2 coloration the counts ranged from 22 to 38 with a mean of 32.8. Ohsumi etal. ( 1970) gave a range of 26 to 30 grooves in three animals with a mean of28, and Williamson (1961) a single count of 30. These are all in reasonableagreement, indicating no significant difference in this character between
Type 3 and other southern minke whales. In much larger samples, however,
Doroshenko ( 1979) gave mean values (presumably for total counts) of 46 fortwo different populations ("Indian" and "New Zealand"), while for the Brazilian population da Rocha ( 1980) found a range of 15-35 with a mean of 22 inhalf-counts of grooves and Singarajah (1984) a mean of 47 in whole counts
for both sexes. These results seem rather low compared to the present data,
and may either represent population differences or (more likely) differences
in interpretation. Da Rocha and Braga (1982) also give ventral groove countsof 19 to 29 (mean 23. 7) for three minke whales landed in Brazil with (apparently) Type 3 flipper coloration, and state that the number and position ofventral grooves were "normal".

Sci. Rep. Whales Res. Inst.,
No. 36, 1985

26

BEST

24
22
20

18
16
~

cQ)

14

::>

~
u..

12
10
8
6
4
2
0
200

220

240

260
280
No. of baleen plates

300

320

340

Fig. 9. Counts of baleen plates in minke whales at Durban.

Number of Baleen Plates
During the 1969 season at Durban, the whaling inspectors counted thenumber of baleen plates on one side of the mouth in 88 whales landed. These
counts ranged from 215 to 310, but with three outlying counts of 135, 151
and 154. The latter are considered to be probable errors in recording, andhave been omitted from the subsequent analysis.
The means of counts of left and right series were not significantly different (t-test, p > 0.2, df = 83), the samples being independent as they werefrom right and left sides of different animals, and so the data have been combined (Fig. 9). The distribution of counts approximates to a normal distribution, for which the mean was calculated as 268.3 ± 2.1.
Previous counts of baleen plates in southern minke whales are in generalagreement with these values (270 either side-Van Utrecht and Van der Spoel,
1962; 247 on left side and 264 on right - Williamson, 1961), though Ohsumi
et al. ( 1970) listed one animal in the four they examined with 359 plates on
one side, more than in any animal examined at Durban. The remaining four
series of baleen they counted ranged from 261 to 302. Doroshenko (1979)
gives the mean number of baleen plates in the "Indian" population of minke
whales as 242 and in the "New Zealand" population 274. Da Rocha (1980)
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

27

SOUTHERN MINKE WHALES
31~----------------------------.

30

131

29
28
27

.
E

26

~

25

]

24

"

~ 23
0
..0 22

j

21

0 20
~ 19
~

18

17
16
15
14

13
12

.___20~___,,21:-----,'22:-----,',23:--_..,..24-----,',25-----:""26--2:'::-7--,2:'::-8---:2":-9---:3~0-~3~1--3~2-"'.:"'.35,....-----'
Body length (ft)Fig. 10. Length of largest baleen plate against body length in minke whales at
Durban (cross and vertical line = mean ± two standard errors for Type 1 and 2
whales, sample size in brackets; solid dot = individual data for Type 3 whales).

found a median value of 273 (range 155 to 415) in 246 minke whales from
Brazil, while Singarajah (1984) gives an average count of 237 excluding hairs.
There is no indication from these data of polymorphic variation.
The juvenile stranded at Kommetjie had 200 baleen plates on the left
and 205 on the right, outside the range for Durban animals, but both series
were incompletely erupted. The Cordons Bay juvenile had 251 plates on theleft and 244 on the right, well within the range recorded at Durban. From thissmall sample, therefore, there does not seem to be any evidence of a significantly different number of baleen plates in minke whales with Type 3 coloration.
Dimensions of Baleen Plates
The largest baleen plates in minke whales with Type 1 and 2 coloration
reached an average length of 25 to 27 cm in adult animals from Durban (Fig.
10). Other minke whales with this coloration have had baleen plates measured
at 28 and 29 cm (Williamson, 1961), 30 cm (Van Utrecht and Van der Spoel
1962) or 22 - 26.1 cm (Ohsumi et al., 1970) in length. The largest baleen
plates in the seven whales with Type 3 coloration examined did not exceed
20 cm and averaged 18 cm in length (Fig. 10). Even when whales in the same
size range are compared, the values for the Type 3 animals all fall below theaverages for Types 1 and 2, indicating that in relative terms also Type 3
whales seem to have shorter baleen plates for their size.
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

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BEST

The shape of the longest baleen plates (as portrayed by the proportion
breadth/length) did not differ significantly between Type 3 whales (average
0.43 ± 0.02, n = 5) and Types 1 and 2 whales (average 0.48 ± 0.01, n = 34),
when the comparison was restricted to animals of the size range 21 to 24 ft (t= 1.64, p > 0.10). Overall, the proportion for minke whales with Type 1 and2 coloration at Durban ranged from 0.37 to 0.78, with a mean of 0.51 ± 0.04
(n = 331): this compares with published values elsewhere of 0.42 to 0.64, witha mean of 0.52 (Ohsumi et al., 1970).
DISCUSSIONIn summary, two colour phases were found amongst the minke whales landed
at the Durban whaling station. The majority of animals had asymmetricallycoloured baleen, in which the right side bore a larger number of anterior
white plates than the left, and in which the remaining plates had a black outerborder whose width amongst the largest plates averaged about 31 or 34% of
the width of the plate, depending on which series was examined. These animals also had flippers whose pigmentation could be described as either plain
or two-tone (Type 1 or 2) but on which white patches were never found.
There also appeared to be asymmetry in the pigmentation of their flippers,
the left flipper generally being brighter in contrast than the right, but there
was no correlation between flipper and baleen coloration. The transitionalzone between the dark dorsal and light ventral pigments on the neck was on alevel with the eye and the flipper insertion. These animals seemed closest to
the southern minke whales described by Williamson (1959, 1961), Van
Utrecht and Van der Spoel (1962) and Ohsumi et al. (1970), although the occurrence of two-tone flippers was not mentioned by these authors. However,
the apparent continual range in variation of flipper coloration within this colour phase suggests that the animals with two-tone flippers may have been
overlooked. Following Williamson (1959), and taking into account the baleencoloration of the type specimens of B. bonaerensis (Burmeister, 1867) andB. huttoni (Gray, 1874; Williamson, 1959), Type 1 or 2 whales could be referred to as "bonaerensis"-type.
Whales of the second colour phase had all-white baleen or baleen withan unusually large proportion of white plates. The largest baleen plates ofthese animals were either completely white or carried a narrow black outerborder less than 10% of the width of the plate. The flippers carried a striking
white patch connected to a roughly circular white blaze on the shoulder(Type 3). There was no asymmetry of coloration in the flippers and little (ifany) in baleen coloration. The transitional zone between the dark dorsal andlight ventral pigmentation on the neck extended down onto the ventral
grooves as a tongue of black pigmentation between the eye and flipper insertion on both sides of the head, to a roughly equal extent. These animals appeared to be born and to reach sexual maturity at a significantly smaller size
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

SOUTHERN MINKE WHALES

29

than normal southern minke whales, with a dorsal fin possibly situated somewhat farther forward. The largest baleen plates in adults of this colour phasewere less than 20 cm in length, compared to an average of 25 to 27 cm inadults of the normal colour phase.
Whales of the latter phase have been described previously only by Baker(1983) and possibly da Rocha and Braga (1982), though neither accountmakes clear the distinction in baleen coloration between these and normal
southern minke whales nor the difference in size. Although there have beenother references to southern minke whales with "light" flippers or flippers
with white patches (see Introduction), the majority of these have been sightings; it is possible that some of these records may have been of minke whales
with Type 2 flippers, which, when seen in the living animal through thewater, stand out clearly in contrast to the darker dorsal pigmentation (personal experience of the author).
The incidence of this second colour phase off Durban is low. There is no
significant difference between the incidence of Type 3 flippers on right andleft sides of the whales (chi-square test, p > 0.8, df = 1), and their incidence if
the data are combined is 3.24% (n = 370). The incidence of whales with ablack border to. the baleen plate less than 10 % of the baleen in width also did
not differ significantly between left and right sides of the whales (chi-square
test, p > 0.25, df 1), and their incidence if the data are combined is 3.41 %(n = 469). The incidence in the catch is therefore estimated to be 3 to 4% of
all minke whales landed.
Singarajah ( 1984) states initially that no minke whales with white stripeson their flippers were found amongst 1745 animals examined in Brazil between 1979 and 1981, but later that on rare occasions (e.g. in 1980 and 1981
about 0.2% of the catch) a second type with a white stripe was recorded. It is
not clear whether the latter include the three animals in a sample of 902
minke whales examined in Brazil in 1980, which were described as having a'white spot' on the flippers, distinct from the 'all-black' flippers normallyfound (da Rocha and Braga, 1982). If the latter are true Type 3 animals, theirincidence off Brazil is apparently even lower than off Durban. However itshould be pointed out that in both areas the data originates from whaling
operations, where commercial incentives may have resulted in selection forthe larger form.
No whales resembling this second colour phase were seen amongst the
161 animals examined in the Antarctic in 1978179. Photographs and/or
sketches of this colour phase were shown to flensing plant foremen and otherpersonnel aboard the Nisshin Maru no. 3, and subsequently to Japanese scientists with first-hand experience of Antarctic minke whales. None claimed tohave ever seen a whale resembling it, and it must be concluded that this colour phase does not normally migrate to higher latitudes of the Antarctic.
Against this must be balanced the data presented by Wada and Numachi(1979), which seems to show that minke whales with white-banded flippers,
Sci. Rep. Whales Res. Inst.,
No. 36, 1985

30

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and some with no black outer margin to their largest baleen plate, are foundin the Antarctic. Given the authors' own reservations about their data, however, this conclusion must be treated with caution.
Besides Durban (ea 30°S, 31°E) and Costinha, Brazil (ea 7°S, 34°W),
whales corresponding to this colour phase have been recorded from several
other localities in the Southern Hemisphere (Table 3). These records indicate

50-Type 3

minke

[n

~

13)

-

All minke, 1972(n

~ 130)

40

~

~u

0

~

"-

30

20

10

0

10

20

30

40

50

60

70

80

Distance offshore

90

100

(n. miles)

Fig. 11. Distribution of minke whale catches from coast, Durban whaling ground.

a latitudinal distribution from 7° to 41°S, and a presence in all three major
oceans. Nowhere apart from the whaling grounds off Durban and Brazil isthere a measure of its relative abundance, although Baker (1983) refers to it
as "rare" compared to the "common" colour form. Apart from its probableexclusion from the higher latitudes of the Antarctic, the form appears to havethe same overall distribution as the Type 1 or 2 animals. Patterns of schoolingbehaviour, onshore-offshore distribution and seasonality, however, may serve
to segregate the animals to some extent.
Inspection of catch positions and times for the 13 Type 3 animals
examined at Durban (Table 4) reveals that they were all captured singly, sothat there is no evidence of schooling together with Type 1 or 2 animals. The
onshore-offshore distribution of catch positions for the same 13 animals has
been compared with that for 130 minke whales (coloration type unknown)landed at Durban in 1972 (as extracted from Best and Surmon, 1974, Fig. 1),
the data being grouped in 10 n. mile intervals (Fig. 11). The animals withType 3 coloration were distributed closer inshore than minke whales as aSci. Rep. Whales Res. Inst.,
No. 36, 1985

SOUTHERN MINKE WHALES

31

whole, 77% of them being killed within 30 n. miles of the coast compared toonly 10% of all minke whales. The mean distances offshore (27.0 ± 7.5 and60.0 ± 5.6 n. miles respectively) were significantly different (t = 5.62,
p<0.001). (The dissimilarity in distribution might have been greater if it had
been possible to identify and thus exclude any Type 3 animals killed in 1972).
Of the 13 Type 3 animals examined at Durban, 12 (or 92 %) were killed in thefirst half of the season (April to June) whereas in the same years (1970, 1971
and 1973) only 33% of the 530 other minke whales were killed in the same
period. These proportions are significantly different (chi-square = 17.4, p <0.001), suggesting a difference in seasonality of occurrence of Type 3 relative
to Type 1 and 2 minke whales off Durban. (The alternative hypothesis, that
more searching effort was spent inshore in the first half of the season, is considered very unlikely, as it was the last half of the season in which weather
usually deteriorated).
Thus, at least for the Durban whaling area, there are indications of somespatial and temporal segregation of minke whales with Type 3 colorationfrom other minke whales. This segregation was not complete, however, andmore information is needed on the seasonal movements and reproductive behaviour of Type 3 minke whales before any conclusions can be reached on
the degree of reproductive isolation of this colour form from other minke
whales. A decision on the taxonomic status of these animals is therefore premature.
It can be pointed out, however, that the differences in size, body and baleen coloration found between Type 3 and Type 1 and 2 (or "bonaerensis"type) animals are at least as great as those between B. acutorostrata from theNorthern Hemisphere and "bonaerensis"-type animals from the Southern
Hemisphere (and the same seems to be true for skull characters - paper in
preparation).

ACKNOWLEDGEMENTS
I would like to express my thanks to M.A. Meyer and P.G. Reyburn for theirtechnical assistance in the field and laboratory, to the whaling inspectors K.
Bates, R.A.W. Greeff, J.F. Groenewald, H.S. Huysamen, P.C.B. Jurgens, I.
Muir, A.C. Paterson, P. van Rooyen, W.E. van Zyl and A. von Litsenborg fortheir help in collecting data and material, and to B. Mbonambi and P.
Mthembu for practical assistance to the whaling inspectors on the flensing
platform. M.W. Cawthorn (Fisheries Research Division, Wellington), H.
Marsh Qames Cook University, Townsville) and G.J.B. Ross (Port Elizabeth
Museum) kindly provided information on stranded minke whales from New
Zealand, Australia and the Eastern Cape Province respectively.

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