ISSN 0083-9086

THE

SCIENTIFIC REPORTS
OF
THE WHALES RESEARCH INSTITUTE
No. 38

THE WHALES RESEARCH INSTITUTETOKYO· JAPANMARCH 1987

il~lRes. Inst., No. 38~

THE
SCIENTIFIC REPORTS
OF
THE WHALES RESEARCH INSTITUTE

No. 38

THE WHALES RESEARCH INSTITUTETOKYO, JAPANMARCH, 1987

THE WHALES RESEARCH INSTITUTE
3-32-11 OHJIMA, KOTO-KU, TOKYO 136

THE SCIENTIFIC REPORTS OF THE WHALESRESEARCH INSTITUTE
CONTENTS OF NUMBER 38Page

ARNOLD, P., H. MARSH and G. HEINSOHN
The occurrence of two forms of minke whales in east Australianwaters with a description of external characters and skeleton of thediminutive or dwarf form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
KATO, H.
Density dependent changes in growth parameters of the southernminke whale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
LOCKYER, C.
Observations on the ovary of the southern minke whale . . . . . . . 75
MIYAZAKI, N., I. NAKAMURA, S. TANABE and R. TATSUKAWA
A stranding of Mesoplodon stejnegeri in the Maizuru Bay,Sea of Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
DELHON, G. A., E. A. CRESPO and G. PAGNONI
Stranding of a specimen of Cray's beaked whale at Puerto Piramides(Chubut, Argentina) and its gonadal appraisal . . . . . . . . . . . . . . . . 107
GmLER, E. R., H. BURTON and N. GALES
On three odontocete skulls from Heard Island . . . . . . . . . . . . . . . 117
KASUYA, T. and H. OcIDistribution of mother-calf Dall's porpoise pairs as an indicationof calving grounds and stock identity . . . . . . . . . . . . . . . . . . . . . . . 125
SHIMURA, E. and K. N UMACHI
Genetic variability and differentiation in the toothed whales . . . . 141
ZINCHENKO, v. L. and M. v. IVASHIN
Siamese twins of minke whales of the southern hemisphere . . . . . 165
PINEDO, M. c.
First record of a dwarf sperm whale from southwest Atlantic, withreference to osteology, food habits and reproduction . . . . . . . . . . 171
AGUAYO L., A. and S. T. RAFAEL
Sighting records of Fraser's dolphin in the Mexican Pacific waters . 187

目 次

ARNOLD, P.
, H. MARSHa
ndG. HEINSOHN

震小型ミンククジラの外部形態と骨格の記述ならぴにオーストラリア近海に二型が分布することの例証．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．

1

加藤秀弘

南半球産ミンククジラ成長特性値の密度依存的変動．．．．．．．．．．．．．．．．．．．．

47

LOCKYER, C.

南半球産ミンククジラの卵巣の観察．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．

7
5

宮崎信之・中村泉・田辺信介・立川涼1
舞鶴の海岸に漂着したオオギハクジラ............................. 9
DELHON, G. A., E.A. CRESPO andG. PAGNONI

アルセe ンチン，プエルトピラミデスにおけるミナミオオギハクジラの漂着例とその生殖腺鑑定........................................... 1
0
7
GUILER, E.R.
,H. BURTON andN.GALES

ハード島で発見された三個のハクジラ類頭骨........................ 1
1
7
粕谷俊雄・小城春雄
2
5
イシイルカの親仔連れの出現と系統群分離..........................1
志村悦子・沼知健一
41
歯鯨類の遺伝的変異性と分化について.............................1
ZINCHENKO,v.L.andM. v.IvASHIN

南半球産ミンククジラのシャムの双生児........................... 1
6
5
PINEDO, M.

c.

南西大西洋におけるオガワコマツコウの初例とその骨学，食性ならぴに繁殖.............................................1
7
1
AGUAYO L
.
,A
.andS
.
T
.RAFAEL

メキシコ沖太平洋におけるサラワクイルカの目視記録...................1
8
7

THE OCCURRENCE OF TWO FORMS OF MINKE WHALES IN
EAST AUSTRALIAN WATERS WITH A DESCRIPTION OF
EXTERNAL CHARACTERS AND SKELETON OF
THE DIMINUTIVE OR DWARF FORM

PETER ARNOLD*, HELENE MARSH** AND GEORGE HEINSOHN**ABSTRACTTwo forms of minke whales occur in eastern Australian and adjacentsouth west Pacific waters: a dark shouldered form previously widely reported
from southern hemisphere temperate to Antarctic waters, and a cold
temperate to tropical diminutive form, referred to in this paper as thedwarf minke whale. We have examined in detail a 7.1 m sexually mature
female dwarf minke whale and photographs of 15 other individuals forexternal characters. Skeletal features were examined on the 7 .1 m female
and two juveniles.
Dwarf minke whales had a light rostral saddle, blowhole streaks, darkthroat patch, white shoulder patch containing a dark flipper oval, grey
shoulder blaze, white flipper base and light peduncle patch. This characteristic colour pattern varied only slightly over a wide geographic range(Australia, New Zealand, New Caledonia, South Africa). Dwarf minke
whales appeared to differ from southern hemisphere dark shoulder minke
whales in size, position and shape of the dorsal fin. Previously reported
characters of the baleen plates of dwarf minke whales were generally confirmed. Skeletal features of the dwarf minke whale are described for the
first time, and compared with descriptions of other forms from bothhemispheres. The majority of features suggested a greater affinity with thenorthern hemisphere forms than with the southern hemisphere dark
shoulder form. Within Australia, the dwarf minke whale has been recorded from Victoria (!at. 38° S) to northern Queerrsland (!at. 11°55' S)
during May to December.
Our observations generally confirmed previously reported colour
patterns for the southern hemisphere dark shoulder form. Examination ofskulls in Australian museums also confirmed previous information, especially concerning the form of the vertex. Records of dark shoulder minke
whales within Australia ranged from Tasmania (42°50' S, identification
tentative) to central Queensland (23°08' S), overlapping with the dwarf
form at the latter locality.

* Department of Marine Biology, ** Department of Zoology, James Cook University of North
Queensland, Townsville, Qyeensland 4811, Australia
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 1-46

2

ARNOLD, MARSH AND HEINSOHNINTRODUCTION

The occurrence of a southern hemisphere minke whale which lacks the whiteflipper band of the northern hemisphere Balaenoptera acutorostrata Lacepede
1804 has been recognized since the last century. The species B. bonaerensis
Burmeister 1867 and B. huttoni Gray 1874 were erected for specimens of thisform collected near Belgrano, Argentina and Otago Head, New Zealandrespectively. There have also been scattered reports of a white-flippered form
from the southern hemisphere (Lillie, 191 O; Taylor, 1957; Kasuya and Ichihara,
1965; Gaskin, 1976; Wada and Numachi, 1979; Best, 1982; Wada, 1983;
Singarajah, 1984) but it has only recently been well illustrated (Baker, 1983)
and clearly documented (Best, 1985). In addition to differences in colour
pattern, Best showed that this second form of minke whale was reproductively mature at a smaller size than the form having flippers with a single or
two tones of grey. He thus called it the "diminutive" form. In this paper wewill refer to this form as the dwarf minke whale, and to the other southernhemisphere form as the southern hemisphere dark shoulder minke whale.
The taxonomic status of the various forms of minke whales in bothhemispheres is still unclear, despite studies on colour pattern, morphometrics,
osteology and electrophoretic patterns (Kasuya and Ichihara, 1965; Omura,
1975; Omura and Kasuya, 1976; Doroshenko, 1979; Wada and Numachi,
1979; Best, 1982, 1985; Wada, 1983; Singarajah, 1984). In the case of thedwarf minke whale documented by Best (1985), this is partly a function oflimited material. Morphometrics, for instance, were available for only twovery small individuals (1.9, 2.5 m long) and detailed information on colour
pattern of the animal and baleen plates was primarily froi:n one locality (South
Africa). There is also little information on the distribution of the dwarf minke
whale, which to date has been reported from South Africa (Best, 1985),
Australia (Best, 1985; Marsh, 1985), New Zealand (Baker, 1983) and Brazil(Best, 1985).
In this paper, we describe the colour pattern of the body and baleen
plates, external morphometrics, and skeletal morphology of the dwarf minke
whale based primarily on material from eastern Australia. Limited data arealso given on colour pattern and skeletal morphology of the dark shoulder
form from Australia. Both forms are compared with minke whales from otherareas, based on a review of the literature.
Finally, we give preliminary information on the distribution of bothforms in eastern Australia and the seasonality of their occurrence.
MATERIALS AND METHODS

Detailed information is available for a 7 .1 m female dwarf minke whale
which was first reported in a lagoon at Hook Reef, Qld (19°52' S) on August
31, 1982. It was observed and photographed, both from the surface andSci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

3

underwater, between September 6 and November 28, 1982 when it died. A
necropsy was carried out on the 29-30 November, allowing detailed measurements and further observations of colour pattern. Measurements were asrecommended by Norris ( 1961). All ventral grooves were counted, in line withthe eye. All characters identified as of potential systematic value by Doroshenko(1979) and Wada and Numachi (1979) were examined. An attempt to recover
ear plugs was unsuccessful; Sergeant (1963) has noted that ear plugs of minke
whales decompose unless removed within about six hours of death. A liver
sample was taken for electrophoresis but the specimen was subsequently lost
due to a freezer breakdown.
Data on the reproductive status of the animal are in Marsh (1985), who
also included a preliminary account of the necropsy, with observations on
pathology by R. Speares (School of Tropical Veterinary Science, James Cook
University).
The complete skeleton was recovered and is registered with the Queensland Museum (JM 3861). Measurements of the skeleton generally follow
Omura ( 197 5) and Omura and Kasuya ( 1976). A skull discussed by Omura(1975) was re-measured by Marsh to ensure consistency when taking similar
measurements on the Hook Reef specimen. Additional measurements weretaken on the hyoid bones as recommended by Satake and Omura (1974).
The entire baleen plate series from each side of the animal was kept dry.
Following Williamson (1973), we counted anterior hairs and baleen plates, but
ignored posterior hairs (sensu Williamson). We had difficulty in determining thenumber of posterior plates, and our figures may be underestimates (but only
by one or two plates). The longest baleen plate in the series was measured as
outlined by Omura and Fujino (1954). A length of string was placed along theouter edge of the plate to follow its contour and the length .marked off, to bemeasured with a ruler. There was difficulty in determining the level of thebase of the bristles, which may introduce some error. Breadth of the plate wasa straight line measurement taken with vernier calipers across the baleen
plate series. There was some warping of the baleen plates in series and thebreadth will be somewhat lower than if the plates were pressed flat and measured. Further, the measure could include some dried gum. Thickness of thedried gum was measured with vernier calipers and this value subtracted fromthe breadth of the baleen plate series. The breadth of the dark lateral borderof baleen plates was measured with vernier calipers. Measurements forbreadth/length ratios and width of dark border Uust above the gum) weretaken on the longest plates, to be comparable with data in Best (1985).
Information is also available for a 4.0 metre female dwarf minke whale
stranded at Wonga Beach, Qld (16°28' S) on August 24, 1982. This animal
was not examined by us, however 29 colour photographs were taken, mostlyof the left side but also including ventral and oblique dorsal views. The
carcass was buried and the skeleton recovered approximately a year later. The
skull was disarticulated and partially damaged in recovery. Mandibles andSci. Rep. Whales Res. Inst.,
No. 38, 1987

27°24'S153°27'E

27°24'S
153°27'E

l6°47'S146°16'E3>

16°28'5!45°23'E

l 9°52'S149°10'E

4. Point Lookout

5. Point Lookout*6. Milne(?Milln)Reef*7. Wonga Beach*8. Hook Reef

Co
~~-

'O ~

4-18. 9.82
3

seen andphotographedtrapped in reeflagoon, seen andphotographed
underwater;
necropsiedstrandingseen andphotographed
underwater

surfacingat sea,surfacingat sea,at sea,surfacingseen
underwater

underwater

surfacingunderwater

23°1 l'S
151°54'E

1

1

1

3

1

2

1

1

Lengh
(m)

-

-

-

"about l Sft"
(5.5m)

7.1

4.04"15, l 5-20,20ft'"(4.5,4.5-6.1,6. lm)

white
white

9
9

-

white

white

-

white

white

-

white

white

white

white

-

-

-

-

white

cream

cream

-

-

-

Colour Qattern
Flipper Shoulder Baleen
patch

-

-

-

-

-

-

-

Sex

-

I. QUEENSLAND

seen andphotographedat sea,,?o ?;

10. 12 miles NWW
North Reef

15. 9.82

31. 8.82

24. 8.82

16. 7.82

13. 7.82

13. 7.82

18. 6.82

5. 8.814

Sighting
circumstances............

18°24'5147°00'E

27°24'S
153°27'E

3. Point Lookout*9. Kelso Reef

16°05'S145°44'EI)*2. Crispins Reef

7.80

Numberof whales

Date
D.M.Yr.

""::i::i

~
<:
1:..
;:i ~

~

::i::i~

14°40'S145°28'E

Coordinates*I. Lizard Island

Record location
numberTABLE I. SIGHTINGS OF MINKE WHALES IN EASTERN AUSTRALIA

Titmarsh

Ward,
Springett,JohnsonHeinsohn,
Marsh,
Arnold

Wall

Waugh

BrydenBrydenBrydenPrettejohn-

Observerz

ments andskeleton at
JCU
photos at
JCUmeasure-photos,photos at
JCU

photos at
JCU of oneof the threewhales---drawing+
description
atJCU 2>0Victoria

z

::r:

0

rJl

z

M

::r:

t::I

s::
>
~
rJl
::r:
>
z

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~

xerox ofphoto ofone atJCU,
original atMuseum oftationDocumen-..,..

"'""'

~~

~

""'!"

"'"""

'J""

_Co..g_.._.
::g ~3.12.85.85

May-July
4. 7.86
5. 7.86

I l 0 55'S
143°50'£I 9°50'S149°35'£19°10'S
152°17'£14°40'S145°28'£14°02'S
143°51'£16°32'S
I46°08'E?* 15. Ashmore Banks,near Star Reef?* 16. Between Ross
Reef and Hewitt
Reef* 17. Marion Reef

* 18. Lizard Island
region* 19. Grub Reef?*20. Hope Reef

near Grafton

29°47'5153°!8'E!8. 6.85

15°05'S145°44'£*14. Ribbon ReefNo.8+I. Minnie Waters

5. 6.85

23°31'S
I52°03'E*13. One Tree
Island8.81

13. 7.86

seen "often"

19.11.85-30. 8. 83

11. 8.83

23°08'S150°45'£23°08'5
150°45'£*12. Yeppoon+ 11. Yeppoon

I

2

I
2-3

8

I

4(5?),
separated

I

2

I

I

stranding

4.0

2. NEW SOUTH WALES"20ft"(6.lm)

at sea,"15ft"(4.5m)

see text

white

white

-

-

white

white

-

-

white

white

atingtwotones

no patch

white

white

white

white

-

Goodall

Alderson

Zann

Gladstone(1984)

Rockman(I986a,b)

Marsh

-

Oke

SimmonsMarsh-apparently
light

-

white

white

white

dark base, no patch apparSimmons
ently
distallydark
grey, withthin white
posteriorly ontransverseright sideline separ--"8-!0m"photographed4m

surfacingseen andphotographed
underwater

seen andphotographed
underwater

seen andphotographed
underwater

aerial survey
sighting

aerial survey
sighting

underwater

seen andaerial survey
sighting

strandingstrandingphotos at
JCU

sighting
sheet atJCU

photo at
GBRMPA

articleatJCU

article atJCU

photos at
JCU

photo at
Q.NPWS

photo inRockhampton
Morning
Bulletin,held atJCU

photos at
JCU

~

(.lt

r
M

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:r:

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38°21 ·s
141°38'E

37°53'S147°55'E

38°25'S145°04'E

35°50'S137°06'E

34°44'S135°52'E*2. Reeves Channel,
Lakes Entrance*3. Point Leo,
Western port
Bay

+I. Brownlow Beach
Kangaroo Island+2. Tulka, Eyre
Peninsula (PortLincoln)

36°22·s
150°23'E

33°27'S151°27'E+ I. Portland Bay

3. Ocean opposite
Ulladulla*2. Terrigal

TABLE I (Cont.)

19. 9.78

29. 9.75

26. 6.76

3. 6.66

13.10.46

7. 9.82

I

1

I

I

I

I

I

4.54m

2.2m

"6-7ft"(1.8-2.lm)

3. VICTORIA

7.6

4.1

strandingstranding

5. TASMANIA

10'10"(3.3m)

4. SOUTH AUSTRALIA

strandedstrandingstrandingat seastranding

cJ

¥

¥

¥

dark

dark

white

dark

white

white

no patch

Warnecke

AitkenAitkenlight
Dixon
anteriorly

light

no patch dark
posteriorly

-

white

Wakefield(1967)

Tuna spotter,
via Bryden--

no patch fromphotosappearslight

Ted Smith

-

white

photo in
Ling&
Aitken;photo of skull
atJCU

photo in
Ling&
Aitken 4l

xerox ofphotos at
JCU

xerox ofphoto (lateral& ventralview) atJCU,
originals at
Mus. of Victoria; skull
C249362 photos inarticleatJCU

photo at
JCU

z

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43°08'5147°57'E?3. Fortescue Bay
6. 8.73

8.72

7. 6.57

1

1

stranding,thought to havebeen dead overa monthstrandingstranding,thought to havebeen dead 4-6
wks

3.65

5.48

2.16

Guiler(1978)

c.51

Davies,Guiler

Guilerlight band
about half
way along
flipper;much decomposed
specimen

9?

1) position for St. Crispins Reef, Roberts (1978)
2) JCU = School of Biological Sciences, James Cook University of North Queensland3) position for Milin Reef, Roberts (1978)
4) identified as Bryde's whale; 3 additional photos seen and returned to South Australian Museum
GBRMPA = Great Barrier Reef Marine Park Authority
Q.NPWS = Queensland National Parks and Wildlife Service+ southern hemisphere dark shoulder form

* dwarf minke whale

40°50'S147°45'E

42°50'S147°37'E?2. Tomahawk? I. Lenasham

Guiler (1978),article at JCU

identification
by Guilerfrom photograph; Guiler(1978)

Davies &Guiler (1958),
article at JCU....:r

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t""

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8

ARNOLD, MARSH AND HEINSOHN

most of the post-cranial skeleton were also recovered. A portion of the left
hand baleen plate series was also available for examination. Although incomplete, the additional skeleton has allowed confirmation of certain features
noted in the Hook Reef specimen.
The skull of a 2.23 m female dwarf minke whale from Lakes Entrance,
Victoria (Museum of Victoria number C24936) was examined and photographed by Heinsohn.
Photographs of the vertex and posterior underside of two skulls of minke
whales in the Australian Museum (S272 and Sl396) were also examined. As
indicated later (Dwarf minke whale Results: Skull) these showed the characters of the dwarf minke whale, but data on external appearance were notavailable for confirmation of the identification.
All known records have been collated, based on published and unpublished photographs of both forms of minke whales. Details of those records
from eastern and southeastern Australia are given in Table 1. Coordinates ofreefs along the Queensland shelf are from Roberts (1978). The account ofvariation in colour pattern of dwarf minke whales is based largely on photographs of 16 individuals, which are referred to in the text by site locality. The
photographs are retained at James Cook University.
A southern hemisphere dark shoulder minke whale skull (not listed inTable 1) in the Queensland Museum (]2 1708) was examined by Marsh andphotographs taken. An additional skull of this form in the South AustralianMuseum (M 11,375) was also examined for us by Museum staff, and photographs taken of the dorsal side.
DWARF MINKE WHALE
RESULTS

Colour pattern
The rostrum is predominantly dark slate grey, however there may be arim of light grey just above the gum. In underwater photographs of animals
from Hook Reef, Kelso Reef, Grub Reef, Ribbon Reef 8, Milne Reef, Marion
Reef (Rockman, l 986a,b), apparently in an animal from New Caledonia(Laboute and Magnier, 1979), as well as a surfacing animal from the subantarctic (Kasamatsu, unpublished photograph) there is a saddle of lighter
grey. This was of variable extent, but could cover most of the head, at least
back to the level of the flipper base (Fig. la, rs; Fig. 3e). It was particularly
obvious in photographs of the animal from Ribbon Reef 8, but the lighter
pigment was not seen in photographs of stranded animals.
The lower jaw overlying the mandible is light slate grey in living animals,
but may darken rapidly after death. On the Wonga Beach specimen the grey
extended downward over about six ventral grooves, just in front of thedownturn in the angle of the mouth. The extent of grey at the angle of theSci. Rep. Whales Res. Inst.,
No. 38, 1987

9

DIMI
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No.38,1987

DIMINUTIVE MINKE WHALE

11

dark grey streaks (Fig. 3b). The effect of this asymmetry was quite striking
when the Hook Reef animal was observed underwater. On the left side, theconnecting band was hardly visible and the flipper, when held against thebody, seemed to be contained in a continuous band of white. On the righthand side, the broad connecting band merged with the distal dark portion of
the flipper, so that the white was much less extensive.
Dorsal to the shoulder patch is a roughly triangular, light grey shoulder
blaze. Its anterior margin extends obliquely backwards until level with theupper jaw, then is reflexed forward to a shoulder blaze peak (Fig. lb, sbp). In
the animals from Wonga Beach (Fig. 3b) and Marion Reef (Rockman, l 986a),
this extension ran almost directly forward, while in other animals (e.g. from
Ribbon Reef 8) it extended obliquely forward and dorsad. The posterior
margin of the shoulder blaze runs in a broad arc from this reflexed peak backto a level just beyond the flipper when it is pressed in against the body (Fig. 2;
Figs 3b and 3e). In an underwater photo of the top of the head and shoulderof the Hook Reef animal, the shoulder blazes appeared of comparable size on
both sides of the animal. They could be seen to run forward in parallel, rather
than extending onto the top of the shoulder region to link up as a white crescent sensu Best, 1985, for the southern hemisphere dark shoulder form: seeSouthern hemisphere dark shoulder form Results: colour pattern. However,in the animal from Grub Reef, the right shoulder blaze appeared to extend
almost to the midline of the back, while the left shoulder blaze extended moreanteriad and not onto the back of the neck.
A dorsal view of an animal from Marion Reef (Rockman, l 986a,b) clearly
showed blowhole streaks running posteriad and curving to the left.
Behind the flipper, about half way to the dorsal fin, there is a dark grey
cape which extends down almost to the belly (Fig. la, tc). This divides thesides into the shoulder patch and shoulder blaze anteriorly and the light grey
flank patch posteriorly. Often it has a series of 6-10 oblique dark rib-likestreaks (Fig. la, ts; Figs 2 and 3b; see also Gladstone, 1984). The flank patch(Fig. la, fp (1)) continues past the level of the dorsal fin and onto the caudal
peduncle, the posterior half of which is again dark grey. In most animals from
Australia for which we have photos, this flank patch seemed entire, however
there were indications of a dorsal cape (Fig. la, de; Fig. 2) on the animal from
Grub Reef.
On the caudal peduncle, within the light grey flank patch, the white of
the underside may continue as a narrow band at least half way up the tailstock. Dorsally it may continue further as a grey-white band (Fig. la, pp).
This feature was very conspicuous on the left side of the Wonga Beach specimen (Fig. 3c) and evident on the right side of the Kelso Reef animal. Theband appears to be present on the animals illustrated by Rockman (1986b),
Laboute and Magnier (1979) and Baker (1983) from Marion Reef, New
Caledonia and New Zealand respectively.
On the Wonga Beach specimen, the white peduncle band was separated
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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Eye height
Length genital slit
Length anal opening
Flipper: anterior insertion to tip: axilla to tip: maximum width
Dorsal fin height

Eye length

1.27
1.10
3.06
1.54
0.07
0.36
0.68
0.20, 0.20
(R,L)
0.06
slit 0.11
0.08
0.46
0.05
1.02
0.75
0.26
0.34
0.8
slit 1.5
1.1
6.5
0.7
14.3
10.6
3.7
4.8

17.9
15.5
43.1
21.7
0.98
5.1
9.6
2.8, 2.7

28.9
23.8
17.0

2.05
1.69
1.21

to centre eye
to centre blowhole
Girth at axilla
at anus
Projection lower jaw
Centre eye to external auditory meatus
Centre eye to centre blowhole
Blowhole length

76.0
72.9
69.6
55.8
52.9

5.40
5.18
4.94
3.96
3.76

Snout to centre anus
to centre genital aperture
to tip dorsal fin
to centre umbilicus
to posterior extremity ofventral grooves
to anterior insertion of flipper
to external auditory meatus
to angle gape

100.0

0.3
4.6, 4.8
1.3, 1.4
19.2, 16.5
12.6, 11.7
5.3, 4.0
5.6, 4.8

1.5, 1.4

19.2, 18.3
13.2, 14.0
46.5
28.5, 27.0
1.0, 1.0
6.1
10.8
4.0, 3.9

31.5, 28.9
25.2, 24.2
18.2, 17.9

100.0
l.9m, 2.5m
absolute sizes
72.5, 72.8
64.9, 65.6
71.5, 71.3
54.3, 52.4
51.5, 48.6

(mean, range)

7.10% total length

lengthDwarfll(South Africa)% total

Total length

absolute(metres)

Dwarf1)(Australia)

3.7 ( 2.8- 4.1)
3.7 ( 3.0, 4.2)

15.8 (12.5-17.5)

20.0 (18.3-22.0)
14.3 (12.2-16.0)

29.3 (24.0-32.0)
25.1 (23.4-27.0)
18.7 (17.1-20.5)

53.7 (47.5-62.4)
48.0 (43.5-54.8)

73.0 (68.7-76.4)
68.l (n=2)

100.0(mean, range)% total length

Dark shoulder
southernhemisphere3)(Antarctic)-

30.8 (28.1-32.7)7)
21.6 (19.9-23.0) 8 )16.l (13.3-18.7,
n=lO)
15.8 (13.3-18.6)
13.3 ( 11. 7-14.9)

12.1 ( 9.4-15.8,)
8.9 ( 7.3-11.4, 14 ) 10.0 ( 8.8-12.4)
3.8 ( 3.5- 4.0, 12 ) 3.6 ( 3.2- 3.9)
4.2 ( 3.1- 5.0, 10 ) 3.6( 2.9-4.4, 72

18.0 (15.7-19.3)
13.2 (11.0-14.8)

17.89 )

54.0 (48.0-62.7)
48.5 (41.3-56.5)-

74.0 (69.9-81.3)

100.0(mean, range)% total length

North Atlantic5)(Norway)

53.8 (51.6-57.7)
46.2 (39.5-54.4)-

73.5 (70.7-76.1)
70.7 (68.8-72.1)6)

100.0(mean, range)% total length

North Pacific4)
Oapan)TABLE 2. EXTERNAL MORPHOMETRICS OF MINKE WHALES

z

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0.94
0.48

8.4
24.6 11 )
26.4
6.8
1.7, 1.2

8.3, 7.5

8.3, 8.9
24.2, 23.0

5.5 ( 3.7- 7.7)
29.0 (25.1-35.8)

7.4 ( 5.9- 8.8, 11
30.6 (27.6-33.8)12)
6.8 ( 5.8- 7.5)

27.8 (24.0-30.8) 13)) 5.69)1) this paper, 1 9. 2) Best 1985, (specimens= 2). 3) Ohsumi, in Best 1985 (10'.3'0, 2 99 ). 4) Omura & Sakiura 1956 (15 99 ). 5) Jonsgard 1951
(75 99). 6) n = 699 6.58-7.97m, measures 100%-(10+13). 7) n = 599 6.58-7.97m, measures 6-17. 8) n = 699 6.58~7.97m, measures 5+ 7.
9)19, Turner (1892). 10) left fluke damaged, second figure length Of right fluke. 11) second% right fluke X 2. 12) 1399, measure 23 X 2.
13)7499 , measure 12 X 2.

0.07
0.9
1.8
0.13
41.4
2.94
0.29, 0.30
4.1, 4.2(R,L)
Diameter auditory meatus
9.5 X 4.5mm
Blubber thickness: anterior to dorsal fin
38 mm: mid lateral, mid length
34.5mm: mid ventral, mid length 22 mm: anterior to flippers
48 mm: nearest point on anterior: margin to notch: depth notch
Centre eye to angle gape
Girth half way from axilla to umbilicus
Length mammary slit

Dorsal fin length base
Flukes: width tip to tip

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16

ARNOLD, MARSH AND HEINSOHN

Morphometrics
Measurements of the Hook Reef specimen are given in Table 2.
Baleen plates
The longest baleen plates of the Hook Reef animal were 18.3 and 18.5
cm long for the right and left series respectively. The breadth of the right andleft baleen plate series was 8.2 and 8.6 cm (7.9 and 8.3 cm with width of driedgum excluded). This gives a breadth/length ratio of 0.45-0.46 for both sides(0.43-0.45 with gum excluded).
There were 235+ baleen plates on the right side and 225+ on the left. It
was impossible to separate consistently the most posterior plates. Using
Williamson's (1973) criteria there were eight and nine anterior hairs in theright and left series.
The outer border of a baleen plate was considered dark if over a third of
the length was darkly pigmented. On the right side, 5 plates had a dark grey
to black border, while 24 plates had a dusky grey border. On the left side, 18
plates had a dark grey to black border, while 29 had a dusky grey border.
Plates with only a lingual band or median strip were not counted, following
Best (1985). The percentage of white baleen plates is thus 87.7 and 79.l forright and left sides (see Figs 6g and 6h).
The outer dark border of baleen plates was most extensive on posterior
plates, which were entirely dark except for the bristles. In order to be comparable with measurements by Best (1985), the width of the dark border was
taken on the longest plates, about two-thirds of the way back in the series.
Width of the border was 2.5 mm on both sides, (3.0% and 2.9% of total
breadth of right and left plates respectively).
Skeleton
Unless otherwise noted, the description is based on the Hook Reef
speomen.
Skull

Measurements of the skull are given in Table 3 (measurements 1-32,
41-54). These were compared with specimens from the Antarctic (Omura,
1975; Omura and Kasuya, 1976), N. Pacific (Omura, 1957, 1975) and N.
Atlantic (Table 4). The features in which the dwarf minke whale differedfrom previously described forms included proportional lengths of both premaxillaries; median length of nasals; breadth of rostrum at the base; breadthof frontal across the nasals; breadth between the maxillaries at nares; and median length from the tip of the premaxillaries to the anterior end of thevomer. These and other differences will be considered in detail in the discuss10n.
The margin of the rostrum was slightly convex in dorsal view. An
approximate measure of maximum curvature, taken at right angles to a ruler
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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18

ARNOLD, MARSH AND HEINSOHNTABLE 3. OSTEOLOGICAL MEASUREMENTS OF HOOK REEF DWARF MINKE WHALE
Measurements*l. Condylo-premaxillary length
2. Length of premaxillary, right 1l
3. Length ofpremaxillary, leftll
4. Length of maxillary, superior, right
5. Length of maxillary, superior, left
6. Tip of premaxillary to vertex
7. Tip of premaxillary to nasals
8. Length of nasals, median
9. Breadth of nasals, anterior2l
JO. Length of rostrum
11. Breadth of rostrum at middJe3)
12. Breadth of rostrum at base
13. Breadth across maxillaries at vertex
14. Breadth of frontal across nasals
15. Breadth between maxillaries at nares
16. Breadth of skull, squamosal
17. Breadth of skull, frontal
18. Breadth of skull, maxillaries
19. Length of orbit, frontal, right
20. Length of orbit, frontal, left
21. Breadth of occipital bone
22. Breadth across occipital condyles 4 l
23. Height of occipital condyle, right
24. Height of occipital condyle, left
25. Breadth of foramen magnum aperture
26. Height of foramen magnum aperture
27. Length from foramen magnum to vertex5l
28. Tip of premaxillary to ant. vomer, median
29. Tip of premaxillary to ant. palatine, median
30. Tip of premaxillary to post. palatine, median
31. Tip of premaxillary to post. pterygoid
32. Breadth across hamular process of pterygoid
33. Length of mandible, straight, right
34. Length of mandible, straight, left
35. Length of mandible, curved, right

36. Length of mandible, curved, left
37. Heightofmandibleatcoronoid, right
38. Height of mandible at coronoid, left
39. Height of mandible at condyle, right
40. Height of mandible at condyle, left
41. Tympanic bulla, length, right
42. Tympanic bulla, length, left
43. Tympanic bulla, greatest breadth, right 8l
44. Tympanic bulla, greatest breadth, left 9l
45. Tympanic bulla, thickness at middle, right
46. Tympanic bulla, thickness at middle, left
47. Malar length, right
48. Malar length, left
49. Matar breadth, right 10l
50. Matar breadth, left 10l
51. Lachrymal length, right
52. Lachrymal length, left
53. Lachrymal breadth, right

Absolute measure(mm)% of total length

1640.01252.01248.01182.01191.01222.01038.0178.0
105.8
1145.0
381.3
604.1
221.9
257.8
244.2
905.0
880.0
808.0
167.3
164.l
647.0
174.9
98.3
101.5
70.5
65.7
427.0
177.8
1012.01314.01432.0160.31602.01630.01756.01686.01788.01719.0
218.8
219.2
179.5
178.8
79.5
77.3
62.0
58.8
42.2
41.9
202. l
213.0
71.6
72.0
118.5
118.0
58.5

100.0
76.3
76.l
72.l
72.6
74.5
63.3
10.8
6.4
69.8
23.2
36.8
13.5
15.7
14.9
55.2
53.7
49.3
10.2
10.l
39.4
I0.7
6.0
6.2
4.3
4.0
26.0
I0.8
61.7
80.I
87.3
9.8
97.7
99.4
107.16)102.87)
I 09.06J
104.87)
13.3
13.4
10.9
10.9
4.8
4.7
3.8
3.6
2.6
2.5
12.3
13.0
4.4
4.4
7.2
7.2
3.6

of skull~~~--~~~~:r~~!-~::.~~~~_,_!:.~~---------------------------------------------------------?-~~?---------------------------~-·-~------------55. Scapula, greatest breadth, right
56. Scapula, greatest breadth, left
57. Scapula, greatest height, right

630.5
631.5
369.5

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

19

DIMINUTIVE MINKE WHALE
TABLE 3 (Cont.)
58. Scapula, greatest height, left
59. Length of acromion, inferior 1 I)
60. Breadth of acromion, distal end
61. Length of coracoid, inferior I 2)
62. Breadth of coracoid, distal end
63. Length of glenoid fossa 13)
64. Breadth of glenoid fossa
65. Scapula, ratio breadth/height
66. Stylohyal, length
67. Stylohyal, maximum width
68. Basihyal length, straight
69. Pelvis, length
70. Pelvis, width
71. Pelvis, degree of curvature 15l
72. Pelvis, point of maximum width from wider end
73. Sternum, length
74. Sternum, maximum breadth
75. Sternum, point of max. width, from wider end
76. Sternum, point of base to wider end
77. Sternum, shaft length376.5
L 195.5
L 49.3
L 88.5
L 31.1
L 140.5
L 90.3
1.7
L
L 252.2
L 63.3

R 195.5
R 57.9R 99.1
R 33.0R 121.5 14l
R 91.9R
1.7
R 244.8
R 64.8452.2
R 258.2
R 28.8R 31.8(12.3)R 101.8

L 259.5
L 36.5
L 29.5(11.4)
L 102.3
329.5
233.9
116.0
143.9
185.6

1) broken at tip. 2) between premaxillaries at anterior end of nasals. 3) at 572.5mm from tip of premaxillae. 4) to base of spongy bone. 5) measured at posterior parietals. 6) outside curve. 7) inside curve.
8) on to process. 9) process broken. 10) max. ant. end obliquely across. 11) lateral tip to centre of base.
12) to base of glenoid fossa. 13) smooth bone to smooth bone. 14) cartilage present. 15) percentage oflength in parentheses. *) After item 55, only absolute measure indicated.

laid along the edge of the maxillaries, ranged from 7-12 mm.
The anterior margin of each nasal bone was convex (Fig. 5a), with agroove (sensu Omura, 1975) ventrad (Fig. 5b).
Details of the vertex are shown in Fig. 5c. The. supraoccipital curved
gently posteriorly in the mid-line. Its anterior edge was bordered laterally by
the parietals and antero-medially was fused with the inter-parietal. The interparietal was angulato-ovate (Stearn, 1973; Fig. 19) and was bordered along its
entire anterior margin by the frontal. The frontal extended across the vertexof the skull and inter-locked with the posterior margin of the nasals. Laterally
it was over-ridden by the premaxillaries and ascending processes of the maxillaries. The posterior margins of the nasals, premaxillaries and maxillaries
were approximately in a straight line.
The vertex of skull S 1396 agreed in all details with that of the Hook Reef
animal. The nasal bones had a convex anterior margin, and were elongate,
the posterior tip reaching the posterior borders of the ascending processes ofthe maxillaries. The nasals were widely separated from the interparietal by
exposed frontal bone. Skull S272 also had the parietals and inter-parietal
incorporated in the vertex and the anterior of the nasal bones convex. However,the posterior of the nasals appeared to be well in front of the posterior bordersof the ascending processes of the maxillaries.
The skull of the Lakes Entrance specimen had elongate nasal bones with
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

20

ARNOLD, MARSH AND HEINSOHNTABLE 4. MEASUREMENTS OF SKULLS FOR THE VARIOUS FORMS
OF MINKE WHALE AS PERCENTAGE OF SKULL LENGTH

Length rostrum
Breadth rostrum(mid length)
Breadth rostrum(base)
Breadth skull(at squamosal)
Length premaxillaries
Length mandibles(straight line)
Length mandibles(outer curve)
Height mandibles(at condyle)
Height mandibles(at coronoid)

Dwarf1l

Antarctic2l

N. Atlantic 3l

N. Pacific4 l

N. Pacific6l

69.8
23.2

64.0- 69.4
18.9- 22.7

60.8- 67.8
20.7- 24.3

61.8- 64.0
17.9- 20.7

57.4- 62.9
18.0- 19.l

36.8

29.8- 32.8

32.9- 36.5

32.7- 35.0

30.9- 32.6

55.2

50.8- 53.4

54.6- 57.2

54.7- 57.3 7)

50.9- 53.9

76. l, 76.3 5)

70.4- 72.8

73.8- 75.7

73.6- 75.9

69.3- 73.0

97.7, 99.4 5 )96.4- 98.l

100.0-101.4

107.l, 109.25)

102.8-106.9

l 05.0-l 09.3

10.9

8.8-

9.9

13.3

l l.8- 14.3

88.2- 97.3
109.8

9.3, 10.5
12.8- 13. l

91.7-101.8
9.4- 10.2

12.7

12.3- 13.2l) this paper. 2) Omura (1975); Omura and Kasuya (1976). 3) Turner (1892); True (1904); Allen (l9l6).
4) Tomilin 1967, table 64. 5) right and left sides. 6) Omura (1957; 1975). 7) Zygomatic width.

convex anterior margins and an inferior anterior groove Q. Dixon, personalcommunication to Heinsohn). The posterior margin of the nasals was in linewith the posterior of the premaxillaries, however the ascending process of themaxillary extended further posteriad for about one-third the length of thenasals (0.35-0.37, based on measurements from three photographs). The
maxillary processes were bordered on their posterior edges by frontal bonewhich formed a medial triangular area bounded laterally by maxillary,anteriorly by nasals and posteriorly by parietals and inter-parietal. The
parietals and inter-parietal were similar to those of the Hook Reef specimen;
the inter-parietal was clearly separated by a suture from the left parietal.
The skull of the Wonga beach specimen was damaged and disarticulated,with the nasals missing. However, the form of the vertex was similar to thatjust described. The anterior margin of the supraoccipital was somewhat more
irregular but also curved posteriorly in the mid-line. The inter-parietal
appeared to be partially fused to the right parietal, but was clearly separate on
the left side and could be seen as a distinct bone on the inner roof of the skull.
The frontal was oriented as described for the Hook Reef specimen.
Lachrymal and malar bones are shown in Figs 5d and 5e respectively;
dimensions are given in Table 3 (measurements 4 7-54).
The posterior margin of the palatine was sharply angulate (Fig. 5f) in
specimens from Hook Reef and Lakes Entrance, and possibly skull Sl396,
although that skull was damaged. The shape of the palatines could not be
determined in skull S272 or the Wonga Beach specimen.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

21

In the Hook Reef specimen, the hamular process of the pterygoid (Fig.
5£) was long (41 % and 44% of the length between the tip of the process andthe intersection of pterygoid and palatine bones on the medial side). The
ratio of basal width/length of the hamular process was 0.68 for both right andleft sides. Skulls of the Wonga Beach animal, 5272 and 51396 were all broken
on the underside so that details of the pterygoids could not be seen. The
hamular processes were elongate in the Lakes Entrance specimen.
Mandibles are shown in Figs 5g and 5h. Measurements are included inTable 3 (measurements 33-40).
Axial skeleton
The epiphyses were completely fused to the posterior caudal and firsttwo cervical vertebrae only; they were unfused to thoracic vertebrae.
The main feature previously identified as of potential systematic value isthe presence or absence of the parapophysis on the seventh cervical vertebra.
It was present as a tubercle in the Hook Reef specimen.
Ribs

There were ten pairs of ribs, with one possible pair of much reduced ribs
(18.4 and 25.8 cm long). Proportions can be seen from Figs 6a and 6b(reduced ribs not shown). The Wonga Beach specimen had eleven pairs of
ribs.
Sternum
The sternum was roughly T-shaped, with the point of maximum breadth
71.0% of the total length (Fig. 6c). The point of maximum breadth wasreached 35.2% from the wider end, while the shaft of the sternum was 56.3%
of the total length. Measurements of the sternum are given in Table 3(measurements 73-77).
Scapula and flipper bones
The scapulae are shown in Fig. 6d. Measurements are given in Table 3(measurements 55-65). The maximum breadth/length ratio was 1.71 and1.68 for the right and left scapulae.
The phalangeal formula for both flippers (based on X-radiographs) was
4,7,7,4. In the left flipper, the terminal phalanges of II and III (numberingsystem from Omura, 1975) were minute.
Hyoid bones
The hyoid bones are shown in Fig. 6e. The posterior margin of eachwing of the fused basihyal-thyrohyals curved posteriad sub-medially but thenran obliquely forward toward the anterior margin which was almost at rightangles to the mid-line.
Measurements are given in Table 5. The tips of the right and left wings
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

22

ARNOLD, MARSH AND HEINSOHNTABLE 5. MEASUREMENTS OF HYOID BONES OF HOOK REEF DWARF MINKE WHALE'
Absolute measure(mm)% total length

Fused basihyal and thyrohyals
Total length
Straight length
Greatest height
Height at centre
Forward notch, depth
Height at middle of right wing
Height at middle of left wing
Thickness at middle of right wing
Thickness at middle of left wing
Height at distal end, right
Height at distal end, left

533.0
452.2
152.0
118.9
32.3
70.5
72.1
33.2
38.5
33.8
34.5

100.0
84.8
28.5
22.3
6.1
13.2
13.5
6.2
7.2
6.3
6.5

Stylohyal
Total length, right
Height at middle, rightThickness at middle, right
Degree of curvature, right
Total length, left
Height at middle, left
Thickness at middle, left
Degree of curvature, left

244.8
58.0
23.8
34.5
252.2
56.3
23.3
35.3

100.0
23.7
9.7
14.1
100.0
22.3
9.2
14.0

1) See Satake and Omura (1974) for definitions of measurements.

of the fused basihyal-thyrohyals and the tips of the anterior projections of thebasihyal were eroded so that proportions based on overall lengh (Table 5) will
be over-estimates. Nonetheless, the stylohyals were proportionately short(length of the right and left stylohyal was 45.9 and 47.3% of the overall lengthof the fused basihyal-thyrohyals). The stylohyals were strongly curved (degreeof curvature 14.1 and 14.0% of total length of the right and left stylohyal).
Pelvic bones
The pelvic bones are shown in Fig. 6f. They were long (258.2 and 259.5mm for right and left bones) and knife-like. The maximum width (11.2 and14.1 % total length) was reached 39.4% of the distance from the wider end.
The bones were strongly curved (maximum curvature 12.3 and 11.4% of total(straight line) length of right and left bone). Further measurements are given
in Table 3 (measurements 70-72).
Other features
Unless otherwise noted, the following observations are for the Hook
Reef speciman.
The longest ventral groove did not reach to the umbilicus; this corresponds to the type B animals of Wada and Numachi (1979).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

23

The flukes had a deep median notch, corresponding to type 2 ofDoroshenko ( 1979).
The palate was uniformly cream coloured.
J acobsen's organ was represented by two pairs of pits. The anterior andposterior pairs were 28 and 52 mm from the tip of the snout, while the anterior
fringe of baleen was 50 mm from the tip.
The lateral edge of the left liver lobe was even.
The animal was reproductively mature. Further details were given by
Marsh (1985).
Healed skin lesions were evident on the Hook Reef specimen and at least
one open, circular lesion was noted on the Wonga Beach specimen.
Distribution
Known records of dwarf minke whales are given in Table 1. Sight
records from Queensland with a question mark lacked detailed notes on
colour pattern or photographs, but were made by observers familiar with theappearance of dwarf minke whales at sea. The record from Point Leo, Victoria
was based primarily on the dark throat patch visible in one photograph, butother colour features could not be determined from material available. The
stranded animals were 4.04 m (Wonga Beach), 4.1m(Terrigal),4 m (Yeppoon,
length estimated), 2.23 m (Lakes Entrance) and 4.5 m long (Point Leo,
Victoria). The Hook Reef specimen was 7.1 m, while estimates of animals
observed at sea ranged from 15 ft (4.5 m) to 10 m. The fourteen records from
central and northern Queensland (11°55' -23°08'S) were from July to
December, with most sightings from July (5) and August (4).
The stranding at Terrigal, N.S.W. (33°27' S) occurred in early September,while the two records from Victoria (about 38° S) occurred in June.
Six of the records were of single animals (including three single strandings). Five sightings were of pairs, one of three animals and two of fouranimals. A sight record west of Barrow Island, Western A11stralia (20°28' S) offour animals seen on June 23, 1983 (Pattenden, pers. comm.) appears to havebeen of dwarf minke whales.
Sight records on the northern Queensland shelf are from the mid- toouter shelf.
DISCUSSION

Colour pattern
The colour patterns of the various forms of minke whales are comparedin Table 6.
Our observations confirm Best's ( 1985) description of the dark throat
patch, flipper pigmentation, and presence of a white shoulder patch andshoulder blaze. These, in combination, separate the dwarf minke whale fromall other forms.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

"''

Oo -

'O ~

..........

;_,,, ::>:l
,?o ~

~~

~

~

;:i:i

?,

-

-

x;i
x

x
x

(indistinct)

x
x

-

x
x

-

?
x

-

x
x

(indistinct)

?

?
?

x
x
x
x
x
x
x

x
x
x
x

x
x
x
x
x
x
x
x
x

x
x
x
x
x

-

Present
Study 1>

Baker (1983)

Best (1985)

MagnierLaboute(1979)

Dwarf minke whale

x
x

x

x
x
x
x

Southern hemispheredark shoulder minke

x3>

?
x

x 2)
?
x
x
x
x?4>
x?2>
x;is>

x

North AtlanticxNorth Pacificl) including photos from Gladstone (1984); Rockman (l986a,b). 2) Leatherwood et al. (1982). 3) Blake, in Allen (1916). 4) Norris and Prescott(1961). 5) Stern, unpublished photograph.

10. Caudal chevronl I. Peduncle patch
12. Dorsal fin flare
13. Specklingl. Rostral saddle
2. Dark throat patch
3. White shoulder patch
4. White flipper base5. Thorax blaze
6. Gray crescent dorsad
7. Blowhole streaks
8. Flank patch
9. Dorsal capeColour pattern

TABLE 6. COMPARISON OF COLOUR PATTERNS OF MINKE WHALE FORMS

...

>

z

::r:

0

CFl

z

l:'l

::r:

tl

>
z

::r:

~

s::
>

p

t""'

0

z

;r::i

N:l

25

DIMINUTIVE MINKE WHALE

TABLE 7. AVERAGE SEA SURFACE TEMPERATURES (°C) ON QUEENSLAND SHELF AT TIMESOF REGULAR SIGHTINGS OF MINKE WHALES. DATA FROM BRANDON
Latitude
Month

June
July
Aug.
Sept.

25°

23°

20°

18°

16°

14°

21.3
19.4
21.5
22.7

21.7
20.9
20.5
21.3

22.3
21.2
20.5
22.7

23.0
22.2
22.8
23.3

23.5
22.7
22.8
24.5

23.8
23.7
24.3
24.8

The dark throat patch contrasts sharply with the light lower jaw of thesouthern hemisphere dark shoulder form but is similar to the pigment inspecimens from the North Pacific and North Atlantic (see figures in Omura
and Sakiura, 1956; Sergeant, 1963).
Best (1985) did not report what we have called the flipper oval within theshoulder patch, nor did he comment on the asymmetrical development ofdark pigment running into the shoulder patch from its posterior margin. Thisasymmetry was confirmed on two of the animals for which we have photos ofboth sides and is suggested by photographs of other animals taken fromdifferent angles. The asymmetry also seems to be present in South Africanmaterial, based on a comparison of Best's (1985) Fig. le (right side) and
Fig. 8 (left side).
Best ( 1985) reported that one of the stranded dwarf minke whales had acrescent-shaped mark running towards the mid-dorsum. This statement is
supported by his Fig. 8 in which the pigment does run onto the back. He considered this analagous to the crescent marks extending onto the back of dark
shoulder minke whales and further noted that there were indications of asimilar pattern in the dwarf minke whale from New Zealand illustrated by
Baker (1983). On our material, this streak ran more anteriad and did notappear to meet on the back. This feature was seen especially clearly in
specimens from Hook Reef and Wonga Beach, although in other animals it
appeared to run obliquely dorsad. The animal from Grub Reef seemed to beasymmetrically coloured with the right shoulder blaze extending further onto
the back. The orientation and extent of the blaze thus may be variable.
Dorsal views of animals from South Africa (Best, 1985) and Marion Reef
(Rockman, 1986b) showed a medial patch of light pigment between theblowhole and level of the flipper insertion.
Best (1985) reported blowhole streaks in a dwarf minke whale fromSouth Africa. We did not see these in the Hook Reef animal, nor are they
apparent in any photographs of this or other dwarf minke whales from theBarrier Reef region. However, Rockman (l 986a,b) has a dorsal view of adwarf minke whale from Marion Reef, Coral Sea, which clearly shows thesestreaks.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

26

ARNOLD, MARSH AND HEINSOHN

The light head and rostral saddle may be apparent only in living or
recently dead animals; it has not been previously noted in the dwarf minke orother forms.
Neither we nor Best (1985) have seen a dorsal fin flare (such as hereported in the southern hemisphere dark shoulder form) in the dwarf minke
whale.
Best ( 1985) described a flank patch reaching to the level of the dorsal fin
and a peduncle patch, or extension of white up the side of the tail stock. On
animals of which we have photographs or have examined, the flank patch
extends past the dorsal fin, onto the latter half of the tail stock. In most cases,
it appears to be entire, but in the animal from Grub Reef and the one illustratedby Baker (1983) there is an obscure dorsal cape (Fig. la, de), just in front of
the dorsal fin, dividing the flank patch into two parts. On our animals, theextension of white up the tail stock, which appears to be the peduncle patchof Best, occurred within the flank patch, and was bordered on either side bylight grey. The tail stock darkened just behind the peduncle patch. Thesefeatures can also been seen in the photograph of the New Zealand specimen(Baker, 1983).
The shoulder blaze is a consistent feature which may not be found inother forms. In a dwarf minke whale from New Zealand illustrated by Baker(1983) there is a clear shoulder blaze dorsal to the flipper, plus a dusky dorsal
cape just in front of the dorsal fin, which divides the flank patch into twoparts. The anterior part of this flank patch is of similar form and overlaps inposition the 'thorax blaze' described in the southern hemisphere dark shoulder
form by Best (1985), and seen in other minke whales from the North Pacific(Leatherwood, Reeves, Perrin and Evans, 1982; Figs 104and105). We thus
distinguish between the shoulder blaze, above the flipper and reported only
from the dwarf minke whale, and the flank patch, which may be divided into
two parts, the anterior of which has been called a "thorax blaze".
In our specimens of dwarf minke whale, the light grey either side of thepeduncle patch continued ventrad, then turned sharply anteriad, forming achevron. Best ( 1985) noted 'indications' of a chevron on a stranded specimen
from South Africa and the chevron can be seen in the specimen illustrated by
Baker (1983).
Both the chevron and peduncle patch appear to be variably developed in
the east Australian specimens, both being very clear on the Wonga Beach andKelso Reef animals but poorly developed (peduncle patch) or absent (chevron)in the Hook Reef specimen.
The caudal chevron appears to occur in the North Pacific and both
southern hemisphere forms, based on photographs of animals from thoseregions. A caudal chevron is shown in the illustration by Blake of a minke
whale from Massachusetts (Allen, 1916), so that it appears to be a generalfeature of all forms.
The peduncle patch may be a characteristic feature of the dwarf minke,
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

27

as suggested by Best (1985). However, an eastern North Pacific minke whale
illustrated in Norris and Prescott ( 1961) shows an extension of white and greyon the peduncle, similar to the patch we have seen in eastern Australiandwarf minke whales.
Speckling of the sides was not noted in the east Australian dwarf minke
whales, nor has it been reported by Best (1985).
The dorsal fin flare has been documented only in the southern hemispheredark shoulder form but may occur in the North Pacific from (Leatherwood
et al. 1982; Fig. 104).
Comparison of morphometrics with other dwarf minke whales
Best ( 1985) included a full set of measurements for two specimens ofdwarf minke whale 1.9 and 2.5 metres long. The Hook Reef specimen differedfrom these in: (1) greater distance from snout to anus (76% versus 72.5,
72.8%); (2) more anterior position of dorsal fin (69.6% versus 71.5, 71.3%);(3) shorter mouth (17% to angle of gape, versus 17.9, 18.2%); (4) greater
breadth of flukes (26.4% versus 23.0, 24.2%); (5) shorter (14.3% versus 16.5,
19.2% - insertion to tip) and narrower (3.7% versus 4.0, 5.3%) flippers.
The height and basal length of the dorsal fin of the Hook Reef specimen(4.8 and 8.4% of total length) agreed well with the figures given by Best
(1985; 5.6, 4.8% and 8.3, 8.9% respectively).
Comparison with other forms
We have no measurements of Australian dark shoulder minke whales.
Best (1985) compiled data on proportions of southern hemisphere minke
whales, including data of Ohsumi, Masaki and Kawamura (1970) on 10 males
and two females from the Antarctic. We also have examined data compiled
from Omura and Sakiura (1956), Jonsgard (1951) and Turner (1892) forNorth Pacific and North Atlantic animals. It should be considered that not all
the measurements were taken in the same manner, especially in those studies
published before Norris ( 1961).
The distance from snout to anus (76%) was greater than the values for
dwarf minke whale in Best (1985: 72.5, 72.8%). The difference may simply
reflect the varying sizes of the specimens and is within the range of variation
noted for other forms of minke whales.
The tip of the dorsal fin was further forward on the Hook Reef animal(snout to tip 69.6%, versus 71.5, 71.3% for Best's specimens). Best (1985)
noted that the dorsal fin was placed more anteriorly in his two specimens ofjuvenile dwarf minke whales, than in six southern hemisphere dark shoulder
minke whales of comparable size. The even more anterior position of the finon the mature Hook Reef specimen supports this difference, and suggeststhat it is maintained, if not augmented, with growth. Exact comparison withlarger specimens of other forms of minke whales is impossible as most authors
have measured to the posterior emargination of the dorsal fin. However
Sci. Rep. Whales Res. Inst.,
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28

ARNOLD, MARSH AND HEINSOHN

given that the tip of the dorsal fin is more posterior than the posterior emargination of the fin, the fact that the fin tip of the Hook Reef animal was moreanterior than the posterior emargination of the fin in dark shoulder southernhemisphere (Best, 1985) and North Pacific (Omura and Sakiura, 1956) minke
whales indicates that the fin was more anterior than in those forms. Fromdata summarized by Omura and Sakiura (1956), the dorsal fin is situatedfurther forward in northern hemisphere Atlantic minke whales than in thosefrom the North Pacific, and may be similar in position to that of the dwarf
minke whale.
The broad dorsal fin with strongly convex anterior margin and shallowly
emarginate posterior border (Fig. 3d, Laboute and Magnier, 1979; Rockman,
1986a) may be characteristic of the dwarf minke whale. Photographs of animals
from the North Atlantic (True, 1904; Plate 28.4), North Pacific (Leatherwood
et al., 1982; Figs 108 and 110) show a tall, more slender fin with deeply emarginate posterior margin. A similar form of fin may occur in the southernhemisphere dark shoulder form (Lillie, 1910; Plate 5.2).
The mouth of the Hook Reef animal was short (17.0% to angle of gape,which is below the figures given by Best (1985) for the dwarf minke whaleand outside the range of the figures given for dark shoulder minke whales
quoted from Ohsumi, Masaki and Kawamura (1970). Doroshenko (1979)
figured marked differences in the length of mouth in southern hemispheredark shoulder minke whales from different sectors of the Antarctic. A similar
range of proportions could be expected for the dwarf minke whale. The value
for our specimen is lower than in animals from the North Atlantic measured
by Turner (1892) and Allen (1916): 17.4-22.6%, but within the range of
specimens from the North Pacific. The wide variability in gape measurements
may reflect different measuring techniques and the character seems of limited
value.
The height and basal length of the dorsal fin of the Hook Reef specimen(4.8 and 8.9%) agree well with figures for dwarf minke whales by Best (1985)(5.6, 4.8% and 8.3, 8.9% respectively). They are outside the range reported indark shoulder minke whales by Ohsumi et al. (1970) (x =3.7% (3.0-4.2) and
x =5.5% (3.7-7.7) respectively) and for height, outside the range for North
Atlantic animals given by J onsgard ( 1951; n = 72 females). Both dorsal finheight and basal length are within the range given for North Pacific animals
by Omura and Sakiura ( 1956).
The left fluke of the Hook Reef animal was damaged and the relative
total width (24.6%) is thus suspect. Doubling the value of the right fluke gives
a value of 26.4%, which is within the range reported for southern hemispheredark shoulder (Ohsumi et al. (1970) cited in Best (1985) and North Atlantic
minke whales Qonsgard, n = 74 females), but outside the range of the North
Pacific animals (Omura and Sakiura, 1956). The width of flukes is greaterthan that reported for the juvenile dwarf minke whales. That this may simply
be a function of growth can be seen by comparing the figures in Best (1985;
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

29

Table 5) which shows that the proportional width of flukes in six small southern hemisphere dark shoulder minke whales was smaller than in the larger
specimens quoted from Ohsumi et al. (1970).
The flippers of the dwarf minke whales described in Best (1985) were
proportionately longer and broader than those of the Hook Reef animal.
However, our figures for the mature specimen agree well with those forsouthern hemisphere dark shoulder minke whales (Ohsumi et al., 1970) ofcomparable size. The discrepancy with Best's specimens may again simply
reflect the markedly different ages of his and our specimens.
The number of ventral grooves (67) of the Hook Reef specimen is
between the values for the two dwarf minke whales given by Best ( 1985) (76,54 respectively), and does not differ from his figures for the dark shoulder
minke whale juveniles (x =65.6 (44-76)). The summary of reported values
for number of ventral grooves by Best suggest that the feature is either veryvariable or subject to large differences in counting by different observers. In
this respect, we counted grooves at the level of the eye, which is anterior to
the position recommended by Williamson (1973), and now apparently ingeneral use.
In summary, the differences in measurements between our specimen
and those documented in Best (1985) fall within the range of variation reported from other forms of minke whales. The greater size and more anterior
position of the dorsal fin, compared with the dark shoulder southern hemisphere form, has been confirmed.
Baleen plates
The number of baleen plates is within the range reported for both thedwarf minke whales by Best and other workers on dark shoulder minke
whales as summarized by Best (1985). We counted only anterior hairs andbaleen plates so that our estimates may be lower than others given in theliterature, but only by a few baleen plates. Doroshenko ( 1979) noted that in
the southern hemisphere dark shoulder minke whale, there was a direct relationship between length of jaw and number of baleen plates. The relatively
low numbers of plates thus may reflect the shorter mouth of the Hook Reef
specimen (see Dwarf Minke Whale Discussion; Comparison of morphometrics
with other dwarf minke whales and Table 2).
Although the method of measuring breadth of baleen plates differedfrom that given by Omura and Fujino (1954) and that used by Best (1985),
the differences seem slight. Subtracting the width of the gum made little difference to the values. A greater potential error arises from the variability inthe breadth of plates in the series even in the section with longest baleen
plates. However, the ratio reported here (0.43-0.45) agrees well with thevalue given by Best (1985; x = 0.43, n = 5) for the dwarf minke whale.
The length of the longest baleen plates of the Hook Reef animal is inagreement with Best's (1985)report that plates of the dwarf minke whale are
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

30

ARNOLD, MARSH AND HEINSOHN

relatively shorter than those of the dark shoulder form, not exceeding 20 cm.
The values of 18.3 and 18.5 cm for right and left side agree well with therµean of 18 cm reported by Best. Baleen length also appears to be shorter
than in North Atlantic minke whales as reported by Jonsgard (1951), althoughthat author noted a wide range of values and indicated that baleen plates offemales were shorter than those of males, at least for specimens from the
Lofoten area.
The colour pattern of the baleen plates is similar to that described byBest (1985) for the dwarf minke whale. However, Best (1985) noted thatanimals with predominantly white plates, with a few plates bearing a thin(about 0.3 cm wide) black border, as shown in his Fig. lf, were scored ashaving all white baleen. The Hook Reef animal (Figs 6g and 6h) had a similar
colour pattern to Best's Fig. lf, and would probably be scored as having 100%
white plates. This might explain the discrepancy between our value for theright hand series (87.7% white) and the figures in Table 4 of Best (1985),
which showed completely white plates in the right series of all but one animal.
The width of the dark border of mid-series plates found in the Hook
Reef animal also fits the pattern described by Best (1985). However, theposterior plates on both sides were increasingly dark and the most posterior
plates were all dark, except for the bristles. This feature was not commented
on by Best (1985), who extracted baleen plates more from mid-series, nor canit be seen in his Fig. 1f of the baleen series of a "Type 3" whale.

Skeleton
Our present observations represent the only available data on the skeletal
features of the dwarf minke whale.
The Hook Reef animal was sexually mature (although physically immature) and should be comparable with specimens of the southern hemispheredark shouldered form, as documented by Omura (1975) and Omura andKasuya (1976). The two forms overlapped only in proportional breadth of theoccipital bone, height of right occipital condyle and height of both mandibles
at the coronoid. The disarticulated skull of the Wonga Beach specimen could
not be measured. Clearly, more specimens (especially of the dwarf form) must
be measured to establish if there are consistent differences in the proportionsof the skulls.
Omura (1975) and Omura and Kasuya (1976) have indicated skeletal
features of apparent systematic value in separating North Pacific and thesouthern hemisphere dark shoulder form. They noted, however, that thesmall number of animals from both localities, and their discrepancy in size(the North Pacific animals being much smaller) made comparisons difficult.
In Table 4 we present data on the dwarf minke whale, the southern hemispheredark shoulder form (Omura, 1975; Omura and Kasuya, 1976), small North
Pacific minke whales (specimens with skulls less than l .5m, from Omura,1957), large North Pacific minke whales (from Tomilin, 1967), and large
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

31

North Atlantic animals (Turner, 1892; True, 1904; Lilljeberg in True, 1904;
Allen, 1916; Tomilin, 1967). An examination of Table 4 (and Fig. 6 inOmura, 1975) shows that two features used by Omura (1975) to separate theNorth Pacific and Antarctic forms (breadth of skull, breadth of rostrum atbase) differed only in the largest animals, listed by Tomilin (1967). The
smaller North Pacific animals listed by Omura differed as much from thelarge North Pacific specimens listed by Tomilin (1967) as they did from theAntarctic specimens. Similarly, the large North Atlantic specimens agreed
more closely with the large North Pacific specimens listed by Tomilin ( 1967)
than they did with the smaller animals listed by Omura (1957). It would
clearly be misleading to compare measurements of the dwarf minke with dataon North Pacific animals measured by Omura (1957). Unfortunately, only the
relatively few measurements given in Table 4 seem to be available for maturenorthern hemisphere specimens.
Of the nine measurements in Table 4, four refer to the mandible. The
Hook Reef specimen overlapped in two and one of the four measurementswith specimens from the Antarctic and North Atlantic respectively, while
there was no overlap with specimens from the North Pacific.
The dwarf minke whale was closest to the southern hemisphere dark
shouldered form in length of rostrum, although still outside the range forthat form (69.8 vs 64.0-69.4%). True (1904) and M'Intosh (1917) noted thatthe rostrum was proportionately more elongate in the largest skulls of North
Atlantic minke whale; their values overlap those of the dark shouldered form
and approach that of the dwarf minke whale. However, even including thedata from Tomilin (1967) North Pacific minke whales appear to have a shorter rostrum than either southern hemisphere form.
The basal breadth of the rostrum (36.8%) was larger in the dwarf minke
than in all the Antarctic and North Pacific forms. Northeast Atlantic minke
whales also seem to have a narrower rostrum (X.=34.2 (32.9-36.5) %, n = 5),
although one specimen from Norway had a broad rostrum (Allen, 1916).
More data are needed, but the basal breadth of the rostrum may be a distinctive
f eatu re of the dwarf form.
The dwarf minke whale overlapped the North Atlantic specimens in
breadth of rostrum at mid-length and was close to Antarctic specimens in thisvalue. Again it was the North Pacific animals which had a narrower rostrum
at mid-length.
In breadth of skull at the squamosal, the dwarf minke whale differedfrom the dark shouldered form but overlapped with the Atlantic and possibly
larger North Pacific animals, based on zygomatic widths from Tomilin (1967).
In length of premaxillaries, the dwarf minke whale was much closer to
the North Atlantic and large North Pacific specimens than to those from theAntarctic.
Omura (1975) and Omura and Kasuya (1976) also noted several qualitative
differences in skulls from North Pacific and Antarctic animals. Of these, theSci. Rep. Whales Res. Inst.,
No. 38, 1987

32

ARNOLD, MARSH AND HEINSOHN

profile of the skull and margin of the rostrum as seen in dorsal view seemparticularly subject to variable interpretation, and are difficult to measureconsistently. Moreover, M'lntosh (1917) noted a prominent flattening of thepremaxillary region of a large (1.83 m) skull, compared with a small (0.81 m)skull of a North Atlantic minke whale. The difference between young North
Pacific whales compared with mature Antarctic specimens noted by Omura(1957) may thus simply reflect the different ages of the animals. However, theskull of the mature dwarf minke whale did more closely resemble in profile
the North Pacific than the Antarctic specimens (compare Fig. 4c of thepresent study with Omura, 1975; Plate 3).
The anterior margins of the nasal bones in the dwarf minke whales from
Hook Reef and Lakes Entrance were convex and had an antero-ventral groove.
Skulls in the Australian Museum had nasal bones of similar shape, but thepresence of an inferior groove has not been confirmed. This contrasts withthe southern hemisphere dark shoulder minke but agrees with specimensfrom the North Pacific (Omura, 1975). Minke whales from the North Atlantic
also have nasal bones with convex anterior margins (Flower, 1864; True,
1904) but the antero-ventral groove has not been recorded.
The vertex of the skull of the dwarf minke differed from previously
described forms. The inclusion of parietals in the vertex and presence of aninter-parietal were as in specimens from the North Pacific (Omura, 1975) andNorth Atlantic (Carte and MacAlister, 1868; True, 1904), but differed fromthe dark shoulder form as described by Omura (1975). The configuration of
the inter-parietal in the dwarf minke whale was rhomboidal, rather than
triangular as in the northern hemisphere specimens. Moreover, the posterior
margins of the nasals, premaxillaries and maxillaries all appeared at the samelevel in the mature dwarf minke whale. This agreed with southern hemisphere dark shoulder minke whales but differed from the northern hemisphere forms (Carte and MacAlister, 1868; True, 1904; Omura, 1975). In thejuvenile specimen from Wonga Beach and skull S1396 both frontals andparietals were an obvious feature of the vertex. Moreover, in skull S272, there
appeared to be a forward extension of the frontal bone between the ascending processes of the maxillaries, similar to the triangular region of interparietal and frontal bones described in the vertex of North Pacific minke
whales. This was clearly the case in the 2.2 m specimen from Victoria. Thus
the position of nasals, maxillaries and premaxillaries may be age dependent;
this would fit with information in Miller (1923) on telescoping of the baleen
whale skull (see Southern hemisphere dark shoulder form Discussion:
Skeleton).
The Hook Reef and Lakes Entrance dwarf minke whales had angulate
palatines and elongate hamular processes unlike the southern hemispheredark shoulder form but as in the North Pacific specimens (Cowan, 1939;
Omura, 1975). The angulate palatine is not a general feature of northernhemisphere minke whales, however, as can be seen from Plate 24 of True
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

33(1904) which shows North Atlantic minke whales from Massachusetts andNorway with elongate hamular processes but curved, rather than angulate
posterior margins of the palatine.
The malars appear to be similar to those in other forms of minke whale
as illustrated by Omura (1975). The lachrymals, however, appear to be closer
to those of the North Pacific specimen than to the Antarctic specimen(Omura, 1975).
The presence of a tuberculate parapophysis on cervical vertebra 7 of thedwarf minke is a feature shared with northern hemisphere forms but not
southern hemisphere dark shoulder minke whales.
The presence of ten pairs of ribs (plus one possible very reduced pair)in the Hook Reef animal was anomalous, but seems of no systematic value
given that the Wonga Beach animal had the usual complement of eleven.
The sternum differed in shape only slightly from some of the many
variants illustrated by Tomilin ( 1967). The fused basihyal~thyrohyals, andpelvic bones were not closely similar to any of these bones figured in Omura(1957, 1975), Omura and Kasuya (1976), or Satake and Omura (1974). All are
subject to considerable variation as indicated in the articles just quoted. The
proportional length of the stylohyals was outside the range given by Satake
and Omura (1974) for the southern hemisphere dark shoulder form. It wascloser to the short stylohyals of animals from the North Pacific (Satake andOmura, 1974) and North Atlantic (Turner, 1892; M'Intosh, 1917). The significance, if any, of differences in these bones, based solely on the Hook Reef
animal, must await examination of further material.
The breadth/length ratio of the scapula was lower than for mature
southern hemisphere dark shoulder minke whales but within the range forNorth Pacific animals (Omura, 1975). However, Tomilin (1967) has shownthat this ratio is size dependent, with relatively greater growth in breadth inlarger animals. This, with the small sample size and slight proportional
differences (l.68-1.71 versus 1.76-1.81) make conclusions tentative.
The phalangeal formula of the Hook Reef specimen fell within the values
for southern hemisphere dark shoulder minke whales (Omura, 1975) except
for digit II and within the ranges compiled for northern hemisphere minke
whales by Tomilin (1967).
Geographical range

Tomilin (1967) and Watson (1981) reported the minke whale to be rarein the tropics. Morzer-Bruyns (1971), while giving various sightings fromtropical locations, especially in the Indian Ocean, noted that minke whales
were "relatively rare" in the south-west Pacific. Stewart and Leatherwood(1985; Fig. 2) showed no records of minke whales around Australia, north of
Tasmania. Clearly these impressions are misleading.
Within Australia, the dwarf minke whale extends into low latitudes (atleast 11°55' Son the east coast, and possibly 20°38' Son the west). AlthoughSci. Rep. Whales Res. Inst.,
No. 38, 1987

34

ARNOLD, MARSH AND HEINSOHN

there are two records from Victoria, most sightings have been from northern
New South Wales to northern Queensland; all confirmed records north of
23°08' S have been dwarf minke whales.
Records of both forms of minke along the Queensland coast and off
northern New South Wales have been in June to December, with most in Julyand August. Temperature data (Table 7) from Brandon (1973) show the
expected decrease in temperature with increasing latitude, so that in August
sea surface temperatures were 22.8°C. at latitudes 16°-18°, compared with
20.5°C at 23° S. Lowest temperatures at all latitudes occurred in July andAugust, which is the time of peak sightings.
Gladstone ( 1984) reported minke whales (apparently all dwarf form)
near Lizard Island (14°40' S) from May to July. This is somewhat earlier thanour records. According to Brandon's (1973) data, animals near Lizard Islandin May would experience much warmer water, with a mean surface temperature of 27.8°C, versus a June average of 23.8°.
Within New Zealand, the two forms overlap in the Cook Strait region(records in Baker, 1983; W.H. Dawbin, personal communication). Unpublished photographs of an animal stranded at Timaru, N.Z. (44°S) and referred
to as a white flipper form by Gaskin (1976) show an extensive throat patch;
the animal was almost certainly a dwarf minke whale. Miyashita (personalcommunication to Marsh) reported a possible dwarf minke whale with a"white flipper band" from the Tasman Sea (39°05' S, 160°35' E) - about half
way between Australia and New Zealand - on Novembr 24, 1983. Otherwise,
the most southerly record is Plimmerton, N.Z. (about 41°05'S) (Cawthorn, in
Best, 1985). Baker (1983) described the dwarf minke whale as 'rare' in New
Zealand. Given its predominance in warm waters along the east Australiancoast, it may be at the edge of its range in New Zealand. Against this argument
are records from Timaru and even further south in the sub-Antarctic (seebelow).
The minke whale from near the Isle of Pines, New Caledonia illustratedin Laboute and Magnier ( 1979) is clearly the dwarf form. Further details areunavailable (Laboute, personal communication to Arnold).
Best (1985) summarized records of dwarf minke whales from South
Africa. The animals seem to be in low numbers at Durban (30°S), forming
only 3-4% of the catch there. However, a stranding was reported at 34°09'S,
close to the southern extremity of the Cape Province and Best noted that thelow percentage of dwarf minke whales in the Durban catch could reflect selectivity by the gunners.
Best (1985) considered some of the records from Brazil tentative, butlisted the occurrence of dwarf minke whales there, based on a specimen witha dark throat patch, reported by Williamson (1973). Singarajah (personalcommunication to Marsh) has not seen the dwarf form in the Brazilian
fishery, however other Brazilian scientists have reported that the "diminutive
form" of Best was regularly sighted but rarely captured off Brazil because of
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

35

its small size (Anon, 1985 ). While the dwarf minke whale clearly occurs in theBrazilian region, more information on its distribution and abundance there isneeded.
No specimens of dwarf minke were noted by Best (1985) in the Antarctic, nor have they been seen by Japanese workers (Wada, pers. comm. to
Marsh). None of the 1179 photographs of minke whales from the Antarctic
taken by Japanese scientists and examined by Marsh were of the dwarf form
(Marsh, 1985). Best (1985) has already pointed out the difficulty in assessing
the colour of the flipper at sea and one must question some of the sightrecords of white-flipper forms from the Antarctic (e.g. Lillie, 1910; Taylor,1957). The most southerly records of dwarf minke whales, supported byphotographs, appear to be at 52°57' S, 112°32' E and 53°08' S 112°30' E bothon Dec. 26, 1984 (Kasamatsu, personal communication to Marsh). While this
could suggest latitudinal migration, we also have records of dwarf minke
whales at 11°55' and 19°50' S in late November and. early December respectively. Thus nothing can be said about long distance movements of this formin the southwest Pacific.
Records in the literature of minke whales from the tropical Indo- Pacificare generally inconclusive. Deranyigala (1948, 1960) reported the southernhemisphere dark shoulder form from Sri Lanka, but with no details to support
the identification. In 1963 he then described a new subspecies from Sri
Lanka, B. acutorostrata thalmaha. This was based on differences in the colourof the baleen plates, with black and white plates anteriorly, but entirely blackplates (except for bristles) posteriorly. There are some discrepancies in thedescription. Figures of "two feet, six inches" and "two feet, five inches" were
given for the height and length of the dorsal fin respectively (about 8.6% total
length). This is nearly twice the height reported for any form of minke whale,
but is comparable to the length of the base of the dwarf form. The fluke width
listed was 17 .2% of the total body length. Deranyigala ( 1963) noted that thiswas narrower than reported in the southern hemisphere dark shoulder form.
In fact, it is much smaller than for any form from either hemisphere. The
length of the baleen plates (17 cm) suggests the dwarf minke whale, but only
parts of the baleen series were available and the longest plates may not havebeen collected. The colour of the baleen, if it was as described, would seemto rule out the dwarf form. No information was given on diagnostic colour
patterns of the body, while the illustrations and description of the skull are
insufficient to establish the identity of the animal. The total body length of
28ft (8.5m) would suggest that it was not a dwarf minke whale, of which thelargest specimen measured was a 7.8 m female (Best, 1985).
Lekagul and McN eely ( 1977) recorded minke whales from Thailand.
They described the animals as having white flipper bands, but the accountseems to be a compilation from the literature and the colour pattern may bebased on descriptions of animals from higher latitudes of the northernhemisphere.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

36

ARNOLD, MARSH AND HEINSOHNHarrison (1974) noted that records of B. edeni from Malaysia andSingapore "appear to be the local representative of the Lesser Rorqual
B. acutorostrata". No description or other support for this statement is given.
One of the records of minke, "Pulau Sugi in 1950" is suspiciously like therecord of B. edeni from Pulu Sugi described fully by Junge ( 1950). Harrison
stated that the colour of the minke whale in Malaysian waters is still unknown.
Herre (1925) reported a minke whale from the Philippines, but with nodescription which could confirm his identification.
On the basis of present records, confirmed sightings of the dwarf minke
whale appear confined to the west Indian Ocean (South Africa), southwest
Pacific (Australia, New Zealand, New Caledonia) and in the Atlantic, off
South Africa and Brazil. Accounts of the minke whale in the Philippines,
Thailand, Malaysia, Singapore and Sri Lanka need to be confirmed.
School size and distribution from shore
Most of the records of dwarf minke whales in northern Queensland wereof single animals, with one sighting of three animals '15-20 ft' long. Gladstone(1984) reported diving with five dwarf minke whales off Lizard Island (14°40'
S). Rockman (1986a,b) reported a group of eight dwarf minke whales from
Marion Reef (19°10' S, 152°17' E).
The predominance of sight records from the mid and outer Queensland
shelf probably partly results from the concentration of reefs in those areas.
Thus sport divers, fishermen and research scientists are more likely to spend
time anchored in such spots, where they can be approached closely by minke
whales. It is usually only under such circumstances that sufficient detail can beobserved and/or photographed to allow positive identification of the dwarf
minke whale. In the only systematic aerial survey of the region ( 111 cross-shelftransects between 11°30' S and 20°30' S during November-December 1985)
dwarf minke whales were recorded only twice, both from the mid to outer shelf(Marsh, unpublished data). In contrast, Best (1985) showed that dwarf minke
whales off Durban occurred closer inshore than other minke whales.
The length of sightings (up to several hours) and the high proportion ofsightings supported by underwater observations and photographs suggests a
behaviour similar to other forms of minke whale which have been reported toclosely approach vessels (e.g. Leatherwood et al., 1982).
SOUTHERN HEMISPHERE DARK SHOULDER FORMRESULTS

Colour pattern
We have less extensive information on the dark shoulder form. Unlessotherwise noted, the following notes are based on a 4 m minke whale
stranded near Coffs Harbour, N.S.W. (29°47' S) in August 1981, and photographed alive at the Pet Porpoise Pool, Coff s Harbour. Photographs (see Figs
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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38

ARNOLD, MARSH AND HEINSOHN

7a, 7b) were taken of the left side only.
The rostrum was slate grey, with a margin of light grey to white along
the gum.
The lower jaw overlying the mandible was light grey, but there was nodark throat patch. The head appeared light grey in colour. The area aroundthe eye was light grey, but merged posteriorly with a darker grey band runningposteriorly towards the base of the flipper. There was no white shoulder
patch. Dorsal to the flipper the side was light grey, with a thin dark grey
streak running obliquely forward and ventrad from the back, dividing thelight grey into two parts. The anterior of these continued dorsally to form a
distinct light crescent on the back of the neck (Fig. 7b). There was a darkstreak, apparently level with the ear, which merged posteriad with a white
stripe. This stripe ran dorsally, increasing in width, and merged with theanterior light grey patch above the flipper (Fig. 7a).
The flipper was light grey to white along the anterior edge, but was
darker grey over most of the upper surface. A small oval patch of light grey
to white extended onto the upper surface of the flipper base from the axilla.
A fine dark line crossed the flipper at its base, gently curving outwards toward
the tip of the flipper (Fig. 7a). A similar thin dark line continued across thelight grey of the side towards the dark grey back. The underside of the flukes
were white, except for a thin dusky margin.
Unpublished photos of a dark shoulder minke whale stranded on
Kangaroo Island, South Australia (record in Ling and Aitken, 1981; 35°50' S)
also show the distinctly light grey to white leading edge of the flipper but with
an otherwise dark upper surface (there appeared to be some white at theaxilla as well, but no transverse band was seen). The thorax was light greywith two dark grey bands originating at the axilla and running upwards
toward the back, becoming somewhat wider dorsally.
An animal stranded at Yeppoon (23°08' S) had a light grey flipper, inwhich the anterior margin and most of the tip appeared lighter, almost white.
The base of the flipper was much darker, contrasting sharply with the flipper
itself. The two grades of grey were separated by a thin white line, the central
portion of which curved sharply outwards toward the tip of the flipper (Fig.
7c). This white line occurred on both flippers.
Skeleton
The anterior ·margin of the nasal bones in skulls from Queensland andSouth Australia were flattened or concave; the nasals in the Queensland
specimen definitely lacked an inferior elliptical groove. The South Australianskull definitely had the parietals excluded from the vertex. The parietals also
seemed to be excluded from the vertex of the specimen from Queensland,
however it was difficult to interpret the formation of the vertex due to a strong
supraocciptal crest overhanging the peak.
The posterior margin of the palatines was curved and the hamularSci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

39

processes of the pterygoid bones were short and stout in the South Australian
specimen. The hamular processes appeared to be stout in the Queensland
specimen as well, but both pterygoids were damaged.
Finally, the nasals, premaxillaries and maxillaries all appeared at about
the same level in both the skulls. This was obvious even in the South Australianskull, from a young animal only 3.3 m long.
Other features
A conspicuous feature of the southern hemisphere dark shoulder minke
whales stranded near Coffs Harbour and Yeppoon was numerous circular tooval lesions, in which plugs of blubber were missing. At least 26 open lesions
were present in a photograph of the one side of the Coff s Harbour animal.
Over thirty open lesions were counted in photos of the Yeppoon animal.
Distribution
Animals from Tasmania reported by Davies and Guiler (1958) andGuiler ( 1978) are tentatively considered the dark shoulder form, but insufficient information was given to allow positive identification.
The smallest animals were recorded from Tasmania and Victoria, basedon the reports in Davies and Guiler (1958) and Wakefield (1967). Estimatedlengths of these animals were 2.2 m and 6-7 ft (l.8-2.1 m) respectively.
With the exception of a neonate (or late fetus) stranded in Tasmania(42°50' S), probably in May, all records of dark shoulder minke whales fromsoutheastern Australia and the central Queensland coast are from August to
October. The most northerly record of a dark shoulder minke whale was theanimal stranded near Yeppoon (23°08' S); it stranded around August 11,
1983 while a dwarf minke whale was found nearby in the last week of August
1983. Sight records from southern Queensland (27°24' S) of unidentified
forms of minke whale were in June and July.
Records of the dark shoulder form are based on strandings and thus giveno information on distribution of the animals offshore.
DISCUSSION

Colour pattern
Our material of the southern hemisphere dark shoulder minke whale
confirms features such as the light grey to white lower jaw and absence ofthroat patch, which have been described previously. The white line behindthe eye, noted in the Coff s Harbour specimen, is similar to that reported by
Kasuya and Ichihara (1965). However, in their figure and in photographs ofdark shoulder minke whales from the Antarctic which we have seen, the line
was curved ventrally toward the flipper rather than dorsally as in the Australian specimen. The alternating light and dark grey of the body above theflippers and the dorsal extension of light pigment onto the back as a crescentSci. Rep. Whales Res. Inst.,
No. 38, 1987

40

ARNOLD, MARSH AND HEINSOHN

agrees with previous descriptions of this form.
The specimens from Yeppoon and northern New South Wales both hada thin transverse band on the flipper, although one was dark and the otherlight coloured. The light coloured band separated a dark grey base from thelighter flipper. Both forms would fit Doroshenko's (1979) flipper type 2,
which he reported from 75.2% of specimens taken in the New Zealand sectorof the Antarctic. van Beek and van Biesen ( 1982) found that the differences inbanding of the flipper between areas reported by Doroshenko were statisticallysignificant but noted that his categories did not encompass the full variationin colour pattern reported from the Antarctic. Best (1985) documented
asymmetry of colour pattern, in which on one side, the flipper was banded
while on the other it was not. He found that bands occurred more frequently
on the left side. The animal from Coff's Harbour, N.S.W. was only photographed from the left side, but the Yeppoon specimen was photographedfrom both sides and had bands on both flippers.
SkeletonObservations of Australian material generally confirms previous reports
based on specimens from the Antarctic (e.g. Omura, 1975). The frontals
appeared to be proportionately more exposed in the skull of an immaturedark shoulder minke whale Q2 1708), when compared with the larger skullsof this form illustrated by Omura (1975) and Omura and Kasuya (1976).
However, there was no triangular region of parietal and frontal bone separating
the nasals from the supraoccipital. In the South Australian skull, from animmature animal, the nasals, premaxillaries and maxillaries were at the samelevel as illustrated for Antarctic specimens by Omura (1975). Thus, although
telescoping of the skull may be less developed in juveniles (see Miller, 1923),
the differences noted between the southern hemisphere dark shoulder minke
whale and other forms can not be simply attributed to differences in the agesof the specimens examined.
Other features
Shevchenko ( 1977) has used frequency of 'white scars' to separate stocks
of sei whales from the southeast Atlantic and Indian Oceans. Such lesions
have been for a long time associated with movement of baleen whales into
tropical waters and have been attributed either to a deep-water squaloid shark,
Isistius Q ones, 1971) or to shedding of parasitic copepods of the family Penellidae (Ivashin and Golubovsky, 1978). Neither the dwarf minke whales nor
the dark shoulder minke whales which we have seen have the intensity ofscars shown for sei whales by Shevchenko, although the few specimens ofdark shoulder minke whales seem to be the more heavily scarred (Note, however, what appear to be numerous scars on the specimen of dwarf minke
whale from New Caledonia figured by Laboute and Magnier (1979) and obvious lesions on Marion reef specimen in Rockman (1986a,b)). Shevchenko
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

41( 1977) suggested that intensity of scarring might be used to separate stocks ofbaleen whales from the east Indian Ocean and Tasman Sea. More material isneeded to assess its use for minke whales.
Distribution
The few records of the dark shoulder form in Table 1 do not adequatelyreflect its distribution. Published records of minke whales from southern
Australia usually contained inadequate information to identify the form orsometimes even the species. We have been unable, except in a few cases, toexamine the skeletal material in Australian museums and have had to rely on
photographs of animals and skulls (or even photocopies of these). It has been
impossible to identify some of these records positively and they were notincluded in Table 1. A detailed examination of skeletal material in Australianmuseums would provide useful information on the distribution of minke
whales, especially around the southern half of the continent and off Tasmania.
STATUS OF THE DWARF MINKE WHALE

Wada ( 1983) analyzed electrophoretic patterns of North Pacific, Antarctic andBrazilian southern hemisphere dark shoulder minke whales and one dwarf
minke whale from South Africa. He suggested an uniformity of the southernhemisphere forms, which were considered to differ subspecifically from theNorth Pacific anim;ils. His conclusions regarding the dwarf minke whale must
be considered tentative given the single sample available.
Moreover, there are a range of osteological, morphometric and pigmentation differences between the dwarf minke whale and the southern hemispheredark shoulder form. Some of these features (e.g. skull breadth, length ofrostrum, profile of skull) are age dependent and must be compared between
animals of similar size. Other features such as length of mouth and number ofbaleen plates appear to be inter-related and may be variable irrespective ofage. Features such as size and form of baleen plates may be subject to shortterm selection, possibly associated with diet. In this respect, Best (1977) has
documented two forms of Bryde's whale which have different forms of baleen,different distributions off the South African coast, and different diets.
The differences in morphometrics and osteology which remain whencomparing the two southern hemisphere forms of similar size are still impressive. Our examination of skulls of young dark shoulder minke whales (previously described on the basis of skulls from large animals) and morphometrics
and the skull of a sexually mature dwarf minke whale (in which morphometrics were previously based on immature animals and osteology was previously undocumented) helps resolve problems of comparing forms of widelydifferent sizes and thus ages. Some of the previously reported differences inthe dwarf minke whale have been confirmed while we have been able to document further differences. There are also differences in size at reproductive
Sci. Rep. Whales Res. Inst.,
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42

ARNOLD, MARSH AND HEINSOHN

maturity (Best, 1985, Marsh, 1985) and apparently in distribution (see Dwarf
minke whale Discussion: geographical range) between the two southernhemisphere forms.
Differences in colour pattern between the two southern hemisphere
forms further support a degree of genetic isolation. Although many variants
in colour pattern have been described for the dark shoulder form (e.g.
Doroshenko, 1979; Wada and Numachi, 1979), none approaches the flipper
and shoulder colouration of the dwarf form. Throughout its wide range, thedwarf minke whale appears to have a remarkably consistent colour pattern.
The lack of intermediates, despite known areas of overlap with the dark
shoulder form in South Africa, Australia, and New Zealand, argues for agreater degree of genetic isolation than suggested by Wada ( 1983). A similarargument was used by Kasuya ( 1978) for genetic isolation between colour
forms of Dall's porpoise in the North Pacific. However, unlike the Dall's
porpoise (Kasuya, 1978), the dwarf minke whale appears to be separated
from the southern hemisphere dark shoulder form by characters other thancolour pattern, e.g. morphometrics, skull characters and size at reproductive
maturity. In this respect, it is closer to the apparently isolated population ofCommerson's dolphin, Cephalorhynchus commersonii, from the Kerguelin
Islands which shows a range of character differences from the main SouthAmerican population (Robineau and de Buffrenil (1985), in addition to retention of juvenile pigment pattern (Leatherwood and Cornell, 1985)).
Present data on skeleton and morphometrics strongly suggest a closer
affinity of the dwarf minke whale with either of the northern hemisphere
forms than with the southern hemisphere dark shoulder form. Omura (1975:
fig. 14) identified 17 characters differentiating the geographical "populations"of minke whale. Three of these (dorsal view of rostrum, profile of skull, pelvic
bone shape) we consider difficult to evaluate or too variable, while one (flipper
colour) is unique to the dwarf minke whale. Of the remaining 13 characters,
11 differed between the two southern hemisphere forms but were shared
between the dwarf minke and at least one of the northern hemisphere"populations". Of the two characters shared by the two southern hemisphere
forms, only one (position of bones in vertex) was not also shared with one of
the northern hemisphere forms. Moreover, that feature may be variable,
especially with age. There appears to be sufficient grounds to recognize thetwo southern hemisphere forms as taxonomic entities, at least as subspecies.
If the relative resemblances of the dwarf minke with the northern hemisphere
forms are supported by examination of more material and the differences
between the two southern hemisphere forms are maintained, then it could beargued that the dark shoulder form deserves full specific status, in which case
Balaenoptera bonaerensis would have priority. Final resolution of these questions
will require examination of more material from all oceans. However, it is easy
to separate the two southern hemisphere forms on the following combinationof features:
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DIMINUTIVE MINKE WHALE

43

External morphology
Lower jaw overlying mandible grey, extending over ventral grooves as adark throat patch; base of flipper white; thorax around flipper white, containing a dark patch (flipper oval, Fig. 1) and bordered dorsally by a triangularlight grey shoulder blaze which may run obliquely anteriad onto the back; lightgrey flank patch extending past dorsal fin and containing an extension ofwhite from the underside of the tail stock (peduncle patch, Fig. la); living
animals with light grey on upper surface of rostrum and head; baleen plates
predominantly light, with black at most as narrow band along lateral margin,
except for most posterior plates which may be almost entirely black; dorsal fin
well forward (69.6-71.5% total length to tip of fin), tall (4.8-5.6% total
length) and long at base (8.3-8.4% total length) ...... dwarf or diminutive form
Lower jaw light grey with no dark grey pigment over throat; flippers withsingle or two tones of grey, especially light along the leading edge but neverwhite at base; thorax in region of flipper insertion light grey, extending as
forwardly directed crescent onto the back; light flank patch extending high onsides just in front of the dorsal fin, without peduncle patch; living animals withdark grey upper surface of rostrum and head; baleen plates asymmetricallycoloured with light plates occupying x=34-37% and 12-16% of the length ofright and left baleen plate series respectively in specimens from the Antarctic
and South Africa; dorsal fin further posterior (72.9-76.1 % total length ofjuveniles to tip of fin); low (3.0-4.2% total length of adults) and short at base
(3. 7-7. 7 % total leng~h of adults; Best, 1985) ................ dark shoulder form
Skull
Anterior of nasal bones convex, with inferior elliptical groove; parietals
incorporated into vertex with angulato-ovate inter-parietal; ascending
processes of maxillary may extend posteriad to level of nasals and premaxillaries in juvenile specimens but are at about same level in mature specimens;posterior of palatine bones angulate; hamular process of pterygoid elongate(Fig. 5f) ................................................................... dwarf or diminutive form
Anterior of nasal bones straight or concave, extending forward laterally andwith no inferior elliptical groove; parietals and inter-parietal excluded fromvertex; posterior borders of ascending processes of maxillary, nasals andpremaxillaries at about same level in both juvenile and mature specimens;posterior of palatine bones smoothly curving; hamular process of pterygoidbones stout (Omura, 197 5; Fig. 5) ................................. dark shoulder form
ACKNOWLEDGEMENTS

We would like to thank the many volunteers who helped with the observations
on and subsequent necropsy of the Hook Reef specimen, especially W.H.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

44

ARNOLD, MARSH AND HEINSOHN

Dawbin, W. Dowd, H. Goodall, V. Harriot, G. Kelly, R. Speares, T. Walker,
L. Winsor, L. Zell and the pilots of Air Whitsunday. Information, often
unpublished, on various forms of minke whales was provided by the late P.
Aitken,]. Bannister, P. Best, M. Bryden, W.H. Dawbin,]. Dixon, D. Gaskin,
W. Gladstone, H. Goodall, F. Kasamatsu,]. Ling, T. Miyashita, R. Molnar, G.
Oke, M. Simmons, J. Stern, S. van Dyke, D. Wall and M. Waugh. We thankstaff of the South Australian and Queensland Museums, especially S. van Dyke,
for arranging to draw and or photograph skulls of minke whales in theircollections. T. Kasuya and N. Miyazaki arranged for measurements of skulls
to be taken at the National Science Museum, Tokyo by Marsh.
Field expenses incurred in the observation and necropsy of the Hook
Reef specimen were partially covered by funds from the Great Barrier Reef
Marine Park Authority to Marsh. We also thank the Great Barrier Reef
Marine Park Authority for permission to publish several photographs takenby their staff.
We thank the James Cook University Photographic Section, and especially
R. Yeldham and B. Pump, for efficient, speedy preparation of photographs
used in the plates.
Finally we thank the two anonymous referees for their exceptionallycareful reviews.
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DIMINUTIVE MINKE WHALE

45

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Sci. Rep. Whales Res. Inst.,
No. 38, 1987

46

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Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DENSITY DEPENDENT CHANGES IN GROWTH PARAMETERS
OF THE SOUTHERN MINKE WHALE*

HIDEHIRO KATO**
ABSTRACT
Changes in growth parameters with time were examined for thesouthern hemisphere minke whales, using materials collected by Japanese
Antarctic whaling expeditions in Areas III (0° ~ 70°E) and IV (70° ~ 130°E)· during seasons from 1971172 to 1982/83. Mean age at sexual maturity(50% maturation) for both sexes estimated from the transition phase inearplug declined from 12~13 years in the 1940s year-classes to 7~8 years
in those of late 1960s to early 1970s, and the female trend agreed with the
decline in mean age of females having a corpus luteum of first ovulation,
but the mean body length of first ovulation remained constant around27.5 ft (8.4 m) in all year-classes and in year of capture. Both analyses ofgrowth curve and epiphyseal fusion of vertebrae suggested an increase in
the growth rate and body length at attainment of physical maturity inrecent year-classes, while it was not enough to examine changes in age at
the attainment of physical maturity. These changes are thought to haveresulted from the decline of possible competitative whale stocks such as
blue and fin whales.
INTRODUCTION

Census data indicate that the populations of some penguins (Sladen, 1964)
and pinnipeds (Laws, 1973; Payne, 1977) in the Antarctic had increased during
1940s to 1970s. Laws (1977a, b) considered these increases attributable to thedecline of the populations of ecological competitors such as blue whale
Balaenoptera musculus (Linnaeus, 1758), and fin whale, B. physalus (Linnaeus,
1758). The southern minke whales, B. acutorostrata (Lacepede, 1804), also
share their habitat and food resources with the above whales, so they may
have received same kind of similar or stronger influence from the changes.
Decline of minke whale age at sexual maturity from 14 years in the 1940s
year-classes to 6 years in late 1960s year classes was suggested by the analysisof transition phase in earplugs (Masaki, 1979; Best, 1982; Kato, l 983a). And* An earlier version of this report was presented to the Scientific Committee of the International Whaling Commission
in 1985 and 1986 as documents SC/37/MiJJ and SC/38/Mi15, respectively, and constitutes some sections of Ph D
thesis submitted to Hokkaido University.
** Whales Research Institute, 3-32-11, Ohjima, Koto-ku, Tokyo 136, Japan.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 47-73

48

KATO

this was once considered indicating increase in minke whale population prior
to the start of full exploitation in 1971172 (International Whaling Commission(IWC), 1979).
Recently, however, Cooke and de la Mare (1983) expressed a doubt on thevalidity of transition phase analyses which had been adopted for several large
whale stocks, and suggested that the apparent decline of age at sexual maturity
could be the result of ageing errors and possible data handling biases such as
truncated sampling problems. Since then, no general concensus has beenobtained on this subject among the Scientific Committee of IWC in spite ofmany studies in this field (IWC, 1985).
Truncated samples will most seriously exaggerate the estimation of yearly
trends of decline in age at sexual maturity (IWC, 1985 ). Kato ( l 983a) has
solved this problem by excluding data possibly under the effect of the truncation bias. The present study compares annual changes in the age at sexual
maturity suggested by his method with other changes in several parameters
related to the growth of minke whales.
MATERIALS AND METHODS

Materials 'in this study were collected from minke whales taken by Japanese
Antarctic whaling expeditions in 1971172 to 1982/83 of austral summers in
the waters south of 60°5 to ice edge zone. To increase sample size, data from
Areas III (0° to 70°E) and IV (70° to 130°E) were combined. Number ofcatches by the Japanese fleets by sex, whaling season and area is given in
Table 1. Individual age was determined using growth layers in earplug, andassuming annual deposition of the layer (a pair of light and dark laminae tobe formed annually--Best, 1982; Kato and Best, unpublished). Growth layers
were counted with stereoscopic microscope (6 ~ 10 X) by myself (for samples
after 1978179 season), or by Drs Yasuhiko Masaki and Seiji Ohsumi (before
1977178 season). No systematic ageing error was detected among those three
readers (IWC, l 984a).
Age and length at sexual maturity
Following parameters were calculated for each year-class group and yearof capture using samples shown in Table 2.
Lmav: Mean body length of females soon after the attainment of sexual
maturity (first ovulation), identified by the presence of a corpus luteum(CL) and no corpus albicans (CA) in the ovaries.
Lm50%: Body length where 50% of females are sexually mature, usingpresence of corpus luteum or albicans in the ovaries as the indicator ofsexual maturity. This length was calculated by fitting logtistic curve(weighted by sample size) to the proportion of sexually mature females at
each length. If the Chi-square (goodness of fit) of the logistic curve to theobserved values was low (p > 0.95), the Lm50% was not estimated. AlthoughSci. Rep. Whales Res. Inst.,
No. 38, 1987

49

SOUTHERN MINKE WHALE

TABLE I. NUMBER OF CATCHES OF THE SOUTHERN MINKE WHALES BY THE JAPANESESFLEETS BY SEX, WHALING SEASON AREAS. DATA FROMINTERNATIONAL WHALING STATISTIS
Whalingseason1971171
1972173
1973174
1974175
1975176
1976177
1977178
1978179
1979/80
1980/81
1981/82
1982/83

Male

Area III
Female

170

184

320
554
417
446
398
642
521
327
188

1,174
805
604
939
614
958
732
292
71

Male

Area IV
FemaleWhole Antactic*
Female
Male

930
1,116
761
430
198
521
128
386
1,048
529
582
530

1,728
975
1,282
410
237
429
353
573
482
664
1,043
490

1,100
1,116
1,116
1,247
1,464
1,678
1,012
1,097
1,952
1,472
1,578
1,083

1,912
975
2,597
2,252
1,553
2,272
1,388
1,635
1,327
1,647
1,999
2,140

7,159

8,666

15,915

21,697-----------------------------------------------------------------------------------------------------------------------------------------------Total

3,983

6,373

*) including Areas I (60°-120°W), II (60°W-0°), V (130°E-170°W) and IV (170°-l20°W) as well as Areas III(0°-70°E) and IV (70°-l30°E) where the present study has been done.

TABLE 2. NUMBER OF SAMPLES USED FOR ANALYSES OF AGE
AND BODY LENGTH AT SEXUAL MATURITY

Data grouping

Number of samples examined
Male
Total
FemaleLmov

Year of captureYear-class

512
222

512
222

Lm50%

Year of capture

12,332

12,332

tm01.1

Year of capture

222

222

tm50o/cYear of captureYear-class

6,872
6,872

6,872
6,872

lmf1

Year-classYear of maturation

1,721
2,272

2,842
3,810

Parameter*I, 121
1,538•) Lmov, mean body length of females having CL of the first ovulation.
Lm50%, body length at 50% sexual maturity.
tmov, mean age of females having CL of the first ovulation.
tm50%, age at 50% sexual maturity.
tmp, mean age at sexual maturity estimated from transition phase in earplug (both sexes).

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

50

KATO

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N

52

KATO

was initially classified into stages after Ohsumi, Nishiwaki and Hibiya ( 1958)
and Laws (1961), then the absence of cartilage between the epiphyses and thecentrum (stages a and A of Ohsumi et al. (1958) and EJV and EJI of Laws
(1961)) was used as the indicator of physically mature individuals. Physicallyimmature individuals of the present study therefore include stages N and n of
Ohsumi et al. (1958) and UTC and UFC of Laws (1961 ). This study included
data of limited number of whales examined by Dr P. B. Best (University of
Pretoria, South Africa) on board Nisshin Maru No. 3 in 1978179 season.
Grouping of samples
Present analyses were done after grouping materials by year of capture,
year-class, and year of maturation as defined below.
Year of capture: Used for Lmov, Lm50% and tmov. Fishing season normally
starts in November and closes in March of the next year.
Year-class (= year of birth): Year-classes were defined by;Year-class = (starting year of the season) - (age at capture).
and used for Lmov, tm50%, tmp, growth curve and physical maturity analyses.
Both values of tmp and tm50% were calculated for each year-class, while Lmov
and growth curve (as well as physical maturity) were analysed by combining year-classes of three and 10, respectively.
Year of maturation: Year of maturation of each individual was calculated
as follows and used for tmp analysis;(year of birth) + (age at transition phase)Year of maturation(starting year of the season) - (time after sexual
maturity).
RESULTSAge and body length at sexual maturity
1) Mean body length of females having CL of the first ovulation (Lmov)
Since gestation of the minke whale lasts less than one year and the longevityof corpus luteum of ovulation must be shorter than this period (IWC, l 984b),
females having a corpus luteum of pregnancy or ovulation (with no corpus
albicans) were considered to have matured within one year.
Fig. 3 (left) shows body length distribution of recently matured females by
year of capture. A mode existed at 27-28 ft (8.2-8.5 m), and Lmov ranged
from 27.0 (8.2 m) to 28.0 ft (8.5 m) with no significant yearly trend(0.1 < p < 0.2, t-test of the regression coefficient of Lmov on year of
capture).
Even when Lmov was analyzed by year-class group, the annual trend was
also insignifiant (0.2 < p < 0.3; Fig. 3, right).

2) Body length at 50% sexual maturity (Lm50%) for females
Fig. 4 shows Lm50% values as well as the relationships between sexual
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

53

SOUTHERN MINKE WHALE

Year of Capture
Lmov=27.5(n=l 31)20
040

Lmov=27. 1(n=25)

20

Year Class

080

40 1973/74

Lmov=27.3(n=63)

20

60

pre 1956 YC

Lmov=27.0(n=30)

40
20

O._,r---,-~r-"..,.,.....,,,.._"'+-"......_,r---.-

20 ~7-59

0~~ Lr.mv=27.4~(n=l4)I:: t

Lmov=27.4(n=l6)

1960-62

0I~

I

1977 /78
20
OL....r~..,-1~~~~1-,...~~i:iiD

Lmov=27.5(n=38)

40
20
0 L......,~.........~~.µ::~~~"""i"""-......~
Lmov=27.9
20 1979/80~30)

l

011~1
40
20

1980/81

Lmov=27.9(n=46): tl975-77~

0
40
20
0

~

QI

24

26

2a

30

24

26

28

Lmov=27.2(n=22)f"
30

Body length (ft)Fig. 3. Length distribution of females at the first ovulation having only one corpus
letum and no corpora albicantia in the ovaries and Lmov for the southern minke
whales in Areas III and IV. Grouped by year of capture (left) and year-class (right).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

54

KATO
lOO

1971/72

50- - - - - - - - -.

lOo

1972/73so---------

lOO

1973/7450---------

Lm50%:26. 60

Lm5Q%:::26, 30

Lm50%=26. l6

.
20

22

24

26

lOO

1974/7550---------

28

30

32

34

20

22

24

lOO

1975/7650--------

26

Lm50%=26. 34

=
"E
"><

..
en
:i

20
lOO

22

24

26

28

30

32

34

20
100

1977/78

50

22

24

26

50

2a

30

32

32

34

22

24

26

28

30

32

34

-------------------

20

50

28

30

32

50

----------

20

50

22

24

26

28

30

32

22

24

26

32

34

22

24

26

28

30

32

34

----------

20

34

22

24

26

28

30

32

34

1982/8350---------

20

30

1979/80

Lm50%=26. 38

34

28

Lm50%=26.92

100

lm50%=26.87

26

''

26

1976/77100

1981/82

24

24

lOO

34

100

22

22

Lm50%=26. 24

1980/8120

20

Lm50%=26.25

1978/79

Lm50%=26. 64

20

30

Lm50%=26. 39

50 - - - - - - - - - - ·

100

2ff

28

30

Body length32

Lm5Q%:26. 58

34

20

22

24

26

28

30

32

34

(ft)

Fig. 4. Body length at 50% sexual maturity (Lm50%) of the female southern minke
whales collected in Areas III and IV, expressed for year of capture. Logistic curves
are fitted by the least squares weighted by sample size.

maturity rate (proportion of sexually mature individuals in the sample) andbody length analysed by the year of capture (1971172 to 1982/83 seasons).
The relationship was almost identical between seasons, and sexuallymature individuals appeared at body length over 25 ft (7 .6 m) and most of
the individuals completed maturation below the length 28 ft (8.5m). Lm50%
values were approximately at 26.5 ft (8.1 m), with no siginificant yearly
trend (0.1 < p < 0.2, t-test of the regression coefficient of Lm50% on year of
capture).
3) Mean age of females having CL of the first ovulation (tmov)
Fig. 5 shows distribution of age at the first ovulation (tmov) by year of
capture. The tmov values have decreased from about 9 years in early 1970's
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

55

SOUTHERN MINKE WHALE~

lO-f 1971/72

""~ ~
~I

"_
0

~
C'

~

0

5

5

t

5

t

~

t 1975/76

l.~tmov= B. 57~

1980/81l

1981/8215

1~ tmov=B.07~

r 1982/83

0

I E'$'9

1~ ~ tmov=7: 1

1
0
5

tmov=739<W
1

5

tmov= 9 .17

10trnov= 9.19

rn~....,
I
I

f

:

~~

~
5

:l

trnov= B. 83

1976/77o-

1978/79010

1974/7505

tmov= 6 .11-t~ 1979/BO

1973/74o05

tmov= 9.22

.~,rn

l

"SjS'

I

5 ~ 1972/73:..

tmov= s.oo......
t:=921

20!:!IS'"=

I

tmov=7.75

,rn
10

15

20

Age in years

Fig. 5. Age distributions of females having only one corpus luteum and no CA in
ovaries and tmov, data from Areas III and IV.

to about 7 years in late 1970s and early 1980s. The trend was expressed by
the following least square regression (tmov on year of catch; weighted bysample size):tmov = 9.164 - 0.138t------------------Equation 1(r = -0.548, 1 < t < 12)
where, t is year of capture setting 0 for 1970171.
Slope of the above regression was significantly different from zero (t-test,p < 0.05).
4) Age at 50% sexual maturity (tm50%) for female
Fig. 6 shows tm50% values as well as the relationships between sexual
maturity rate (proportion of sexually mature individuals) and age at capture for females. Except for the 1974175 season when the value was apparently high (7. 7 5 years), all the other figures of tm50% ranged between 6 and7 years with no specific annual trend. The regression coefficient of tm50% on
season was not significantly different from zero (t-test, 0.2 < p < 0.3) as reported by Kato (1982).
Even if the relationship between sexual maturity rate and age isanalysed by year-class using the same data set (Fig. 7), the tm50% values were
the same as above and showed no significant change among year-classes(t-test, 0.4 < p< 0.5).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

56

KATO

..

100
1971/72l•l
50

100
1977 /78--------

50

tm50%=6.00--------

tm50%=6.60

•'

I

10
100

1972/73

50

15

10

10

20
100

50

tm50%=6.08

.;

100

..

15

-------· I

20

5
100

..

20

tm50%=6 .44

I

1973/7415

1978/79

10

15

20

1979/80

l•l

~

-...
-"'

50

-------

50

tm50%=6 .00--------

tm50%=6 .86

G>

"'

10

~

15

20

100

10

15

20

100
1980/81

1974/75:JE

50-----------

50

trn50%=7. 75--------

tm50%=6. 76

"'

:J
)(

G>

Vl
10
100

50

15

100

-------1• l

1020

1975/76

50

tm50%=5.82

•'

15

20

1981/82--------

tm50%=6.33

I
I
I............
10

100

1976/77

50

15

15

100

15

20

1982/83--------;

no estimate

10

10

20

20

tm50%=6. 20

10

15

20

Age ( y rs)

Fig. 6. Age at 50% sexual maturity (tm50%) of the female southern minke whales inAreas III and IV, expressed for each year of capture. Logistic curves are fitted by
the least squares weighted by sample size (closed circles in parenthesis were notused for fitting logistic curve).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

57

SOUTHERN MINKE WHALE
100

100

1965

50

100

1966

year-classyear-class

••

1967

year-cl ass••-------

50----- - -50••'

tm50%=6.08

tm50%=6.33•----- ---1.
•

I
I
I
I

cl?

)

100

50

-------

•

:>

i:

1•1

I

I

50
tm50%=6 .06

••

•

Oi

10

:>
100

UI

ysar-class

50

15

.,
I

tm50%=6.35

10tm50%=6. 78

15

10

15

1973

year-c;l ass

50

50 ---1·1- -1e1tm50%=6. 34

10

15

Age

.. :
I

• ••
tm50%=5. 93

I
I
I

•
10

••

100

tm50%=6.65

•

15

•

year-class

•

•

•

-------

I
I

1972--------

•

I

50

100

•

1971

1970

year-cl ass- - - - - -·- • I

tm50%=6. 23

10
100

••

I

15

1969

year-class

•

;

..

10
100

~

GI

15

year-cl ass

!
:'2

...>-

10
1968

•

15

10

15

(years)Fig. 7. Age at 50% sexual maturity (tm50%) of the female southern minke whales inAreas III and IV, expressed for each year-class. Logistic curves are fitted by theleast squares weighted by sample size (closed circles in parenthesis were not used
for fitting logistic curve).

5) Mean age at sexual maturity estimated from transition phase (tmp) for
both sexes
As indicated in Table 3 and Fig. 8 (left), the mean age at sexual maturity estimated from the transition phase in earplug (tmp) seemed to be almost
constant in both sexes in year-classes before 1940, but then it has declined
from 12-13 years of year-classes in mid 1940s to 7- 8 years of those in late1960s. The regressions of tmp for both sexes on year-class weighted by sample size are expressed by the following equations;Male,tmp = 22.15 - 0.219k (r= -0.971, 45::;k::;70) - Equation 2
Female, tmp = 21.64 - 0.206k (r= -0.963, 45::; k::; 70) - Equation 3
where, k is year-class setting 0 for 1900. Both of the slopes were significantly different from zero (t-test, p < 0.001).
The values of tmp and its standard deviation for each year of maturation
are given in Table 4, and are plotted in Fig. 8 (right). Due to the small sample size of the observed data, the values of tmp and its standard deviation
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

58

KATO

~ : ~,. I j I jjfjl \l~l\ il ~1~t: tpt:~..
....,,::s

E 20

.,,
::s
)(

(I)
I/)

....,,

15

I

1930

apparent

10

tttt
1940

1950

Female

1960

Ma 1e

15

1970

I'" ];

•
1940

:~~::

1950

1960

1970

I '""'"

t

1980

""'

S.D.

(I)

Cl

<(

10

1940
1930

1940

1950

1960

1970

1950

1960

1970

1980

Year of maturation

Year class

Fig. 8. Changes in age at sexual maturity deduced from transition phase in earplug
for males (top) and females (bottom) of the southern minke whales. Range of one
standard deviation (solid line) is expressed on each side of the mean age (tmp; closed
circle). Samples are grouped by year-class (left) and year of maturation (right).

after 1978 were not examined for both sexes. Kato ( 1983a) pointed out theapparent increasing trends of tmp were to be produced by the procedure ofconverting data of year-class to year of maturation in the beginning several
years of the time series of year of maturation, unless the time series of thedata infinitely continued. Later this fact was identified again by the simulation
study of Sakuramoto, Kato and Tanaka (1985). Therefore the apparent
increasing trends of tmp values for both sexes before 1949 are artefact.
Then, only those trends from 1950 to 1977 have biological meaning. The
tmp values declined from around 12 years in 1950s to 8 years in early 1970s.
This is shown by the following least square regressions (tmp on year of maturation weighted by sample size):Male,tmp= 18.38 - 0.138t (r= -0.921, 50::St::S77 - - - Equation 4
Female, tmp = 19.59 - 0.152t (r= -0.919, 50 :::St ::S 77) - - - Equation 5
where, t is year of maturation setting 0 for 1900. Both of the slopes weresignificantly different from zero (t-test p<0.001).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

59

SOUTHERN MINKE WHALE
TABLE 3. STANDARD DEVIATION (s.d.) AND THE MEAN (tmp) OF AGE AT SEXUAL
MATURITY ESTIMATED FROM TRANSITION PHASE IN EARPLUG FOR
THE SOUTHERN MINKE WHALES COLLECTED IN AREAS III AND IV,
1971172 TO 1982/83. YEAR-CLASS GROUPING
Year
class
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970

lmp

Male
s.d.

n

13.00
11.00

13.00
15.40
15.33
13.67
13.67
12.75
12.75
10.67
16.25
14.00
11.50
10.89
9.16
12.56
11.09
12.53
11.54
12.25
11.94
10.79
11.38
10.81
10.49
11.17
10.43
9.96
9.45
9.75
9.72
9.02
9.09
9.05
8.46
8.94
8.00
8.34
7.49
6.72
6.85
6.85
6.95

tmp

Female
s.d.

n

18.00

5.122
0.471
3.682
3.682
2.681
2.681
3.399
2.385
2.204
2.617
2.885
2.115
2.715
2.503
2.849
2.664
4.122
2.488
2.041
2.518
2.891
2.493
2.325
2.330
2.410
1.958
2.306
2.420
2.184
2.032
1.965
1.562
1.605
1.469
1.882
1.517
1.484
1.079
1.292
1.356

1
5
3
3
3
4
4
3
4
7
10
9
6
16
11
15
26
20
31
24
39
48
59
43
44
26
58
53
46
61
44
73
63
50
38
41
39
25
27
13
19

11.00
10.00
9.00
14.00
22.00
15.00
14.20
12.90
12.67
14.83
12.25
13.57
11.40
13.80
13.47
13.00
13.04
12.08
12.78
11.53
11.68
11.77
11.45
11.60
10.55
10.25
11.04
11.27
10.11
9.41
9.48
9.71
8.97
9.01
8.99
8.65
8.67
8.62
7.86
7.80
7.81
7.72
6.50

I
I
I

3.266
2.608
1.720
2.548
3.300
3.023
3.269
2:195
3.231
2.822
2.329
2.134
2.091
3.370
3.071
3.154
2.823
3.370
2.745
2.673
2.033
2.193
2.172
2.497
2.168
2.054
2.103
2.220
1.865
1.941
1.742
1.717
2.030
I.747
1.398
2.111
1.704
0.989
1.402

3
I
5
5
10
9
6
8
7
10
15
17
18
24
25
27
40
56
57
76
62
69
77
53
55
129
96
80
69
69
99
90
100
60
66
37
35
16
18
14

Growth curve
The growth curves (mean body length plotted on age at capture) are
shown in Fig. 9 and the corresponding body length values in Table 5. The
mean body lengths of the recent year-classes came always above those for thesame age in earlier year-classes, the difference was significant in 9 (female)
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

60

KATO

TABLE 4. STANDARD DEVIATION (s.d.) AND THE MEAN (tmt,) OF AGE AT SEXUAL MATURITY
ESTIMATED FROM TRANSITION PHASE IN EARPLUG FOR THE SOUTHERN MINKEWHALES COLLECTED IN AREAS III AND IV COMBINED, 1971172 TO 1982/83.
YEAR OF MATURATION GROUPING
Year ofmaturation
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1046
1947
1948
1949
1950
1951
1952
1953
19q4
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977

Imp

Male
s.d.

n

tmp

Female
s.d.

n

10.00

0.816

3

11.00
13.00
8.00
11.00
9.00
9.00
8.50

3.000
0.500

1
1
2
2

11.00
13.40
11.00
10.40
10.14
12.08
9.87
10.80
11.17
12.00
10.39
9.70
10.41
10.51
9.75
9.69
10.40
10.01
9.48
9.50
9.34
9.37
8.77
8.62
8.58
8.41
8.72
8.01
8.64
7.96
8.22
7.57

0.943
3.250
3.674
4.224
2.167
3.430
3.145
3.682
4.079
2.852
3.630
3.035
2.949
2.943
2.332
2.681
3.178
2.651
2.469
2.898
2.610
2.849
2.528
2.326
2.688
2.350
2.170
2.239
2.708
2.724
2.620
1.450

3
5
4
5
7
13
6
10
12
15
18
20
22
39
40
47
57
59
66
80
99
105
113
104
120
103
95
67
69
62
23
14

10.00
18.00
7.00
10.00
9.33
10.00
11.33
11.40
12.73
12.75
15.17
10.32
11.16
11.35
10.90
10.63
11.33
11.09
10.27
10.15
10.43
10.37
10.43
9.75
9.64
9.78
9.43
9.13
8.56
8.71
8.81
8.83
8.87
8.08
8.90
8.57
7.89

2.115
2.739
1.700
2.417
0.119
2.634
2.115
3.588
3.498
3.838
3.161
2.836
3.107
3.029
2.585
2.776
2.775
2.808
2.775
3.077
2.906
2.803
2.650
2.571
2.476
2.052
2.189
2.128
2.041
2.193
2.414
2.129
2.315

1
1
1
1
6
4
3
5
9
8
6
II

19
20
20
32
42
33
49
59
125
120
125
120
119
140
175
173
187
172
137
135
110
60
31
29
27

and 10 (male) of the 15 pairwise comparison for each sex (t-test, p < 0.05;
Table 5). The magnitude of the difference of mean body length between
pairs tended to be larger in younger age classes, but it should be noted that
there are still statistically significant difference of mean body lengths between
pairs which are age 25 years in males and ages 25 and 28 years in females(t-test, p < 0.05; Table 5), which were close to or over the age at physicalmaturity (see below).
Sci. Rep. Whales Res. Inst.,

No. 38, 1987

61

SOUTHERN MINKE WHALE
Male
28

1970 - 79 year class"'/•-•,./•,. o-o.

r::.l>·ne,-E' ·-t;· , ••• - • - - , /•,0• .D·o•'e·• r;·t:;··A'
.,•-•
o' D

•.,
\

26

•

I

f{.

/

,Li'

I

t

•

?

D

0

'. p' \ ,C!

o' '. 'b'01950 - 59 year class

/

,E

/ ,fl

,E

1960 - 69 year class/• r::

1940-49 year class

I
24

....

22

•

.c

....Clc

Q)

30

Female

>-

"C

0

en
2a
1940-49 year class

26

24

5

10

15

20

25

30

35

Age in years

Fig. 9. Mean body length plotted on age at capture of the southern minke whales
in each 10 year-class group. Data from Areas Ill and IV combined, 1971172 to
1982/83.

Sci. Rep. Whales Res. Inst.,
No. 38, 198740

Oo "~\C ~............

,,,Oo ~

"'::0

~ ?;;

<; ~

~

~

::0

"'",...

-

-

1.31
1.11
1.45
1.27
1.33
1.23
1.13
0.88
1.19
1.32
0.98
0.91
1.03
1.41
1.48

27.3
27.9
27.8
27.9
27.8
28.2
28.1
28.0
27.4
27.9
28.2
27.3
27.8
27.0
28.2

-

-

-

14
12
2
10

11

21
28
47
27
26
36
28
33
23
27

-

-

-

-

-

-

-

-

-

3.77(100) 4)
1.54( 82)0.45( 97)
1.27( 61)0.84( 58)

-

-

-

-

-

-

-

-

I
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

-

t(df)ll

1940- 1950 YCG
Mean
s.d.
n

Age

<Male>

27.3
27.4
27.5
27.6
27.9
27.8
27.9
27.8
27.5
27.9
28.3
28.3
27.7
28.3
28.1

-

-

-

1.21
1.14
1.07
1.27
1.29
1.33
1.26
1.26
0.79
1.31
0.98
1.23
1.15
1.06
0.95

-

-

-

-

-

81
81
82
91
102
119
147
138
83
90
81
56
52
36
34

-

-

-

-

1950- 1959 YCG
Mean
s.d.
n

3.38(289) 4 )2.40(263) 2l
2.94(253) 3l
3.22(241 )3l
0.84(252)---t(df) I)

25.6
25.9
26.2
26.5
26.9
27.3
27.4
27.4
27.5
27.6
27.9
27.8
28.0
28.2
38.0

1.92
1.93
1.88
1.40
1.38
1.42
1.40
1.25
1.27
1.31
1.28
1.29
1.24
1.22
1.28

68
66
95
114
145
172
225
288
247
249
210
184
173
152
108

-

-

1960 - 1969 YCG
Mean s.d.
n--

3 .49(212) 4)4.28(207) 4)
3.32(250) 4 )4.87(282) 4 )2.96(254) 3)-

t(df) 1)

-

-

22.0
24.4
25.2
25.8
26.4
26.9
26.8
27.3
27.4

-

2.61
2.02
1.65
1.34
1.39
1.33
1.26
1.26
1.21

-

6
75
143
138
146
143
157
170
111

1970-1979 YCG
Mean
s.d.
n

TABLE 5. CHANGE IN MEAN BODY LENGTH (FT) AT AGE OF SOUTHERN MINKE WHALES INDICATEDS FOR
FOUR YEAR-CLASS GROUPS (YCG). AREAS III AND IV

~
0

~

O>

~

<: ;<'
~·

;;:;.

~

~

::0

S"

~~
'l.,

.Co~

"'::0
......

?

28.8
29.7
29.3
29.5
29.1
29.3
29.4
29.1
29.7
30.1
30.0
28.8
29.2
29.8
29.9

-

-

-

-

-

-

-

1.28
2.17
1.44
1.35
1.27
1.38
1.50
1.47
1.25
1.10
1.39
2.00
1.47
0.94
1.21

-

-

-

-

-

41
51
56
47
63
41
40
54
40
39
19
28
17
12
13

-

-

-

-

-

-

1940- 1950 YCG
Mean
s.d.
n

4.07( I 69) 4l
0.61(147)
0.87(145)
0.44(104)
2.05(111 )2l

-

-

-

-

-

-

t(df)I)

28.9
29.1
29.0
29.3
29.l
29.2
29.4
29.2
29.3
29.5
29.7
29.5
29.5
29.6
29.6

-

-

1.43
1.32
1.27
1.56
1.30
1.34
1.17
1.29
1.28
1.23
1.21
1.22
l.18
l.18
1.29

-

-

-

-

90
132
133
145
186
225
210
208
201
156
130
98
91
59
50

-

-

-

1950- 1959 YCG
Mean
s.d.
n

-

-

1.53(350)
0.96(375)
3.20(346) 3 )2.06(338) 2l
3.63(304) 4l

-

-

-

t(df) 1ll) t-value and degree of freedom between nearest YCGs.
2) difference between adjacent YCG is statistically significant at 0.0 I < p < 0.05.
3) difference between adjacent YCG is significant at 0.001<p<0.01.
4) difference between adjacent YCG is significant at p < 0.001.

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39

I

Age

TABLE 5. (Cont.)<Female>

-

25.0
26.3
27.2
27.5
27.9
28.4
28.3
28.5
28.8
28.9
29.2
29.3
29.4
29.3
29.6

-

-

-

2.11
1.95
1.71
1.62
1.56
1.50
1.48
1.95
1.36
1.40
1.32
1.37
1.27
1.35
1.12

-

-

74
89
131
158
222
245
329
351
326
279
262
245
215
195
118

-

-

1960-1969YCG
Mean s.d.
n

-

-

-

1.81(233)
4.47(244) 4l
2.17(273) 2l
2.29(308) 2)
4. I 7(336) 4 l-t(df) 1l

-

-

-

-

23.7
23.8
24.7
25.7
26.5
27.3
27.7
27.9
28.6

-

-

-

-

1.97
2.20
1.78
1.94
1.64
1.70
1.71
1.52
1.26

-

-

-

6
77
141
130
161
157
144
152
116

1970- 1979 YCG
Mean
s.d.
n

0

cri

(.)0

M

r>

:r:

~

M

z
;;::

~

:r:M
;o
z

c
....,

r./l

64

KATO
TABLE 6. RELATIONSHIP BETWEEN BODY LENGTH AND PHYSICAL MATURITY
IN THE SOUTHERN MINKE WHALES TAKEN IN 1978179 AND 1979/80
IN AREAS III AND IV
Body length
(ft)

18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Im mat.

Mat.

Male
To.

Mat.rate(%)

Immat.

Mat.

FemaleTo.

Mat.rate(%)

0

5

0

5

0.00

5
16
33
37
43
15
5

0
2
6
14
21
13
6

5
18
39
51
64
28
II
2

0.00
11.11
15.38
27.45
32.81
46.42
54.54
50.00

4
12
10
10
19
42
53
56
47
18
0
0

0
0
0
0
0
7
11
22
27
14
I
2

0.00

4
12
10
10
19
49
64
78
74
32
I
2

0.00
0.00
0.00
0.00
0.00
16.67
17.19
28.21
36.48
43.75
100.00100.00TABLE 7. RELATIONSHIP BETWEEN AGE AND PHYSICAL MATURITY IN THE
SOUTHERN MINKE WHALES TAKEN IN 1978179 AND 1979/80
IN AREAS III AND IV
Age class(years)
I- 3
4- 6
7- 9
10-12
13-15
16-18
19-21
22-24
25-27
28-30
31-33
;:;;34

Immat.

Mat.

Male
To.

Mat.rate(%)

Im mat.

Mat.

Female
To.

6
13
24
21
18
19
12
4
6
2
2

0
0
I
5
5
6
6
12
8
5
4
3

6
13
25
26
23
25
18
16
14
7
6
4

0.00
0.00
4.00
19.23
21.73
24.00
33.33
75.00
57.14
71.42
66.67
75.00

13
23
41
42
39
29
21
11
17
9
3
4

0
0
0
7
8
9
6
10
11
8
5
12

13
23
41
49
47
38
27
21
28
17
8
16

Mat.rate(%)
0.00
0.00
0.00
14.17
17.02
23.68
22.22
47.61
39.28
47.05
62.50
75.00

Physical maturity

Table 6 shows the relationships between physical maturity and bodylength. Physically mature animals appeared at the body lengths over 25 (7.6m) and 27 ft (8.2 m) in males and females, respectively, and the proprtion of
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

65

SOUTHERN MINKE WHALE
100

0~1940s Year-classes
age, 29-39 )

Q)
.....

...co
.....>.
...:::s 50/•· - , : ___ o

.....

/

co
E
co

•

/

(,)

I

0

'...

/
I

/1950s year-classes( age, 19-29 )I''o-- __ o ,/

/

•

I/)

>.

I

.t:!

c.

. -· --· ---·
--

0

22

-

24

/
1

.:

_,• .......... ,,,.. • .../

1960s year-classes( age, 9-19 )

'/

---~

26

28

30

32

Body length ( ft)Fig. 10. Relationship between physical maturity rate and body length of female
southern minke whales in Areas III and IV. The physical maturity is determined by
the fusion of epiphysis with the centrum of the 6th theoracic vertebra.

physically mature individuals increased with increasing of body length.
When physical maturity is compared with age, the physically mature
animals first appear at the age of 7 -9 years and 10- 12 years in males andfemales, respectively (Table 7). And the proportion of physically mature individuals increases slowly with increasing age in both sexes.
The physical maturity rate (proportion of physically mature individuals)
and body length are compared in Fig. 10 between year-classes ( 10 year-classes
combined) among females for which sample size was relatively large. Although
the proportion of physically mature individuals increased with the increase ofbody length in all three year-class groups examined, it is always higher in theearlier year-classes of the same body length, which are older at capture. The
proportion of physically mature individuals is statistically different between
three year-class groups (1940-'49, 1950-'59, 1960-'69) and for the twolength groups (28-29 ft, 30-31 ft) compared (p < 0.001-0.05, x2 - test;
Table 8).
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

66

KATO
TABLE 8. COMPARISON OF PHYSICAL STATUS OF FEMALES BETWEENYEAR-CLASS GROUPS (YCG) IN EACH BODY LENGTH CLASS

Body length
Class (ft)Physicalstatus

1940s YCG

Number of animals
1950s YCG
1960s YCG

Test

28-29

Immature
Mature

8
10

23
8

58
9

x2 = 14.248
df=2, p<0.001

Immature
Mature

5
10

19
20

27
11

x2 = 7.412
df=2, p < 0.05-----------------------------------------------------------------------------------------------------------------------------------------------30-31

The body lengths of females at 50% physical maturity are estimated to beapproximately 28.4 ft (8. 7 m) and 29.8 ft (9.1 m) for the 1940s and 1950s
year-class groups, respectively. Less than 50% of individuals are physicallymature in the 1960s year-class group in all length classes.
Any examination on the age at physical maturity for year-classes has notbeen made out due to the small sample size and too short time series of thedata to be analyzed.
DISCUSSION

Age and body length at sexual maturity
Present study indicated for the southern minke whales that the mean bodylength of females at the first ovulation (Lmov) and the mean length where 50%of the females were sexually mature (Lm50%) remained constant at about 27.5ft(8.4 m) and 26.5ft (8.1 m), respectively, during the seasons studied (1971172
to· 1982/83). The mean of 12 Lm50% values is 26.5 ft (8.1 m), and is close to thecorresponding figures of 26 ft (7.9 m) estimated for samples in late 1960s to
early 1970s (Ohsumi, Masaki and Kawamura, 1970; Ohsumi and Masaki,1975) or 26.3 ft (8.0 m) estimated for 1971172 to '76177 samples (Masaki,1979). But these values are lower than Lmov estimated in the present study by
about 0.5- l .5ft (0.15-0.45m).
The present study estimated Lm50% by fitting logistic curve to sexual
maturity rate. This procedure should give value which is substantially close to
the mean body length at the first ovulation if there is no sample bias, because
the curve is symmetric at the point of 50% maturity and the fitness of thepresent data is good. DeMaster (1984) indicated using artificial data set thatdifferent methods may produce different estimates of mean age (or length) at
sexual maturity, and that the estimate obtained by least square method (Lm50%
or tm50%) is always higher than the mean of the individual ages at maturation(Lmov or tmov). This is totally reversed to the result of this study (Lm50% < Lmov),and I suspect that there must be some biological bias in the present minke
whale data.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SOUTHERN MINKE WHALE

67

Ohsumi and Masaki (1975), Masaki (1979) and Best (1982) pointed out,
for the southern minke whale stocks, that sexually mature animals tend tosegregate in the Antarctic whaling ground. This causes samples to overrepresent the proportion of sexually mature animals, and consequently underestimates the population mean of body length where 50% of individuals aresexually mature, even when Lm50% correctly represents the mean value for the
population migrating into the whaling ground. On the other hand, Lmov isfree from such segregation by maturity. This will be the reason of the discrepancy of 0.5 to l.5ft (0.15-0.45m) observed between Lm50% and Lmov, and thelatter will represent the mean body length of females at the attainment ofsexual maturity in the southern minke whale population.
Fig. 11 compares tmov, tm50% and tmp values obtained by two different datagroupings, i.e. year-class and year of capture (equivalent to year of maturation). Estimate of tmp covers longer period (28-40 years), while tm50% and tmov
only nine and 11 years, respectively. In years when .comparison is possible(1971-78) in the grouping year of capture the tmp values agree with the tmov
values in both absolute figures and trend. However, tm50% values are always
about 0.5-2 years lower than tmov or tmp in both groupings (X2 -test, p < 0.05),
as pointed out by Cooke (1985). This discrepancy can be explained by the
segregation of sexually mature animals in the Antarctic whaling ground, as
considered above for body length at sexual maturity. This is supported byBest ( 1982). He estimated tm50% of female minke whales to be about 8 years
using samples collected off Durban during breeding season in the early
1970s, which is higher than tm50% obtained from the Antarctic ground in thepresent study, but is very close to tmov and tmp of the present study. Thus the
tmp and tmov are considered to be free from the segregation and give correct
value for the population.
It is known that truncated sampling seriously biased tmp value downward
in recent year-classes (Free and Beddington, 1980; IWC, 1984a). However, thepresent study used only samples which are free from this bias. Another possible factor that may cause bias in the transition phase analysis is the ageing
error. Cooke and de la Mare (1983) argued that an apparent decline of tmp is
produced by assuming a mean ageing error of 25-50% of the true age, evenwhen true tmp remained constant over the period. However, comparison ofage readings between readers showed that ageing error of experienced
readers is not proportional to the age of whales, but that it is always 2-4
layers (IWC, l 984a). Following this result Sakuramoto, Kato and Tanaka(1984) and Sakuramoto, Tanaka and Kato (1985) showed that the observed
declining trend of tmp is real based on a simulation under the assumption ofageing error of 2-4 layers (absolute values which is independent of the age ofwhales) for each of the transition phase age and age at capture.
While there is no independent parameter, such as tmov of females, to confirm the male tmp estimate, I consider the decline of male tmp is also valid because
the male trend is almost the same as that of females and the recent increase of
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

68

KATO
11

>

·'=

1955

~

"
~

co

.,"

1960

1965

1970

1975

1970

1975

Year class

12

)(

..."'
"'
.,

10

"'

<(

8

1955

1960

1965

1980

Calendar year

Fig. 11. Comparison of three kinds of estimates of age at sexual maturity for female
southern minke whale (Areas III and IV). tm50%; age at 50% maturity rate, tmov;
mean age of females having corpus luteum of the first ovulation, tmp; mean age oftransition phase in earplug.

the growth rate has been identified in both sexes.
Thus I conclude that the age at sexual maturity of the southern minke
whale declined from 12-13 to 7-8 years in the past 30 years, while female
body length at sexual maturity remained unchanged at around 27.5 ft(8.4m)
at least in the past 20 years. Similar finding has been made by Ohsumi(1986b) in the North Pacific fin whale stock. He found that the female age atsexual maturity (tm50% and tmov) delined from 12 years in the middle 1950s to 6
years in the middle 1970s, while body lengths at sexual maturity (Lm50%) remained unchanged at around 57ft and 61ft in males and females, respectively.
Growth curve and physical maturity
The present study showed that recent year-classes attains larger body size
than the previous ones of the same age and attaine larger size at ages close to
the attainment of physical maturity. If the growth increase had appeared only
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SOUTHERN MINKE WHALE

69

in the young fast growing ages, it would be possible to attribute it to an artefact
due to possibly intensified fishery selection for larger whales. However, theincrease of the growth rate in older age classes strongly suggests that the
recent increase in growth rate is real.
The analysis on epiphyseal fusion at the 6th thoracic vertebra showedphysical maturity rate in recent year-classes is lower than that in earlier yearclasses of the same body length. One possible explanation for this would attribute it to the fact that samples of earlier year-classes tend to include older
individuals than those of recent year-classes, and reject the possibility that the
body length at physical maturity have increased over the period. Other explanation will consider that the attainment of physical maturity is not dependent
on age but on physiological factors which can be decided by some environmental factors such as nutrition, and that the recent increase in body length at
physical maturity is real. However, due to short data series available, it isinconclusive which interpretation is more appropriate.
Possible factors causing changes in growth parameters
It is generally known on various mammal and fish populations thatgrowth parameters, such as age at sexual maturity, change with the depletionof the stock or increase of food availability. As shown in Fig. 12, for thesouthern minke whale stocks, since changes in growth parameters wereobserved in the period prior to the start of full-exploitation of this stock, thereasons causing such changes will be required for another factors rather thanstock depletion. Laws, Parker and Johnstone (1975) reported for the Africanelephant, Loxodonta africana, that the mean ages at sexual maturity differ between populations in different habitats, and attributed it to difference onfood availability. Yamagishi (1977) made a detailed cohort analysis of human
growth in comparison with the historical changes in food availability, and concluded that recent Japanese year-classes grew faster and to larger body size
mainly by improved nutrition in the adolescent growth spurt stages.
From analogizing above studies, the decline in the age at sexual maturity
and increases in growth rate (and presumably in body length at physicalmaturity) will be attributable to the increase of food availability of minke
whales (per capita) in the Antarctic feeding ground, which is considered tohave been produced by the depletion of whale stocks such as blue, fin andhumpback whales which share an ecological niche with minke whales (Gambell,
1973, 1975; Laws, 1977a, 1977b).
Laws (l 977a) estimated that extra food availability for krill-feeders
brought from the depletion of large whale stocks due to the past Antarctic
whaling will be about 14 7 ,000,000 tons/year during 1920s to 1970s. Additionally, Lockyer (1981) estimated through the analyses of energy cost and growthof the southern minke whale that females will require 3.5% of the additional
food to attain sexual maturity one year earlier. In order to make roughexamination if the above increase in food availability allows for minke whales
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

70

KATO

...... 40

,,

I

I

J\
),(,~•\".-~........................

M...0)( 30

/,

I

'I

'

I • \ ',_,
I

.c

I •

2 20

1,

Ill
(.)

10

,\
, .. ,'

1920' . /•
I

',

1

.'
'

Blue

catah

1930

\,...

,_1

•

•·e.e, ... ,

I

....,

'·~ '

' '

\

\
I

.......

10\'.·••-.+•,

I\,' / ......... _

Fin
catch

E

.......

\\ .•I

l~inke

catch

_

'

.. .. __ .... _

1950

1960

\,·,_ ,'1'

1940... -"'

\

I
\.""

15

Minke.tm

I

I I~/,-~""'"' .~~='./'",/•, . /1910

I/\.,,.'/,, ',.,, ' 1

'

\

,'.I

I

,-,;

1970

1980

SeasonsFig. 12. Historical changes in mean age at sexual maturity of females (tm, •-• )deduced from transition phase in earplug in the present study female by year-classand in the catch by the whole Antarctic (~) for the southern minke whales, aswell as blue ( -·- ) and blue+ fin ( --- ) whale catches. Catch data from International Whaling Statistics.

to decrease juvenile period from 12 years in middle 1940s to 7 years in early
1970s, I have made a calculation assuming;(a) Mean food intake for both sexes in 1940s was 280kg/day whale(Ohsumi, 1979), which was constant within feeding season.
(b) Minke whales feed in the Antarctic for 135 days and feed nothingoutside the Antarctic.
(c) Total minke whale population in 1940s was 382,074 as calculated
from sighting surveys in late 1970s to early 1980s (IWC, 1985).
(possible increase of the total population size from 1940s to 1970s
suggested by the decline of age at sexual maturity was not incorporated)
These assumptions give total krill consumption by the southern minke whale
population at the Antarctic as about 14,442,400 tons/year in 1940s. This has
to be increased to 14,442,400 X (1 +0.035) 5 in 1970s, or net increase of foodintake of about 108,400 tons/year to allow the five year decrease of the
prepubertal stage. This is only 111,356 of the food surplus estimated by Laws
(1977a). And even under the extreme assumptions of two folds population
size in 1940s and daily food consumption during the period, it is still only 1/352
of the food surplus produced by the depletion of the large whale stocks.
Thus, there is still room to support the possible increase of other krill-feeder
populations such as seabird and seals indicated by seveval authors (Sladen,
1964; Laws, 1973, 1977b; Payne, 1977). The total biomass of above competitors is estimated to be 3,561,000 tons, which is brought from 580,000 tonsof seabirds (Group of specialist on living resources of the southern ocean,Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SOUTHERN MINKE WHALE

71

SCAR and SCOR, 1977) and 2,981,000 tons of seals, including all seal species
which have the possibility to feed krill regardless of its amount, based on
0ritsland (1977), Laws (1977a) and Gilbert and Erickson (1977), and is about
1.11 folds of the total minke whale biomass (382,074 X 7.0 tons (average bodyweight)). Furthermore, the biomass of several species of fishes and squids,
which are yet other krill-feeders at the Antarctic, will not exceed 10 folds ofthe minke whale biomass (Mr Ichii, pers. comm.), though the practical estimation on the biomass of these fishes has not been done. Then, the total biomassof krill-feeders other than minke whales in the Antarctic is about 29,420,000
tons (about 11 folds of minke whale biomass). However, even when foodrequirement of those krill-feeders has historically increased, I consider that
there has been an ample supply of krill to allow the changes in minke whalegrowth parameters in the present study judging from considerably small
proportion of aditional food requirements for these changes to the foodsurplus brought from the stock depletion of the l.arge whales.
ACKNOWLEDGEMENTS

My sincere thanks are due to Dr T. Kasuya, Far Seas Fisheries ResearchLaboraotry, for his critical and useful review of manuscript. I would like toalso express my thanks to Dr S. Ohsumi of Far Seas Fisheries ResearchLaboratory who kindly and critically reviewed the eariler version and madevaluable suggestions. Drs Peter B. Best, University of Pretoria, Republic ofSouth Africa and Y. Masaki, South East Regional Fisheries Research Laboratory, kindly permitted to use their data for the present study. Dr H. Omura,director of my institute, kindly encouraged the present study. Drs S. Mishima,
K. Amaoka and A. Kawamura, Faculty of Fisheries, Hokkaido University,
kindly reviewed the earlier version of the present paper. Mr T. Ichii, Far Seas
Fisheries Research Laboratory, provided some informations on the krillfeeder biomass. Ms T. Shirai of my Institute assisted making the manuscriptof the present study. I am largely indebted to the staffs and crew of Nisshinmaru #3, especially Messrs K. Yamaguchi, M. Sato, S. Tabata and K. Maeda,
and I would not be able to carry out several researches in the present study
without their cooperations.
REFERENCES
BEST, P.B., 1982. Seasonal abundance, feeding, reproduction, age and growth in minke whale off Durban(with incidental observations from the Antarctic). Rep. int. Whal. Commn, 32: 759-86.
COOKE, J.G., 1985. Has the age at sexual maturity of southern minke whales declined? Rep. int. Whal.
Commn, 35: 335-40.
COOKE, J.G. and W.K. DE LA MARE, 1983. The effect of variability in age data on the estimation of biologicalparameters of minke whales (Balaenoptera acutorostrata). Rep. int. Whal. Commn, 33: 333-46.
DEMASTER, D.P., 1984. Review of techniques used to estimate the average age at attainment of sexual
maturity in marine mammals. Rep. int. Whal. Commn (special issue 6): 175-79.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

72

KATO

FREE, C.A. and J.R. BEDDINGTON, 1980. A technique for estimating mean and variance of age at sexual
maturity for data obtained from the transition phase of ear plug laminae. Rep. int. Whal. Commn,
30: 375-377.
GAMBELL, R., 1973. Some effects of exploitation on reproduction in whales. ]. Reprod. Fert. Suppl.,
19: 533-553.
GAMBELL, R., 1975. Variations in reproduction parameters associated with whale stock size. Rep. int. Whal.
Commn, 25: 182-189.
Group of specialists on living resources of the southern ocean, SCAR and SCOR, 1977. Biological investigations of marine Antarctic systems and stocks (Biomass), 1: 1-79.
·
GILBERT, J.R. and A.W. ERICKSON, 1977. Distribution and abundance of seals in the pack ice of the Pacificsector of the Southern Ocean. pp. 703-748. Jn: G.A. Llano(ed.) Adaptations within Antarctic Ecosystems. Smithsonian Institution, Washirigton, D.C. 1252 pp.
International Whaling Commission, 1979. Report of the special meeting on southern minke whales, Seattle
1978. Rep. int. Whal. Commn, 29: 349-58.
International Whaling Commission, 1983. Report of the Scientific Committee. Rep. int. Whal. Commn,
33: 43-190.
International Whaling Commission, l 984a. Report of the minke whale ageing workshop. Rep. int. Whal.
Commn, 34: 675-700.
International Whaling Commission, l 984b. Report of the workshop. Rep. int. Whal. Commn (special issue 6):
1-26.
International Whaling Commission, 1985. Report of the Scientific Committee. Rep. int. Whal. Commn,
35: 31-64.
KATO, H., 1·982. Some biological parameters for the Antarctic minke whale. Rep. int. Whal. Commn,
32: 935-45.
KATO, H., 1983a. Some consideration on the decline in age at sexual maturity of the Antarctic minke
whale. Rep. int. Whal. Commn, 33: 393-99.
KATO, H., 1983b. Relation of earplug growth and skull growth in the Antarctic minke whale. Paper
SC/A83/AW5 submitted to minke whale ageing workshop of IWC. 6pp.
KATO, H., 1985. Further examination of the age at sexual maturity of the Antarctic minke whale as determined from earplug studies. Rep. int. Whal. Commn, 35: 273-81.
LAWS, R.M., 1961. Reproduction, growth and age of Southern Hemisphere fin whales. Discovery Rep.
31: 327-486.
LAWS, R.M., 1973. Population increases of fur seals at South Georgia. Polar Record, 16: 856-58.
LAWS, R.M., 1977a. Seals and whales of the Southern Ocean. Phil. Trans. R. Soc. B., 279: 81-96.
LAWS, R.M., 1977b. The significance of vertebrates in the Antarctic marine ecosystem. pp. 411-38.
In: G.A. Llano (ed.) Adaptations within Antarctic Ecosystem. Proc. 3rd SCAR Symp. on Antarctic
Biology. Smithsonian Institution, Washington, D.C. XLIV 1252pp.
LAws, R.M., I.S.C. PARKER and R.C.B. JOHNSTONE, 1975. Elephants and their habitats. The ecology of elephants inNorth Bunyoro, Uganda. Claren Don Press, Oxford. 366 pp.
LOCKYER, C., 1972. The age at sexual maturity of the southern fin whale (Balaenoptera physalus) using
annual layer counts in the earplug.]. Cons. int. Explor. Mer., 34(2): 276-94.
LOCKYER, C., 1981. Estimation of the energy costs of growth, maintenance and reproduction in the femaleminke whale, Balaenoptera acutorostrata, from the Southern Hemisphere. Rep. int. Whal. Commn,
31: 337-47.
MASAKI, Y., 1979. Yearly change of the biological parameters for the Antarctic minke whale. Rep. int. Whal.
Commn, 29: 375-96.
OHSUMI, S., 1979. Feeding habits of the minke whale in the Antarctic. Rep. int. Whal. Commn, 29: 473-476.
OHSUMI, S., 1986a. Earplug transition phase as an indicator of sexual maturity in female Antarctic minke
whales. Sci. Rep. Whales Res. Inst., 37: 17-30.
OHSUMI, S., 1986b. Yearly change in age and body length at sexual maturity of-a fin whale stock in the eastern North Pacific. Sci. Rep. Whales Res. Inst., 37: 1-16.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SOUTHERN MINKE WHALE

73

0HSUMI, S. and Y. Masaki, I975. Biological parameters of the Antarctic minke whales at the virginal
population level.]. Fish. Res. Board Can., 32(7): 995-1004.
0HSUMI, S. and Y. Masaki, I977. Age-length keys and growth curves of the Southern Hemisphere sei
whale. Rep. int. Whal. Commn, 28: 43I-48.
0HSUMI, S., M. NISHIWAKI and T. HIBIYA, I 958. Growth of fin whale in the North Pacific. Sci. Rep. Whales
Res. Inst., 13: 97-133.
0HSUMI, S., Y. MASAKI and A. KAWAMURA, 1970. Stock of the Antarctic minke whale. Sci. Rep. Whales Res.
Inst., 22: 75-125.
OMURA, H., 1975. Osteological study of the minke whale from the Antarctic. Sci. Rep. Whales Res. Inst., 27:
1-36.
OMURA, H. and T. KASUYA, 1976. Additional information on skeleton of the minke whale from theAntarctic. Sci. Rep. Whales Res. Inst., 28: 57-68.
0RITSLAND, T., 1977. Food consumption of seals in the Antarctic pack ice. pp. 749-768. In: G.A. Llano(ed.)
Adaptations within Antarctic Ecosystems. Smithsonian Institution, Washington, D.C. 1252 pp.
PAYNE, R.M., 1977. Growth of fur seal population. Phil. Trans. R. Soc. London Ser. B., 279: 67-79.
SAKURAMOTO, K., H. KATO and S. TANAKA, 1985. A simulation study about several factors influencing theestimates of a trend in age at sexual maturity of the Antarctic minke whale. Rep. int. Whal. Commn,
35: 285-90.
SAKURAMOTO, K., S. TANAKA and H. KATO, 1986. A simulation study evaluating the effects of ageing error
on estimates of a trend of age at sexual maturity of the Antarctic minke whale. Rep. int. Whal.
Commn, 36: 213-20.
SLADEN, W.J.L., 1964. The distribution of Adelie and chinstrap penguins. In: R. Carrick, et al. (eds),
pp. 359-365. Biologie antarctique. Paris, Hermann.
WHEELER, J.F.C., 1930. The age of fin whales at physical maturity. Discovery Rep., 2: 403-34.
YAMAGISHI, H., 1977. Biology of growth. Koodansya. Tokyo. 198 pp. (in Japanese).

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

OBSERVATIONS ON THE OVARY OF
THE SOUTHERN MINKE WHALECHRISTINA LOCKYER*
ABSTRACT

Ovaries of minke whales appear similar in shape, form and structure
to those of related balaenopterid whales. However, the size and weight ofthe ovaries and their internal structures are smaller. In particular, themean sizes of the active corpus luteum (CL) and regressed corpora albicantia (CA) are smaller. A high number of corpora appear to be present in theovaries relative to age, consistent with a more frequent ovulation rate and/or shorter reproductive interval than observ~d in other balaenopterids.
The types of corpora observed in the minke whale are similar to those reported for other whales, although the CA in minke are characteristicallyvery yellow in colour. The CA appear to persist in the ovary despite considerable shrinkage and degeneration, thus forming a complete record of
the individual's ovulation history. The cyclical changes in the ovary in relation to reproductive condition appear similar to those observed in otherbalaenopterids.
INTRODUCTION AND BACKGROUND

The minke whale, Balaenoptera acutorostrata, the smallest of the balaenopterid
cetaceans, attaining a maximum size in the southern hemisphere of 10. 7 m(Lockyer, 1984) and weight of about 13.87 t (Lockyer, 1976; Ohsumi, 1979),
is found in all latitudes of the world's' oceans. Although the life history,
longevity, pattern of feeding, growth and reproduction have many similarities
with other balaenopterids, the duration of the reproductive cycle appears todiffer, and in minke whales is closer to one year rather than two years as in
the majority of this genus (Best, 1982; Christensen, 1974; lvashin and
Mikhalev, 1978; Jonsgard, 1951; Larsen and Kapel, 1983; Lockyer, 1981,
1984; Masaki, 1979; Mitchell and Kozicki, 1975; Williamson, 1975).
The most reliable estimate of reproductive cycle length is 14 months(IWC, 1979), comprising 10 months' gestation and 4 months' suckling of asingle calf. The female appears to commence a subsequent pregnancy either
during lactation or at weaning of the calf. The evidence for this is derived
from ovulation rates calculated by plotting ovarian corpora numbers versus
age, from foetal growth records and timing of parturition, and from propor-* Sea Mammal Research Unit (NERC), c/o British Antarctic Survey, Madingley Road, High Cross, Cambridge CBJ
OET, England.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 75-89

76

LOCKYER

tions of pregnant, lactating and anoestrous females in the mature portion of
the commercial catches.
Studies of minke whale populations have been made in both hemispheres, and include polar waters of the Antarctic, off Norway and Greenland,
and more temperate seas off South Africa, Canada, Japan and Korea, as wellas equatorial waters off Brazil. The biology of the different populations has
generally been comparable.
The subject of the present study is the Antarctic minke whale. The
mature female usually conceives in August-September, and gives birth in
May-June of the following year to a 2.8 m neonate (Ivashin and Mikhalev,
1978; Lockyer, 1984). The mean age at first ovulation and possibly conception, ranges between 6-14 years (Masaki, 1979; Kato, 1983, 1985) at an
average body length of 8.0 m and weight of 6.05 t. In this study, a detailed
account is presented of the macroscopic structure of the ovaries of the minke
whale, and analyses of cyclical activity in relation to reproductive age andstatus.

MATERIAL AND METHODS

The study material comprised 67 pairs of ovaries, collected during theJapanese Antarctic minke whaling expedition December 1980-March 1981.
The ovaries were removed intact from freshly killed carcases on board factory
ships, were maintained frozen between - l5°C and -20°C, and shipped backto Japan where, after initial palpation and examination at the Far Seas
Fisheries Research Laboratory, Shimizu, they were fixed and preserved wholein neutral buffered 10% formalin (4% formaldehyde) and freighted toCambridge. On arrival, the ovaries were in excellent anatomical and histological condition. Data on sexual status and condition, age, date of capture, bodylength, geographical position of capture and foetal length (if present), were
provided. The classification of the reproductive status, e.g. pregnant, anoestrous, lactating, was determined on site when the whale was first dismemberedafter capture and the ovaries collected. This was done by careful macroscopic
investigation of the uterus and mammary glands. Ages of individuals were
determined by Dr H. Kato (Whales Research Institute, Tokyo).
After soaking/rinsing in running water for 24-hours, the individual
ovaries were trimmed of adhering fallopean tube and connective tissue,
weighed and examined for gross general appearance and presence of corpora
lutea. These latter, if found, were detached, weighed, and cut vertically fromthe ovulatory scar along two planes at right angles to each other and to a third
transverse plane of cut. The maximum diameters through these three planes
were measured to give an average diameter of the corpus luteum (CL).
The ovaries were then sectioned at intervals of 2-3 mm, using a commercial meat slicing machine. During this procedure, slices were accumulated
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

MINKE WHALE'S OVARY

77

serially and examined for the presence of corpora albicantia (CA), follicles
and various other ovarian structures, all of which were recorded and measured
for mean maximum diameter in at least two planes. Unusual items, such as
corpora atretica, were excised and put aside in 10% formalin for subsequent
histological examination for confirmation of their identity.
The classification of ovarian bodies was made by reference to work ofLaws(l961) and the International Whaling Commission report (IWC, 1984).
The categorization of the CA into young, medium and old in terms of state ofregression and resorption has been based on the terminology of Laws( 1961).

RESULTS AND DISCUSSION

The ovarian structure is typically mammalian (Mossman and Duke, 1973),
and generally conforms to the findings of Harrison (.1969), Laws ( 1961) and
Slijper (1966) for other cetaceans. In the following analyses, the ovaries were
sorted by reproductive category of the female, as defined below:
Immature-where ovaries contain follicles but no evidence of ovulation;
Mature-where ovaries, of which at least one half of the pair, containevidence of ovulation; there are sub-categories of maturity status:a. Pregnant-where ovaries contain an active corpus luteum, and there isevidence of foetal development in the uterus;b. Ovulating-where ovaries contain a large active corpus luteum, butthere is no evidence of a foetus in the uterus; note however, that fertilisation may have occurred but not implantation;c. Regressing CL-where ovaries contain a no longer active corpus
luteum which is undergoing shrinkage and histological changes commensurate with becoming a corpus albicans (Marsh, 1985; Marsh andKasuya, 1984);
d. Anoestrous -where ovaries contain no corpora lutea, active or regressmg;
e. Lactating-where milk is present in the mammary glands, but theovaries may contain a regressing CL, an active CL or no CL; ovulationand pregnancy may occur during lactation.
Gross appearance of the ovaries
1) Size
The elongate, slightly flattened ovaries are lobulate in mature andmaturing females and smooth in juveniles. The overall external colour is a
mixture of pink, white and grey. The hilus is long, similar to that in the fin
whale, B. physalus (Laws, 1961). Corpora (both CL and CA) generally protrude from the surface, and are connected at the base by a thick "neck" to themain body of the ovary. The ovary surface is frequently criss-crossed by "tags"
and adhesions such as observed for sei whales, B. borealis (Gambell, 1968 andSci. Rep. Whales Res. Inst.,
No. 38, 1987

78

LOCKYERTABLE I. OVARY WEIGHTS IN MINKE WHALES
Reproductive classand category
Immature
MatureAnoestrous < 1OCA
ll-24CA>25CA
All groups
Pregnant All groups
Ovulating (CL+ l 9CA)*)
Regressing CL (2-1 lCA)**)No individual
ovaries

Mean ovary weight(g)±s.d.
Ovary without CL
Ovary with CL

2250.4±37.92

10
12
8
30
36

77.75±31.72
167.50±45.40
218.12±97.24
150.11±81.13
161.14±68.62
200
78.17±5.012
6339.17± 113.16
480
131.67± 16.07•) corpora count of ovary pair,**) range of corpora counts in the 3 ovary pairs.

personal observation); 18% of juveniles and 12.5% of mature females showing this feature. Sometimes mushroom-like appendages dangle from themain body' of the ovary, but have no unusual internal structure. These havealso been observed in fin whales (Laws, 1961 ).
The paired ovaries are usually of similar size and weight, except where a
CL is present, when the CL-bearing ovary greatly exceeds the weight of theother.
2) Weight
The average weight of ovaries for different reproductive classes areshown in Table 1. The minke ovaries, by reproductive class, are almost one
tenth the weight of those reported for the much larger fin (Laws, 1961) andsei whales (Gambell, 1968). As expected, the immature ovaries are lightest. In
the mature ovary, weight increases significantly with the accumulation of CA,
although the overall mean weight of the anoestrous ovary is similar to that of
the non-CL-bearing ovary of the pregnant female. The combined effects ofcorpora number and stage of pregnancy have not been investigated, as sample
size is inadequate. The CL-bearing ovary in both the fully pregnant and postlactational phase (with regressing CL), is significantly heavier than its partner.
This, as will be shown later, is almost certainly due to the additional weight of
the CL. The single ovulating female in the sample, also demonstrates a weight
assymetry with greater weight in the recently ovulated ovary.

Internal structure of the ovary
Internally, the encapsulating tunica albuginea in mature ovaries is
between 0.83-2.99 mm in thickness with a modal range 1.25-1.50 mm. This iscomparable to the 0.95-1.60 mm observed in fin whales (Laws, 1961). The
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

79

MINKE WHALE'S OVARYTABLE 2. MEAN DIAMETER OF THE LARGEST FOLLICLES IN MINKE WHALES
Reproductive classand category
Immature(age 2-7 years;
length 6.2-8.6 m)
MatureAnoestrous
Pregnant(foetus <30 cm)(foetus 30-130 cm)(foetus> 130 cm)
OvulatingRegressing CL (2-1 lCA)*l

No females

Mean diameter of the largest
follicles (mm) ±s.d.

116.41±3.35179.29±4.908262

9.87±5.92
13.74±3.81
13.00±0.07
14.00
3.50±2.18

I

3•) range of corpora counts in the 3 females.

body of the ovary, particularly the medulla, is well supplied with blood vessels, and the cortex contains varying numbers of follicles of differing sizes
with developing oocytes, the stage dependent on reproductive condition of
the female, and products of ovulation, the CL and CA. In addition, various
other bodies are found near the cortical surface, including different typesof corpora atretica, cysts and cystic follicles. These ovarian bodies aredescribed below.
1) Follicles
The dimensions and abundance of gel-filled Graafian follicles, foundthroughout the cortex of the ovary, vary in size with stage of maturity, andwith stage of the reproductive cycle (Table 2). The immature ovaries ofjuveniles and animals approaching puberty have smaller follicles than thosein most mature ovaries. In very young females, the follicles are not macroscopically visible.
Ovulating and mid- and late-term pregnant females have the largest
follicles, whilst follicles in ovaries of anoestrous and early-term pregnant
females are smaller. The smallest follicles, indicating little follicular activity,
are seen in the ovaries of females with a regressing CL.
Follicular activity in terms of size, throughout the reproductive cycle inminke, is broadly similar to that of fin whales (Laws, 1961).
No mature ovaries were observed to lack follicles as has been reported by
Marsh and Kasuya (1984) for older "post-reproductive" or senescent pilot
whales (Globicephala macrorhynchus).
2) Corpus luteum
The active CL is similar in appearance to those described for fin (Laws,
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

80

LOCKYERTABLE 3. SIZE OF THE CORPUS LUTEUM IN MINKE WHALES
Reproductive classand category

Mean size of CL±s.d. (n=sample size)
Diameter (mm)Weight (g)Pregnant(foetus <30 cm)(foetus 30-130 cm)(foetus >130 cm)
OvulatingRegressing CL

62.68±8.78
66.40±6.79
70.58± 12.94
75.70
41.37±3.60

(8)
(26)
(2)
(1)
(3)

137.25±45.27 (8)156.73±48.39 (26)202.50±137.89 (2)180.00(1)
48.00±11.31 (3)1961 ), sei (Gambell, 1968) and blue whales, B. musculus (Mackintosh andWheeler, 1929); its form and structure is as described in the IWC report(IWC, 1984).
The CL of the ovulating female (determined as such from the absence ofa foetus) was similar in appearance to those of the pregnant females, confirming the view (IWC, 1984; Marsh, 1985) that the CL of ovulation andpregnancy are not readily distinguishable, if at all. Of course, during the preimplantation phase when the blastocyst is unattached, the reproductive statusof the female is impossible to differentiate from that of the condition with arecent unfertilised ovum.
The stigma, site of the follicular rupture at ovulation, was usually clearlyvisible at the apex of the protruding CL, and was often surrounded by aslightly raised rim or corona. The colour of the CL was pinkish-grey to yellow.
One unusual form of CL was found where a surrounding fold of tunica
albuginea from the ovary had formed around the body, enfolding it like a cup
around an acorn. Central vesicles within the CL were observed in 25% of
early-pregnant (n=8; foetus length<30 cm) and 33.3% of mid-pregnant
females (n=26; foetus length 30-130 cm), but none were observed in latepregnant females (n=2; foetus> 130 cm). There was no significant association
with stage of pregnancy. Larsen (1984) reported an incidence of 13% ofvesicular CL in pregnant minke whales, but no breakdown by stage of pregnancy was presented.
Variation in size of the CL throughout the reproductive cycle is shown in
Table 3. Volume and weight appear to increase with advance of pregnancy.
However, the differences in size are not significant with these small samples.
The regressing CL, determined as such from shrinkage of the secretory
lobules and commencement of fibrous replacement of the luteal tissue, appears
very small in relation to the size at ovulation, and approaches the mean
largest size of the youngest CA.
The additional weight of the CL explains the assymetry in the weight ofovaries from pregnant females (Table 1).
The size range of the minke CL (Table 3) is similar to that observed byBest ( 1982) for minke whales off South Africa, and by Larsen and Kapel
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

81

MINKE WHALE'S OVARYykey :o pregnant• anoestrous
t:..

40

regressing CLDo ovulating

D

•
D
D

D

D

30
D
D

•

...z
::>

D

0
u

O

<(

...0"'

D

"'0
u

D
D

D

•D
OD

D

•

••

0
...-~~~~~---,-~----,~~~~~~~~---,-~----,~~x

0

10

20

AGE

30

40

50

IN YEARS

Fig. I. Observed relation of ovarian corpora number with age from ear plug growthlayers in minke whales.

(1983) for the minke whale off Greenland. Larsen (1984) gave a mean size of
CL of pregnancy as 56.6±5.8(s.d.)mm for Greenland minke whales, rather
smaller than the values for the southern hemisphere. He considered that thesmaller size of the CL of tpe northern hemisphere animals might be due totheir smaller body size. The size of the CL of ovulation observed here seems
large by comparison with the data summarised by Lockyer (1984), approaching nearly twice the diameter given by Larsen (1984). However, no significance can be ascribed to this solitary observation. The mean sizes of the minke
CL are smaller than those of all other baleen whales quoted by Lockyer ( 1984)
for pregnant females, including:blue, 136.5 mm (Mackintosh and Wheeler, 1929),
fin, 114.4 mm (Laws, 1961),
sei, 76-84mm (Gambell, 1968),
humpback, Megaptera novaeangliae, 106-123 mm (Matthews, 1937;
Chittleborough, 1954),
Bryde's, B. edeni, 72-78 mm (Best, 1977), and gray, Eschrichtius robustus,
82-87 mm (Rice and Wolman, 1971).
In all these baleen species, the mean size of the CL of ovulation is smaller
than that of pregnancy.
No examples of accessory CL, as described by Laws (1961) and IWC
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

82

LOCKYER(1984), were found. However, there is a possibility of their existence, particularly with reference to c. atretica described later, whose function and fate areunclear.
3) Corpora albicantia
All CA were classified into young, medium and old categories (Laws,
1961), and mean diameters measured. The first impression gained in examining the ovaries, was the high numbers of CA accumulated even in young
females, so that it was not unusual to observe many females of age 15 years
and over with as many corpora as years (Fig. 1). This suggests two points: 1)
females probably ovulate at least annually, and may be poly-ovulating; 2)complete resorption even of old CA is unlikely, so that CA are permanentfeatures of the ovary, even when greatly regressed in size.
The young CA, are in fact most usually highly pigmented and yellow-tan
in colour, whereas fin or sei ovaries are usually pale greyish-brown (personalobservation). In the minke whales, the medium and old CA generally becomebrown and greyish, but some CA are still well pigmented. The difference between a highly pigmented CA and a corpus aberrans (Laws, 1961) equivalent
to a corpus atreticum type a (IWC, 1984) (see Plate la) is not immediately
obvious, since the latter is often regularly shaped and bright yellow or orangeyellow in hue.
Fig. 2 shows the course of regression of the CA with time in different
reproductive classes.
4) Young CA
The mean maximum diameter range of the young CA is 28.14-16.50mm,with pregnant and ovulating females tending to bear slightly larger and, inthe former, more numerous young corpora than females in anoestrus andwith regressing CL, despite similar total counts of all ages of corpora. Thismight suggest that hormones of pregnancy may temporarily allay degenerative processes and shrinkage of the CA. Such explanations have been proposed for fin whales where similar observations were made (Laws, 1961 ).
Marsh and Kasuya (1984) found slower rate of shrinkage of CA in pregnant
pilot whales. Larsen (1984) gave a mean diameter of young CA of
21.4±3.5(s.d.)mm for Greenland minke whales, within the range presented
here.
Initially the CL shrinks rapidly to 40% of its original diameter (Larsen,
1984, gave a figure of 37.8%), and then continues to about 25% of original
CL diameter (Fig. 2a).
5) Medium CA
The range of mean diameters of the medium CA is 19.17-10.00 mm,
the smallest being about 15% of original CL diameter, and 40% of initial diameter of the youngest CA. The shrinkage of the CA in this medium phase isSci. Rep. Whales Res. Inst.,
No. 38, 1987

83

MINKE WHALE'S OVARY
b MEDIUM

a YOUNG~::~ \_. _, 1~

C OLD

~-~~-

Jj%:'"":~~ j~!~,-~~~
i~\1~
j"""fH+Ht+HIHl!i!o 'IHI 'I+

Pcegnant-partum

I

J

16

!

CORPUS,6;\5

NUMBERAND CLASSIFICATION

2bI', .bl\i''' 2b

"~'

ab

.~

Fig. 2. Regression of accumulated corpora albicantia, measured by mean diameter,in decreasing order of c.albicans size, by different reproductive classes:a. Young c.albicantia;
b. Medium c.albicantia;
c. Old c.albicantia.

slower (Fig. 2b), and there is considerable size overlap with the old CA category below (Fig. 2c). Larsen (1984) observed a shrinkage in diameter of
medium CA in Greenland minke to 15.8±2.4(s.d.)mm, similar to results here,
and 27.9% of original CL diameter.
6) Old CA
The range of mean diameters of the old CA is 18.5-7.5 mm. The shrinkage here is very slow (Fig. 2c), and not greatly different from that for medium
CA. The similar size range with the medium CA, suggests not so much continued shrinkage, but a continued histological change in the structure.
It seems unlikely that CA which have regressed to this third stage will regressor alter further; they become a permanent feature in the ovary. Examples of
old CA are shown in Plates la and ld.
The general pattern of corpus regression in minke whales is similar tothat in fin whales (Laws, 1961), but the sizes of minke CA in the different
ovarian age categories are smaller. The ultimate regressed modal diameter(about 10 mm) of the old CA in minke being approximately half that for thefin whale (Laws, 1961). However, this body is still quite readily visible macroscopically. Larsen (1984) found a mean diameter of old CA of
10.0±2.4(s.d.)mm in Greenland minke, and shrinkage to about 17.7% of original CL diameter. The equivalent shrinkage here is 15.2% of CL size, close to
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

84

LOCKYERthe estimate of Best (1982) of 15.7%.
7) Corpora atretica, cystic follicles and cysts
Corpora atretica-type a: The corpus atreticum type a (IWC, 1984) identified here is equivalent to the corpus aberrans described by Laws (1961 ).
These bodies exhibit follicular origins, there being evidence of apparent
rupture or ovulation through presence of a stigma on the germinal
epithelium overlying the body (Plate lb). However, they fail to luteinise fully
and undergo instead a fatty degeneration over time (Plates le and ld). These
corpora often attain a moderate size, e.g. 23mm in diameter, and are very
bright yellow in colour (Plate le). When recently formed they appear as
lobules protruding from the mass of the ovary, and frequently a CA in form.
The presence of older regressed or atrophied ones is often ascertained only
after cutting into the ovary. A few maintain central vesicles (Plate lf).
No c.atretica a were found in the ovaries of the eleven juveniles, none in
the ovaries of the ovulating female, or of the three females with a regressing
CL. The anoestrous females (n=l4) showed an incidence of 78.6%. Half of
the anoestrous females had only a single c.atreticum a, while 7% had two,
14.3% had 3, and 14.3% had four. The mean diameter of the c.atreticum a
was 10.82±4.50(s.d.)mm. Among pregnant females, the incidence of c.atretica
a was 62.5% for those with a foetus <30 cm (n=8), 37.5% having a single
body and 25.0% having two. The mean diameter was 10.08±3.78(s.d.)mm.
The incidence in the group of foetal size 30-130 cm (n=26), was lower, at
26.9%, with 15.4% having a single body, 7.7% having two and 3.8% having
three. The mean diameter was 10.50±5.4(s.d.)mm. The two females in latepregnancy had no c.atretica a. Sample size is too small in several categories
for a valid x2-test, but restricting the test to incidences in anoestrous andpregnant females, x2= 10.6751 with d.f.=2, and is significant at p<0.01. It istherefore suggested that these bodies are directly associated with certain
phases of the reproductive cycle, and by implication, certain hormone levels.
Laws (1961) observed a decrease in incidence of c.aberrantia (c.atretica a) withadvance of pregnancy in fin whales. In odontocetes, Best ( 1967) reported thehighest incidence of c.atretica a in recently ovulated females, 45.5%, withlower levels of 4.6% in pregnant, 7.7% in lactating and 13.6% in anoestrous
sperm whales, Physeter macrocephalus. Marsh and Kasuya (1984) found an
apparent association of incidence of c.atreticum a with states of oestrus, ovulation and early pregnancy in pilot whales. The bodies appeared to degenerate
post-partum and in anoestrus.
The fact that percentage occurrence varies so much between reproductive classes in minke whales also suggests that most c.atretica a degeneratecompletely, perhaps within a year, the usual reproductive interval. Laws
( 1961) held a similar view on the fate of c.aberrantia (c.atretica a) in the fin
whale.
Of females with ovaries having a vesicular CL (n= 11), 54.5% had aSci. Rep. Whales Res. Inst.,
No. 38, 1987

MINKE WHALE'S OVARY

85

c.atreticum a, compared with 24.0% of those females with ovaries having a
non-vesicular CL (n=25). The difference, however, was insignificant with
p>0.05 using a x2test.
Corpora atretica-type b: This category corresponds with the definition ofc.atreticum used by Laws (1961) and with the c.atreticum type b (IWC, 1984).
These bodies are usually smaller than the c.atreticum a, and, unlike the frequently regular internal shape of the latter, are usually stellate or amoeboid inshape and deep yellow-orange or tan in colour. They never protrude fromthe ovary surface, and none examined exhibited a stigma. Usually, thesec.atretica b lay deeper in the cortex than the c.atretica a.
No c.atretica b were observed in females with immature ovaries (n= 11),and none were observed in the ovulating ovary or in the three pairs of ovaries
with regressing CL. The incidence in anoestrous females (n= 14) was 35.7%,
with 14.3% having one, 7.1 % having two, and 14.3% having seven c.atretica
b. The maximum diameter of the c.atreticum b was 8.3mm, but many weremuch smaller. Among pregnant females, the early pregnant (n=8) group had
an incidence of 12.5% with two c.atretica b, and very small diameter, <5 mm,
while mid-pregnant females (n=26) had an incidence of 34.6%, with 19.2%
having one and 15.4% having two c.atretica b. The maximum diameter observed was about 7 mm. Marsh and Kasuya (1984) observed no c.atretica bin
immature pilot whales, but found 75% of all mature ovaries bore thesebodies. Best ( 1967) found an average incidence of 50% in all reproductiveclasses of sperm whales.
Using similar criteria as above for the c.atreticum a data, a x.2-test
showed no significant differences between reproductive states, excluding
juveniles. A similar finding was obtained in fin whales (Laws, 1961), and alsoin pilot whales (Marsh and Kasuya, 1984) and sperm whales (Best, 1967).
The persistence of these bodies is uncertain, 'particularly because of theirsmall irregular form which may mean that some are inevitably overlooked ina macroscopic examination of the ovaries. Marsh and Kasuya (1984) suggestthat these bodies do not persist. Total resorption is a possibility. Also, theoverall incidence of c.atretica b are lower than for c.atretica a.
8) Cysts
Follicular, gel-filled cysts: In the present sample of ovaries, this type of cyst
appears to occur exclusively in ovaries of pregnant females, with an incidenceof 12.5% and a mean diameter of 31.7 mm in females in early pregnancy(n=8), and 3.8% and a mean diameter of 40 mm in females in mid pregnancy(n=26). No other examples of cystic follicles were observed. These cysts were
often multichambered, resembling a thin-walled honeycomb filled withmucous gel. The ultimate fate of such cysts is not known, but presumably
they regress, because they are not observed in other reproductive groups.
Should some luteinisation or hyalisation occur, they may regress to a form ofyellow body such as c.atreticum b, but this is speculative.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

86

LOCKYER

Cornified solid cysts: Only one example of a solid cyst was observed, andthis was present in the cortex of a female in early pregnancy, in the form of asmall whitish and homogeneous sphere, with a fibrous collagen-type of
texture. The origin of this body was unknown.
Differential activity in the ovary pairs
The side of the whale from which the ovary was collected was not generally known or identifiable. The possibility of bi-lateral activity could thus not
be evaluated as to preferential left or right activity. However, a simple analysis
was performed to identify whether or not one ovary, regardless of side, might
be more active than the other.
The pairs of ovaries with a total corpora count of 2 or more (52 pairs)
were arranged in ascending order of corpora count. The individual ovary
corpora counts of each pair were compared and the difference between them(d) was squared (d2) and divided by the total corpora count (N). A plot ofd 2/N on N revealed no pattern of increasing variability with corpora count,and insignificant correlation of p>0.05 with r=-0.127, d.f.=50. We may
therefore conclude that there is no indication of differential activity between
halves of ovary pairs.
Both ,Slijper (1949) and Laws (1961) found a tendency for the rightovary to be more active in fin and blue whales. Larsen (1984), examining left
and right ovaries for a small sample of Greenland minke, found no significant
bi-lateral ovarian activity.

ACKNOWLEDGEMENTS
The assistance from and collaboration with staff of the Far Seas Fisheries
Research Laboratory, Shimizu, are gratefully acknowledged; their provisionof the material and associated data have enabled this study to be carried out.
Dr Seiji Ohsumi is especially thanked for his help. The advice and criticism
from Dr John Harwood, Dr Richard M. Laws and Dr Helene Marsh in theanalysis and preparation of the paper have been useful, and they are thanked
for their help. The advice of Dr Hidehiro Kato and anonymous referees wasof great assistance.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

MINKE WHALE'S OVARY87

REFERENCES
BEST, P. B., 1967. The sperm whale (Physeter catodon) off the west coast of South Africa. I.Ovarian changes
and their significance. Div. Sea Fish. Invest/ Rep., 61: 1-17.
BEST, P. B., 1977. Two allopatric forms of Bryde's whale off South Africa. Rep. int. Whal. Commn (special
issue I): 10-34.
BEST, P. B., 1982. Seasonal abundance, feeding, reproduction, age and growth in minke whales off Durban(with incidental observations from the Antarctic). Rep. int. Whal. Commn, 32: 759-786.
CHITTLEBOROUGH, R. G., 1954. Studies on the ovaries of the humpback whale, Megaptera nodosa(Bonnaterre), on the western Australian coast. Aust.]. Mar. Freshw. Res., 5(1): 35-63.
CHRISTENSEN, I., 1974. Minke whale investigations in the Barents Sea and off East and West Greenland in
1973. Fiskets Gang., 14: 278-286.
GAMBELL, R. G., 1968. Seasonal cycles and reproduction in sei whales of the Southern Hemisphere.
Discovery Rep., 35: 31-134.
HARRISON, R.J., 1969. Reproduction and reproductive organs. pp. 253-348. In: H.T.ANDERSEN (ed.) The
biology of marine mammals. Academic Press, New York and London. 511 pp.
INTERNATIONAL WHALING COMMISSION, 1979. Report of the special meeting on Southern Hemisphere minke
whales, Seattle, May 1978. Rep. int. Whal. Commn, 29: 349-358.
INTERNATIONAL WHALING COMMISSION, 1984. Report of the workshop on reproduction in whales, dolphinsand porpoises. Rep. int. Whal. Commn (special issue 6): 2-24.
IVASHIN, M.V. and Yu.A.MIKHALEV, 1978. To the problem of the prenatal growth of minke whales,
Balaenoptera acutorostrata of the Southern Hemisphere and of the biology of their reproduction.
Rep. int. Whal. Commn, 28: 201-205.
]ONSGARD, A., 1951. Studies on the little piked whale or minke whale (Balaenoptera acuto-rostrata Lacepede).
Report on Norwegian investigations carried out in the years 1943-1950. Norsk Hvaifangsttid, 40(5):5-54.
KATO, H., 1983. Some considerations on the decline in age at sexual maturity of the Antarctic minke whale.
Rep. int. Whal. Commn, 33: 393-399.
KATO, H., 1985. Further examination of the age at sexual maturity of the Antarctic minke whale as determined from ear plug studies. Rep. int. Whal. Commn, 35: 273-278.
LARSEN, F., 1984. Reproductive parameters of the minke whale, Balaenoptera acutorostrata, at West Greenland. Rep. int. Whal. Commn (special issue 6): 233-236.
LARSEN, F. and F.O. KAPEL, 1983. Further biological studies of the west Greenland minke whale. Rep. int.
Whal. Commn, 33: 329-332.
LAWS, R.M., 1961. Southern fin whales. Discovery Rep., 31: 327-486.
LOCKYER, C., 1976. Body weights of some species of large whales.]. Cons. int. Explor. mer, 36(3): 259-273.
LOCKYER, C., 1981. Estimation of the energy costs of growth, maintenance and reproduction in the femaleminke whale, (Balaenoptera acutorostrata), from the Southern Hemisphere. Rep. int. Whal. Commn, 31:
337-343.
LOCKYER, C., 1984. Review of baleen whale (Mysticeti) reproduction and implications for management.
Rep. int. Whal. Commn (special issue 6): 27-50.
MACKINTOSH, N.A. and J. F. G. WHEELER, 1929. Southern blue and fin whales. Discovery Rep., I: 257-540.
MARSH, H., 1985. Observations on the ovaries of an isolated minke whale: evidence for spontaneous sterile
ovulation and structure of the resultant corpus. Sci. Rep. Whales Res. Inst., 36: 35-39.
MARSH, H. and T.KASUYA, 1984. Changes in the ovaries of the short-finned pilot whale, Globicephalamacrorhynchus, off the Pacific coast of Japan. Rep. int. Whal. Commn (special issue 6): 311-341.
MASAKI, Y., 1979. Yearly change of the biological parameters for the Antarctic minke whale. Rep. int. Whal.
Commn, 29: 375-396.
MATTHEWS, L.H., 1937. The humpback whale, Megaptera nodosa. Discovery Rep., 17: 7-92.
MITCHELL, E. and V. M. Koz1cK1, 1975. Supplementary information on minke whale, (Balaenoptera acutorostrata) from Newfoundland fishery.]. Fish. Res. Bd Can., 32(7): 985-994.

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No. 38, 1987

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LOCKYERMossMAN, H. W. and K. L. DuKE, 1973. Comparative morphology of the mammalian ovary. University of Wisconsin Press. 461 pp.
OttsUMI, S., 1979. Feeding habits of the minke whale in the Antarctic. Rep. int. Whal. Commn, 29: 473-476.
RICE, D. W. and A. A. WoLMAN, 1971. The life history and ecology of the way whale (Eschrichtius robustus).
(Special Publication 3). The American Society of Mammalogists, Washington. 142 pp.
SLIJPER, E.J., 1949. On some phenomena concerning pregnancy and parturition of the Cetacea. Bijd. Dierk.,
28: 416.
SLIJPER, E.J., 1966. Functional morphology of the reproductive system in Cetacea. pp. 277-319. In: K.S.
NORRIS (ed.) Whales, dolphins and porpoises. University of California Press, Berkeley and Los Angeles.
789 pp.
WILLIAMSON, G.R., 1975. Minke whales off Brazil. Sci. Rep. Whales Res. Inst., 27: 37-59.

EXPLANATION OF PLATE
PLATE Ia. Old corpus albicans (on right) and corpus atreticum type a (on left) showing pigmentation.
b. External appearance of a recent corpus atreticum type a, showing the stigma (siteof rupture).
c. Internal appearance of recently ruputured follicle above (Plate lb) showing commencement of luteinisation.
d. Uneven luteinisation of corpus atreticum type a, with a fibrin-filled vesicle (onleft), showing the stigma and adjacent old c. albicans (on right).
e. Corpus atreticum type a (centre) showing yellow pigmentation and the stigma(point of follicular rupture), and adjacent follicles.
f. Corpus atreticum type a with a central vesicle.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

68

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A STRANDING OF MESOPLODON STEJNEGERI IN
THE MAIZURU BAY, SEA OF JAPAN*NOBUYUKI MIYAZAKI**, IZUMI NAKAMURA***, SHINSUKE TANABE****,AND RYO TATSUKAWA****

ABSTRACTOn 13 June 1984 a Stejneger's beaked whale, Mesoplodon stejnegeri, wasfound to have stranded on the beach of Maizuru Bay (35° 31'N,135°24'£),the Sea of Japan. This whale was probably one of two unidentified whales
occasionally sighted in the bay since eight months before the stranding.
The animal was a juvenile male having testes of 34 g and measuring396.5 cm in body length. It had 44 vertebrae, composed of 7 cervical (first
three cervical bones were fused into one unit), 9 dorsal, 11 lumbar and 17
caudal vertebrae. Only vertebral epiphyses of the 3rd-7th cervicals andthe l 6- l 7th caudals were fused with the centrum. The external, cranial
and vertebral measurements, and organ weights were presented. The
PCBs and p,p'-DDE levels in blubber were 7.0 and 44 µ,g/g on wet weightbasis, respectively. The distribution of the five species of Mesoplodon known
from the North Pacific Ocean was discussed.
INTRODUCTION

In the Sea of Japan, there have been reported four Mesoplodon stejnegeri True,
1885 and one Mesoplodon ginkgodens Nishiwaki and Kamiya, 1958. A strandingof Mesoplodon bowdoini (Andrews, 1908) reported by Nishiwaki (1962b) was
reidentified by Moore ( 1963) as M. stejnegeri. This was the first record of thespecies in the Sea of Japan. Later, Nishimura and Nishiwaki (1964) reported
two additional specimens of M. stejnegeri incidentally taken by the salmon drift
gill net fishery in the Sea of Japan. They were a 520 cm male taken in 39°32'N,
137°03'E on 23 April 1963 and a 238 cm female taken in 39°08'N, 135°16'E
on 10 May 1963. The species was identified based on the external characters,
and the skulls were later lost by an earthquake in the Niigata area on 16 June
1964. The fourth specimen was a male (body length: 490 cm) found on thebeach of Niigata Prefecture on 10 May 1984 (Ikehara, Shimizu, Hiyama, Ito,
* This work was partly supported by the Grant-in-Aid for Scientific Research from the Ministry of Education,
Japan (grant no. 61560224).

** Department of Zoology, National Science Museum, 3-23-1 Shinjuku-ku, Tokyo, 160 Japan.
*** Fisheries Research Station, Kyoto University, Nagahama, Maizuru-shi, Kyoto, 625 Japan.
**** Department of Environment Conservation, Ehime University, 3-5-7 Matsuyama, Ehime, 790 Japan.
Sci. Rep. Whales Res. Inst.,
No.38,1987,91-105

92

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

Ogawa and Kamiya, 1985). Only record of M. ginkgodens is a juvenile femaleof 344 cm in body length. It was captured in a set net off Hiyoriyama in the
Sea of Japan on 16 March 1984 (Hiyoriyama Aquarium, 1984) and was identified to the species by Dr T. Tobayama (T. Tobayama, pers. comm.). These
five records (M. stejnegeri and M. ginkgodens) were obtained during March toJune when the oceanographic condition changes from the winter type to thesummer.
Present study is to describe the M. stejnegeri found on the beach of Maizuru
Bay on 13 June 1984, and to describe the ontogenetic change of cranium, thesexual dimorphism and the level of organochlorine pollutant. The distribution of the species is briefly discussed in comparison with other species ofMesoplodon in the North Pacific.
MATERIAL AND METHODSOn 13 June 1984, a male beaked whale of 396.5 cm in body length was foundon the beach of Taira (35°3l'N, 135°24'£), coast of the Maizuru Bay, Sea ofJapan. The first observer told to one of the authors (Nakamura) that the
animal had been already dead at his first sighting. After identifying thespecimen as Mesoplodon on 15 June, Nakamura transported it to the Fisheries
Research Station of Kyoto University for further examination. In the station,
Nakamura recorded the pigmentation, dissected the specimen and weighed
the organs with cooperation of Messrs H. Tanaka and Y. Yamamoto ofEhime
University. The measurements of external proportion and photographs werealso taken. The cranial and vertebral bones were measured by Miyazaki after
cleaning and deposited at the Fisheries Research Station, Kyoto University(FAKU M851). Other bones were lost during preparation. As the major
portion of the teeth of the specimen were embedded in the alveoli, only right
tooth was removed from the alveolus for examination after cutting a part of
the right mandible.
PCBs and p,p'-DDE were extracted using the alkaline alcohol digestion
method of Wakimoto, Tatsukawa and Ogawa (1971). The organochlorines in
the final extracts were quantified by a gas chromatograph with electron
capture detection (Tanabe, Tatsukawa, Tanaka, Maruyama, Miyazaki andFujiyama, 1981). Values of p,p'-DDE reported here also include those ofp,p'-DDT, because p,p'-DDT is converted to p,p'-DDE during alkaline alcohol
digestion.
RESULTS

External morphology
The body shape was typical of beaked whales, characterized by a relatively
large thorax and small head, flippers and tail (Plate I). The body proportionof the specimen is shown in Table 1. The dorsal fin was placed well posterior
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

93

STRANDING RECORD OF MESOPLODON STE]NEGERITABLE 1. EXTERNAL MEASUREMENTS OF MESOPLODON STEJNEGERISTRANDED ON THE BEACH OF MAIZURU BAY KYOTO, 1984
Measurments*cm%

1. Body length
2. Tip of rostrum to apex of melon
3. Tip of rostrum to angle of gape
4. Tip of rostrum to blowhole
5. Tip of rostrum to center of eye
6. Tip of rostrm to ear
7. Tip of rostrum to an~erior insertion of flipper
8. Tip of rostrum to anterior insertion of dorsal fin
9. Tip of rostrum to umbilicus
10. Tip of rostrum to center of genital aperture
11. Tip of rostrum to anus
12. Width of flipper at the base
13. Anterior insertion of flipper to tip
14. Posterior insertion of flipper to tip
15. Basal length of dorsal fin
16. Anterior insertion of dorsal fin to tip
17. Posterior insertion of dorsal fin to tip
18. Height of dorsal fin
19. Width of tail flukes
20. Anterior insertion of fluke to tip (left)
21. Anterior insertion of fluke to notch (left)
22. Center of flukes to tip (left)

396.5
13.0
19.5
33.0
35.0
45.0
78.0
244.0
188.0
249.0
290.0
18.5
41.0
25.5
37.5
33.0
18.5
8.8
94.0
54.5
34.0
48.5

100
3.3
4.9
8.3
8.8
11.3
19.7
61.5
47.4
62.8
73.l
4.7
10.3
6.4
9.5
8.3
4.7
2.2
23.7
13.7
8.6
12.2

* Measurements parallel to the body axis.

to the middle of body (tip of rostrum to anterior insertion of dorsal fin :61.5% of body length) and nearly at the level of genital aperture (tip of rostrum to genital aperture : 62.8%). The length of visceral cavity represented
by the proportion of anterior insertion of flipper to anus (55.4%) was longer
than the head (tip of snout to ear : 11.3%), the tail (anus to the center of posterior margin of tail flukes : 26.9%) or the remaining portion (ear to anterior
insertion of flipper : 8.4%). The height of dorsal fin (2.2%) and the flipper
length (anterior insertion of flipper to the tip: 10.3%) were relatively small.
Other characteristic features of the specimen were long and narrow snout,
forehead smoothly tapering to the rostrum, absence of demarcation between
the melon and the rostrum, a pair of prominent throat grooves (left: 24.5 cm
in length, right: 26.0 cm), and absence of a median notch on the posterior
margin of tail flukes (Plate I).
The color of the animal was black on the dorsal side and lighter on themandible and the ventral side of the body. The flippers and tail flukes were
pigmented black on both sides. In the adult male of Mesoplodon carlhubbsi, therostrum and anterior portion of the mandible back to the posterior edge ofthe tooth are a brilliant white (Orr, 1953; Mead, Walker and Houck, 1982).
This pigmentation was absent on the present specimen of M. stejnegeri.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

94

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWATABLE 2. BODY AND ORGAN WEIGHT OF MESOPLODON STEJNEGERISTRANDED ON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Measurments
Body weightBrain
MuscleBlubber
BoneVisceraOthersInternal organs (included in viscera)
Heart
Lungs
Liver
Diaphragm
Pancreas
Kidney (left)(right)SpleenTestis (left)(right)g%

544,973783
343,780
112,659
50,93435,258
1,559

100
0.14
63.l
20.7
9.35
6.47
0.29

2,530
6,480
5,100
2,730
255
1,200
1,480
76
15
19

0.46
1.19
0.94
0.50
0.05
0.22
0.27
0.01

Body and organ weights
Body weight of the animal was calculated at 544.973 kg as the total of theweights of muscle, blubber, bone, viscera, brain and other miscellaneous
tissues. This value seemed to be underestimation of the true body weightbecause some of the blood and body fluid were not included. This will causesome inaccuracy in the proportional weights of organs and tissues in Table 2.
Brain weight was 0.14% of the body weight, which was smaller than those of
seven delphinid species, ranging from 0.53% in Stenella coeruleoalba to 1.48%
in Delphinus delphis (Bryden, 1972; Miyazaki, Fujise and Fujiyama, 1981).
Muscle (63.1 % of body weight) was the largest and followed by blubber(20.7%), bone (9.3%) and viscera (6.5%). Among internal organs, lungs(1.2%) were the heaviest organ, and followed by liver (0.94%), diaphragm(0.50%), kidneys (0.49%), heart (0.45%), pancreas (0.05%) and spleen(0.01 %). Testis weight was 15 gin the left and 19 gin the right.
Osteology
The cranial and vertebral measurements are shown in Appendix Tables 1
and 2, respectively. It is noted that this specimen had a pair of antorbital
notches, but no prominental notches which are characteristics for M. carlhubbsi(Plate II).
This specimen had the following characters of M. stejnegeri described by
Moore ( 1963): ( 1) Each antorbital notch opened with an obtuse angle of more
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

STRANDING RECORD OF MESOPLODON STEJNEGERI

95

than go 0 • (2) The profile of the premaxillary crest above the superior nares
showed an abrupt turn forward, forming about 90° turn in dorsoanterior faceof each premaxillary. (3) In the anterior view, this go 0 turn showed a deep
crease across the premaxillary on the portion of its greatest width and descended laterally about 20° below the horizontal. (4) Both the dorsal andventral profiles of beak were virtually straight. These points are characteristic
to M. stejnegeri (Moore, 1963). The alveolus of the mandible was entirely
posterior to the symphysis. This separates M. stejnegeri from M. carlhubbsi
having alveolus overlapped with the symphysis. The tooth was a triangularshape and was laterally compressed. The ratio of the greatest thickness to thegreatest antero-posterior width of the right tooth was 0.15 in the present
specimen and was within the range (0.13-0.20) of M. stejnegeri (Moore, lg63).
The mesirostral canal was not filled with bone. The anterior margin of the
tooth was not of a straight line and the apex of the tooth was not found to lie
on that line (Plate III). Apex of the teeth was not worn becaus.e the teeth were
not erupted. The pulp cavity was widely open. These characters were virtuallydifferent from those of adult male of the species described by Moore ( 1963).
The thyrohyals were not fused with the basihyal. Vertebral formula was
C:7+D:g+L:ll+Ca:l7=44. The first to third cervicals were fused on bothneural arches and centra, and formed one unit. Only posterior epiphysis of
the third cervical and all epiphyses of the 4-7th cervicals were fused with
their centrum as well as those of the 16th and l 7th caudal vertebrae. These
indicate that this animal is juvenile and physically immature.

Organochlorine residues
Concentrations of PCBs and p, p'-DDE in some organs and tissues weres]f n in Table 3. Among the tissues, the concentration was highest in the
blubber on wet weight basis. This is because, the blubber contains larger
quantity of fat and these pollutants have high lipophilicity. The p, p'-DDE
concentration was higher than that of PCBs in all parts of the body analyzed.
M. stejnegeri showed higher burdens of both PCBs and p, p'-DDE in blubber
than other tissues as seen in other marine mammals (dolphin and seal) having
higher fat content in the blubber (Tanabe et al., 1981; Hidaka, Tanabe andTatsukawa, lg83).
DISCUSSION

Since October l g83, several staffs of the Fisheries Research Station of Kyoto
University sometimes observed a pair of medium-sized whales during theirown investigations in the Maizuru Bay, but they were not able to identify the
species because the whales were very shy against the vessel and didn't comewithin about 100 m of the R/V Ryouyomaru (g.8 tons) of the station or didn't
jump from the surface. Then in February 1984, a 4-5 m whale was strandedin the Maizuru Bay at the almost same position as that of the present strandSci. Rep. Whales Res. Inst.,
No. 38, 1987

96

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWATABLE 3. CONCENTRATIONS OF PCBS AND p,p'-DDE IN THE TISSUESAND ORGANS OF MESOPLODON STEJNEGERI STRANDEDON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Tissue
and
organ

Fat
content(%)

Wet weight basis(µ,gig)
PCB p,p'-DDE*

Blubber
MuscleLiver
Kidneys

90
1.2
8.9
3.6

7.0
0.048
0.29
0.086

44
0.21
0.82
0.31

Fat weight basis(µ,gig)
PCB p,p'-DDE*
7.8
4.0
3.2
2.4

49
17
9.1
8.7

Burden(mg)
PCB p,p'-DDE*
790
4900
16
72
1.5
4.2
0.14
0.52

• p,p'-DDE includes p,p'-DDT (See text).

ing. This animal was buried under the ground without scientific examination.
Since there were no sightings of whales in the Maizuru Bay after these two
strandings, there is a high possibility that the present specimen is one of thepair of the medium-sized whales sighted since October 1983.
The detailed cranial measurements of the present specimen are shown inAppendix Table 1, and selected measurements of five available M. stejnegeri
specimens in Table 4. The proportion of rostrum length (measurement no. 2)
to skull length (no. 1) is higher in the larger individuals in both sexes. The
same tendency is observed in the following four measurements (measurement
nos 3, 5, 6 and 8) related with rostrum length.
The relative and absolute sizes of tooth (nos 56, 57 and 59) and the lengthof alveolus (no. 53), are obviously larger in adult males than adult females as
described by Moore (1963). The ratio of the skull width (nos 17, 18 and 19) toskull length (no. 1) is larger in males than females. The same tendency isobserved in the ratio of the premaxillary width at midlength of rostrum(no. 32), the span of premaxillary crests (no. 29) and the nasal breadth onvertex (no. 26) to skull length. The absolute values of both superior nares
width (no. 39) and inferior nares width (no. 40) are larger in males thanfemales as well as their proportional values to skull length. The ratios of
occipital condyle measurements (nos 21, 22 and 23) to skull length, are larger
in males than females as well as that of breadth of foramen magnum (no. 24).
Fig. 1 shows the reported positions of the catches or strandings of the fivespecies of Mesoplodon (M. stejnegeri, M. carlhubbsi, M. ginkgodens, M. densirostrisand M. hectori) from the Sea of Japan, the Bering Sea and the North Pacific
Ocean (Ogawa, 1938; Jellison, 1953; Nishiwaki and Kamiya, 1958, 1959;
Nishiwaki, 1962a, 1962b; Moore, 1963; Galbreath, 1963; Yang, 1964;
Nishimura and Nishiwaki, 1964; Fiscus, Rice and Johnson, 1969; Kasuya andNishiwaki, 1971; Nishiwaki, Kasuya, Kureha and Oguro, 1972; Mead, 1981;
Mead, et al., 1982; Loughlin, Fiscus, Johnson and Rugh, 1982; Leatherwood,
Reeves, Perrin and Evans, 1982; Nakajima, 1984). Present record extends therange of M. stejnegeri in the Sea of Japan to the south by about 1.5 degree inSci. Rep. Whales Res. Inst.,
No. 38, 1987

97

STRANDING RECORD OF MESOPLODON STE]NEGERITABLE 4. COMPARISON OF SKULL MEASUREMENTS (mm) OF 6 SPECIMENSOF MESOPLODON STEJNEGERJ*
Measurements
1. Condylobasal length
2. Rostrum length
3. Rostrum tip to post.
margin of pterygoid
4. Rostrum tip to post. ext.
of pterygoid wing
6. Rostrum tip to post. ext.
of max. on palate
8. Rostrum tip to ant.
margin of sup. nares
17. Breadth across frontals
18. Breadth across zygomatic proc.
19. Breadth across orbits
21. Span of occipital
condyles
22. Width of occipital
condyles
23. Length of occipital
condyle26. Breadth acrossexoccipitals
29. Pmx. crest to right nasal
32. Pmx. width at midrostrum
39. Width of sup. nares
40. Width ofinf. nares
53. Alveolus length
56. Mandibular tip toalveolus
57. Length of tooth
59. Thickness of toothPresent
specimenuuv. d1 ) (ad. d1 )Nushagak**Akita***(ad. d1 )Kasilof**(im. 9 )Tofino**(ad. 9 )Cedros ls.**(im. no sex)612 ( 100)
327 (53.4)
446 (72.9)

686 ( 100)

682 ( 100)
403 (59.1)
560 (82.1)

708 ( 100)
405 (57.2)
540 (76.3)

782 ( 100)474 (60.6)
625 (79.9)

631 ( 100)
323 (51.2)

270 (44.1)

335 (48.8)

313 (44.1)

395 (50.5)

277 (43.9)

351 (57.4)

426 (62.1)

429 (62.9)

412 (58.2)

500 (63.9)

368 (58.3)

404 (66.0)

480 (70.0)502 (73.6)

482 (68.1)

572 (73.1)

422 (66.9)346 (50.7) 336 (47.5)
333+(48.8+) 329 (45.6)

355 (45.4).337 (43.1)

277+(43.9+)340 (49.9)
118 (17.3)

323 (45.6)
108 (15.3)

335 (42.8)
111 (14.2)

277 (43.9)
103 (16.3)

39 ( 5.5)42 ( 5.4)

40 ( 6.3)

63 ( 8.9)70 ( 9.0)62 ( 9.8)270 (38.1)

278 (35.5)

247 (39.1)

41 ( 6.0)

42 ( 5.9)29 ( 4.1)

30 ( 3.8)
26 ( 3.3)

36 ( 5.7)
31 ( 4.9)
52 ( 8.2)
85 (13.5)302 (49.8)
289 (47.2)
289 (47.2)
95 (15.5)

115 (16.8)

36 ( 5.9)42 ( 6.1)

63 (10.3)

72 (10.5)80 (11.7)

252 (41.2)
26 (12.7)30 ( 4.9)
49 ( 8.0)
101 (16.5)
20 ( 3.3)
147 (24.0)

55 ( 8.0)
94 (13.7)
119 (17.3)
145 (21.l)

52
116
121
149

( 7.6)(17.0)(17,.7)(21.8)

53 ( 7.5)
87 (12.3)30 ( 4.2)
165 (23.3)

55 ( 7.0)
88 (11.3)
26 ( 3.3)
211 (27.0)

51 ( 8.3)
8 ( 1.3)

153 (22.3)
18 ( 2.6)

164 (24.0)
24 ( 3.5)

56 ( 7.9)9 ( 1.3)

61 ( 7.8)
9 ( 1.3)• Figures in parentheses indicate the percentage to the condylobasal length. For details of measurements
see Appendix Table I.
•• Measurements from Moore (1963) .
*** Measurements from Nishiwaki (1962a).

latitude, but does not require to alter the current knowledge of the distribution that it is distributed in the colder waters of the North Pacific Ocean, theSea of Japan, and deep waters of the southwest Bering Sea (Tomilin, 1967;
Leatherwood and Reeves, 1983; Loughlin and Perez, 1985). Comparison of
the sightings among the five species of Mesoplodon in the North Pacific indicates that M. stejnegeri was found in the coldest waters and M. densirostris in thewarmest waters. M. carlhubbsi was found in the colder waters than M. ginkgodens
and M. hectori.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

98

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

QPresent specimen• M. stejnPgeri
o M. carlhubbsi

so•• M. ginkgodens.&M. hectori
OM. densirostris

50°

40°
30°
20°
10°

Fig. I. Locations of the present specimen and the five species of Mesoplodon that have been reported fromthe North Pacific and adjacent seas.

The organochlorine concentrations in the present specimen (7 .0 µ,gig of
PCBs and 44 µ,gig of p, p'-DDE in wet blubber) are within the range of theconcentrations represented by two males M. densirostris (PCBs: 14 and 29 µ,gig,
DDT: 38 and 65 µ,gig) from northwestern Atlantic (Taruski, Olney and Winn,
1975), a female M. densirostris (PCBs: 4.8 µ,gig, DDT: 11 µ,gig) from Mediterranian Sea (Aguilar, Jover and Nadal, 1982), and one female and three malesof Ziphius cavirostris (PCBs: 7.9 to 12 µ,gig, DDT: 12 to 45 µ,gig) from Bermuda(Knap and Jickells, 1983).
ACKNOWLEDGEMENTS

I wish to thank Mr M. Ueno of Kyoto University, and Messrs H. Tanaka,
K. Yamamoto and S. Watanabe of Ehime University for their invaluable assistance in the examination of this study. Mr K. Kameda of the Fishermen's
Cooperative Union of Kyoto Prefecture helpfully gave us the stranding information of the present Stejneger's beaked whale. Dr T. Tobayama of the
Kamogawa Sea World kindly permitted us to use the stranding record of
M. ginkgodens as his personal information. Drs Toshia Kasuya of Far Seas
Fisheries Research Laboratory, Japan and James Mead of Smithsonian
Institution, U.S.A. reviewed the manuscript and made helpful suggestions.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

STRANDING RECORD OF MESOPLODON STEJNEGERI99

REFERENCES
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beaked whale, Mesoplodon densirostris (de Blainville, 1817) from the Mediterranian Sea. P. Dept. Zool.
Barcelonas, 7: 85-90.
BRYDEN, M.M., 1972. Growth and development of marine mammals. pp. 1-79. In: R.J. Harrison (ed.)
Functional anatomy of marine mammals Vol. 1. Academic Press, London and New York. 451 pp.
Fiscus, C.H., D.W. RICE and A.M. JOHNSON, 1969. New records of Mesoplodon stejnegeri and Ziphiuscavirostris from Alaska.]. Mamm., 50: 127.
GALBREATH, E.C., 1963. Three beaked whales stranded on the Midway Islands, Central Pacific Ocean.
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HIDAKA, H., S. TANABE and R. TATSUKAWA, 1983. DDT compounds and PCB isomers and congeners in
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HIYORIYAMA AQUARIUM, 1984. Annual report of the Japanese zoo and aquarium society (in Japanese). No. 3.
IKEHARA, H., E. SHIMIZU, Y. HIYAMA, T. ITo, T. OGAWA and T. KAMIYA, 1984. On Mesoplodon stranded on thebeach of Niigata (in Japanese). Abstract of Spring Annual Meeting of the Society of JapaneseFisheries. No. 404.
JELLISON, W.L., 1953. A beaked whale, Mesoplodon sp., from the Pribilofs.]. Mamm., 34: 249-251.
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LEATHERWOOD, J.S. and R.R. REEVES, 1983. Whales and dolphins. Sierra Club Books, San Francisco. 302pp.
LEATHERWOOD, J.S., R.R. REEVES, W.F. PERRIN and W.E. EVANS, 1982. Whales, dolphins, and porpoises ofthe eastern North Pacific and adjacent arctic waters. National Marine Fisheries Service Circular444. 245pp.
LOUGHLIN, T.R. and M. PEREZ, 1985. Mesoplodon stejnegeri. Mammalian Species, 250: 1-6.
LouGHLIN, T.R., C.H. Fiscus, A.M. JOHNSON and D.J. RUGH, 1982. Observations of Mesoplodon stejnegeri(Ziphiidae) in the central Aleutian Islands, Alaska.]. Mamm., 63: 697-700.
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MEAD, J.G., 1981. First records of Mesoplodon hectori (Cetacea, Ziphiidae) from the northern Hemisphereand a description of the adult male.]. Mamm., 62(2): 430-432.
MEAD, J.G., W.A. WALKER and W.J. HoucK, 1982. Biological observations on Mesoplodon carlhubbsi (Cetacea:
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MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA

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EXPLANATIONS OF PLATESPLATE I
External features of the present Mesoplodon stejnegeri found on the beach of Maizuru Bay (35°31 'N,
135°24'E) on 13 June 1984. The male, 396.5 cm in body length (Photographs by H. Tanaka).
Fig. 1. Lateral view of head.
Fig. 2. Dorsal fin.
Fig. 3. Left flipper.
Fig. 4. Throat region of head.
Fig. 5. Ventral view.
Fig. 6. Dorsal view of tail flukes (dorsal).
PLATE II
Skull of the present specimen, M. stejnegeri.
Fig. 1. Dorsal view.
Fig. 2. Ventral view.
Fig. 3. Lateral view.
PLATE III
Skull and skeleton of the present specimen, M. stejnegeri.
Fig. 1. Lingual aspect of the right tooth.
Fig. 2. Buccal aspect of the right tooth.
Fig. 3. Mesia! aspect of the right mandible.
Fig. 4. Mesia! aspect of the mandibles.
Fig. 5. Hyoid bones.
Fig. 6. Dorsal view of the cervical vertebrae.
Fig. 7. Lateral view of the cervical vertebrae.
Fig. 8. Lateral view of the dorsal vertebrae. The eight and 9th dorsal vertebrae have been used for pollutant
analysis, and are missing from the figure.
Fig. 9. Lateral view of the lumbar vertebrae.
Fig. 10. Lateral view of the anterior segment of caudal vertebrae.
Fig. 11. Lateral view of the posterior segment of caudal vertebrae.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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104

MIYAZAKI, NAKAMURA, TANABE AND TATSUKAWA
APPENDIX TABLE 1. SKULL MEASUREMENTS OF THE PRESENT SPECIMEN
OF MESOPLODON STEJNEGERIMeasurements
1. Condylobasal length*
2. Rostrum length*
3. Tip of rostrum to posterior margin of pterygoid nearest mid-sagittal plane*
4. Tip of rostrum to most posterior extension of wing of pterygoid (L)
5. Tip of rostrum to most anterior extension of pterygoid (L)
6. Tip of rostrum to most posterior extension of maxillaries between the pterygoids on the palate*
7. Tip of rostrum to most posterior extension of maxillary plate (L)
8. Tip of rostrum to anterior margin of superior nares*
9. Tip of rostrum to most anterior point of premaxillary crest
10. Tip of rostrum to most posterior extension of temporal fossa (L)
11. Tip of rostrum to most posterior extension oflateral tip of premaxillary crest (L)
12. Tip of rostrum to most anterior extension of pterygoid sinus (L)
13. Greatest length of temporal fossa (L)
14. Greatest length of orbit (L)15. Greatest length of right nasal on vertex of skull
16. Length of nasal suture
17. Greatest breadth of skull across postorbital process of frontals
18. Greatest breadth of skull across zygomatic processes of squamosals
19. Greatest breadth of skull across centers of orbits
20. Least breadth of skull across posterior margins of temporal fossae
21. Greatest span of occipital condyles
22. Greatest width of occipital condyle (L)
23. Greatest length of occipital condyle (L)24. Greatest breadth of foramen magnum
25. Greatest height of foramen magnum
26. Greatest breadth of skull across exoccipitals
27. Greatest breadth of nasals on vertex
28. Least distance between premaxillary crests
29. Distance from anterior process of premaxillary crest to posterior to right nasal on vertex
30. Greatest span of premaxillary crests
31. Width of rostrum at midrostral length
32. Width of premaxillae at midlength of rostrum
33. Width of rostrum at 1/4 rostral length from the tip
34. Width of premaxillae at 1/4 rostral length from the tip
35. Width of rostrum at 3/4 rostral length from the tip
36. Width of premaxillae at 3/4 rostral length from the tip
3 7. Greatest depth of rostrum at midrostral length
38. Width of rostrum in apices of antorbital notches
39. Greatest width of superior nares
40. Greatest width of inferior nares, at apices of pterygoid notches, on the pterygoids
41. Height of skull, distance between vertex of skull and most ventral point on pterygoids
42. Greatest width of temporal fossa approximately at right angles to greatest length (L)43. Least distance between maxillary foramina
44. Least distance between premaxillary foramina
45. Greatest length of vomer visible on palate
46. Greatest condylar length of mandibular ramus (L)4 7. Greatest length of mandibular symphysis
48. Greatest height of mandible at coronoid process (L)49. Height of mandible at midlength of alveolus (measured from lingual margin of alveolus) (L)50. Height of mandible at midlength of alveolus (measured from buccal margin of alveolus) (L)51. Length from most posterior extension of mandibular symphysis to most posterior extention of condyle (L)52. Length from posterior margin of alveolus to condyle (L)53. Length of alveolus (L)54. Width of alveolus (L)55. Tip of mandible to anterior margin of alveolus (L)56. Tip of i:nandible to center of alveolus (L)5 7. Greatest length of tooth (R)58. Greate~t antero-posterior width of tooth at approximately right angles to long axis of tooth (R)59. Greates·t thickness of tooth (R)

mm

%

612
327
446
472
270
351
557
404
436
574
469
311
101
89
41
42
302
289
289
199
95
36
63
40
42
252
37
21
26
116
39
30
24
24
48
32
38
156
49
101
214
60
63
36
65
518
94
105
46
45
426
365
20
9
136
147
51
55
8

100
53.4
72.9
77.1
44.1
57.4
91.0
66.0
71.2
93.8
76.6
50.8
16.5
14.5
6.7
6.9
49.8
47.2
47.2
32.5
15.5
5.9
10.3
6.5
6.9
41.2
6.0
3.4
12.7
19.0
6.4
4.9
3.9
3.9
7.8
5.2
6.2
25.5
8.0
16.5
35.0
9.8
10.3
5.9
10.6
84.6
15.4
17.2
7.5
7.4
69.6
59.6
3.3
1.5
22.2
24.0
8.3
9.0
1.3

* These characters were measured parallel to the condylobasal length while the others by distance between points.
L and R indicate left and right, respectively.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

105

STRANDING RECORD OF MESOPLODON STEJNEGERIAPPENDIX TABLE 2. MEASUREMENTS OF VERTEBRAE (mm) OF MESOPLODONSTEJNEGERI STRANDED ON THE BEACH OF MAIZURU BAY, KYOTO, 1984
Serialno.

Segment
no.

I

Cl

2

2

3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

3

4
5
6
7
DI
2
3
4
5
6
7
8*
9*
LI
2
3
4
5
6
7
8
9
10
11
Cal
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

Greatest
B
H

B

Centrum
H

L

14.3
13.9
11.8
10.1
9.1
8.6
12.8
15.2
15.2
15.0
14.8
14.8
14.9
11.6

13.0
13.0
12.1
10.7
10.5
14.5
19.4
22.5
24.5
24.9
25.7
26.7
27.4
27.5

5.9
5.6
5.4
5.4
6.0
5.3
5.4
5.5
5.4
5.7
5.9
6.2

4.1
3.8
4.1
4.3
4.3
4.3
4.3
4.2
4.1
4.3
4.5
4.7

1.1
1.0
1.2
1.5
2.3
3.5
4.4
5.0
5.6
6.3
6.7

27.1
27.5
27.8
28.2
27.7
27.8
27.7
27.8
27.9
27.2
26.4
24.9
22.4
20.1
17.9
15.4
12.5
10.1
8.7
7.7
7.2
6.7
5.8
5.1
4.6
4.0
3.3
2.1

30.7
31.9
32.8
34.3
35.0
35.3
35.1
34.4
35.2
34.2
33.7
33.2
30.8
28.3
24.6
21.6
18.7
16.3
14.2
11.8
9.1
6.5
5.1
4.0
3.5
2.8
2.0
1.4

7.4
7.7
7.9
8.1
8.3
8.4
8.6
9.0
9.2
9.4
9.4
9.7
9.8
9.5
9.4
9.6
9.6
9.9
8.7
7.7
7.2
6.7
5.8
5.1
4.6
4.0
3.3
2.1

5.5
5.9
6.2
6.3
6.7
6.9
7.4
7.6
7.8
8.0
8.2
8.4
8.6
8.6
8.5
8.7
9.1
9.1
9.0
8.8
7.7
6.4
5.0
3.8
3.3
2.7
2.0
1.4

8.4
8.8
9.3
9.4
9.7
10.1
10.5
11.1
11.2
11.7
11.6
11.5
11.0
10.4
9.7
9.2
8.9
8.2
7.4
6.6
5.3
4.0
3.6
3.3
2.9
2.6
2.0
1.3

Neural canal
B
H
5.1

3.7

4.4
4.2
4.3
4.6
5.1
5.2
5.0
4.7
4.4
4.2
4.0
3.7

4.0
4.2
4.5
4.8
5.0
5.1
5.3
5.5
5.6
5.6
5.5

3.4
3.1
3.0
3.0
3.0
3.2
2.9
2.9
2.5
2.3

2.2
1.8
1.6
1.4
1.4
1.4
1.4
1.3
0.9
0.8
0.6

5.4
5.3
5.2
5.1
5.0
5.1
4.6
4.2
3.6
3.2
2.4
2.6
2.3
1.9
1.8
1.6
1.2
1.0
1.0
0.7
0.5

Fusion of
epiphyses
yes
yes
yes
yes
yes
yes
yes
no
no
no
no
no
no
no

no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
yes
yes

44
* These two vertebral bones were used for analysis of organochlorine compounds without making
measurement.
B: breadth, H: height, L: length.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

STRANDING OF A SPECIMEN OF CRAY'S .BEAKED WHALE
AT PUERTO PIRAMIDES (CHUBUT, ARGENTINA)
AND ITS GONADAL APPRAISALGUSTAVO A. DELHON*, ENRIQUE A. CRESPO**,AND GUSTAVO PAGNONI**
ABSTRACTA single specimen of Mesoplodon grayi was stranded at Puerto
Piramides (42°35'S, 64°53'W), on the Patagonian coast (Chubut, Argentina). Some external body measurements were taken in situ and the skull
was preserved. A list of skull measurements is given. Histological study ofthe testes showed the specimen to be sexually mature. Noteworthy was thepresence of adipocytes in the interstitial tissue, which can be easily confusedwith Leydig's cells. Age could not be determined since the lower jaws were
missing and the teeth could not be recovered.
INTRODUCTION

Previous records of Gray's whale have been summarized by Goodall (1978),
Lichter and Hooper (1983) and Lichter (in press), for the Argentine coast,
including two specimens near the site of the present stranding of Peninsula
Valdes (True, 1910; Merm6z, 1979) (Fig. 1).
Other species of Ziphiidae have also been found in this area, such as a
Tasman whale (Tasmacetus shepherdi) reported by Mead and Payne (1975).
The present paper presents external and skull measurements and ahistological study of the testes.
MATERIAL AND METHODS

Features of the stranding
We were informed of the stranding by the Gamekeeper of the Sealion
Reserve at Punta Piramides, Chubut, Argentina. A medium-sized cetacean,which was later determined as a Gray's beaked whale Mesoplodon grayi,• Catedra de Histologia, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Chorroarin 280 (1427),
Buenos Aires, Republica Argentina.
** Centro Necional Patag6nico, C.O.N.I.C.E.T., 28 de Julio 28, 9120 Puerto Madryn, Chubut, Republica
Argentina.
Sci. Rep. Whales Res. Inst.,
No.38,1987,107-115

108

DELHON, CRESPO AND PAGNONI

Fig. 1. Location of the stranding. PV: Peninsula Valdes, GN: Golfo Nuevo, GSJ:
Golfo San Jose, St: Stranding.

stranded on June 28, 1983. It was in good condition, except that the body had
ulcerations made by sea-birds (gulls and petrels), there were wounds and scarsof unknown origin in the skin, the beak was broken, and the lower jaws had
been sectioned, possibly by fishermen.
Identification of the species
The species was identified in the field as Mesoplodon grayi, by means of thecolor pattern, presence of seven maxillary teeth and descriptions given by
Ross (1979) and Lichter and Hooper (1983) "body elongate, compressed laterally to some degree, bulgy melon, long and slender beak, small dorsal fin
inserted at about two-thirds of body length from the anterior, small flippers
and flukes lacking of caudal notch". Subsequently study of the skull confirmed
the species determination. The cranial rostrum is "slender, elongate, narrowat its base, with a straight dorsal margin in profile view, without prominential
notches in dorsal view" (Ross, 1979).
Biological data and samples
Standard external measurements (Norris, 1961) were taken to the nearest
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

109

GRAY'S BEAKED WHALE
TABLE I. EXTERNAL BODY MEASUREMENTS OF THE PRESENT SPECIMEN(MEASURED AFTER NORRIS, 1961)
Measurementscm

1. Total length, from tip of upper jaw to middle of the posterior margin of tail flukes
2. Tip of upper jaw to anterior insertion of flipper
3. Tip of upper jaw to anterior insertion of dorsal fin
4. Tip of upper jaw to midpoint of genital aperture
5. Tip of upper jaw to centre of anus
6. Tip of upper jaw to centre of blow hole
7. Tip of upper jaw to angle of gape
8. Tip of upper jaw to centre of eye
9. Girth on a transverse plane intersecting axilla
10. Girth, maximum
11. Girth on a transverse plane intersecting anus
12. Length of the flipper, anterior insertion to tip
13. Length of the flipper, axilla to tip
14. Maximum width of flipper
15. Length of dorsal fin base
16. Height of dorsal fin
17. Width of flukes tip to tip
18. Distance from nearest point on anterior border of flukes to notch

452.5
120
340
300
343
60
37.5
63.5
186
206
148
55
46
18
31
19
117
35

5 mm with a tape measure and are listed in Table 1. Skull measurements weretaken with a caliper and a metal ruler to the nearest 1 mm, following themethods of Ross (1979) (Table 2). Color pattern was recorded in the field andvertebral count was made directly on the cleaned skeleton.
The gonads were fixed in 10% formalin, embedded in paraffin, cut into
7 µ,m thick sections and stained with Hematoxylin-Eosine, Masson's Trichrome
and Periodic Acid Schiff-Hematoxylin. Frozen pieces were cut in a criostateand stained with Sudan for lipid detection. Sub-capsular, perimediastinic, andintermediate zones of the entire glands were studied in this evaluation.
RESULTS

The specimen was a 452 cm adult male. Other external body measurements
are listed in Table 1.
The dorsal surface of the body was black, gradually becoming grayish
laterally. The ventral surface was black with unpigmented patches (5 to 30 mm
in diameter). The dorsal fin, flippers and flukes were black. As is usual in theZiphiidae, the specimen had two ventral throat grooves.
Four different positions of the skull can be seen in Fig. 2. Seven small
maxillary teeth were observed in the stranded specimen, but these were lost
during the cleaning of the skull.
The vertebral formula was C7, TIO, Ll 1, C18+ = 46+.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

110

DELHON, CRESPO AND PAGNONITABLE 2. SKULL MEASUREMENTS OF THE PRESENT SPECIMEN IN MILLIMETER(MEASURED AFTER ROSS, 1979)
Measurements

mm

1. Condylobasal length
2. Length of rostrum, tip of beak to line connecting apices of antorbital notches
3. Tip of rostrum to most anterior extension of pterigoid
4. Tip of rostrum to most posterior extension of maxillaries between pterygoids
5. Tip of rostrum to most posterior extension of maxillary plate
6. Tip of rostrum to anterior margin of superior nares
7. Tip of rostrum to most anterior point on premaxillary crest
8. Tip of rostrum to most posterior extension of temporal fossa
9. Tip of rostrum to most posterior extension of lateral tip of premaxillary crest
10. Tip of rostrum to most anterior extension of pterygoid sinus
11. Length of temporal fossa
12. Length of orbit
13. Length of right nasal on vertex of skull
14. Length of nasal suture
15. Breadth of skull across postorbital process of frontals
16. Breadth of skull across zygomatic processes of squamosales
17. Breadth of skull across centers of orbits
18. Least breadth of skull across posterior margins of temporal fossae
19. Greatest span of occipital condyles
20. Greatest width of an occipital condyle (right)
21. Greatest length of an occipital condyle (right)
22. Greatest breadth of foramen magnum
23. Breadth of skull across exoccipitals
24. Breadth of nasals on vertex
25. Least distance between premaxillary crests
26. Greatest span of premaxillary crests
27. Least width (strictly transverse) of premaxillae where they narrow opposite
superior rares
28. Greatest width of premaxillae anterior to place of measurement No. 27
29. Width of premaxillae at midlength of rostrum
30. Width of rostrum in apices of antorbital notches
31. Width of rostrum in apices of prominential notches
32. Greatest width of rostrum at midlength of rostrum
33. Greatest depth of rostrum at midlength of forstrum
34. Greatest transverse width of superior nares
35. Greatest width of temporal Fossa approximately at right angles to greatest length(right)36. Least distance between (anterior) maxillary foramina
3 7. Least distance between premaxillary foramina
38. Distance from posterior margin of left maxillary foramen to most anterior extensionof left maxillary prominence
39. Length of tympanic bulla, left
40. Length of tympanic bulla, right
41. Height of mandible at coronoid process

810
535
465
510
720
595
620
760
650
500
90
90
55
35
298
288
285
190
109
45
68
50
235
31
17
127
100
111
31
180
97
45
46
48
65
65
34
35
48
53
115

Histological study of the testes and related organs
Before fixing, testes weight and measurements were taken as follows:

weight (g)measurements (mm)

left
86.5
90X45X50

right112
120X50X50
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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GRAY'S BEAKED WHALE

113

Seminiferous tubules: All zones observed possesed typical functional
mature tubules (Fig. 3a) with an average diameter of 195.31 µ,m (S.D. ± 22.5).
Despite postmortem changes it was possible to distinguish the different stagesof the spermatogenic cycle. Qualitative and quantitative analyses of the seminal epithelium showed spermatogonial mitotic divisions (Fig. 3b), as well ascomplete spermatocytogenesis and spermiogenesis. All of the tubules counted(300 tubules x three zones) showed spermatogenic activity.
The tubuli recti and rete testis structure of the intratesticular seminal
pathways, confirmed the sexual maturity of this individual. Both the tubules
and the rete had terminal states of differentiation at epithelial and stromatallevels but no spermatozoa were observed in the lumen.
The interstitial space of Mesoplodon testes follows the general delphinid
pattern of organization (Harrison, 1969). Interstitial cells are relatively unconspicuous, hard to distinguish in routine preparations and occur isolated in
an abundant regular connective tissue stroma. Large and small blood vessels
are distributed randomly in the stroma, but no apparent relation exists between these vessels and the interstitial cells. The lymphatic vessels could not
be seen because we could not perform the intravascular perfusion of thegland (Harrison, 1969; Fawcet, Neaves and Flores, 1973; Sergeant, 1962).
An interesting feature of the interstitial space is the presence of adipocytes. These appear isolated in the interstitium or form masses of closely compacted cells (Figs 3c and 3d). Adipocytes with few intracytoplasmic lipid droplets can be easily confused with interstitial cells. In mammalian testis literature,
no reports concerning these cells (in physiological or pathological conditions)appeared (Courot, Hochereau and Ortavant, 1970; Setchell, 1978). Suchadipocytes in a normal functional gland are remarkable; further observations
are needed to confirm the Mesoplodon interstitium histology (Roosen-Runge,
1962, 1969).

Fig. 3. Histology of the testes of the present specimen.
a. Subcapsular zone. Seminiferous tubule (ts) and intertubular space (ti). (Masson's
Trichromic Staining, original magnification
100 x).
b. Subcapsular zone. Seminiferous tubule epithelium. s: Sertoli cell nuclei, m:gonial mitosis, p: pachitene primary spermatocytes, d: diplotene primary
spermatocytes, ti: interstitial tissue showing abundant fibrilar material. (PasHematoxylin Staining, 630 original magnification 630 X).
c. Subcapsular zone. lntertubular space (ti) showing and isolated adipose cell (a)resting on the lamina propia of the seminiferous tubule (ts). (Sudan-Hematoxylin
Staining, original magnification 400 X).
d. Mediastinum testes showing adipocytes clusters (a) between the tubuli recti (tr)and rete channels (rt). (Sudan-Hematoxylin Staining, original magnification
100 X).
e. Spermatozoa in the epididymal duct. See the lateral view of the heads (arrows)
with the typical flat anterior segment. (Hematoxylin-Eosin Staining, original
magnification
100 X).

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

114

DELHON, CRESPO AND FAGNONI

Epididymis and ductus deferens: These extragonadal tubular structures
are lined by a single or pseudostratified columnar epithelium. Despite theintense desquamation, it was possible to find a great number of spermatozoa.
The flat anterior segment of the sperm head observed in other cetaceans wasevident in profile views (Fig. 3e).
DISCUSSION

Mesoplodon grayi has a circumpolar distribution in the southern hemispherebetween 30°S and 45°S (Ross, 1979). More southern records of this species arelisted for Tierra del Fuego (54°S), including one nearly complete skeleton,
three crania and one group of thoracic vertebrae (Goodall, 1978). Few strandings along the Argentine coast have been reported in several papers, andreviewed by Lichter and Hooper (1983).
The present paper include measurement data and original considerations
about the sexual maturity.
There is little information on lengths of specimens of this species. Ross
(1979) gave total lengths of four adult males as follows: 1) 4.72 m, 2) 4.27 m,
3) 5.64 m, 4) 4.53 m (x = 4.79 m, s.d. -1 = 0.59). The specimen from Puerto
Piramides measured 4.52 m, falling within this range. The condylobasal
length of Ross's specimen No. 1 was 802 mm, and expressed as percentages ofbody length was 16.99%. The present specimen's CBL was 810 mm, being the17.92% of the body length.
The vertebral formula of the present individual agrees with that of six
specimens discussed by Ross (1979), but individual variation can be seen in
the number of thoracic vertebrae (range from 9 to 11), lumbar vertebrae(range from 10 to 12), caudal vertebrae (range from 16 to 20), and the total
number of vertebrae (range from 46+ to 49).
Unfortunately, age determination could not be performed because thelower jaws had been cut off and the teeth were lacking, but the histologicalappraisement of the specimen testes, epididymis, and ductus deferens,
enable us to determinate that the animal was sexually mature and in an active
state of spermatogenesis.
ACKNOWLEDGEMENTS

The authors are indebted to Mr Mariano Van Gelderen, and J.C. Lopez and
J.M. Musmeci (Direcci6n de Conservaci6n del Patrimonio Turistico), whohelped with the specimen in the field, to Dr Guillermo Harris for valuable
information, to Dr Atila Gozstonyi (Centro Nacional Patag6nico), whocorrected the English manuscript, to Lie. Hugo P. Castello (Mus. Arg. Ciencias
Naturales "Bern. Riv.") and Mrs Nathalie Goodall who read critically themanuscript and Dr Toshio Kasuya (Far Seas Fish. Res. Lab.) who read an
early draft of the histological study.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

GRAY'S BEAKED WHALE

115

REFERENCES
CouROT, M., T. HocHEREAU and R. 0RTAVANT, 1970. Spermatogenesis. pp. 339-432. In: A.D. JOHNSON,
W.R. GOMES and N.L. VANDEMARK(eds) The Testis. Academic Press, N.Y. 649 pp.
FAWCET, D. W., W. B. NEAVES and M. N. FLORES, 1973. Comparative observations on intertubular limphatics
and the organization of the interstitial tissue of the mammalian testis. Biol. of Rep., 9: 500-532.
GOODALL, R. N. P., 1978. Report on the small Cetaceans stranded on the coast of Tierra <lei Fuego. Sci. Rep.
Whales Res. Inst., 30: 197-230.
HARRISON, R.J., 1969. Reproduction and reproductive organs. pp. 253-348. In: T.H. ANDERSEN (ed.) The
biology of Marine Mammals. Academic Press, N. Y. and London. 511 pp.
LICHTER, A. and A. HOOPER, 1983. Guia para el reconocimiento de cetaceos del Mar Argentina. Fundaci6n Vida
Silvestre Argentina, Buenos Aires. 96 pp.
LICHTER, A., 1986. Record of Beaked whale (Ziphiidae) from the Western South Atlantic. Sci. Rep. Whales
Res. Inst., 37: 109-127.
MEAD, JG. and R.S. PAYNE, 1975. A specimen of the Tasman Beaked Whale Tasmacetus shepherdi, from
Argentina.]. Mamm., 56: 213-218.
MERM6z, J.F., 1979, Hallazgo de una ballena picuda de Gray, Mesoplodon grayi, en el Golfo San Jose,(Chubut, Argentina). Rev. Mus. Arg. Cienc. Nat. Bern. Riv., 12 (10): 137-142.
NORRIS, K.S., 1961. Standarized methods for measuring and recording data on smaller cetaceans.
]. Mamm., 42 (4): 471-476.
RoosEN-RUNGE, E.C., 1962. The process of spermatogenesis in Mammals. Biol. Rev., 37: 343-377.
RoosEN-RUNGE, E. C., 1969. Comparative aspects of spermatogenesis. Biol. Repord. Suppl., 1: 24-39.
Ross, G.J. B., 1779. The smaller cetaceans of the south east coast of Southern Africa. PhD. Thesis Univ. ofPort Elizabeth. 415 pp.
SERGEANT, D. E., 1962. The biology of the pilot or pothead whale Globicephala melaena (Traill) in Newfoundland waters. Bull. Fish. Res. Board Can., 132: 84.
SETCHELL, B.P., 1978. Chap. I and VII. Jn: C.A. Finn (ed.) The Mammalian Testis. Cornell Univ. Press.
Ithaca, N.Y. 450 pp.
TRUE, F. W., 1910. An account on the beaked whales of the family Ziphiidae in the collection of the U.S.
Nat. Mus. with remarks on some other specimens in other Museums. Bull. U.S. Nat. Mus., 73: 1-89.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

ON THREE ODONTOCETE SKULLS
FROM HEARD ISLANDERIC R. GUILER*, HARRY R. BURTON**,
AND NICHOLAS]. GALES**ABSTRACTTwo crania and a rostrum were recovered from Heard Island by the1985 Australian National Antarctic Expedition to that island. The specimens
were assigned to three species, two of which, Globicephala melaena andMesoplodon layardi, are confirmed other than by sighting reports as occurringin Antarctic Seas. The third species, Phocaena spinipinnis, of which cranialmeasurements are given, was previously known only from coastal SouthAmerican waters and is shown to have a much wider distribution thanhitherto suspected.
INTRODUCTION

Heard Island (Lat. 53 °S, Long. 73 ° 30' E) is infrequently visited but served asa base for an Australian National Antarctic Expedition which camped on theisland from October to November, 1985. Three cetacean skulls were broughtback from the island by the party and these were the first collection, albeit
small, of whale material from the island.
THE SPECIMENS

Pilot whale, Globicephala melaena (L.)
A complete cranium with some minor damage to the ventral surface wasrecovered from an entire skeleton stranded on the northern face of the Spiton the eastern extremity of the island. The carcase was estimated to havebeen stranded for less than a year. Another skeleton, possibly of the same
species, was stranded 500 metres distant on the same beach but the skull was
missing. Both carcases had been exposed for an apparently similar period andmuch of the external covering remained. The cranium was full of brain tissue
when collected. The baso-condylar length was 62.7 cm.
The cranium was identified from photographs in the collection of one ofus (E. R. G.) which had previously been assigned to this species by Dr P.H. van
Bree.
* Zoology Department, The University of Tasmania, Hobart, Tasmania, Australia 7001.
** Antarctic Division, Department of Science, Kingston, Tasmania, Australia 7150.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 117-124

118

GUILER, BURTON AND GALES

According to Watson (1981) pilot whales have been sighted by whaling
expeditions as far south as the Antarctic Convergence but they were not listed
by Parker ( 1978) or Brownell ( 197 4) as occurring in Antarctic Seas. However,Globicephala has been sighted at sea in these waters, a school of at least 6
individuals being sighted by one of us (E.R.G.) in Lat. 60° OS'S, Long. 90°
lO'E on 23 Jan. 1980 and a large group of 75 individuals was sighted in 60°
44'S, 55° 51 'W by the "Polar Star" (Hanson and Erickson, 1985). These two
authors quote a personal communication from P. Best to the effect that over1750 of these whales were sighted south of 60°S by five I. W. C. cruises. All ofthese reports are to the south of Heard Island.
Mercer (1975) noted that the northern form of Globicephala melaena
penetrated into Arctic waters during the summer period in pursuit of squid
and it would seem likely that a similar seasonal migration into Antarctic waters
takes place.
The record from Heard Island represents the first confirmation by skeletal
evidence that pilot whales occur south of the Antarctic Convergence.
The cranium has been lodged in the Tasmanian Museum, Reg. No. A1409.
Strap-toothed Whale, Mesoplodon layardi (Gray)
The material consisted only of the rostrum of which about 1 cm was missing from the distal end (Fig. 1). The right maxilla was intact but the left was
broken on both the posterior and post-lateral borders. The internal nares
were intact but all of the posterior cranium, including the vertex, was missing.
The ventral surface of the posterior rostrum was extensively damaged with allof the ventral bones either absent or reduced by erosion. No mandibles, teeth,
jugal arch or otic bones were found.
The rostrum was dry and clearly had been ashore for many years.
The asymmetry of the nasals clearly assigned the rostrum to the Fam.
Ziphiidae and the arrangement of the antorbital notch, maxillary tubercle andthe premaxillary and maxillary foramina indicated that the specimen could be
assigned to Mesoplodon layardi. The steps in this identification are intended tobe published elsewhere by the senior author.
The firm sutures indicated that the specimen was derived from an adultwhale.
The bones of the beak were strongly sutured with no space between thedorsal surfaces of the premaxillaries and the maxillaries. The mesorostralgroove was filled by osseus material which was believed to b.e a feature of themale (Besharse, 1971). However, Moore (1960) had earlier noted that thegroove filled more slowly in females than in males and he suggested that thiswas also an age related factor. To some extent this view was supported by thefindings of McCann (1965) who observed that the groove was filled with replacing bone formed by the transformation of the mesethmoid cartilage, commencing at the proximal end. He found that there was some sexual
dimorphism in that the groove in females often is irregular and not completely
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

ODONT OCETESKULLS

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121

ODONTOCETESKULLS

Falkland Is (Bruyns, 1971; Rice, 1977) and Tierra del Fuego (Goodall, 1978).
It is relatively common in New Zealand (Gaskin, 1972). The Australian records
were reviewed by Dixon ( 1980) and a breeding population occurs in or close
to Tasmanian waters (Guiler, 1984). The species has been sighted by whaling
fleets as far south as the Antarctic Convergence (Watson, 1981), but it was notlisted as living in Antarctic Seas by Brownell (1974), nor do there appear to be
any records of this whale from the Antarctic Peninsula or the associated islands.
The present record from Heard Is. is the first report of this species fromsouth of the Antarctic Convergence and also is the first time that the genus
Mesoplodon has been recorded from Antarctic Seas.
The specimen has been deposited in the Tasmanian Museum, Reg. No.
Al410.
Burmeister's porpoise, Phocaena spinipinnis Burmeister
The genus Phocaena until recently was represented in southern waters by
two species, P. spinipinnis (Burmeister) and P. dioptrica Lahille. The latter
species has recently been moved into the new genus Australophocaena
TABLE 1. CERTAIN SKULL MEASUREMENTS OF AUSTRALOPHOCAENA DIOPTRICA,
P. SPINIPINNIS AND THE SKULL FROM HEARD ISLAND
A. dioptrica(Baker, 1977)

Cranio-basal lengthMax. heightPre-orbital width
Zygomatic width
Max. width
Parietal width
Rostral length
width at basemiddleflengthheight at middle
Width premax. at middle
Height premax. at middle
Length of fused premax.
to ant. margin of nares
to vertex of nasalsof temporal fossa
Height of temporal fossa
Length of upper 1. toothrow
upper r. toothrow
Ratio width to length of rostrum
width of skull to length
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

310
155
162
180
180
157
117
84
51
51
15
29
3.5
open
165
221
61
58
81
82
0.727

P. spinipinnis
Norris andMacfarland, 1958

273

168

152
83

open

79
0.517
0.560

Heard Is.
skull
303
163
164
169
169
156
162
82
51
38
24
31
5
open
159
235
42
39
71
79
0.513
0.550

122

GUILER, BURTON AND GALES(Barnes, 1985). A good comparison of these two species is given by Norrisand McFarland (1958) together with details of two northern hemispherespecies, P. sinus Norris and McFarland and P. phocaena (L.).
The specimen was relatively fresh and in our opinion the porpoise had
been stranded within the prior 12 months.
The skull was complete except for the absence of teeth and mandibles
and some minor damage in the palatine and otic regions. The jugal arches
were absent.
The skull is identified as belonging to Phocaena spinipinnis Burmeister.
This identification is based on a comparison of the specimen with photographs
in Norris and McFarland (1958) which showed good agreement in the featuresof the skull and the arrangement of the sutures (Fig. 2).
The measurements of the skull show that this was a large individual(Table 1) and this fact, combined with the complete closure of all the sutures,indicates that the animal was an adult.
Although the skull was larger than that described by Norris and McFarland,
the ratio of rostral width : rostral length (0.513) is similar to that found by
those two authors (0.517) as is the ratio of skull length : skull width (0.55
compared to 0.560). These ratios are different from those found for P. sinus(0.630 and 0.637 respectively) and for P. phocaena (0.470 and 0.537). The
rostral proportions for A. dioptrica are 0.737.
The number of alveoli in the upper jaw of the Heard Is. specimen was
14 on the left side and 13 on the right which is similar to that for P. spinipinnis
whereas A. dioptrica and P. sinus have a total of 45 and 46 alveoli respectively.
DISTRIBUTION OF BURMEISTER'S PORPOISE

Burmeister's Porpoise has hitherto been known only from the southern Atlantic
and Pacific coasts of South America (Praderi, 1971), extending as far as
Uruguay (Pilleri and Gihr, 1972, 1975). The presence of the cold waters on
the western side of the continent enables the species to range as far as Peru
where one was found in a fish market at Chimbote (Clarke, 1962). Watson( 1981) believed it possible that substantial numbers of this so-called rare
porpoise were sold every year in the 100,000 kg or more of dolphin meat
which passes annually through the fish markets.
No records have come to our attention of the presence of this species
around the Antarctic Peninsula.
This record is evidence of a wider distribution of this species than its
previously known limits. The porpoise must be able to undertake oceanic trips
and it must be able to make penetrations into Antarctic waters, at least to theextent of crossing the Antarctic Convergence.
This is not the only South American "coastal" porpoise which has beenfound on Antarctic or Sub-Antarctic islands. The spectacled porpoise,
Australophocaena dioptrica (Lahille), has been discovered in comparatively
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

ODONTOCETESKULLS

123

recent years to occur in the Auckland Islands (Baker, 1977) and at Macquarie
Island (Fordyce, Mattlin and Dixon, 1984). Neither of these localities are
south of the Convergence. This species may have been seen at sea near New
Zealand (Cawthorn, 1977) as well as at the Kerguelen Islands (Frost and Best,1976).
We suggest that a similar distribution could eventually be found for
Phocaena spinipinnis.
The cranium has been lodged in the Tasmanian Museum, Reg. No. Al411.

ACKNOWLEDGEMENTS
Thanks are given to all members of the 1985 A. N. A. R. E. to Heard Island
whose field support made this collection possible. We also wish to thank thestaff of the Photographic Section, Antarctic Division for the photographs ofthe specimens.

REFERENCESBAKER, A. N., 1977. Spectacled porpoise, Phocaena dioptrica, new to the Subantarctic Pacific Ocean. N. Z.J.
Mar. Freshw. Res., 11: 401-6.
BARNES, L. G., 1985. Evolution, taxonomy and antitropical distributions of the porpoises (Phocaenidae,
Mammalia). Mar. Mammal. Sci., 1: 149-65.
BESHARSE, J.C., 1971. Maturity and sexual dimorphism in the skull, mandible and teeth of the beaked
whale Mesoplodon densirostris.]. Mammal., 52: 297-315.
BROWNELL, R. L., 1974. Small Odontocetes of the Antarctic. American Geographical Society Antarctic Map Folio
Series. Folio 18.
BRUYNS, W.F.J.M., 1971. Field Guide to the Whales and Dolphins. Amsterdam. 258pp.
CAWTHORN, M., 1977. Whale Identification. Field Guide for New Zealand Whales. Mimeo. (quoted by
Fordyce et al., 1984).
CLARKE, R., 1962. Whale observations and whale marking off the coast of Chile. Norsk Hvalfangst-Tid., 51:
265-87.
DIXON, J. M., 1980. A recent stranding of the Strap-toothed whale, Mesoplodon layardi (Gray) (Ziphiidae)
from Victoria and a review of Australian records for the species. Viet. Nat., 97(1): 34-41.
FORDYCE, R. E., R.H. MATTLIN and J. M. DIXON, 1984. Second record of spectacled porpoise from
Subantarctic southwest Pacific. Sci. Rep. Whales Res. Inst., 35: 159-64.
FROST, P. G. M. and P. B. BEST, 1976. Design and application of a coded format for recording observationsof cetaceans at sea. S. Afr.]. Antarct. Res., 6: 9-14.
GASKIN, D.E., 1972. Whales, Dolphins and Seals. Heinemann, Auckland. 200pp.
GooDALL, R. N.P., 1978. Report on the small cetaceans stranded on the coasts of Tierra de! Fuego. Sci.
Rep. Whales Res. Inst., 30: 197-230.
GUILER, E. R., 1984. A young Strap-toothed whale in Tasmanian waters. Pap. Proc. R. Soc. Tasm., 118: 65-8.
HANSON, M. B. and A. W. ERICKSON, 1985. Sightings of toothed whales along the Antarctic coast and in theSouth Atlantic Ocean. Antarctic journal of the United States, 20(2): 16-19.
MERCER, M. C., 1975. Modified Leslie-Delury population models of the long-finned pilot whale (Globicephalamelaena) and an annual production of the short-finned squid (lllex cerebrosus) based on their interaction
at Newfoundland.]. Fish. Res. Bd. Can., 32(7): 1145-54.
McCANN, C., 1965. The mesorostral groove in Ziphiidae, with special reference to its closure by ossificationin Mesoplodon - Cetacea. Ree. Dom. Mus., 5: 83-8.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

124

GUILER, BURTON AND GALESMOORE, J.C., 1960. New records of the Gulf Stream Whale, Mesoplodon gervaisi, and some taxonomic
considerations. Amer. Mus. Novitat., 1993: 1-34.
NORRIS, K.S. and W.N. MACFARLAND, 1958. A new Harbor Porpoise of the genus Phocaena from the Gulf
of California.]. Mammal., 39: 22-39.
PARKER, D.A.A., 1978. Observations of whales on ANARE voyages between Australia and Antarctica. Aust.
Wildl. Res., 5: 25-39.
PILLER!, G. and M. GrnR, 1972. Burmeister's Porpoise, Phocaena spinipinnis Burmeister, 1865 off the Punta<lei Diablo, Uruguay. Investigations on Cetacea, 4: 171-81.
PILLER!, G. and M. GrnR, 1975. Second record of Burmeister's Porpoise, Phocaena spinipinnis, off Los
Cerres, Uruguay. Investigations on Cetacea, 5: 151-3.
PRADER!, R., 1971. Contribucion al conocimiento de Genero Phocaena (Cetacea: Phocaenidae). Rev. Mus.
Argent. Cienc. nat. Bernardino Rivadavia Inst. nac. Inv. Sci. nat. (Zool.), 7: 251-66.
RICE, D. W., 1977. A list of the marine mammals of the world. NOAA Tech. Rep. NMFS SSRF, 711: 1-15.
WATSON, L., 1981. Sea Guide to Whales of the World. Hutchinson, London. 302pp.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DISTRIBUTION OF MOTHER-CALF DALL'S PORPOISE PAIRSAS AN INDICATION OF CALVING GROUNDSAND STOCK IDENTITYTOSHIO KASUYA * AND HARUO OGI**
ABSTRACT

Eighty nine mother-calf Dall's porpoise pairs were sighted in Augustand September 1982, 1983 and 1985 in the Bering Sea and the western
North Pacific (outside the principal range of the truei-type population).
These sightings were analyzed with an attempt to determine the range ofthe calving ground and the identity of the stocks. Three discrete concentrations of such pairs were found in the study area, two in the Pacific area
north of 45°N and another in the central Bering Sea. The dalli-type Dall's
porpoises in the surveyed area represent at least two local stocks each
breeding to the north and south of the western Aleutian Islands. In addition to these, there is probably another stock which calves off the east
coasts of the northern Kuril Islands, although its relationship with the Sea
of Japan-Okhotsk Sea stock needs additional examination.
INTRODUCTION

Using sightings data of Dall's porpoise, Phocoenoides dalli (True, 1885), fromthe western North Pacific south of the Aleutian Islands obtained between
August and September 1982 (which corresponds to the mating season after
the parturition peak of the species (Newby, 1982)), Kasuya and Jones (1984)
indicated that mother-calf pairs occurred north of the Subarctic Convergence.
They also noted the dominance of weaned juveniles and presumably of males
in the Subarctic Convergence zone, and their behavior of approaching vessels.
Ogi and Fujise (1984) conducted a cruise during the same season in 1983 andrecorded similar geographical behavior differences (Kasuya and Shiraga,1985).
Miyazaki and Fujise (1985) reported the results of a similar cruise in May
and June 1984, south of the western Aleutian Islands. Although their sightingsof mother-calf Dall's porpoise pairs were limited due to the period before theparturition peak, their data indicated the presence of latitudinal difference ofcatchability of the species which probably reflected the difference in the bow
riding behavior. This suggests that the Dall's porpoise segregates by growthstages, sex and reproductive status even prior to the parturition peak.

* Far Seas Fisheries Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan** Faculty of Fisheries, Hokkaido University, 6-1-1, Minatomachi, Hakodate-shi, Hokkaido, 041 Japan
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 125-140

126

KASUYA AND OGI

The above studies brought to question if such segregation within thespecies, especially that of the calving individuals extends further north into
the Bering Sea. In order to resolve this question, Japan Fisheries Agency
conducted in 1985 a 47 days cruise of the Hoyomaru No. 12 in the Bering Sea
for sighting and collecting biological sample from the species by harpooning(Ogi, Tanaka, Kuramochi and Yamamoto, 1986).
Using data obtained during these three cruises conducted after the
parturition peak for Dall's porpoises, the present study analyzes segregationof their breeding population, and attempts to identify the local stocks of thespecies in the western North Pacific and Bering Sea.
MATERIALS AND METHODS

Materials used are sighting records of Dall's porpoises obtained during three
cruises ( 17 August to 17 September 1982, 10 August to 16 September 1983,
and 6 August to 17 September 1985) of theHoyomaruNo. 12. This vessel waschartered by the Japan Fisheries Agency for the purpose of studying thebiology of the Dall's porpoise incidentally taken in the Japanese salmon gillnet
fishery. During these cruises sightings were conducted in the same way as
those described by Kasuya and Jones (1984). Most of the Dall's porpoiseschools were chased for possible harpooning, although the length andmethod of the chase were not the same between the cruises and the proportion of passed schools (schools neither chased or closed for harpooning or for
further observation) were significantly higher in the 1985 cruise as mentioned
below. In the following section the former survey mode (i.e., research vessel
stops ordinary sightings activity and to approach the porpoise schools forobservation or harpooning) is expressed as closing mode, and the latter (i.e.,the vessel continues sighting on the prefixed track line even after finding aschool) as passing mode.
Biologists on board the 1982 cruise were Y. Fujise, T. Kasuya and C.
Thomson. Outline of the cruise track line and proportion of individuals
constituting mother-calf pairs in the daily sightings of the Dall's porpoise are
given in Fig. 1 and Appendix Table 1. Further details of the cruise andsightings are in Kasuya and Jones (1984).
Y. Fujise, H. Ogi and S. Shiraga were on board of the 1983 cruise, except
for the two days period (14 August and 8 September) when it cruised within
fishery conservation zone (FCZ) of the Union of Soviet Socialist Republics(USSR), the survey was conducted in the Pacific area south of the FCZ of theUnited States of America (USA) and all Dall's porpoise schools encountered
were chased. Sightings were discontinued on 2 days of rough weather, but
continued on days of poor visibility. Results of the sightings and the cruise
track line are given in Fig. 2 and Appendix Table 2.
The 1985 cruise was conducted with four biologists on board, H. Ogi,
H. Tanaka, T. Kuramochi and Y. Yamamoto. Most of the period of the northSci. Rep. Whales Res. Inst.,
No. 38, 1987

DALL'S PORPOISE STOCKS

127

bound cruise and days spent in the northern Bering Sea the vessel cruised the
FCZ of the USA or the USSR, and the chasing or harpooning was not conducted (8-12 August, 16-21 August, 5-6 September, 11-12 September).
Sightings were discontinued in rough weather (27 August), but continued onsome days of poor visibility (7 to 11, and 25 August). The sighting track line
and sightings of Dall's porpoises are shown in Fig. 3 and Appendix Table 3.
RESULTS

Density distribution
Kasuya and Ogi ( 1986) analyzed segregation between the two color typesof Dall's porpoise (dalli-type and truei-type, terminology after Kasuya (1978)),
using data which became available after Kasuya (1978), i.e. Kasuya and Jones(1984), Miyazaki, Jones and Beach (1984), Miyazaki, Fujise, Komuro and
Taketomi (1984), Ogi and Fujise (1984) and Ogi et al. (1986). Recently
Miyashita and Kasuya (1987) made similar analysis using additional dataobtained during several whale sighting cruises, and indicated that although
the ranges of the two color types overlap the truei-type predominates in thesummer season in the Pacific area between 40°N and 45°N latitude and between 145°£ and 155°£ longitude and that the northern boundary does notchange significantly during May to September when the Japanese coastal
Pacific is predominated by dalli-types from the Sea of Japan-Okhotsk Sea
Stock.
Our survey data do not show clear density change in the northern boundary area of truei-types (Appendix Tables 1 to 3). Additionally, distribution of
the Dall's porpoise in the surveyed area did not show clear density gap which
may correspond to the stock boundary deduced in the present study, although
there were detected some apparently high density areas, i.e. around thewestern Aleutian Islands (Appendix Table 3) and in the Pacific area at around
45°N latitude and 160° to 165°£ longitude (Appendix Tables 1 and 2; Kasuya
and Jones, 1984). The density was low in the northern Bering Sea north of
59°N latitude (Appendix Table 3).
Dall's porpoises are reported to be uncommon to the north of the capeN avarin (Anon., 1986) and on the continental shelf in the eastern and northeastern Bering Sea (Anon., 1985). Our survey in 1985 confirmed this (Appendix Table 3).
Mother-calf pairs in the western North PacificIn the 1982 cruise there were 39 sightings of mother-calf pairs in thewaters predominated by the dalli-type and three of unidentified type in thetruei-type area (Kasuya and Jones, 1984). None of the former sightings was
identified as the truei-type. The majority of them (36 pairs) were concentrated
in a small area between 165°£ and 174°£ (eastern end of the research area)
longitude and north of 45°N latitude (Fig. 1). The remaining three pairs were
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

128

KASUYA AND OGI

0~30 - - - - - - , 50°N,,.,-........ __71,;/'"'"-.c_).,o,.,I/?'
7 I ~ t:'-'?.
~~~
I------S!;ls------7---~~~---~~~', -~,'-'9 '11 '
0

0

O

9

{/ 9

70

0

II /_,,-'/\

0'\, '\\ Se~.N
'

-~

0

I

0

.._ '+--------1 4 OoN'o--Aug.18---=-=--!.-"''-------140°E

Aug.30 13

5-.:,---...

150°E

Fig. 1. Distribution of mother-calf pairs of the Dall's porpoise indicated by thepercentage of individuals constituting such pairs in the daily number of individuals
sighted. Hoyomaru No. 12 Cruise, 17 August to 17 September, 1982. Solid line
indicates track line surveyed, dotted line track line not surveyed, and closed circle
noon position. No mother-calf pairs of the truei-type were identified during the cruise.

d•• ~ • DaD

.

•o
0

~~-+~~-A-~f~~--lo-~~~~~~~~-+-~~--jsooN

2r-----·

0 :I

----~

/~

~ (/
'.Y-- 0 t'-./ ,/'cf ~------~-----_j 0 0f Sep.1____~-----

140°E

--~
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170°E

Fig. 2. Distribution of mother-calf pairs of the Dall's porpoise indicated by thepercentage of individuals constituting such pairs in the daily number of individuals
sighted. Hoyomaru No. 12 cruise, 10 August to 16 September, 1983. Solid line
indicates track line surveyed, dotted line track line not surveyed, and closed circle
noon position. No mother-calf pairs of the truei-type were identified during the cruise.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

129

DALL'S PORPOISE STOCKS

,.
f

IO

0

J_j.o. .__o~
39 /~·,,,,~ 32ok.13 E~-------

9...-..--~- ,/, ,- '

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.r'°' . . \~S.ep.S
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170°E

140°E

180°

160°E

170°E

Fig. 3. Distribution of mother-calf pairs of the Dall's porpoise indicated by thepercentage of individuals constituting such pairs in the daily number of individuals
sighted. Hoyomaru No. 12 cruise, 7 August to 17 September, 1985. Solid line
indicates track line surveyed, dotted line track line not surveyed, and closed circle
noon position. No mother-calf pairs of the truei-type were identified during the cruise.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

130

KASUYA AND OGIsighted in the dalli-type area but occurred in the three isolated positions, i.e.
approximately in 47°N, 160°E; 44°N, 168°E; 43°N, 159°E.
The 16 mother-calf pairs recorded during the 1983 cruise in the Pacificarea occurred in the dalli-type area and none were identified as the truei-type.
One of them was sighted on 18 August in 47°N and 160°E, which was about
500 nautical miles (nm) west of the western limit of the rest of the pairs (Fig.
2), but it was close to the position of one of the three isolated records ofmother-calf pair in the 1982 cruise (see above). The remaining 15 pairs weresighted in the Pacific area east of l 72°30'E and north of 45°N. The westernboundary of this range is located about 300 nm east of the possibly corresponding calving area identified in the previous year (east of l 65°E and northof 45°N, see Fig. 1) and these two identified ranges overlapped only in thearea east of l 72°E.
Of the 34 mother-calf pairs identified in the 1985 cruise, 12 pairs weresighted in the Pacific area (6 pairs on 11 August, 5 pairs on 7 September, andone pair on 9 September, see Appendix Table 3). They were found north ofthe major range of the truei-type distribution (Fig. 3), and none of them wereidentified as the truei-type. The positions of the 5 pairs encountered on 7
September (50°N, 165°E) were situated on the western limit of the aggregation of 36 mother and calf pairs encountered during the 1982 cruise (seeabove), but the remaining 7 pairs (11 August and 9 September) situated westof l 60°E longitude and were close to the position of two isolated western records in 1982 and 1983 cruises.
We conclude from the above data that the distribution of mother-calfpairs suggests the presence of two discrete calving areas for dalli-type Dall's
porpoise in the western North Pacific. One is found approximately between
45° and 49°N latitude and west of 160°E longitude. This was deduced fromonly 9 sightings and additional data are still needed to confirm the range andmagnitude of this area. However, we consider the presence of this calving
area to be reliable because it was confirmed during the three survey cruises.
The other is the area east of 165°E longitude and north of 45°N latitude. Thiscalving area extended at least to l 78°W longitude, but the eastern limit is notknown because of the limitation of survey area. The identified western rangeof this calving area was variable. In 1982 it was situated at l 65°E longitude,
possibly as in the case of 1985 season when only western portion of the range
was surveyed. The apparent eastern shift of this area in 1983 was possibly due
to the northward shift of the area into the USA FCZ (see Discussion). We do
not consider that two mother-calf pairs sighted in isolated locations south of
44°N and east of 159°E on 3 and 14 September (Fig. 1 and Appendix Table 1)
represent another breeding area, because it has not been confirmed bysubsequent cruises in the area (Appendix Tables 2 and 3, Figs 2 and 3).
The two calving areas in the western North Pacific described above are
separated by about 5 degree in longitude or about 250 nm in the minimum
linear distance (distance between the sightings on 11 August 1985 (48°16'N,
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DALL'S PORPOISE STOCKS

131

158°32'£) and that on 7 September (49°59'N, 164°10'£)). They were further
separated in 1982 and 1983. This indicates the discontinuity of these twocalving grounds.*

Mother-calf pairs in the Bering Sea
The Bering Sea was surveyed in 1985, and there were sightings of 22
mother-calf pairs. None of these pairs were identified as truei-type. The
southern most sighting of a mother-calf pair in the Bering Sea occurred on
13 August in 54°27'N and 170°04'£, or just on the southern boundary of theBering Sea. The other 21 pairs were sighted in the central portion of theBering Sea. No mother-calf pairs were sighted in the northern Bering Sea(north of the 59°N) in spite of the sightings of 82 Dall's porpoises in this area
(Fig. 3).
The proportion of mother-calf pairs in the Bering Sea declined toward
the Aleutian Islands (Fig. 3), from the highest figure of over 39% in the middle
part of the Bering Sea at 58°N latitude (24 August) to 8% at 55°N latitude (2September). During this time the survey method was the closing mode. During
the five day period in the FCZs of USA and USSR around the Aleutian Islands(12-13 August and 4-6 September), the passing mode was used and only one
mother-calf pair (mentioned above) was identified among 396 Dall's porpoises.
This apparently low proportion of mother-calf pairs in the Aleutian Islands
area can not be fully explained by the difference of detectability between thetwo survey methods.
On the other hand, mother-calf pairs of Dall's porpoise were identified
even on the days of passing mode survey when no porpoise schools wereclosed or chased (nine mother-calf pairs in the total of 322 individuals sighted
on 11 and 13 August, and 3 and 9 September 1985, see Fig .. 3), but nomother-calf pairs were sighted on some of the subsequent days of closing
mode (six days of 14, 15, and 23 August, and 10 and 12 September 1985,
when total of the 134 Dall's porpoises were sighted). Therefore, not denying
the possibility that more mother-calf pairs might have been identified if we
had used the closing mode in the Aleutian Islands area, we believe that theapparently low abundance of mother-calf pairs in the area reflects the geographically biased distribution of calving individuals, and that the calving
ground in the Bering Sea is discrete from those in the Pacific Ocean.
•: After this manuscript was sent to printer, Yoshioka, Ogura and Shikano (1987) completed a transpacific researchcruise on board of the Hoyomaru No. 12 in August through October 1986 for sightings of Dall's porpoises. They
confirmed calving grounds off the east coast of northern Kuril Islands (represented fry four mother-calf pairs in 43° to
46°N latitude and 155° to 165°E longitude) and south of the Aleutian Islands (seven mother-calf pairs in 47° to 49°N
latitude and 180° to 165°W longitude), and found the third calving ground in the Gulf of Alaska east of 153°W (eightmother-calf pairs). Although the ranges of the two western calving grounds were located considerably to the east of theranges indicated fry the present study, they were apart for over 500 nm and the boundaries were distinct. Thus the cruiseof Yoshioka et al., (1987) provided an additional support to our conclusion on the presence of two calving grounds ofthe dalli-type Dall's porpoise in the northwestern North Pacific.
Sci. Rep. Whales Res. Inst.,
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132

KASUY A AND OGIDISCUSSION

Dall's porpoises in the calving ground tended to avoid vessels and weredifficult to harpoon (Kasuya and Jones, 1984). This was supported by latercruises in the western North Pacific with similar purpose (see above). However,the survey of closing mode in the central Bering Sea in 1985 showed that the
number of Dall's porpoises that rode the ship's bow wave ranged from 0 to
69% (mean was 21 %) of the total number of individuals sighted daily. This
was apparently higher than the figures below 30% in 1982 (Appendix Table 1)
and in 1983 (Appendix Table 2) cruises recorded in the same season for thecalving ground in the south of the western Aleutian Islands. This can be
attributable to two reasons. The first is that the segregation of breeding population may not have been so distinct in the Bering Sea as in the western North
Pacific reported by Kasuya and Jones (1984). This was deduced from the factthat the proportion of mother-calf pairs declined from the highest value at
58°N latitude to the lowest near the USA FCZ (55°N) (and then to almost zeroof the passing mode survey in USA FCZ, 49° to 54°N). The second reason canbe a possible higher intensity of chasing schools during the 1985 Bering Sea
cruise. Few members of a school could have approached the vessel and eventually been harpooned after a long intense chase. During the 14 day cruise ofclosing mode in the central Bering Sea, they caught only 12 Dall's porpoises(0.86 individuals/day). This is considerably lower than the total catch madeduring about one month cruises in the Pacific area including both calving
grounds and other areas, i.e. 72 individuals in the 32 days cruise in 1982
(Kasuya and Jones, 1984), 95 in the 38 days cruise in 1983 (Kasuya andShiraga, 1985), and 187 in the 43 days cruise in 1984 (Miyazaki and Fujise,1985). Therefore, it will be accepted, in general, that the central Bering Sea
area is one of the calving grounds for Dall's porpoises and the individuals in
the area tended to avoid vessels.
Using the incidental take rate from 1981 to 1984 salmon gillnet fishingseasons (June and July) as an index of abundance, Ferrero and Jones (1986)
analyzed distribution of Dall's porpoises by sex and maturity in the western
Aleutian Islands area of the USA FCZ which was bounded by 168°E andl 75°E longitude and 49°N and 55°N latitude. This area is between the two
major calving areas in the Bering Sea and western North Pacific identified
above, and partially overlaps with the latter. Their data indicate that (1) thedensity of immature individuals was higher in the northern latitude in all
years/months and in both sexes, (2) adult female density in July was higher inthe southern latitude except for the opposite trend in July 1983 (the density
was low and had less distinct latitudinal change in June of these years), and(3) the density of the adult males was always lower than that of the adultfemales and the latitudinal trend was indistinct. The first two of these features
can be explained by assuming that the segregation by sex and growth stagesof the Dall's porpoise occurs parallelly in the Bering Sea as in the western
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

133

DALL'S PORPOISE STOCKS

60°

1600

Fig. 4. Calving grounds of the dalli-type Dall's porpoise identified in the present
study (shaded areas). Chain indicates ordinary summer range of the species where
dalli-type predominates, and dotted line that of truei-type predominance. Triangles
indicate three mother-calf pairs of truei-type sighted in July 1984 (Toshimaru No. 25
cruise, Kasuya unpublished) and three mother-calf pairs of unidentified typesighted in the truei-type area in September (Hoyomaru No. 12 cruise in 1982, Appendix Table 1). Information is not available on breeding ground of the Dall's porpoisein the Okhotsk Sea. Some dalli-types from the Sea of Japan-Okhotsk Sea stock summer in the southwestern coastal portion of the truei-type range (Miyashita andKasuya, 1987)

North Pacific, and that the northern range of the Pacific stock (inhabited by
the calving population) overlaps partially with the southern range of theBering Sea stock (predominated by immature individuals). Therefore, we
consider that the two independent calving grounds of Dall's porpoises are
utilized by two isolated local stocks of the species. The adult males of thestocks probably live further north and south of the study area of Ferrero andJones (1986).
The 1983 season was characterized by both the unusual distribution of
adult female density (Ferrero and Jones, 1986) and the apparent eastern shiftof the range of the calving area observed outside the USA FCZ south of thewestern Aleutian Islands (present data). These can be explained by assumingthat the western portion of the calving ground of the western North Pacificstock was located further north during the 1983 season than other seasons.
The apparent overlap of the range of the two local stocks will offer only
a limited chance of interbreeding because the breeding populations of the twostocks do not usually meet in an area (Fig. 4). The similar, but less influential,
effect is also expected in the possible earlier occurrence of the mating season
in the western North Pacific stock. Among 29 adult dalli-type Dall's porpoise
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

134

KASUYA AND OGI

females taken during the 1982 and 1983 cruises in the south of the western
Aleutian Islands, five were pregnant (with fetal body lengths 0.32 to 13.1 cm
and the mean of 4.0 cm), eight had embryonic membrane containing noidentifiable embryo, and 16 females had only corpus luteum of ovulation(Kasuya, unpublished). However, among nine adult females in the Bering Sea
collected in the same season and by the same method, seven had corpus
luteum of ovulation and no fetus or embryonic membrane. The remaining
two adult females had no corpus luteum (Yoshioka, 1986). Therefore, it isprobable that the mating peak occurs late in the Bering Sea.
There are no direct data on migration of adult individuals between
calving grounds in successive years, but we consider it uncommon from theregularity of reproduction of the species, i.e. narrow and successive parturition and mating seasons and one year cycle of female reproduction (Newby,1982). Support for this was found for the dalli-type Dall's porpoise in the
Bering Sea and western North Pacific in the concentration of heavy metals
and organochlorines, and in the parasite load. Walker (1987) compared theoccurrence of cestode, Phyllobothrium sp., and nematode, Crassicauda sp., between the Dall's porpoises of the same growth stage taken in the western
North Pacific and the Bering Sea, and found significant difference of theinfectation rates between the two areas. Subramanian, Tanabe, Fujise andTatsukawa (1986) found geographical difference in the PCB and DDE concentrations and their ratios between individuals taken during the summer inthe Bering Sea and north western North Pacific, and concluded that thoseindividuals used different feeding grounds although two individuals from thewestern Aleutian Islands had intermediate values. Tatsukawa, Fujise, Honda
and Mishima (in prep.) discovered higher cadmium concentrations and lower
mercury concentrations in individuals from the Bering Sea and opposite
ratios from individuals south of the western Aleutian Islands, and arrived at aconclusion which was similar to that of Subramanian et al. (in press). They
also suggested the Aleutian Islands as an intermingling area. Their results
agreed with the possible distribution of two stocks in the Aleutian Islands area
deduced in the present study.
Our study indicated that dalli-type Dall's porpoises also calves in an areaof the Pacific west of the major calving ground south of the western AleutianIslands which was discussed above (Fig. 4). The two calving grounds in thewestern North Pacific did not merge each other, although the ranges probably fluctuated annually. This suggests that these calving grounds are used by
two different populations of the dalli-type Dall's porpoise. Further study isneeded on the extent of this calving ground along the east coast of the northern Kuril Islands and southern Kamchatka Peninsula. Additional research isalso needed on how the Dall's porpoises in this calving ground are related to
the Sea of Japan-Okhotsk Sea stock proposed by Kasuya (1978), because
there remains a possibility of a local intrusion of the Sea of Japan-Okhotsk
Sea stock as well as the possibility of existence of a local stock.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DALL'S PORPOISE STOCKS

135

We found substantial agreement between the major ocean current systems
and the calving grounds of the presently accepted stocks of Dall's porpoise.
The majority of the Sea of Japan-Okhotsk Sea stock (dalli-types) seem to stayin the Okhotsk Sea Gyre during the breeding season, although some individualsof unknown reproductive status from the stock might summer off the Pacificcoast of southern Hokkaido (Kasuya, 1978; Miyazaki and Fujise, 1985;
Miyashita and Kasuya, 1987; Subramanian et al., 1986). Distribution of thestock off the Pacific coast of Ja pan is limited to the waters under the influenceof the Oyashio Current, with the Kuroshio and Tsugaru Currents as thesouthern and western boundaries, respectively. We are still unclear if thisstock is composed entirely of the truei-type individuals (i.e. all the dalli-types
found in the area are migrant from other stock), or a small proportion ofdalli-type individuals are contained in it. We found that the breeding groundof the Bering Sea stock (dalli-types) is limited to the Bering Sea Gyre, and its
breeding population does not intrude into the Wester~ Subarctic Gyre southof the Aleutian Islands, which is inhabited during the summer breeding
season by the breeding population of another stock of the dalli-type Dall's
porpoises (western North Pacific stock). The non-breeding member of thiswestern North Pacific stock is known to segregate in the Subarctic Convergence
Zone south of the breeding ground (Kasuya and Jones, 1984).
Not denying the possibility of some additional local stocks or small scaleintermingling across the current system as suggested by the breeding groundin the East Kamchatka Current area, we consider the above correspondence
is important and presume that the eastern boundary of the calving ground of
the western North Pacific stock will not extend into the Alaskan Gyre. The
ranges of the Western Subarctic Gyre and Alaskan Gyre extends at least
approximately to 160°W and 180° longitude, respectively (Favorite,
Dodimead and Nasu, 1976). Therefore the eastern boundary of the western
North Pacific stock (which breeds in the area east of 165° E) seems to belocated somewhere between these longitudes. Recently the breeding groundof this western North Pacific stock has been confirmed to extend to 165°W(Yoshioka et al., 1987) rather than l 78°W (confirmed in the present study).
Available records of mother-calf pairs in truei-type area are scanty. Three(truei-types) were sighted by myself during the cruise of the Toshimaru No. 25
in July 1984 (southern three records in Fig. 4), which scanned the major
range of the truei-types outside the USSR FCZ (Kasuya, 1986). Other threesightings of mother-calf pairs of unknown type occurred during the 1982
cruise of this study off the east coast of Hokkaido at about 43°N (Fig. 4).

ACKNOWLEDGEMENTS
All the biologists on board of the Hoyomaru No. 12 cruises cooperated incollecting sightings data while many of them were conducting their own
biological tasks. Captain F. Ito and his crew supported every research activity
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

136

KASUYA AND OGI

on the vessel. The principal planning and organization of the cruise weredone by Drs S. Odate, K. Takagi, J. Ito and M. Kato of the Salmon Division of
the Far Seas Fisheries Research Laboratory. Dr R.L. Brownell and Mr W.A.
Walker critically read the draft and corrected English.
REFERENCES
ANON., 1985. Survey of fur seal stocks and ocean environment in the Bering Sea in 1984. Far Seas Fish.
Res. Lab., Shimizu (Japan). 7lpp. (in Japanese).
ANON., 1986. Draft environmental impact statement and economic impact analysis on the incidental takeof Dall's porpoise in the Japanese salmon fishery. Nat. Mar. Fish. Ser. (USA). 240pp.
FAVORITE, F., A.J. DODIMEAD and K. NASU, 1976. Oceanography of the Subarctic Pacific region 1960-71.
Bull. Int. North Pac. Fish. Comm., 33: 1-187.
FERRENO, R.C. and L.L. JONES, 1986. Distribution and movement patterns of Dall's porpoise (Phocoenoides
dalli) in the western North Pacific Ocean during June and July 1981-1984. Document submitted to
the Scientific Subcommittee, Ad Hoe Committee on Marine Mammals, International North PacificFisheries Commission, Tokyo. 24pp.
KASUYA, T., 1978. The life history of Dall's porpoise with special reference to the stock off the Pacific coastof Japan. Sci. Rep. Whales Res. Inst., 30: 1-63.
KASUYA, T., 1986. Distribution and behavior of Baird's beaked whales off the Pacific coast of Japan. Sci.
Rep. Whales Res. Inst., 37: 61-83.
KASUYA, T. and L.L. JONES, 1984. Behavior and segregation of the Dall's porpoise in the northwestern North Pacific Ocean. Sci. Rep. Whales Res. Inst., 35: 107-128.
KASUYA, T. and H. Oc1, 1986. Segregation of Dall's porpoise in the Bering Sea and western North Pacificby color type and reproductive status. Document submitted to the meeting of the ScientificCommittee, Ad Hoe Committee on Marine Mammals, International North Pacific FisheriesCommission, Tokyo. llpp.
KASUYA, T. and S. SHIRAGA, 1985. Growth of Dall's porpoise in the western North Pacific and suggested
geographical growth differentiation. Sci. Rep. Whales Res. Inst., 36: 139-152.
MIYASHITA, T. and T. KASUYA, 1987. Distribution of Dall's porpoises off Japan. Document submitted to themeeting of the Scientific Committee of Ad Hoe Committee on Marine Mammals, International
North Pacific Fisheries Commission, Tokyo, March 10-14, 1987. 24pp.
MIYAZAKI, N. and Y. FUJISE, 1985. Report of the survey by the dedicated vessel, Hoyomaru No. 53, in 1984.
Document submitted to the meeting of the Scientific Subcommittee, Ad Hoe Committee on Marine
Mammals, International North Pacific Fisheries Commission, Tokyo. 25pp.
MIYAZAKI, N., Y. Fu11sE, T. KoMURO and H. TAKETOMI, 1984. Outline of the survey of the porpoises in
the northern North Pacific by the Hoyomaru No. 53 dedicated for the study of Dall's porpoise (10May to 20 June 1984). Far Seas Fis. Res. Lab., Shimizu. 47pp.
MIYAZAKI, N., L.L. JONES and R. BEACH, 1984. Some observations on the schools of dalli- and truei-type
Dall's porpoises in the northwestern Pacific. Sci. Rep. Whales Res. Inst., 35: 93-105.
NEWBY, T.C., 1982. Life history of Dall porpoise (Phocoenoides dalli, True 1885) incidentally taken by theJapanese high seas salmon mothership fishery in the northwestern North Pacific and western
Bering Sea, 1978 and 1980. Doctoral thesis submitted to University of Washington. 155pp.
OGI, H. and Y. FUJISE, 1984. Outline of the research on marine mammals by the Hoyomaru No. 12 in 1983
(August 10 to September 11). Document submitted to the meeting of the Scientific Subcommittee,
Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo.
14pp.
OGI, H., H. TANAKA, T. KuRAMOCHI and Y. YAMAMOTO, 1986. Outline of the research on Dall's porpoiseby the Hoyomaru No. 12 in 1985. Document submitted to the meeting of the Scientific Subcommittee,
Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo.
20pp.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

DALL'S PORPOISE STOCKS137

SUBRAMANIAN, A., S. TANABE, Y. FUJISE and Y. TATSUKAWA, 1986. Organochlorine residues in Dall's andTrue's porpoises collected from northwestern Pacific and adjacent waters. Mem. Natl Inst. Polar Res.,
Spee. Issue, 44: 167-173.
WALKER, W.A., 1987. Geographical variation of the parasites Crassicauda (nematoda) and Phyllobothrium(cestoda) in Phocoenoides dalli in the northern North Pacific and Bering Sea. Document submitted tothe meeting of the Scientific Committee of the Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo, March 10-14, 1987. 17pp.
YOSHIOKA, M., 1986. Report on biological studies of Dall's porpoise taken by the dedicated vessel, Hoyomaru
No. 12, cruise in 1985. Document submitted to the Scientific Subcommittee, Ad Hoe Committee on
Marine Mammals, International North Pacific Fisheries Commission, Tokyo. 12pp.
YosHIOKA, M., M. Ogura and C. Shikano, 1987. Results of the transpacific Dall's porpoise research cruiseby the Hoyomaru No. 12 in 1986. Document submitted to the meeting of the Scientific Committee,
Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo.
22pp.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

138

KASUYA AND OGIAPPENDIX TABLE l. SIGHTINGS OF DALL'S PORPOISES DURING THE
CRUISE ABOARD HOYOMARU NO. 12 IN 1982 5l
No of individuals6l

Date
Noon position
mo.

day

8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.

17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
162)
17
18
19
Total

Lv. Kesennuma
39°27'N, 146°30'E
40°36'N, 151°3l'E
43°32'N, 155°54'E
45°17'N, 158°2l'E
45°59'N, 159°15'E
46°49'N, 160°00'E
48°37'N, 162°22'E
49°4l'N, 163°58'E
49°46'N, 166°55'E
49°13'N, 169°22'E
48°38'N, 172°41 'E
46°58'N, I 74°02'E
44°55'N, l 73°47'E
43°08'N, 173°3l'E
40°59'N, 172°0l'E
43°09'N, 169°37'E
44°05'N, 167°44'E
45°10'N, 165°13'E
42°20'N, 167°48'E
40°00'N, 168°49'E
42°48'N, 165°23'E
43°58'N, 163°37'E
44°14'N, 161°4l'E
44°50'N, 16l 0 27'E
43°52'N, 161°30'E
41°29'N, 163°54'E
41°3l'N, 163°50'E
42°50'N, 158°52'E
42°56'N, 155°03'E
43°02'N, 149°5l'E
42°46'N, 144°52'E
42°14'N, 143°53'E
Ar. Kesennuma

T

D

0
0
0
4
I
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
27
23
43
24
10
12
15
22
15
13
7
0
17
31
7
I
0
4
23)

u

Mothercalf
pairs

0
0
0
0
0
0
0
0
0
0
0
33
I
41
8
0
0
28
12
3
4
12
34
20
11
8
I
3
0
0
0
0
0
2
I
7
0
2
0
0
0
0
0
0
0
0
23
0
2
0
59
25
No sighting surveys conducted
0
0
2
2
0
0
0
2
0
7
5
0
0
0
0
5
17
I
12
15
16
2
31
0
13
0
0
0
0
0
42
55
380
275

Rode
ship's 1l
wave
(%)

50
82
32
87
63
5
4
7
0
0
6
71
100
45
22
100
100
100
85
76
50
0
58
22
63
30

Surfacetem(oeratureOC)4)20.8-23.4
20.9-22.6
20.2-23.7
18.5-19.6
17.5-18.7
16.6-17.8
12.5-16.6
11.8-12.5
9.8-10.2
9.1- 9.5
9.2- 9.9
9.5-10.0
9.7-11.1
11.6-12.8
12.1-16.7
16.0-18.0
13.7-17.6
13.1-14.0
13.7-14.1
15.0-18.9
19.4-19.8
15.8-18.4
14.4-15.4
14.6-17.l
14.8-16.8
14.1-16.8
16.7-18.2
18.0-20.6
14.4-18.3
16.0-17.6
13.8-17.6
14.1-18.0
15.0-18.5
19.1-20.l

461) Porpoise came to the ship's wave, either at bow or side.
2) No porpoises were chased or caught by the vessel.
3) Porpoises were sighted on bow, but sighting survey was not conducted due to rough weather.
4) Temperature ranges during sighting surveys, or during the day if surveys were not conducted.
5) Reproduced from Kasuya and Jones (1984).
6) T, truei-type. D, dalli-type. U, Dall's porpoise of unknown type.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

?:
~
,....

~

~

"' .,

~~

.....

""~
_Oo~

~~

2
3
4
5
6
7
8
9
10

I

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

Hakodate Port
42°11 'N,
145°00'E
43°43'N,
149°40'E
43°47'N,
155°14'E
43°49'N,
160°00'E
45°29'N,
160°04'E
47°12'N,
159°52'E
47°55'N,
164°01 'E
50°39'N,
165°00'E
49°28'N,
167°28'E
48°39'N,
168°34'E
48°39'N,
170°10'E
47°12'N,
171°08'E
48°07'N,
174°28'E
47°31 'N,
179°33'E
45°57'N,
178°05'W44°12'N,
178°13'W
44°01 'N,
177°53'E
43°37'N,
174°04'E
43°08'N,
169°38'E
43°17'N,
165°46'E
43°16'N,
163°04'E
44°04'N,
163°07'E
46°00'N,
164°33'E
45°06'N,
161°26'E
46°05'N,
160°21 'E
44°54'N,
156°11 'E
43°17'N,
151°0l'E
42°ll'N,
145°22'E
Hakodate Port

Noon
position
28
124
149
169
121
84
97
119
120
89
0
84
126
112
111
103
80
113
62
30
94
43
70
63
38
0
84
141
130
31

Distance
surveyed
(nm)

0
0
0
0
0
0

I

0
0
0
0
0
0
0
0
0
0
0
2
0

I

0
12
18
3
0
0
0
0
0

T

4
0
0
4
34
13
21
2
3
4
0
49
8351
96
65
20
0
45
0
0
0

I

59
2341
56
35
29

I

0
5

D
0
6
0
16
0
38
54
11
7
0
0
0
3
18
19
17
2
3
0
0
7
60
34
60
5
0
36
0
0
0

u
0
23
19
78
23
94
89
40
8
5
0
0
7
52
32
38
4
6
4
0
56
147
130
126
25
0
81
0
0
0

sum

No. of individua)s21

1) Includes secondary sightings. All the sightings were chased.
2) T, truei-type. D, dalli-type. U, Dall's porpoise of unknown type.
3) Surface water temperature range during sighting survey.
4) Includes one black type.
5) Includes two black types.

8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.

mo. day

---

Date

I

0
0
0
0
0
0
0
0
0
0
0
0
0
0

I

10
0
17
0
3
0
0
8
63
47
35
40
0
31
0
0
0

I

0
0
0
0

0
0
0
0
0
0
8
6

I

0
10
3
12
16
19
3

Porpoisesrode bow
wave

0
0
0
0
0
0

Mother/calf
pairs
19.2-22.8
12.5-19.9
13.3-16.2
11.5-15.0
13.0-18.4
11.7-12.6
10.5-12.0
10.0-10.9
9.9-10.9
9.4-10.3
no survey
9.2-9.7
9.6-9.9
9.8-10.8
10.9-11.5
11.6-13.2
13.3-16.2
13.1-14.9
13.9-15.9
13.9-14.5
12.4-13.0
13.3-13.8
12.6-13.8
11.6-12.7
13.3-16.2
no survey
11.8-13.8
12.1-17.3
15.2-20.0

Surface water31
temperature(Co)

APPENDIX TABLE 2. SIGHTINGS OF DALL'S PORPOISES DURING THE CRUISE ABOARD HOYOMARU NO. 12 IN 1983ll

<.O

""

......

(f)

~

n

0

(f)
....,

t'"j

c;;

0

"C

:io

0

"C

(f)

i:-:

t:l

>
t'"'

\0 ~
Oo
'l~

..... .....

,?a~'""::0

~~

~

::0
~

"'~-

7
8
9
10
11
12
13
14
15
16
17
I8
I9
20
2I
22
23
24
25
26
27
28
29
30
3I
I
2
3
4
5
6
7
8
9
IO
II
I2

42°I2'N,
42°52'N,
43°2l'N,
46°02'N,
48°46'N,51°30'N,
54°ll'N,
57°13'N,
59°02'N,
62°00'N,
61°00'N,
60°00'N,
60°02'N,
59°09'N,
58°59'N,
58°00'N,
58°00'N,
57°59'N,
57°30'N,
57°30'N,
57°0I 'N,56°30'N,56°30'N,
56°0I 'N,55°30'N,55°30'N,
55°00'N,
54°30'N,
53°28'N,
52°22'N,
50°5I 'N,
49°57'N,
47°59'N,
45°3I 'N,
45°13'N,
40°46'N,
40°40'N,

l44°02'E
l44°25'E
l49°22'E154°21 'E
l59°24'E
l64°44'E
l70°20'E
l75°32'E
I77°58'W
l74°00'W
174°46'W
I 77°00'W
I74°30'W
I73°oo·w
I77°27'W
I 78°20'W
I79°58'W
I 77°07'E
I 77°27'E
I 78°50'W
I 76°57'W
l 78°44'W
l 77°14'E
I75°00'E
I78°00'E
I78°34'W
I 75°58'W
I78°00'E
I73°I7'E
I76°lO'E
I70°24'E
I64°54'E
I60°53'E
I57°ll 'E
I53°50'E
I50°45'E
I47°ll 'E

Noon
position
131.4
68.5
160.0
160.l
167.2
166.9
167.0
156.2
149.3
150.I
159.2
I64.5
26.9
I44.5
I54.5
30.6
57.2
I I5.0
I08.2
97.0
69.7
99.2
I 15.I
I27.4
I24.8
I22.9
I66.4
I I l.9
I32.9
I24.2
I35.6
I l l.8
I09.6
45.0
89.5
I I 9.I
1 IO.ODistance
surveyed
(nm)
3
0
4
0
0
0
l
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
I
2
I9

T
5
5
10
10
6
3
52
16
15
7
0
11
I
0
II
I
I4
8
I5
II
0
0
I7
I2
3
I4
8
5
I5
16
5
I4
10
2
24
0
2

D
l

13
0
3
9
0
0
I2
0
I
I8
10
24
I2
4
8
I5
I7
8
I7
I7
44
I9
I6
40
I5
I
I2
0
6

11

8
3
13
53
40
I85

u
9
13
17
23
59
43
238
27
28
7
3
20
I
0
23
I
I5
26
25
35
12
4
25
27
20
22
25
22
59
35
2I
54
25
3
37
2
27

sum

No. ofindividuals2>I) Includes secondary sightings of 27 individuals in six schools.
2) T, truei-type. D, dalli-type. U, Dall's porpoise of unknown type .
3) Surface water temperature range during the sighting survey.

8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
8.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.
9.

mo. day

Date

0
0
0
0
6
0
l
0
0
0
0
0
0
0
0
0
0
5
4
5
l
0
2
0
I
I
I
I
0
0
0
5
0
I
0
0
0

Mother
/calf
pairs
0
0
0
0
0
0
0
24
10
0
0
0
0
0
0
0
I4
2I
23
35
12
2
23
I4
3
22
4
0
0
0
0
4I
15
0
37
0
26

Porpoiseschased

l
2
0
5
I
0
8
0
7
4
5
9
0
0
6
4
2
9
0
I
2
0
0
I3
5
0
II
0
II

l

l
0
5
4
0
3
28

Porpoisesrode bowwave
14.0-21.0
14.0-19.3
10.9-13.0
7.5-10.l
9.8-10.9
8.7-9.l
8.8-9.4
8.7-9.4
8.7-9.5
8.0-9.0
8.2-8.9
8.2-9.0
8.4-8.6
8.0-9.I8.6-9.0
9.0-9.2
8.6-9.I8.6-8.9
8.4-9.0
8.8-9.I
8.7-9.l
8.5-8.8
8.5-8.9
8.3-9.I
8.3-9.I8.6-9.0
8.6-8.8
8.6-9.I9.2-9.7
5.9-8.8
9.5-I0.2
I0.2-10.3
9.6-10.6
1 l.5-I2. I
I5.7-I7.7
I7.I-2l.0
I6.I-I9.9

Surface water3>
temperature(Co)

APPENDIX TABLE 3. SIGHTINGS OF DALL'S PORPOISES DURING THE CRUISE ABOARD HOYOMARU NO. 12 IN I985'>

t:I00......

~

>
r.n
e
-<::
>
z>

0

~

......

GENETIC VARIABILITY AND DIFFERENTIATION
IN THE TOOTHED WHALESETSUKO SHIMURA* AND KEN-ICHI NUMACHI*
ABSTRACT

Genetic variability and differentiation of three families containing 12
species of toothed whales mainly from the sea around Japan have been
examined by starch-gel electrophoresis at 19 genetic loci encoding enzymes.
The amount of genie variations presented by proportion of polymorphic
loci and average heterozygosity of whole species studied were 0.207±0.151
and 0.063±0.051, respectively, and were found to be similar to the averageof other vertebrates. The genetic distances and genetic identities among
the species, genera and families of the toothed whales studied were discussed, and the degree of genetic divergence of given taxonomic levels wereshown to below in comparison with corresponding taxa of other organisms.
The phylogenetic relationships among the species studied were estimatedby the dendrogram of genetic distances.

INTRODUCTION

Electrophoretic data consisting of allele frequencies have been widely
accumulated in a large variety of organisms, to estimate the amount ofgenetic variation in natural populations and the degree of genetic differentiation at various levels of taxonomic groups. In general, vertebrates including
mammals are known to have lower levels of genetic variability than invertebrates. Selander and Kaufman (1973) and Valentine (1976) supposed thatlarge, mobile animals, especially vertebrates had lower levels of variability
than small, relatively immobile animals of most invertebrates from the viewpoint of adaptive strategy.
The cetacean is an unique group of mammals distinctly different from theother mammals in many aspects of their biology by perfectly adapting to an
aquatic form of life, and is possibly a representative of large, active vertebrates. However, electrophoretic survey of protein molecules in the cetaceans
is relatively few. It is probably because of some difficulties in sample collection. Several preliminary studies of electrophoretic examination of proteins
have dealt with hemoglobin (Horvath, Chiodi, Ridgeway and Azar, Jr., 1968;
Baluda, Kulu and Sparkes, 1972; Border, 1975), some blood proteins (Sharp,
1981) and lactate dehydrogenase (Numachi, 1970). Recently, studies of en* Ocean Research Institute, University of Tokyo, Minamidai, Nakano-ku, Tokyo, 164, Japan
Sci. Rep. Whales Res. Inst.,
No.38,1987,141-163

142

SHIMURA AND NUMACHITABLE 1. MATERIALS USED IN THIS STUDYName of species

No. of samples
Liver Muscle

Locality

Ziphiidae
North pacific giant bottlenose whale (Berardius bairdii)

Wadaura, Boso Pen.

912Delphinidae
Short-finned pilot whale (Globicepha/,a macrorhynchus)
Many-toothed blackfish (Peponocephala electra)
False killer whale (Pseudorca crassidens)
Striped dolphin (Stenel/,a coeruleoalba)
Bridled dolphin (Stenel/,a attenuata)
Bottlenose dolphin (Tursiops truncatus)
Pacific whiteside dolphin (Lagenorhynchus obliquidens)
Routh-toothed dolphin (Steno bredanensis)

Taiji, Kii Pen.
Taiji
Iki Island
Kawana, Izu Pen.
KawanaIki Island
Iki Island
Taiji

39
6
31
370
183
35
30
10

39

Phocoenidae
Harbor porpoise (Phocoena phocoena)
Finless porpoise (Neophocaena phocaenoides)
Dall porpoise (Phocoenoides dalli dalli-type)(P.

dalli truei-type)The east coast of Hokkaido
3
The coast of Kii Pen.
3
North Pacific &483
the east coast of Hokkaido
Off Sanriku region
54

31
204
90
35
27
29

3
5
61
400

zyme polymorphisms and genetic structure of population in the species ofcetacean were made by several authors (Wada and Numachi, 1979; Simonsen,
Kapel and Larsen, 1982; Wada, 1982, 1983a, 1983b, 1984, 1986; Numachi
and Shimura, 1984; Winans and Jones, 1986). Nevertheless, genetic variability and the degree of genetic differentiation in the cetaceans are still unclear.
In the present study, we examine enzyme polymorphism in 12 species of
toothed whales mainly found off the coast of Japan. On the basis of the dataobtained for 19 genetic loci encoding 12 enzymes, estimates of the proportionof polymorphic loci, average heterozygosity, genetic identity and distanceamong the various taxa of different taxonomic levels are presented. These
values obtained here are discussed in comparison with those in other organisms. The dendrogram of genetic distance are presented, and the genetic
relationships and the time of divergence of the species are discussed.
MATERIALS AND METHODS

Liver and/or skeletal muscle were obtained from the specimens caught either
by harpoon, gill net or drive during the course of commercial fishing or
research expedition off the coast of Japan and the North Pacific, between
winter 1978 and autumn 1981. Twelve species, sampling locations andnumber of samples are shown in Table 1. The locations are also shown in
Fig. 1.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

143

GENETIC VARIABILITY
150°E

160°E

l 70°E180°

l ?0°w

140°E

145°E

.. b

•.

·-..; :•.. ____.. :'.,11~

•

50°N

45°N

40°N

40°N

SEA OF JAPANPACIFIC OCEAN

35°N

30°N

Fig. I. Map showing the positions of collection. Shaded area represents the range of catch of Phocoenoides
dalli (dalli-type) in the North Pacific.

Tissue samples were frozen in a container with dry ice, or in a freezing
room on board immediately after the catch and thereafter stored below-20°C until use. For the electrophoretic run, after thawing tissues, cell lysates
were collected by soaking with a small piece of filter paper, and then the filter
paper was inserted in 12.5% starch gel (Electrostarch; Electrostarch Inc.,
Madison, Wisconsin, U.S.A.).
Electrophoresis was conducted horizontally at a high voltage of a 20 V/cm
and stopped when the marker of Amide black 1OB migrated 7 cm from theorigin. During the electrophoresis, gels were set at 5°C and a glass-plate panfilled with ice water was placed on it for cooling the gel. Following two buffer
systems were used by modifying the method of Clayton and Tretiak ( 1972):(1) C-AEA, pH 7.0 consisting of gel buffer, 2 mM citric acid adjusted to pH 7.0
with N-(3-aminopropyl)-diethanolamine (AEA), and electrode buffer of
40 mM citric acid adjusted to pH 7.0 with the same amine, and (2) C-T,
pH 8.0 consisting gel buffer 3 mM citric acid-I 0 mM Tris, and electrode bufferof 16 mM citric acid-62 mM Tris. MgC1 2 (10 mM) was added to all the gels.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

144

SHIMURA AND NUMACHITABLE 2. LIST OF ENZYME AND LOCI EXAMINED AND TISSUE
AND BUFFER USED FOR ELECTROPHORESIS
EnzymeSorbitol dehydrogenase (SDH)
Lactate dehydrogenase (LDH)
Malate dehydrogenase (MDH)
Malic enzyme (ME)
Isocitrate dehydrogenase (IDH)
6-Phosphogluconate dehydrogenase (6-PGD)
Superoxide dismutase (SOD)
Esterase
Glutamate oxaloacetate transaminase (GOT)
Phosphoglucomutase (PGM)

Mannose phosphate isomerase (MPI)
Phosphohexose isomerase (PHI)

Loci encoding

Tissue used

Buffer

Sdh
Ldh-I
Ldh-2
Mdh-I
Mdh-2
Me
Idh-I
Idh-2
6-Pgd
Sod
Est-I
Est-2
Got-I
Got-2
Pgm-I
Pgm-2
Pgm-3
Mpi
Phi

liver
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver, muscle
liver
liver
liver, muscle
liver, muscle
liver, muscle
liver
liver
liver, muscle
liver

C-T
C-AEA
C-AEA
C-AEA
C-AEA
C-AEA
C-AEA
C-AEA
C-AEA
C-T
C-AEA
C-AEA
C-T
C-T
C-AEA
C-AEA
C-AEA
C-AEA
C-AEA

The buffer systems and tissues used for detecting each enzyme are shown in
Table 2. For IDH, ME and 6-PGD, 30 mM NADP was added to the gel andcathodal electrode buffer, and for SDH 30 mM NAD to the both of them.
Details of reaction mixture for staining enzymes are; (1) SDH: 500 mg
sorbitol, 50 mg sodium pyruvate, 20 mg NAD, 20 mg nitro blue tetrazolium(NBT), 5 mg phenazine methosulphate (PMS) or 1-methoxy-PMS, in 100 ml
0.1 M Tris-HCl buffer, pH 8.0, (2) LDH: 0.625 ml sodium lactate (50%),
20 mg NAD, 20 mg NBT, 5 mg PMS or 1-methoxy-PMS, in 100 ml 0.1 M
Tris-HCl buffer, pH 8.7, (3) MDH: 250 mg sodium malate in the same buffer
and reagent mixture as (2), (4) ME: 250 mg sodium malate, 1 ml IM MgC1 2,
20 mg NADP, 20 mg NBT, 5 mg PMS or 1-methoxy-PMS, in 100 ml 0.1 M
Tris-HCl buffer, pH 8.0, (5) IDH: 37 mg isocitric acid as substrate in thesame mixture as (4), (6) 6-PGD: 100 mg 6-phosphogluconic acid in the same
mixture, (7) SOD: 400 mg EDTA·2Na, 2 g ~-o-glucose, 40 mg NBT, 50 mg
PMS, in 100 ml 0.1 M Tris-HCl buffer, pH 9.5, (8) Esterase: detected bynegative staining method of Harris and Hopkinson (1976), (9) GOT: 15 ml of
L-aspartic acid solution (2.7 g I 100 ml D.W.) and 15 ml of 2-oxoglutaric acidsolution (1.5 g I 100 ml D.W.), both adjusted pH 7.5 with 2 M KOH, 500 mg
Fast blue BB, in 70 ml 0.2 M phosphate buffer, pH 7.5, (10) PGM: 150 mg
D-glucose-1-phosphate containing D-glucose-1,6-diphosphate, 80 unit
glucose-6-phosphate dehydrogenase (G-6-PDH), 1 ml 1 M MgC 12 , 20 mg
NADP, 20 mg NBT, 5 mg PMS, in 100 ml 0.1 M Tris-HCl buffer, pH 8.0,
Sci. Rep. Whales Res. Inst.,
No. 38, I987

GENETIC VARIABILITY

145(11) MPI: 25 mg o-mannose-6-phosphate, 50 unit glucose phosphate
isomerase, 80 unit G-6-PDH, 1 ml 1 M MgC1 2, 20 mg NADP, 20 mg NBT,
10 mg PMS, in 100 ml 0.1 M Tris-HCl buffer, pH 8.0, (12) PHI: 150 mg
fructose-6-phosphate, 80 unit G-6-PDH, 20 mg NADP, 20 mg NBT, 5 mg
PMS, in 100 ml 0.1 M Tris-HCl buffer, pH 8.0.
All the gels after electrophoresis and the staining were dried (N umachi,
1981) and then preserved for the future analysis of isozyme pattern.
RESULTS

Genetic variability in the toothed whales
A total of 19 genetic loci encoding 12 enzymes was surveyed in 12 speciesof toothed whales. Electrophoretic patterns of enzymes, the number of
isozymes and tissue distr.ibution showed that all the 12 species essentially havethe same isozyme systems, each under the control of corresponding locus
which is homologous phylogenetically throughout all the species studied.
Electrophoretic patterns and schematic drawings of each enzyme assayed areshown in Plates I-VI. Alleles at the 19 loci are listed in Table 3. The frequencies of phenotypes on electrophoretic patterns were in good agreement with
the Hardy-Weinberg proportion, except for two cases of Idh-1 locus in
Pseudorca crassidens (x2 =6.758, 0.01>p>0.005, d.f.= 1) and of the Sdh locus
in truei-type of Phocoenoides dalli (x2 =7.746, 0.01 > p >0.005, d.f.= 1). In bothcases, the deviation was observed in heterozygotes excess.
The incidence of polymorphic loci (P) and average heterozygosity (H) issummarized in Table 4. P and H values of 12 species of the toothed whales
showed a wide range of 0-0.474, and 0-0.154, respectively. In the two types of
P. dalli, the highest values of P and H were obtained. By average of all the
12 species, proportion of polymorphic loci (P) in the definition of 5% levelwas 20.7%, and 16.4% excluding P. dalli. The average heterozygosity (H) was
0.063 in average of the 12 species, and 0.047 excluding P. dalli. Recently,
Wada (1983b, 1986) showed that the proportion of polymorphic loci and/or
the average heterozygosity were P=0.13 and H=0.021 in the striped dolphin,and H=0.008 in the short-finned pilot whale. Winans and Jones (1986) also
showed that the average heterozygosity of P. dalli is 0.058. These values weresomething different from those obtained here, probably caused by the difference in the sample size and choice of loci examined. However, all the values
obtained by other authors should be considered to be in the range of the values shown in Table 4.
Genetic differentiation between taxa
Genetic identity and genetic distance by N ei ( 1972) were calculated fromthe data in Table 3. Genetic distance (D) and genetic identity (/) between the
populations, X and Y, are given by
Sci. Rep. Whales Res. Inst.,

No. 38, 1987

146

SHIMURA AND NUMACHITABLE 3. ALLELE FREQUENCIES AT THE 19 HOMOLOGOUS LOCI IN THE•
ALPHABETICALLY FROM THE ANODAL SIDE BY THE MOBILIT
THE ALLELES. FREQUENCIES AT THE LOCI EXHIBITIN

Ldh-1 Ldh-2 Mdh-1 Mdh-2 ldh-I ldh-2
l. Berardius bairdii

2. Globicephalamacrorhynchus

3. Peponocephala electra

4. Pseudorca crassidens

5. Stenella coeruleoalba

6. Stenella attenuata

7. Tursiops truncatus

8. Lagenorhynchus
obliquidens

9. Steno bredanensis

10. Phocoena phocoena

11. Phocoenoides dalli(dalli-type)

12. Phocoenoides dalli(truei-type)

13. Neophocaena
phocaenoides

c

a

a

Me

Sdh

6-Pgd Got-I Got-2

b

b

b

c

b

c

c

a(.05l)ad(.949)a(.990) bb(.010)

c

b

b

b

b(.013) b
f (.013)g(.974)

b

d

a

a

b

c

b(.750) bd(.250)

b

g

b

b

d

a

a

c

b(.100) bc (.900)

b

b

g

b

b

d

a

a

b(.948) cd(.052)bbbc(.013) a(.020) bg(.972) b(.980)k(.015)daaa(.022) cb(.978)bbbf(.010) bg(.990)

b

d

a

a

b

c

b

b

b

g

b

b

d

a

a

b

a(.036) bc(.946)e (.018)

b

b

g

b

a(.075)b(.925)

d

a

a

b

b

b

c

b

e(.020) bh(.980)a(.050)b(.950)

e

a

a

b

d

a

a

c

c

e

a

a (.987) b(.983) b(.305) a (.906) a (.074) a (.475) a (.967) b(.013) b(.025)b(.013) e (.017) d(.695) c (.094) c (.916) c (.525) b(.010) c (.987) c (.975)d(.010)i (.023)cb(.011) ae (.989)a(.987) b(.979) b(.280) a(.904) a(.083) a(.441) a(.965) b(.075) cb(.013) e (.021) d(.720) c (.096) c (.903) c (.559) d(.016) c (.925)d(.014)i (.019)

e

a

b

b

d

a

c

c

c

c

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

147

GENETIC VARIABILITYPECIES OF TOOTHED WHALES. ALLELES AT EACH LOCUS WERE DESIGNATEDF HOMOPOLYMER CONSTITUTION OF THE PRODUCTS OFOLYMORPHISMSARE ALSO SHOWN IN PARENTHESES
Sod

Mpi

Phi

Pgm-1

Pgm-2

Pgm-3

e

f(.830)g(.170)

d

a

c

c

b

a(.850) ab(.150)bbe(.750)f(.250)fa(.050) b(.075)b(.950) c (.925)

a

c

b

e

f

b

f(.950)g(.050)a(.100) bb(.900)a(.048) ab(.952)bb(.975) a(.025) c(.025)e(.025) b(.975) e(.800)f(.175)d(.030) f(.050) d(.970) a(.023) d(.105) f (.711) f(.974)e(.030) g(.890) f(.030) b(.977) e (.131) h(.053) i (.026)b(.920) d(.025)
c(.080) e(.025)g(.950)d(.975) b
f(.025)

Est-2

Est-1

not assayeda(.170)b(.830)a(.050) a(.132) c(.210)b(.925) b(.632) d(.026)e(.025)b(.025) f (.400) c (.025)e(.550) g(.025) f(.975)b(.425) b(.075)
c (.550) c (.875)
f(.025) d(.050)d(.275)g(.725)dbe(.825)f(.175)fbb(.480) b(.525)
c (.520) g(.475)bbe(.325)f(.675)ha(.050) ab(.950)

d

a

b

b

e

f

b

a

f (.830)h(.170)bb(.830) cd(.170)cb(.170) not assayedd(.830)af(.725)i (.275)a(.025) a(.025) a(.025) d(.100) a(.075) d(.100) a(.050) e(.029)b(.975) b(.975) c(.800) f (.075) b(.700) e (.075) b(.950) f(.971)
c (.025) f(.025)ac (.025) f(.775) a(.025) b(.977) b(.175)d(.025) i (.175) b(.975) c(.023) c(.725)
f(.100)

a

f

b

b

Sci. Rep. Whales Res. Jnst.,
No. 38, 1987bca (.974)b(.026)cb(.850) d(.025) bc (.100) e(.025)e(.050)f(.950)b

not assayed

b

148

SHIMURA AND NUMACHI

D=-loge I,
l=jxv/~

j xv, j x and j v are defined as
jx = 'L'L(xij) 2 /r)l

jv = LL(yij)2/r)l

J xv = 'L"i:.xij-yijlr
j i(r: number of examined loci)where Xij and yij are the frequencies of the ith allele at the jth locus in X andY populations. When X and Y populations share the same allele frequencies
at all loci, genetic distance and identity are given by D = 0 and I = 1. Conversely when they do not share the common allele over all loci, the values
become D = oo and I= 0. Estimates of D and I values among 12 species of the
toothed whales based on allele frequencies at 18 loci are shown in Table 5.
Allele frequencies of Est-2 were excluded in calculation because of insufficiency of data. The frequency distribution of genetic identity was obtained in
TABLE 4. SUMMARY OF GENETIC VARIABILITY IN THE TOOTHED WHALESSpeciesNo. of Proportion ofpolymorphic loci
loci
(P*)

1. Berardius bairdii
2. Globicephala macrorhynchus
3. Peponocephala electra
4. Pseudorca crassidens
5. Stenella coeruleoalba
6. s.
attenuata
7. Tursiops truncatus
8. Lagenorhynchus obliquidens
9. Steno bredanensis
10. Phocoena phocoena
11. Phocoenoides dalli (dalli-type)dalli (truei-type)
12. P.
13. Neophocaena phocaenoides
Average( 1) ** *A verage(2) * **

18
19
19
19
19
19
19
19
19
18
19
19
18

Averageheterozygosity(H** ± S.E.)

0.056
0.263
0.105
0.211
0.263
0.263
0.105
0.316
0.053
0.167
0.421
0.474
0.000

0.016 ± 0.069
0.054 ± 0: 106
0.035 ± 0.108
0.051 ± 0.092
0.089 ± 0.160
0.089 ± 0.170
0.039 ± 0.113
0.093 ± 0.182
0.007 ± 0.024
0.047 ± 0.111
0.154 ± 0.184
0.147 ± 0.170
0.000

0.207 ± 0.151
0.164 ± 0.112

0.063 ± 0.051
0.047 ± 0.035

P values were calculated in the level which included the loci where frequencies of variant

alleles were found at more than 5%.
** His calculated by averaging the val'-h,e of heterozygosity of each locus (h) over all loci. The
heterozygosity (h) is defined as I - 1:::1_L.xl2 , where X·l is the frequency of the i th allele and n
is the number of alleles at the locus.
*** Average(!) means all the 12 species, and (2) excluding values of 2 types of P. dalli.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

149

GENETIC VARIABILITY
TABLE 5. COEFFICIENTS OF GENETIC IDENTITY (ABOVE THE DIAGONAL)AND GENETIC DISTANCE (BELOW THE DIAGONAL)
BETWEEN SPECIES OF THE TOOTHED WHALESSpeciesI . Berardius bairdii
2. G_lobicephala macrorhynchus
3. Peponocephala electra
4. Pseudorca crassidens
5. Stenella coeruleoalba
6. s.
attenuata
7. Tursiops truncatus
8. Lagenorhychus obliquidens
9. Steno bredanensis
10. Phocoena phocoena
I I. Phocoenoides dalli (dalli-type)
12. P.
dalli (truei-type)
13. N eophocaena phocaenoides

2

3

4

5

6

7

8

9

.34I .325 .29I .409 .383 .407 .356 .450
1.075.893 .902 .829 .827 .853 .85I .777
1.123 .I I3.879 .85I .854 .892 .79I .7I6
1.235 .I03 .129
.8I2 .808 .837 .807 .725
.895 .I88 .I62 .208
.974 .974 .850 .627
.959 .190 .I57 .2I3 .026
.974 .832 .633
.900 .I59 .I I5 .178 .026 .026
.837 .670.655
1.034 .162 .235 .2I4 .I62 .I84 .178
.799 .252 .335 .321 .466 .458 .401 .423
.797 1.078 1.469 1.450 1.457 1.462 1.46 I 1.207 1.253.649 .869 1.192 1.182 I.I78 1.275 1.180 .975 .832
.656 .865 1.185 1.176 I.I 7 I 1.270 1.172 .964 .835
.825 1.109 1.494 1.496 1.496 1.624 1.485 1.239 1.095

10

II

I2

I3

.45I
.340
.230
.235
.233
.232
.232
.299
.286

.522
.4I9
.304
.307
.308
.279
.307
.377
.435
.778

.5I9
.42I
.306
.308
.3IO
.28I
.3IO
.382
.434
.777
.996

.438
.330
.225
.224
.224
.197
.227
.290
.335
.787
.856
.86I

.252
.252
.239

.004
.I56

.I50

all possible pairwise comparisons at every locus between species, genera andfamilies (Fig. 2).
P. dalli consisted of two types, dalli-type and truei-type. These two wererecently considered as the geographic variation of the color patterns of thesingle species (Houck, 1976; Kasuya, 1978, 1982). These two types werehighly polymorphic, but alleles at these loci were common between them. In
terms of genetic identity, almost 100% of the loci were very same (I> 0.95).
Genetic identity and genetic distance between the two types were 0. 996 and0.004, respectively.
Stenella coeruleoalba and S. attenuata were compared for genetic divergency
at specific level. Between the two species, eight of the 19 genetic loci weremonomorphic for the same genes, and common or some species specificgenes were shared at the other 11 polymorphic loci. Thus, about 90% of theloci were nearly identical (J > 0.95), as shown in Fig. 2a. Genetic identity andgenetic distance between the two species were 0.974 and 0.026, respectively.
The 12 species of toothed whales examined here represent 11 genera.
More than 70% of loci were nearly identical (J > 0.95) between these genera(Fig. 2b), but 15% of them were quite different (J < 0.05). Mean genetic
identity and distance between the genera were 0.812 and 0.213, respectively.
The 12 species of toothed whales belong to three families; Ziphiidae(Berardius), Delphinidae (Globicephala, Peponocephala, Pseudorca, Stenella,Tursiops, Lagenorhynchus and Steno), and Phocoenidae (Phocoena, Phocoenoides
and Neophocaena). Levels of genetic identity between the families covered abroad range, and the distribution of the values had a strong U-shaped pattern(Fig. 2c). The identical loci (J > 0.95) in genie compositions were only 30%,
and 65% of loci were replaced by different genes. The frequency distributionof genetic distance (D) ranged widely from 0.6 to 1.65 (Fig. 3). The genetic
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

150

SHIMURA AND NUMACHI
90
80

80

70

70
- 60
0
0

SPECIESIN STENELLA

I = 0.974

60

50

50

~ 40

....I

70
FAMILIES

GENERA60

I = o.812±0.087

50

I = o.330±0.084

I-

40

40

cc
w 30

30

30

20

20

20

10

10

10

0

...

0

0
0 .1 . 2 . 3 .4 . 5 . 6 . 7 . 8 . 9 1.1.2.3.4.5.6.7.8.91

0 .1 . 2 . 3 .4 . 5 . 6 . 7 .8 . 9 1

I DENT ITVIDENTITYI DENTITV

(a)

( b)

(c I

Fig. 2. Frequency distribution of loci with respect to genetic identity when comparing the different speciesof the same genus (a), between the different genera (b) and between the families (c). l is the mean genetic
identity with its standard error.

distances between the families were much larger than those between thegenera. Mean values of the genetic identity and distance between the families
were 0.330 and 1.140, respectively.
Table 6 shows the values of mean genetic distance (D) of 4 taxonomic
levels of the toothed whales and other animals. Higher D values wereobtained in the higher taxonomic levels, but D values showed a wide range ofvariation among the taxa. D values of the toothed whales were generally
small, and thus the degree of genetic divergency of the toothed whales
seemed to be lower than the other animals. D value of the toothed whales at
the family level was similar to those of Drosophila at the specific level (D= 1.056)
and of sunfish and salamanders at the generic level (D= 1.170-1.340), indicating lower genetic divergency between the toothed whale families.
Genetic relationships of the toothed whales

Unweighted pair-group method of cluster analysis (Sokal and Sneath,1963) were applied to the matrix of genetic distance (Table 5), to elucidate
genetic relationships among the species studied. The dendrogram is shown in
Fig. 4. In general, the dendrogram agreed with currently accepted opinions
on phylogenetic relationship in toothed whales deduced from morphology(kasuya, 1973; Mead, 1975; Gaskin, 1982).
A crude estimate of divergence time (t) can be obtained by an equation,t = 5 X 106 D, provided by Nei (1975). The time scale of divergence was also
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

151

GENETIC VARIABILITY
40
~

I>"!
~

>-

D

BETWEEN GENERA jj = 0.213±.0. lll~

BETWEEN FAMILIES

D = 1.140±0.254

30

u

=
w
20
=
G

w

er::

10

lL

0

.1

.2

.3

.4

,5

.6

.7

,8

G E NE T I C.9

1.0 1.1

1.2 1.3 1.4 1.5 1.6 1.7

D I S T A NC E

Fig. 3. Distribution of genetic distances among toothed whales between species in different genera andfamilies. Mean distance and its standard error are indicated in each case.

shown in Fig. 4. The result represented that the families diverged 3.5-5.5
million years ago, and that speciation of the species within the same family
occurred two million years ago.
DISCUSSION

Selander and Kaufman (1973), Powell (1975), Selander (1976) and Nevo
( 1978) made reviews of allozymic variations in natural populations of plants
and animals so far studied. In three major taxa (plants, invertebrates andvertebrates), both P and H values increased in the following order: vertebrates,
plants and invertebrates. Within vertebrates consisting of following fivegroups, fishes, amphibians, reptiles, birds and mammals, no significant difference was found (Nevo, 1978). Nevo (1978) reportedP=0.173 ± 0.119 (in 5%
level) and H=0.0494 ± 0.0365 for 135 species of vertebrates, and P=0.147 ±0.098 and H=0.0359 ± 0.0245 for 46 species of mammals. P and H values of
the toothed whales in the present study were P=0.207 and H=0.047. These
values were slightly larger than those of mammals but similar to those of thevertebrates. Accordingly, the genetic variation level of the toothed whales is
considered to be in the range of vertebrates in spite of their ecological
specialization.
The values of the mean genetic distances of the toothed whales at the fourtaxonomic levels (Table 6) were distinctly smaller than those of other animals
except the birds. The distribution patterns of the genetic identity as shown in
Fig. 2 were also shown in Drosophila (Ayala, Tracey, Barr, McDonald andPerez-sales, 1974), sunfish (Avise and Smith, 1977) and rodents (Zimmerman,
Kilpatrick and Hart, 1978). Compared with these patterns, the genetic
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

152

SHIMURA AND NUMACHITABLE 6. MEAN GENETIC DISTANCES (NEI'S D) AT FOUR TAXONOMIC LEVELS

Taxa
Drosophi/,aSunfishSalamanders
Rodents
Birds
Passerines
Procellariiformes
Parulidae
Toothed whales

Local
Populations

Species

Genera

0.028
0.024
0.051
0.030

1.056
0.626
0.462
0.323

1.340
1.170

0.003

0.100

References
Ayala, 1975
Avise & Smith, 1977
Hedgecock & Ayala, 1974
Zimmerman et al., 1978

0.214
0.435
0.179
0.213

0.100
0.026

(0.004)*

Families

Barrowclough et al., 1981
Barrowclough et al., 1981
Barrowclough & Corbin, 1978
Present study

0.683
1.140

* Two types of Phocoenoides dalli
GENETIC DISTANCE
1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0
Peponocephala electra

Globicepha/a macrorhynchus
Pseudorca crassidens
Stenella coeruleoalba

S.

attenuataTursiops truncatus' - - - - Lagenorhynchus obliquidens...__ _ _ _ _ Steno bredanensis

Phocoenoldes da/11 (da/11-type)
P.

da/11

( truel -type I

Neophocaena phocaenoides

7

6

5

4

3

2

1

0

X 106 YEARSDIVERGENCE TIME

Fig. 4. Biochemical similarity dendrogram of toothed whales based on genetic distance. Divergence timeby calibration of Nei (1975) is also shown.

divergence of the toothed whales was much smaller than those of the otherspecies. The pattern obtained for the species of the toothed whales (Fig. 2a)
was the very same as the populations of the other organisms, and the genus
level (Fig. 2b) was much similar to the species level of the other organisms.
Most of cetologists have considered that Phocoenidae is fully distinguished from Delphinidae. However, Rice (1977) classified true porpoises
into Delphinidae. Our result showed that D value between Phocoenidae andSci. Rep. Whales Res. Inst.,

No. 38, 1987

GENETIC VARIABILITY

153

Delphinidae were considerably high (D= 1.051). Therefore, Phocoenidae andDelphinidae may be differentiated in the family level judging from theallozymic comparison.
The dendrogram showed that three species of globicephalids were not so
different from other delphinids genetically. The D value btween Steno andother species of Delphinidae was slightly large compared with other genera,
but considerably small when compared at the family level of Phocoenidae andDelphinidae. Therefore, the genetic difference of Steno is considered to be at
the generic level in Delphinidae. In regard to the genetic relationship ofDelphinidae, the dendrogram seems to be in good agreement with morphological relationships among the groups in this family.
Berardius bairdii is a species in a well-distinguished family, Ziphiidae.
Gaskin ( 1982) suggested that Ziphiidae diverged from other families of
Odontoceti in early evolutionary time deduced from the karyological characteristic of Ziphiids species. Based on our electrophoretic study, the relationship between Ziphiidae and Phocoenidae was relatively closer than thatbetween Delphinidae and Phocoenidae.
Time of divergence was estimated from D values using the equation ofNei (1975). Our estimation of divergence time is different from that shown by
the geological study. It is supposed that the major families of the toothed
whales were established in Miocene (ea. 10-25 million years ago) (Kellog,
1928), and that morphologically "modern" delphinids became abundant in
the following Pliocene (ea. 1-10 million years ago) (Gaskin, 1982). Our result
by Nei's conversion represented that three families diverged 3.5-5.5 million
years ago, and that the speciation within Delphinidae started from two
million years ago. Accordingly, the time of divergence based on these calculation was much shorter than that of geological one. Possible reasons for thedifferences may be ( 1) the rate of genetic changes presumed by N ei may not
fit to that of the toothed whales, and (2) the time of divergence tends to give
underestimate when D is larger than 1 (Nei, 1975). Carlson, Wilson andMaxon (1978) found that 1 albumin immunological distance (AID) unit was
equivalent to 0.54 million years (r=0.97) through the comparison between
paleontological records and AID. Further, Wyles and Gorman (1980) reported
a D of 1.0 corresponded to 35.6 AID units on the average. Thus, a D of 1.0
represents about 19 million years of continuous separation (Grant, Teel,
Kobayashi and Schmitt, 1984). We estimated the time of divergence of
toothed whale families using this method as about 13.3-20.0 million years,
and for genera in Delphinidae 7.6 million years. These estimates properly
agree with the paleontological time of divergence.
ACKNOWLEDGEMENTS

We are grateful to Dr T. Kasuya of the Far Seas Fisheries Research Laboratory,
for his kindly supplying the specimens for this study and reviewing the manSci. Rep. Whales Res. Inst.,
No. 38, 1987

154

SHIMURA AND NUMACHI

uscript. We wish to thank Dr T. Okazaki of the Far Seas Fisheries ResearchLaboratory, for checking the calculation and critically reading the manuscript.
Dr N. Miyazaki of the National Science Museum, kindly provided many
samples from the specimens associated with his own field work. We areindebted to Dr ]. G. Mead of the Smithsonian Insitution, for giving us
valuable suggestions.
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BARROWCLOUGH, G.F. and K.W. CORBIN, 1978. Genetic variation and differentiation in the Parulidae. Auk,95: 691-702.
BARROWCLOUGH, G.F., K.W. CORBIN and R.M. ZINK, 1981. Genetic differentiation in the Procellariformes.
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SOKAL, R.R. and P.H.A. SNEATH, 1963. Principles of Numerical Taxonomy. Freeman, San Francisco, 359 pp.
VALENTINE, J.W., 1976. Genetic strategies of adaptation. In: F.J. Ayala (ed.) Molecular Evolution. Sinauer
associates, Sunderland, Massachusetts. 277 PP'
WADA, S., 1982. Gene frequency analysis on the Antarctic minke whale. IWC/SC/34/Mil3.
WADA, S., 1983a. Genetic structure and taxonomic status of minke whales in the coastal waters of Japan.
Rep. int. Whal. Commn, 33: 361-363.
WADA, S., 1983b. Genetic heterozygosity in the striped dolphin off Japan. Rep. int. Whal. Commn, 33:
617-619.
WADA, S., 1984. A note on the gene frequency differences between minke whales from Korean andJapanese coastal waters. Rep. int. Whal. Commn, 34: 345-347.
WADA, S., 1986. Genetic differentiation in the two types of Globicephala macrorhynchus off the coast of Japan.
Proceedings of the annual meeting of the Japan. Soc. Sci. Fish., Tokyo, April, 1986. (Abstract) p. 29.
(In Japanese)
WADA, S. and K. NuMACHI, 1979. External and biochemical characters as an approach to stock identification
for the Antarctic minke whale. Rep. int. Whal. Commn, 29: 421-432.
WINANS, G.A. and L.L. JONES, 1986. Electrophoretic variability in the Dall's porpoise (Phocoenoides dalli) in
the North Pacific Ocean and Bering Sea. Document submitted to the meeting of the Scientific
Subcommittee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo,
March, 1986. 20 pp.
WYLES,]. and G.C. GORMAN, 1980. The albumin immunological and Nei electrophoretic distance correlation: a calibration for the saurian genus Anolis (Iguanidae). Copeia, 1980: 66-71.
ZIMMERMAN, E.G., C.W. KILPATRICK and B.J. HART, 1978. The genetics of speciation in the rodent genus
Peromyscus. Evolution, 32: 565-579.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

156

SHIMURA AND NUMACHI

EXPLANATION OF PLATESPLATE I
Figs la and lb. Electrophoretic patterns of tetrameric SDH isozymes from liver
extracts in Phocoenoides dalli (dalli-type) (la). lntraspecific variations appeared on the
zymogram. Schematic drawings show the patterns detected through the species
studied (lb). Designations of alleles (a, b, etc.) correspond to those of Table 3.
Genotypes postulated and positions of homopolymeric isozymes of subunits producedby each allele are shown on the schematic drawings.
Figs 2a to 2d. Electrophoretic patterns of MDH and ME isozymes from muscle
extracts in Phocoenoides dalli (dalli-type) (2a). Dimeric MDH isozymes appeared on
both sides of the gel, and tetrameric ME isozymes only anodal side. Three schematic
drawings show the patterns detected in each isozyme system through the species
studied (2b, 2c and 2d). For designation see Plate I, Fig. 1.
PLATE II
Figs la and lb. Electrophoretic patterns of LDH isozymes from liver extracts of all
the species studied (la). The numbers correspond to those of the species in Table 3.
The positions of homopolymeric isozymes of subunits produced by each allele of two
LDH loci are shown on the patterns. Neophocaena phocaenoides (no. 13) had specificvariation in LDH-2. For LDH-1, three variations corresponded to the interfamilial
differences. Schematic drawings (lb) show the patterns of LDH-1 detected throughthe species studied. Rare variations (ad and be) were observed in Globicephalamacrorhynchus and Phocoenoides dalli (truei-type).
Fisg 2a to 2c. Electrophoretic patterns of dimeric IDH isozymes from liver extracts in
Phocoenoides dalli (dalli-type) (2a). IDH-1 and -2 appeared separately on both sides of

the gel. One or two conformeric bands appeared on the anodal side of the major
bands of IDH-2. Two schematic drawings show the patterns detected in each isozyme
system through the species studied (2b and 2c). For designation see Plate I, Fig. 1.
PLATE IIIFigs la to le. Electrophoretic patterns of 6-PGD isozymes from liver extracts of all the
species studied (la). The numbers correspond to those of species in Table 3. Black
points indicate the differences of the mobility of the patterns. Each band shows themost common one of each species. Electrophoretic patterns of Stenella coeruleoalba arealso shown (lb). Two dimeric variations appeared. Schematic drawings show thepatterns detected through the species studied (le). For designation see Plate I, Fig. 1.
Figs 2a and 2b. Electrophoretic patterns of dimeric SOD isozymes from muscle
extracts in Phocoenoides dalli (dalli-type) (2a). SOD isozymes appeared on the anodal
side of the gel. Very rare variation in this species was detected here. Schematic drawings (2b) show the patterns detected through the species studied. For designation see
Plate I, Fig. 1.
PLATE IV
Figs la and le. Electrophoretic patterns of Esterase isozymes from liver extracts in
Stenella coeruleoalba (la). Two Esterases appeared on the anodal side of the gel.
Esterase-1 had dimeric isozymes and Esterase-2 monomeric. Two schematic drawings
show the patterns detected in each isozyme system through the species studied(lb and le). For designation see Plate I, Fig. 1.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

GENETIC VARIABILITY
Figs 2a and 2b. Electrophoretic patterns of dimeric GOT isozymes from muscle
extracts in Phocoenoides dalli (dalli-type) (2a). GOT-I and -2 appeared separately on
both sides of the gel. In GOT-I patterns, three individuals were heterozygous.
Schematic drawings (2b) show the patterns detected both in GOT-I and -2 isozyme
systems through the species studied. For designation see Plate I, Fig. I.
PLATE V
Figs a to d. Electrophoretic patterns of monomeric PGM isozymes from liver extracts
in Phocoenoides dalli (truei-type) (a). Heavily stained PGM-1 isozymes moved tocathodal side of the gel, and other two PGM appeared on anodal side. Three schematic drawings for each PGM isozyme system show the patterns detected through thespecies studied (b, c and d). For designation see Plate I, Fig. 1.
PLATE VI
Figs la and lb. Electrophoretic patterns of monomeric MPI isozymes from muscle
extracts in Phocoenoides dalli (truei-type) (la). MPI was highly polymorphic in thisspecies. Postulated genotypes of homozygotes in this zymogram are cc and ff, andheterozygotes cf, df andfi as shown in schematic drawings (lb). Arrow indicates aheterozygote of predominant allele f and a rare allele which is not named in thisstudy. The schematic drawings show the patterns detected through the species
studied. For designation see Plate I, Fig. 1.
Figs 2a and 2b. Electrophoretic patterns of dimeric PHI isozymes from liver extracts
in Phocoenoides dalli (dalli-type) (2a). A heterozygote appeared. Schematic drawings(2b) show the patterns detected through the species studied. For designation see Plate
I, Fig. 1.

Sci. Rep. Whales Res. Inst.,

No. 38, 1987

157

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SIAMESE TWINS OF MINKE WHALESOF THE SOUTHERN HEMISPHERE

VALERY! L. ZINCHENKO*ANDMIKHAIL V. IVASHIN**

Several authors have examined the whales which were raised on board more
attentively and with more interest during the past southern ocean whaling
expeditions. It gave the opportunity to reveal rare cases of atavism (Ogawa
and Kamiya, 1957; Nemoto, 1963; Ohsumi, 1965; Zemsky and Berzin, 1961).
Various cases of abnormalities in the development of foetus stage (Nishiwaki,
1957; Ohsumi, 1959; Ivashin, 1960, 1977) and cases of foetus mortality andextrauterine pregnancy (Ivashin, 1960, 1963, 1977; Ichihara, 1962; Kamiya
and Miyazaki, 1974) were recorded.
Formation of conjoint pair of foetus is a pathological case, such cases arerare among marine mammals. Kawamura ( 1969) was the first to describe
Siamese twins of Cetaceans. Zemsky and Budylenko (1970) examined female
humpback whale of the southern hemisphere (body length - 12.7 m), in theuterine horn of which Siamese twins were found. Japanese scientists
registered a blue-white dolphin with abnormal twins, which was collected incoastal water of Japan (Kawamura and Kashita, 1971; Kamiya, Miyazaki and
Shiraga, 1981).
On 4 January, 1981, one female minke whale (body length-9.0m) with apair of Siamese twins was caught, and such twins are for the first time recorded.
It was taken at 64 ° 35 'S, 81 ° 05 'E. In the left uterus horn there were two
females of 50.5 and 49.0 cm in total length, conjointing in abdominal andpartly in lateral areas of the body. Their dorsal and abdominal sides could be
distinguished (Figs 1 and 2). This case can be considered as ventropagus(Patten, 1959).
The foetuses were connected at the tip of the mouth to the umbilicus,
the connected area was about 20.5 cm, that is 40.6% of the total length. The
following parts were separate: upper jaws at the tip of the mouth, partly
lower jaws, caudal peduncles, (which dranched only at the umbilicus level,
where two umbilical cords came together, connected by a mesentery). The
distance between both rostrums was 3.6 cm. The right foetus (with the bodylength - 120 cm) had harelip on the lower jaw (Fig. 3), as in the case with
* Odessa Branch, 53 Mechnikov, GSP-983, Odessa, 270020, USSR** VNIRO, 17, V. Krasnosel'skaya, Moscow, B-140, 107140, USSR
Sci. Rep. Whales Res. Inst.,
No. 38, 1987, 165-169

166

ZI
NCHENKOAND I
VASHIN. MinkewhaleSiame
s
et
w
in
s(
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168

ZINCHENKO AND IVASHINTABLE 1. MORPHOLOGICAL DATA OF SIAMESE TWINS OF MINKE WHALES
Right foetus

Left foetus
cm

%

cm

%

Left;Rightside side

Left;Rightside side

Left;Rightside side

Left;Rightside side

50.5
7.3
12.5/8.4
11.6/10.7
-15.5
14.0
4.3/4.3
24.0
15.7
1.3
2.0
3.5

100
14.5
24.8/16.6
23.0/21.2-/10.927.7
8.5/8.5
47.5
31.1
2.6
4.0
6.9

49.0
6.8
8.4112.3
12.5110.7
4.9/12.0
4.5/4.5
23.5
15.7
1.2
2.0
3.3

100
13.9
17.1125.l
25.5/21.8
10.0124.5
9.2/9.2
48.0
32.0
2.4
4.1
6.7

6.8/6.4
8.4/8.0
7.517.5
2.3/2.3-/16.59.3
5.3
5.8/5.8
11.3

13.5/12.7
16.6/15.8
14.9/14.9
4.6/4.6-/32.7
18.4
10.5
11.5/11.5
22.4

6.8/5.7
7.9/7.9
7.517.5
2.3/2.3
16.7 I 9.5
5.3
5.8/5.8
11.2

13.9/11.6
16.1/16.l
15.3/15.3
4.7/4.7
34.1/ 19.4
10.8
11.8/11.8
22.9

3.5
1.3

6.9
2.6

5.7/7.0
1.1

11.6/14.3
2.2

17.0/21.5
7.3
9.5

33.7/42.6
14.5
18.8

20.5/18.0
7.6
9.3

41.8/36.7
15.5
19.0

Measurements

I. Total length
2. Tip of the snout to the middle of blow holes
3. Tip of the snout to mouth angle
4. End of the snout to eye centre
5. Eye centre to the centre of the ear
6. Tail fork to the notch of the caudal fin
7. Width of the tail flukes
8. Tail fork to umbilicus
9. Tail fork to anus
10. Anus to genital opening (Center to center)
11. Height of the dorsal fin
12. Length of the dorsal fin base
13. Length of the pectoral fin from the end
to the pit
14. Length of the pectoral fin on the external edge
15. Pectoral fin curve length
16. Maximum length of the pectoral fin
17. Length of the head (from snout to ear)
18. Breadth of the head
19. Height of caudal peduncle of the dorsal fin
20. Length of flukes from the fork to the end
21. Span of flukes
22. From the end of the upper jaw to the endof the lawer jaw
23. Length of the blow hole
24. From the snout to the beginning of thepectoral fin
25. Width of the body at the umbilicus level
26. The distance between pectoral fins

TABLE 2. NUMBER OF VIBRISSAE OF SIAMESE TWINS OF MINKE WHALES
Left foetus

Right foetus

Location
Right

Left

Right

3

1

2
3

2
2

3
2
2

2
2

9

7

6

7

Left
Blow hole
Upper jaw
Lower jaw
Lower jaw
protuberance

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SIAMESE TWINS OF MINKE WHALES

169

REFERENCES
IvASHIN, M. V., 1960. On multifetation, abnormalities in the development and embryonic mortality amongwhales. Zool. zh., 39(5): 755-758.
IvASHIN, M. V., 1963. The case of extrauterine pregnancy in sei whale (Balaenoptera borealis Lesson). Zool.
zh., 42(8): 1275-1277.
IvASHIN, M.V., 1977. Cases of pathological embryogenesis of minke whales, Balaenoptera acutorostrata(Cetacea, Balaenopteridae) of the Antarctic part of the Indian Ocean. Zool. zh., 56(11): 1736-1739.
ZEMSKY, V.A and A.A. BERZIN, 1961. On rare example of atavism in sperm whales. Higher School Scientificpapers, Biological Sciences: 56-60.
ZEMSKY, V.A. and G.A. BuDYLENKO, 1970. Siamese twins in humpback whales. Whales of the Southern
Hemisphere. Trudy AtlantNIRO, 29: 225-230.
PATTEN, B.M., 1959. Embryology of a man. Medgize, USSR. 768pp.
ICHIHARA, T., 1962. Prenatal dead foetus of baleen ~hales. Sci. Rep. whales Res. Inst., 16: 47-60.
KAMIYA, T. and N. MIYAZAKI, 1974. A malformed embryo of Stenella caeruleoalba. Sci. Rep. whales Res. Inst.,
26: 259-263.
KAMIYA, T., N. MIYAZAKI and S. SHIRAGA, 1981. First case of dicephaly in Odontocety. Sci. Rep. whales Res.
Inst., 33: 127-129.
KAWAMURA, A., 1969. Siamese twins in the sei whale Balaenoptera borealis Lesson. Nature, 221(5179):
490-491.
KAWAMURA, A. and K. KASHITA, 1971. A rare double monster of dolphin Stenella caeruleoalba. Sci. Rep. whales
Res. Inst., 24: 139-140.
NEMOTO, T., 1963. New record of sperm whales with protruded rudimentary hind limbs. Sci. Rep. whales
Res. Inst, 17: 79-81.
NISHIWAKI, M., 1957. One-eyed monster of fin whale. Sci. Rep. whales Res. Inst., 12: 193-195.
0HSUMI, S., 1959. A deformed fin whale foetus. Sci. Rep. whales Res. Inst., 14: 145-147.
0HSUMI, S., 1965. A dolphin (Stenella caeruleoalba) with protruded rudimentary hind limbs. Sci. Rep. whales
Res. Inst., 19: 135-136.
OGAWA, M. and T. KAMIYA, 1957. A case of the cachalot with protruded rudimentary hind limbs. Sci. Rep.
whales Res. Inst., 12: 197-208.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

FIRST RECORD OF A DWARF SPERM WHALE FROM
SOUTHWEST ATLANTIC, WITH REFERENCE TO
OSTEOLOGY, FOOD HABITS AND REPRODUCTIONMARIA C. PINEDO*
ABSTRACT

A female dwarf sperm whale, Kogia simus, 2,490 mm long with a 260
mm female foetus was found stranded on July, 1983 at Rio Grande do Sulcoast, southern Brazil (32°05'S, 52°0l'W). The species was identified basedon external and cranial characters. The condylobasal length was 283 mm
and the vertebral formula was C7 + Dl3 + LIO + Ca25 = 55, with 14
chevron bones. The first nine pairs of ribs were double headed. The complete
skeleton and foetus were placed in the cetacean collection of the M useu
Oceanografico do Rio Grande (MORG 495). Nematode parasites, shrimp
remains and 78 cephalopod beaks were found in the stomach content. Of
the identified cephalopod beaks, 55% belonged to Histioteuthidae, 14.1 %to Chiroteuthidae and the remainder· to other five families. A review of
foetal records suggests that birth and copulation occur in summer.
INTRODUCTION

On July 5, 1983, a decomposed odontocete carcass was found 10 km north ofthe entrance to the Patos lagoon, Rio Grande do Sul (32° 05'S, 52° 0 l 'W). It
was a 2,490 mm female dwarf sperm whale, containing a 260 mm female
foetus. The specimen was measured, photographed and the stomach collected.
The complete skeleton was recovered and, along with the formalized foetus,
placed in the marine mammals collection of Museu Oceanografico do Rio
Grande (MORG 495).
The external measurements of both specimens were taken according to
Leatherwood, Reeves, Perrin and Evans ( 1982) and are shown in Table 1.
The skull was measured according to Ross ( 1979) and rest of the skeleton according to Nishiwaki, Kasuya, Kureha and Oguro (1972), Pinedo and Castello(1980) and Omura, Shirakihara and Ito (1984). The present study reports theexternal morphology, osteology, stomach contents of this specimen, together
with the review of presently available fetal records of the species.

* Departamento de Oceanografia, FURG, 96200 Rio Grande, RS Brazil.
Sci. Rep. Whales Res. Inst.,
No.38,1987, 171-186

172

PINEDOTABLE 1. EXTERNAL MEASUREMENTS OF A FEMALE KOGIA SIMUS (A)AND FOETUS (B) STRANDED AT RIO GRANDE DO SUL COAST, BRAZIL
A

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.

Tip of upper jaw to deepest part of fluke notch
Tip of upper jaw to center of anus
Tip of upper jaw to center of genital slit
Tip of lower jaw to center of umbilicus
Tip of upper jaw to top of dorsal fin
Tip of upper jaw to leading edge of dorsal fin
Tip of upper jaw to anterior insertion of flipper (left)
Tip of upper jaw to center of blow hole
Tip of upper jaw to anterior edge of blow hole
Tip of upper jaw to auditory meatus, rightleft
Tip of upper jaw to center of eye, rightleft
Tip of upper jaw to angle of gape
Center of eye to center of eye
Height of eye, rightleft
Length of eye, rightleft
Center of eye to angle of gape, rightleft
Center of eye to external auditory meatus, rightleft
Center of eye to center of blow hole, rightleft
Blowhole length
Flipper width, rightleft
Flipper length-tip to anterior insertion, rightleft
Flipper length-tip to axilla, rightleft
Dorsal fin height
Dorsal fin base
Fluke span
Fluke width
Fluke depth of notch
Notch of flukes to center of anus
Notch of flukes to center of genital aperture
Notch of flukes to umbilicus
Notch of flukes to nearest point on leading edge
Girth at anus

B% of total

Measurements% of total

inmm

lengthinmm

length

2,490
1,770
1,715
1,500
1,470
1,170
540
190
230

100.0
71.1
68.9
60.2
59.0
46.9
21.7
7.6
9.2

235
505
12

9.4
20.3
0.5

260
195
195
140
185
160
80
22
23
55
55
44
44
34
52
2

35

1.4

195

7.8

80

3.2

320
250
70
130
125
330
320
230
220
155
305
620
180
10
805
855
1,070
170
1,040

12.9
10.0
2.1
5.2
5.0
13.3
12.9
9.2
8.8
6.2
12.3
24.9
7.2
0.4
32.3
34.3
43.0
6.8
41.8

100.0
75.0
75.0
53.8
71.6
61.5
30.8
8.5
8.8
21.2
21.2
16.9
16.9
13. l
20.0
0.8
0.4
2.3
2.3
10.8
11.5
5.4
5.0
16.2
13.1
4.6
5.8
6.2
15.0
15.0
10.0
10.4
3.5
10.4
22.7
7.7
0.4
31.9
33.1
55.4
7.3
38.5

6
6
28
30
14
13
42
34
12
15
16
39
39
26
27
9
27
59
20
I

83
86
144
19
JOO

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

173

A DWARF SPERM WHALE
TABLE 1. (Cont.)

Girth at axilla
Girth at eye
Blubber thickness (lateral)
Mammary slit length, rightleft
38. Genital slit length
34.
35.
36.
37.

1,360

54.6

25
50
45
50

1.0
2.0
1.8
2.0

175
180

67.3
69.2

RESULTS

External morphology

The specimen was identified as a dwarf sperm whale, Kogia simus (Owen,
1866) (Fig. la) based upon the following external characteristics: height of
dorsal fin equivalent to 6.2% of total body length (over 5% in K. simus accordingto Ross (1979)) and positioned in the midback; 10 teeth in each side of thelower jaw, which is in the ranges of the value for the species given by Handley(1966); the size of 8 lower teeth (15.5 to 20.5 mm) agrees with the values
given by Ross (1979). Teeth were present on the upper jaws.
Due to decomposition, the colour pattern, throat grooves and the bracket
mark behind the eye could not be observed (Fig. lb). The bracket mark seems
to be characteristic of the genus (Ross, 1979), whereas the throat grooves arepresent in K. simus and absent in K. breviceps (Leatherwood et al., 1982). The
blowhole was positioned to the front and directed to the left in an oblique way(Fig. le). It was an adult specimen, since a 260 mm foetus was found in it. The
foetus was a female (Fig. ld) which presented 5 vibrissae in each side of themaxilla (Fig. le) and two throat grooves.
Osteological characteristics

The specific cranial characteristics mentioned by Handley (1966) andRoss ( 1979) were observed on this specimen, especially the condylobasal length,
the shape of the dorsal fossae, the width of the dorsal sagittal septum and thelength and shape of the mandibular symphysis. These characteristics areshown in Fig. 2. The anterior part of the mesethmoid was not ossified (Fig. 2)
and the skull sutures of the frontal in the vertex, the parieto-occipital and themaxillary were visible. The rami of the mandible were not fused together.
Among a total of 8 teeth examined, two had the closed pulp cavity and theremainder were in process of closure. Skull measurements are listed in Table 2.
The vertebral formula was C7 + Dl3 + LIO + Ca25, with total of 55
vertebrae. The vertebral groups are presented in Fig. 3, and measurements ofvertebrae in Table 3. Bones of axial skeleton, as well as the skull, were lightand porous.
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

174

P
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176

PINEDOThe seven cervical vertebrae are fused into a single unit, where posterior
three of them could be individualized. Most of the vertebral epyphyses, 60,
were free from the centrum. The neural arch was closed up to the 13th caudal
vertebra. The transverse and spinous apophyses attained their maximum sizes
in the 5th lumbar vertebra. The last lumbar vertebra was distinguished fromthe lst caudal by the absence of chevron bone in its ventral posterior portion.
The 25th caudal vertebra showed a straightening, which confers it a triangularshape, in dorsal view. There were 14 chevron bones, and the first one was not
fused bilaterally (Fig. 4). The measurements of these bones are provided inTable 4.
There were 12 ribs in the right side and 13 in the left; the last one was
rudimentary for its small size (Fig. 5). The first nine pairs presented double
articulation. Measurements of the ribs are shown in Table 5.
The sternum consisted of two bony sections both presenting a longitudinalrift in the ventral portion, evidencing the bilateral origin already mentioned
TABLE 2. CRANIAL AND MANDIBULAR MEASUREMENTS OF A FEMALE KOGIA SIMUSSTRANDED AT RIO GRANDE DO SUL COAST, BRAZIL
Measurements
1. Total condylobasal length
2. Rostrum length*
3. Rostrum, basal width*
4. Rostrum, width at its middle*
5. Breadth across pre-orbital angles of supra-orbital processes
6. Breadth across post-orbital processes
7. Zigomatic width
8. Height to vertex
9. Width of vertex
10. Width of supra-occipital at narrowest part between posterior margins of
temporal fossae
11. Tip of rostrum to left naris
12. Height of ventral border of foramen magnum
13. Length of maxillary tooth groove - right
14. Length of maxillary tooth groove - left
15. Width between outer margins occipital condyles
16. Tip of rostrum to hind margin of pterygoids
17. Length of mandible
18. Height of mandible at coronoid
19. Length of mandibular symphysis
20. Length of lower toothrow - left
21. Length of lower toothrow - right
22. Height from dorsal border of foramen magnum to vertex% of total
inmm

length

283
123
146
101
241
263
253
185
16

100.0
43.4
51.5
35.6
85.1
92.9
89.3
65.3
5.6

190
112
65
68
65
80
160
243
82
40
87
88
95

67.l
39.5
22.9
24.0
22.9
28.2
56.5
85.8
28.9
14.1
30.7
31.0
33.5

• Measured ventrally
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

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179

A DWARF SPERM WHALE
TABLE 3. (Cont.)
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55

Ca

I

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

154
144
136
125
107
91
78
66
55
49

141
122
115
107
100
95
90
84
77
70
62
57
50
41
32
27
23
21

54
55
52
52
50
51
50
52
49
45
45
42
39
37
33
31
29
27
25
23
21
19
16
13
9

64
54
49
48
48
49
48
47
46
48
44
42
39
33
28
23
22
20
19
16
14
13
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8
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50
49
48
47
46
45
43
42
39
39
36
34
32
25
20
18
17
17
15
14
12
11
10
9
7

triangular shape,
posterior epiphysis
missing* Measured with epiphysis

for K. breviceps by Carvalho (1966) and Vaz-Ferreira and Praderi (1973).
Fig. 5 shows the way sternum measurements were taken, and the measurements are provided in Table 6. The sternal ribs were not found, demonstrating
the attachments of ribs to the sternum only through cartilage, which agrees
with Carvalho (1966) for K. breviceps.
Photographs of the hyoid arch and scapulae and the way measurements
were taken are shown in Fig. 6. Tables 7 and 8 show the measurements ofhyoid arch and scapulae, respectively.
The proximal and distal epiphyses of the right and left humerus werefused, as well as the proximal epiphyses of radius and ulna. The distal
epiphyses of the latter were not fused. Measurements of humerus, radius andulna are provided in Table 9. The phalangeal bones could not be counted.
The pelvic bone was not found.
Sci. Rep. Wha/,es Res. Inst.,

No. 38, 1987

1
80

PI
NEDO

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TABLE4. MEASUREMENTSOFCHEVRONBONESOFA FEMALEKOC/ASIMUSSTRANDEDAT RIO GRANDE DO SUL COAS
T,BR
AZI
L(
I
N MM)
Length •

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3A ﹃
I lll
−−

−nJ30A3U︒
3q303 3auny
O C
口 hdsuI
IP
a1 03
−

No
.
h
k
J AU
v nu

Hei
ght
*

−

234 567

R
ight
L
e
f
t

Leng
t
h
od n v O J 勺 od 勺 nv 円J令
ζ のr n〆旬 ︒4 0 Jv
B 040
︒
︐
︐
句

・

No
.

• Me
a
s
u
te
datmidpoint

S
c
i.Re
p
.W
h
a
l
e
sRe
s
.I
n
s
t
.
,
No.38
,1987

181

A DWARF SPERM WHALE
TABLE 5. STRAIGHT LENGTH OF RIBS OF A FEMALE KOC/A SIMUSSTRANDED AT RIO GRANDE DO SUL COAST, BRAZIL (IN MM)
No.

Right

Left

No.

Right

Left

1
2
3
4
5
6
7

232
312
352
360
352
355
352

229
313
357
360
353
354
356

8
9
10
11
12
13

345
323
280
264
252
0

341
311
276
252
242
64

TABLE 6. MEASUREMENTS OF THE STERNAL BONES OF A FEMALE KOC/A SIMUSSTRANDED AT RIO GRANDE DO SUL COAST, BRAZIL (IN MM)
No.

Manubrium

Sternebrae

90
110
62
51

61
41
34
37

I. Length at medium
2. Maximum breadth
3. Anterior breadth
4. Posterior breadth

TABLE 7. MEASUREMENTS OF THE HYOID BONES OF A FEMALE KOC/A SIMUSSTRANDED AT RIO GRANDE DO SUL COAST, BRAZIL (IN MM)
No.
1. Baiyhyal height at medium
2. Maximum basihyal height
3. Maximum basihyal breadth
4. Thyrohyal length
5. Thyrohyal breadth
6. Straight line thyrohyal*
7. Stylohyal length
8. Stylohyal height at medium

Right

Left

83
64

81
65

74
15

86
9

54
65
77

174

* Measured approximately - not fused with basihyal

Stomach content and parasites
The stomach contained 78 cephalopod beaks (38 upper and 40 lower)
and gladius remains. Beaks were identified by M. J. Imber, Wildlife Service,
Wellington, New Zealand and results are shown in Table 10. Fifty-five percentof the beaks belonged to the oceanic family Histioteuthidae and the remainder
were assigned to six other families. Two beaks could not be identified due totheir small size. Remains of shrimp carapaces were also found but identification
was not possible due to wear. The presence of cephalopods and crustacean in
the K. simus stomachs and the predominance of the former were previously
observed by Fitch and Brownell (1968), Ross (1979), Jones (1981), Maigret
Sci. Rep. Whales Res. Inst.,
No. 38, 1987

1
82

P
INEDO

F
ig.6
. Scapul
ae (
r
igh
t an
dl
e
f
t
) and hyo
i
d bo
ne
soft
he pr
e
s
e
n
t specimen,and
i
l
l
us
t
r
a
t
i
onss
howingme
a
sur
emen
t
si
nTables7and8

TABLE8. MEASUREMENTSOFTHESCAPULA OFA FEMALEKOC/AS/MUSSTRANDEDATRIO GRANDEDO SULCOAST.BRAZIL(
I
N MM)
N口

Right

Lef
t

I Maxi
muml
eng
th

1
87

183

mumheig
ht
2. Maxi

151

149

3
. Cor
辻仁o
i
dl
e
n
g
t
h

54

55

oracoi
dmaximumbr
cad1
h
4
.C

41

52

5.Glenoidf
os
s
al
eng
th

35

37

o出 品 b
r
e
a
d
t
h
6
. Glenoidf

26

26

7.Acromiuml
e
n
g
t
h

53

8.Acr
omiummaximumbr
e
a
d
t
h

26

52
23

TABLE9. MEASUREMENTSOFHUMERUS,RADIUSANDULNAOFA FEMALE
KOC/ASIMUSSTRANDEDATRIO GRANDEDOSULCOAST,BRAZIL(
I
N M九1
)
Humer
us
R
i
gh
t
Le
f
t
Leng
th場
Brea
dth*
ホ

87
37

87
38

Ra
d
i
u
s
R』ght
Le
f
t
57
31

56

30

Ulna
Right

Le
f
t

55
28

55
26

Measuredatmidpo
i
n
t

S
c
i
.R
e
p
.Whal
e
sRe
s
.I
n
s
ι
，
Nο 3
8
,1987

183

A DWARF SPERM WHALE
TABLE 10. NUMBER OF CEPHALOPOD BEAKS FROM A STOMACH OF KOGIA SIMUS
FROM SOUTHERN BRAZIL
Cephalopods

Upper

Lower

Total
number

%of
total

No of
squidsFamily% of total

4
16

4
17

8
33
2

10.3
42.3
2.6

4
17

55.1

3

4

7

9.0

4

9.0

2

2
I

4
2

5.1
2.6

2

I

7.7

2

2.6

II

14.1

6

14.1

3

3.8

2

3.8

4

5.1

3

5.1

2

2.6

Histioteuthidae
Histioteuthis atlantica
Histioteuthis macrohista
Histioteuthis sp. (corpuscula ?)Lycoteuthidae
Lycoteuthis diadema(= Oregoniateuthis longimanus)

Cranchiidae
Megalocranchia maxima
Teuthowenia impennis

Mastigoteu thidae
Mastigoteuthis sp.

I

2.6

Chiroteuthidae
Chiroteuthis capensis

Brachioteuthidae
Brachioteuthis sp.

6

5

2

Sepiolidae
Rossia sp.?

3

Unidentified
Total

38

40

78

42

and Robineau (1981), Nagorsen and Stewart (1983) and Ross (1984).
Nevertheless, in most of the stomachs analyzed fish otoliths were also found.
Nematode parasites were present in great number.
Most of the beaks found in the present specimen belonged to species
Histioteuthis atlantica and H. macrohista, coinciding with what was observed fora K. simus specimen from New Zealand (Imber, pers. corn.).
F etal length
Body length at birth is not known for Kogia simus, but it is suggested to
be around 1 m by comparison with K. breviceps (Ross, 1979). Known recordsof fetal and juvenile K. simus are cited in Table 11 and the Southern HemisphereSci. Rep. Whales Res. Inst.,

No. 38, 1987

'Oo
l ;-

~~

,?o ~

~~

~~

.,~

~

~

"'~-

Nl 132C

-

1,275

1,470
1,035
1,030

femalefemalemale
femalefemalefemalefemale17/ 9175
21112/76
30/ 7177
3/ 3/81
31/ 3/82
5/ 7/83
19110/83
17/ 1/85

10173

28/ 4/70
Apr/May1970
24/ 317115/ 4/71
23/ 8172

21/ 4/39 3

DateSouth Africa
South Africa
South Africa
South Africa
South Africa
BrazilMexicoSouth Africa

U.S.A.

South Africa
South Africa
South Africa

South Africa

South Africa

U.S.A.

RegionRoss (1979)
Ross (1979)
Ross (1979)
Gunter and Overstreet (1974)
Ross (1979)
Ross (1984)
Ross (1984)
Ross (pers. corn.)
Ross (pers. corn.)
Present study
Fleischer et al. (1984)
Ross (pers. corn.)

Ross (1979)

Allen (1941)
Barbour (1950)
Ross (1979)

Sourcea. Although Allen (1941) mentions that this record was found on 2114/39, Barbour (1950) wrote it was found during Autumn of 1939.
b. Due to the great range of the estimated length this calf is not present in Figure 7.
c. Lactating female (PEM N678). Stranded near Gaimtoos River Mouth, Eastern Cape.
d. Lactating and calf stranded alive, Coega River Mouth, Algoa Bay.
e. Stranded 300m from an adult male, Cape Receife, Port Elizabeth. Preserved whole, stomach not examined .

PEMfemalefemale

260
591

-

-

1,610

female

1,220

-

-

PEM 1519172
ELM 935
PEM 1520/66
PEM N678C
PEM N830
MORG495

-

1,360
1,525
c. l ,OOO-I ,300b

female72c.200-250--

femalec.2,440
2,350
2,400

1516/50
1516/97
1518/02

PEM
PEM
PEM

1,525

325
960

2,305

PEM

1,520

-

?

2,240
2,500
2,200
2,410
2,380d2,490
2,270

2,310+

1515/501515/53

male

c. l,500

-

c.300

2,210

Sex ofcalf

Length ofcalf(mm)Sex offoetusLength offoetus (mm)Total length
(mm)

PEM

4038

MCZ

Cat. N°TABLE 11. RECORDS OF KOGIA SIMUS OF CALVES AND FEMALES WITH FOETUS OR CALF.

t:I
0

""z
M

"'"

00

......

185

A DWARF SPERM WHALE

0

8 0

1500

0
0
0

E

.§ 1000

est, length at birth8-------------------------------------

•

.s::.

.....
C>

.,c:

500

•
•

•
JFM

AMJJASONDJ

FMAMJ

JAS

Fig. 7. Lengths of foetuses .(•) and calves (O) of K. simus plottt;d against month ofoccurrence in the Southern Hemisphere.

records of the body length are plotted against the date in Fig. 7. The occurrenceof small foetuses in April and of large foetus and new born calves in November
to February suggests the matings in summer and births in early summer. The
gestation period is possibly about 9.5 months and the length at birth around
l m, agreeing with those suggested by Ross ( 1979).
ACKNOWLEDGEMENTS

I wish to thank Dr G.J. B. Ross and Mr V. G. Cockcroft, Port Elizabeth
Museum, South Africa, for their generous provision of foetuses and calves
unpublished records on Kogia simus from South Africa; Mr M. Imber, Wildlife
Service, Wellington, New Zealand, for identification of cephalopod beaks and
Dr G.J. B. Ross for his valuable comments on the manuscript.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

186

PINEDOREFERENCES
ALLEN, G.M., 1941. Pygmy sperm whale in the Atlantic. Zool. Series, Field Mus. Nat. Hist. (Chicago), 27:
17-36, figs 1-4.
BARBOUR, T., 1950. Naturalist at large. pp206-207. Robert Hale, London. 258 pp.
CARVALHO, C. T. DE, 1966. Notas sobre Kogia breviceps (Cetacea, Physeteridae). Rev. Biol. Trop., 14(2):169-181.
FITCH, J.E. and R.L. BROWNELL, ]R., 1968. Fish otoliths in cetacean stomachs and their importance ininterpreting feeding habits.]. Fish. Res. Bd. Can., 25(12): 2561-2574.
FLEISCHER, L.A., F. CERVANTES, R. FUENTES and G.E. MICHEL, 1984. New records of whales strandings at the
Bay of La Paz, Baja California Sur, Mexico. Presented at IX International Reunion of the Mexican
Society for the Study of Marine Mammals, La Paz, B.C.S., Mexico, 29-31 March.
GUNTER, G. and R. OVERSTREET, 1974. Cetacean notes. I. Sei and rorqual whales on the Mississippi coast,a correction. II. A dwarf sperm whale in Mississippi Sound and its helminth parasites. Gulf Res. Repts.,
4(3): 479-481.
HANDLEY, C. 0., 1966. A synopsis of the genus Kogia (pigmy sperm whale). pp. 62-69. In: K. S. Norris (ed.)
Whales, dolphins and porpoises. Univ. California Press, Berkeley and Los Angeles. 789pp.
]ONES, R.E., 1981. Food habits of smaller marine mammals from northern California. Proc. Calif. Acad. Sci.,
42: 409-433.
LEATHERWOOD, S., R.R. REEVES, W.F. PERRIN and W.E. EVANS, 1982. Whales, dolphins and porpoises of theeastern North Pacific and adjacent Arctic waters. A guide to their identification. NOAA Technical
Report NMFS Circular 444. 245pp.
MAIGRET, ]. and D. RoBINEAU, 1981. Le genre Kogia (Cetacea, Physeteridae) sur les cotes du Senegal.
Mammalia, 45(2): 199-204.
NAGORSEN, D.W. and G.E. STEWART, 1983. A dwarf sperm whale (Kogia simus) from the Pacific coast of
Canada.]. Mamm., 64(3): 505-506.
N1sH1WAKI, M., T. KASUYA, K. KUREHA and N. OGuRo, 1972. Further comments on Mesoplodon ginkgodens.
Sci. Rep. Whales Res. Inst., 24: 43-56.
OMURA, H., M. SHIRAKIHARA and H. ITO, 1984. A pygmy sperm whale accidentally taken by drift net in the
North Pacific. Sci. Rep. Whales Res. Inst., 35: 183-193.
OWEN, R., 1866. On some Indian Cetacea collected by Walter Elliot, Esq. Trans. Zool. Seo. Lond., 6(1):17-47, pl. III-XIV.
PINEDO, M. C. and H.P. Castello, 1980. Primeiros registros dos golfinhos Stenella coeruleoalba, Stenella cfr.
plagiodon e Steno bredanensis para o sul do Brasil, corn notas osteologicas. Bolm. Inst. Oceanogr.
(S. Paulo), 29(2): 313-317.
Ross, G.]. B., 1979. Records of pygmy and dwarf sperm whales, genus Kogia, from Southern Africa, withbiological notes and some comparisons. Ann. Cape Prov. Mus. (Nat. Hist.), 11(14): 259-327.
Ross, G.J. B., 1984. The smaller cetaceans of the South East coast of Southern Africa. Ann. Cape Prov. Mus.,
15: 173-410.
VAZ-FERREIRA, R. and R. PRADER!, 1973. Un nuevo ejemplar de Kogia breviceps (Blainvile) (Cetacea,
Physeteridae) de! Atlantico Sudoccidental. Caracteres y notas. Trab. V Congr. Latinoam. Zool., l:261-277.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

SIGHTING RECORDS OF FRASER'S DOLPHIN
IN THE MEXICAN PACIFIC WATERSANELIO AGUAYO L.* AND RAFAEL SANCHEZ T.*

Lagenodelphis hosei Fraser, 1956 is distributed in the tropical and temperatewaters of the Pacific, Atlantic and Indian Oceans (Perrin, Best, Dawbin,
Balcomb, Gambell and Ross, 1973; Tobayama, Nishiwaki and Yang, 1973;
Miyazaki and Wada, 1978; Leatherwood, Reeves, Perrin and Evans, 1982;
Caldwell, Caldwell and Walker, 1976; Hersh and Odell, 1983).
We report here two additional sighting records of this species in thewaters of the Archipelago of Revillagigedo, Mexico (Fig. 1).
The first was a group of 20 animals sighted by one of us (AAL), on July3, 1981, at l9°47'N, l l0°42'W, 54 km off the nearest coast. The robust body,
short snout, semifalcate dorsal fin, small flippers and lateral stripe were

60"

-·

CllPPERTON IS.

0

.. '

",oo..--',,~o------,..
,o-·----,....0---,-.0------""'rno---•,o----,""o-.....,_--",o-·____......,_ __._.....60 ·60'
Fig. 1. Records of occurrence of Lagenodelphis hosei. Black circles are strandings or
captures and white circles are sightings in the published records. Asterisks represent
present records.

* Laboratorio de Vertebrados, Facultad de Ciencias, UNAM, Apdo. Postal No 70-572, 04510, Mexico, D. F., Mexico
Sci. Rep. Whales Res. Inst.,
No.38,1987,187-188

188

AGUAYO AND SANCHEZ

observed. The surface water temperature was 26°C, and the water depth wasover 1,000 m.
The second was a group of 3 animals sighted by us on January 18, 1985,
at l8°24'N, l l4°23'W, 27 km off the nearest coast. The species was identified
based on the same characteristics as of the first sighting. The surface watertemperature was 25°C, and the water depth there was 3,100 meters.
These sightings represent the most boreal records of this species in theeastern Tropical Pacific.
We want to express our gratitude to Dr Nobuyuki Miyazaki for his help
and constructive comments to the present note, and to M.A. de la Mora fordrawing.
REFERENCESCALDWELL, D.K., M.C. CALDWELL and R.V. WALKER, 1976. First records for Fraser's dolphin (Lagenodelphis
hosei) in the Atlantic and the Melon-headed Whale (Peponocephala electra) in the western Atlantic.
Cetology, 25: 1-3.
HERSH, S. L. and D. K. ODELL, 1983. A mass stranding of Fraser's dolphin from the Marquesas Keys,
Florida. p.44. In: Fifth Biennial Conference on the Biology of Marine Mammals. Abstracts.
November 27- December 1, 1983, Boston, Massachusetts. 112 pp.
LEATHERWOOD, S., R.R. REEVES, W.F. PERRIN and W.E. EVANS, 1982. Whales, Dolphins and Porpoises of theEastern North Pacific and Adjacent Arctic Waters. A Guide to Their Identification. NOAA Technical
NMFS Circular 444. 245 pp.
MIYAZAKI, N. and S. WADA, 1978. Fraser's Dolphin in the western North Pacific. Sci. Rep. Whales Res. Inst.,
30: 231-244.
PERRIN, W.F., P.B. BEST, W.H. DAWBIN, K.C. BALCOMB, R. GAMBELL and G.J.B. Ross, 1973. Rediscovery of
Fraser's dolphin (Lagenodelphis hosei). Nature, 241 (5388): 345-350.
ToBAYAMA, T., M. NISHIWAKI and H. C. YANG, 1973. Records of the Fraser's Sarawak dolphin (Lagenodelphis
hosei) in the western North Pacific. Sci. Rep. Whales Res. Inst., 25: 251-263.

Sci. Rep. Whales Res. Inst.,
No. 38, 1987

THE SCIENTIFIC REPORTS OF THE WHALES RESEARCHINSTITUTE, TOKYO, JAPANNUMBER 1, JUNE 1948
Akiya, S. and S. Tejima. Studies on digestive enzyme in whale. 3-7
Akiya, S., Y. Ishikawa, S. Tejima, and T. Tanzawa. Studies on tryptase from a whale (Balaenoptera borealisL.). 8-10
Akiya, S., S. Tejima, and Y. Ishikawa. Studies on the utilization of whale meat by the use of pancreatic
tryptaseofwhales. 11-14
Akiya, S. and F. Kobo. The test culture of some microorganisms with whale meat peptone. 15-16
Nakai, T. Chemical studies on the freshness of whale meat. I. Evaluation of freshness and changes inquantity of several kinds of nitrogen in whale meat following deterioration of freshness. 17-26
Nakai, T. Chemical studies on the freshness of whale meat. II. On comparison between whale meat andbeef on deterioration of freshness and autolysis. 27-30
Tawara, T. On the simultaneous extraction of vitamin A-D and vitamin B2 complex from the liver of afin whale (Nagasu-Kujira, Balaenoptera physalus L. ). 31-37
Tawara, T. Studies on whale blood. I. On the separation of histidine from whale blood. 38--40
Nakai,J. and T. Shida. Sinus-hairs of the sei-whale (Balaenoptera borealis). 41-47

NUMBER 2, DECEMBER 1948
Ogawa, T. and S. Arifuku. On the acoustic system in the cetacean brains. 1-20
Yamada, M. Auditory organ of the whalebone whales. (Preliminary report). 21-30
Nakai, T. Chemical studies on the freshness of whale meat. III. Effect of hydrogen-ion concentration on
decrease in freshness and titration curve of whale meat with HCl and Na 1 C0 2 • 31-34
Ishikawa, S., Y. Omote, and Y. Soma. Analytical distillation of vitamin A in the whale liver oil. 35--41
Ishikawa, S., Y. Omote, and H. Kanno. Molecular distillation of sperm whale blubber oil. 42--45
Kaneko, A. Molecular distillation of fin whale liver oil. 46--50
Akiya, S. and K. Takahashi. Determination oftryptophane in whale meat. 51-54
Ishikawa, Y. and S. Tejima. Protein digestive power of sperm whale pancreatic enzyme. 55-60
Tsukamoto, S. Experiment on digestion of whale meat by koji-mould. 61-66

NUMBER 3, FEBRUARY 1950
Ogawa, T. and T. Shida. On the sensory tubercles oflips and of oral cavity in the sei and the fin whale.
1-16
Ohe, T. Distribution of the red marrow in bones of the fin whale. 17--22
Hosokawa, H. On the cetacean larynx, with special remarks on the laryngeal sack of the sei whale andthe aryteno-epiglottideal tube of the sperm whale. 23-62
Akiba, T., T. Tsuchiya, M. Umehara, and Y. Natsume. Bacteriological studies on freshness of whale
meat. (Report No. 1). 63-70
Ishikawa, Y. Protein digestive power of sperm whale pancreatic enzyme. II. 71-78
Mori, T. and M. Saiki. Properties of fats and oils contained in various parts of a sperm whale body. 7984
Tawara, T. and R. Fukazawa. Studies on kitol. I. Preparation ofkitol from whalP. liver oil. 85-88
Tawara, T. and R. Fukazawa. Studies on kitol. II. Influence of kitol fraction on the determination of
the International Unit of Vitamin A. 89-91
Tawawa, T. and R. Fukazawa. Studies on kitol. III. The effect of sunlight, air and heat on the vitamin
A and kitol fractions. 92-95

ii
Tawara, T. On the respiratory pigments of whale (Studies on whale blood II.). 96-101
Yoshida, M. Research on methionine in whale. 102-105
Mizue, K. Factory ship whaling around Bonin Islands in 1948. 106-118
Mizue, K. and H. Jimbo. Statistic study of foetuses of whales. 119-131
Nishiwaki, M. and K. Hayashi. Biological survey of fin and blue whales taken in the Antarctic season
1947-48 by the Japanese fleet. 132-190

NUMBER 4, AUGUST 1950
Omura, H. On the body weight of sperm and sei whales located in the adjacent waters of Japan. 1-13
Omura, H. Diatom infection on blue and fin whales in the Antarctic whaling area V (the Ross Sea area).
14-26
Omura, H. Whales in the adjacent waters ofJapan. 27-113
Nishiwaki, M. Determination of the age of Antarctic blue and fin whales by the colour changes in crystalline lens. 115-161
Nishiwaki, M. Age characteristics in baleen plates. 162-183
Nishiwaki, M. On the body weight of whales. 184-209

NUMBER 5, JUNE 1951
Akiba, T., M. Umehara and Y. Natsume. Bacteriological studies on freshness of whale meat. (Report
No. II.). 1--4
Hosokawa, H. On the pelvic cartilages of the Balaenoptera-foetuses, with remarks on the specifical andsexual difference. 5-15
Ohe, T. Iconography on the abdominal cavity and viscera of the Balaenoptera, with special remarks upon
the peritoneal coverings. 17-39
Akiya, S. and 0. Hoshino. Isolation of histidine from whale blood using 3,4-dichlorobenzene sulfonic acid.
41-47
Tawara, T. and R. Fukazawa. StudiP.s on kitol. IV. Purification ofkitol by chromatographic. 49-51
Ishikawa, S., Y. Omote and H. Okuda. Substances related to vitamin A in the whale liver oil. 53-59
Ishikawa, S., Y. Omote, M. Kijima and H. Okuda. Thermal decomposition ofkitol. 61-69
Mizue, K. Grey whales in the east sea area of Korea. 71-79
Mizue, K. Food of whales (In the adjacent waters of Japan). 81-90
Nishiwaki, M. and T. Ohe. Biological investigation on blue whales (Balaenoptera musculus) and fin whales(Balaenoptera pll)'salus) caught by the Japanese Antarctic whaling fleets. 91-167

NUMBER 6, DECEMBER 1951
Hosokawa, H. On the extrinsic eye muscles of the whale. with special remarks upon the innervation andfunction of the musculus retractor bulbi. 1-33
Murata, T. Histological studies on the respiratory ·portions of the lungs of cetacea. 35-47
Kojima, T. On the brain of the sperm whale (Physeter catodon L.). 49-72
Mizue, K. and T. Murata. Biological investigation on the whales caught by the Japanese Antarctic whaling
fleets season 1949-50. 73-131
Nishiwaki, M. On the periodic mark on the baleen plates as the sign of annual growth. 133-152
Nishiwaki, M. and T. Hibiya. On the sexual maturity of the sperm whales (P~yseter catodon) found in theadjacent waters of Japan (I). 153-165
Nakai, T. Chemical studies on freshness of whale meat. IV. Some informations of Archomobacter ubiquitum
isolated from whale carcass. 167-176
Nakai, T. and H. Ono. The effects of electric shock and fatigue on post-mortem changes in muscle. 177185

iii
Omote, Y. Complete recovery of vitamin A from molecular distillation residue of whale-liver oil. 187191
Omote, Y. Chemical structure ofkitol (I). Double bonds and hydroxyl groups. 193-198
Hirata, M. Experime"ntal investigation on flattened head harpoon. An attempt for restraining ricochet.
199-207

NUMBER 7, JULY 1952
Ogawa, T. On the cardiac nerves of some cetacea, with special reference to those" of Berardius bairdii
Stejneger. 1-22
Akiya, S., 0. Hoshino and N. Motohashi. On an attempt to preserve whale meat freshness with 5-nitrofurfuriden aminoguanidine from decay. 23-30
Akiya, S. and R. Sawamura. Colorimetric determination of 5-nitro-2-furfuridene aminoguanidine. 31-36
Tomiyama, S. and M. Takao. Studies on utilization of higher fatty alcohol from sperm whale oil. 37--46
Omote, Y. A rapid method for the separate determination of vitamin A and kitol in the whale-liver oil.
47-50
Arai, Y. and S. Sakai. Whale meat in nutrition. 51-67
Yamaguchi, K. and K. Fujino. On the serological constitution of striped dolphin (Prodelphinus caeruleoalbus(Meyen)) (I). 67-77
Nishimoto, S., M. Tozawa and T. Kawakami, Food ofsei whales (Balaenoptera borealis) caught in the Bonin
Island waters. 79-85
Nishiwaki, M. On the age-determination of Mystacoceti, chiefly blue and fin whales. 87-119
Nishiwaki, M. and T. Hibiya. On the sexual maturity of the sperm whales (Physeter catodon) found in theadjacent waters of Japan (II). 121-124
Ohno, M. and K. Fujino. Biological investigation on the whales caught by the Japanese Antarctic whaling
fleets, season 1950/51. 125-183

NUMBER 8, JUNE 1953
Yamada, M. Contribution to the anatomy of the organ of hearing of whales. 1-79
Omura, H. Biological study on humpback whales in the Antarctic :whaling areas IV and V. 81-102
Fujino, K. On the serological constitutions of the s~i-, fin-, blue- and humpback-whales (I). 103-125
Ogawa, T. On the presence and disappearance of the hind limb in the cetacean embryos. 127-132
Nishiwaki, M. and T. Yagi. On the age and the growth of teeth in a dolphin (Prodelphinuscaeruleo-albus).
(I). 133-146
Kakuwa, Z., T. Kawakami and K. Iguchi. Biological investigation on the whales caught by the Japanese Antarctic whaling fleets in the 1951-52 season. 147-213
Nishiwaki, M. Hermaphroditism in a dolphin (Prodelphinuscaeruleo-albus). 215-218

NUMBER 9, JUNE 1954
Akiya, S., 0. Hoshino and N. Motohashi. Attempt to preserve freshness of whale meat with germicides.
II. 1-10
Ogawa, T. On the musculature of the sinus venosus and its continuation with the so-called conducting
system of the whale's heart. 11-35
Yamada, M. Some remarks on the pygmy sperm whale, Kogia. 37-58
Yamada, M. An account of a rare porpoise, Feresa Gray from Japan. 59-88
Omura, H. and K. Fujino. Sei whales in the adjacent waters ofJapan. II. Further studies on the external
characters. 89-103
Fujino, K. On the serological constitution of the sperm- and Baird beaked-whales (I) Blood groups ofthe sperm- and Baird beaked-whales. 105-120

iv
Fujino, K. On the body proportions of the fin whales (Balaenoptera physalus (L)) caught in the northern
Pacific Ocean (I) (Preliminary report). 121-163
Nishiwaki, M., T. Hibiya and S. Kimura. On the sexual maturity of the sei whale of the Bonin waters.
165-177
Uda, M. Studies of the relation between the whaling grounds and the hydrographical conditions (I).
179-187

NUMBER 10, JUNE 1955
Hosokawa, H. Cross-sections of a 12-mm. dolphin embryo. 1-68
Nemoto, T. White scars on whales (I) Lamprey marks. 67-77
Omura, H. and T. Nemoto. Sei whales in the adjacent waters of Japan. III. Relation between movement and water temperature of the sea. 79-87
Omura, H., K. Fujino and S. Kimura. Beaked whale Berardius bairdi of Japan, with notes of <:,iphiuscavirostris. 89-132
Fujino, K. On the body weight of the sei whales located in the adjacent waters of Japan (II.) 133-141
Nishiwaki, M. On the sexual maturity of the Antarctic male sperm whale (Physeter catodon L.). 143-149
Ohta, K., T. Watarai, T. Oishi, Y. Ueshiba, S. Hirose, T. Yoshizawa, Y. Akikusa, M. Sato and K. Okano,Composition of fin whale milk. 151-167

NUMBER 11, JUNE 1956
Omura, H. and H. Sakiura. Studies on the little piked whale from the coast of Japan. 1-37
Nishiwaki, M., T. Hibiya and S. Kimura. On the sexual maturity of the sperm whale (Physeter catodon)
found in the North Pacific. 39-46
Fujino, K. On the body proportions of the sperm whales (Pr,yseter catodon). 47-83
Fujino, K. On the serological constitution of the fin whales II. Further studies on blood groups. 85-98
Nemoto, T. On the diatoms of the skin film of whales in the northern Pacific. 99-132
Hoshina, T. and Y. Sugiura. On a skin disease and a nematode parasite of a dolphin, Tursiops truncatus(Montagu, 1821). 133-138
Iwai, E. Descriptions on unidentified species of dibranchiate cephalopods. I. An oegopsiden squid belonging to the genus Architeuthis. 139-151
Iwai, E. Descriptions on unidentified species of dibranchiate cephalopods. II. A cranchiidae squid of thegenus Taonius. 153-161
Uda, M. and K. Nasu. Studies of the whaling grounds in the northern sea-region of the Pacific Ocean inrelation to the meteorological and oceanographic conditions. (Part I). 163-179
Kimura, S. and T. Nemoto. Note on a minke whale kept alive in aquarium. 181-189
Ishikawa, Y. A characteristic property of whale oils concerning the absorption of gases. I. On the absorption of carbon dioxide by whale oils. 191-213

NUMBER 12, JUNE 1957
Omura, H. Osteological study of the Ii ttle piked whale from the coast of Japan. 1-21
Nishiwaki, M. Age characteristics of ear plugs of whales. 23-32
Nemoto, T. Foods of baleen whales in the northern Pacific. 33-89
Nasu, K. Oceanographic conditions of the whaling grounds in the waters adjacent to Aleutian Islands andthe Bering Sea in summer of 1955. 91-101
Kimura, S. The twinning in southern fin whales. 103-125
Ichihara, T. An application oflinear discriminant function to external measurements of fin whale. 127189

v
Nishiwaki, M. Very small embryo of cetacea. 191-192
Nishiwaki, M. One-eyed monster of fin whale. 193-195
Ogawa, T. and T. Kamiya. A case of the cachalot with protruded rudimentary hind limbs. 197-208
Uda, M. and A. Dairokuno. Studies of the relation between the whaling grounds and the hydrographic
conditions. II. A study of the relation between the whaling grounds off Kinkazan and the boundaryof water masses. 209-224
Abe, T. Notes on fishes from the stomachs of whales taken in the Antarctic. I. Xenocyttus nemotoi, a new
genus and new species of zeomorph fish of the subfamily Oreosonimae Goode and Bean, 1895. 225-233
Tsuyuki, H. On the oils contained in various blubbers of northern elephant seal, Mirounga angustirostris.
235-240NUMBER 13, SEPTEMBER 1958
Omura, H. North Pacific right whale. 1-52
Nishiwaki, M. and T. Kamiya. A beaked whale Mesoplodon stranded at Oiso Beach, Japan. 53-83
Nishiwaki, M. and C. Handa. Killer whales caught in the coastal waters off Japan for recent 10 years.
85-96
Ohsumi, S. (Kimura), M. Nishiwaki and T. Hibiya. Growth of fin whale in the northern Pacific. 97133
Nishiwaki, M., T. Hibiya and S. Ohsumi (Kimura). Age study of sperm whale based on reading of
tooth laminations. 135-153
Nishiwaki, M., T. Ichihara and S. Ohsumi (Kimura). Age studies of fin whale based on ear plug. 155169
Fujino, K. On the serological constitution of fin whale. III. Human B blood group substances in erythrocytes and some notes on anti-fin Ju specific antibodies. 171-184
Nemoto, T. Cocconeis diatoms infected on whales in the Antarctic. 185-191
Nemoto, T. and K. Nasu. Thysanoessa macrura as a food of baleen whales in the Antarctic. 193-199
Ichihara, T. Gray whale observed in the Bering Sea. 201-205
Ohsumi, S. (Kimura). A descendant of Moby Dick or a white sperm whale. 207-209
Nasu, K.. Deformed lower jaw of sperm whale. 211-212
Omura, H. Note on embryo of Baird's beaked whale. 213-214
Uda, M. and N. Suzuki. Studies of the relation between the whaling grounds and the hydrographic conditions. III. The averaged conditions of the whaling grounds and their trends of variation during
1946-55. 215-229
Seki, Y. Observations on the spinal cord of the right whale. 231-251
Kamiya, T. How to count the renculi of the cetacean kidneys, with special regard to the kidney of theright whale. 253-267
Hosokawa, H. and T. Sekino. Comparison of the size of cells and some histological formations between
whales and man. 269-301
Ogawa, T., T. Tsunoda and M. Osawa. Amino acid composition of whale meat. 303-307
Ishikawa, Y. A characteristic property of whale oils concerning the absorption of gases. II. On the absorption of nitrogen by whale oils. 309-321
Tsuyuki, H. Component fatty acids of northern elephant seal oil. 323-332

NUMBER 14, SEPTEMBER 1959
Omura, H. Bryde's whale from the coast of Japan. 1-33
Nishiwaki, M. and T. Kamiya. Mesoplodon stejenegeri from the coast ofJapan. 35-48
Nishiwaki, M. Humpback whales in Ryukyuan waters. 49-87
Cushing, John E., K. Fujino and K. Takahashi. Glycerol-freezing technique as an aid in blood typingof whales. 89-100

vi
Fujino, K. and John E. Cushing. Blood typing of dried whale erythrocytes with 1311 labelled antibody.
101-106lchihara, T. Formation mechanism of ear plug in baleen whales in relation to glove-finger. 107-135
Nasu, K. Surface water condition in the Antarctic whaling Pacific area in 1956-57. 137-143
Ohsumi, S. (Kimura). A deformed fin whale foetus. 145-147
Nemoto, T. Food of baleen whales with reference to whale movements. 149-290
Yamada, M. and F. Yoshizaki. Osseous labyrinth ofcetacea. 291-304
Nakai, T. Distribution of amino acid in proteins from various parts of whale body. 305-326

NUMBER 15, NOVEMBER 1960
Nishiwaki, M. Ryukyuan humpback whaling in 1960. 1-16
Ohsumi, S. Relative growth of the fin whale, Balaenoptera ph_vsalus (Linn.). 17-84
Fujino, K. Immunogenetic and marking approaches to identifying subpopulations of the North Pacificwhales. 85-142
Nasu, K. Oceanographic investigation in the Chukchi Sea during the summer of 1958. 143-158
Tokita, K. and ECG Research Group. Electrocardiographical studies on bottlenosed dolphin (Tursiops
truncatus). 159-165

NUMBER 16, MARCH 1962
Omura, H. Bryde's whale occurs on the coast of Brazil. 1-5
Omura, H. Further information on Bryde's whale from the coast of Japan. 7-18
Nishiwaki, M. Ryukyuan whaling in 1961. 19-28
Nemoto, T. A secondary sexual character of fin whales. 29-34
Omura, H., M. Nishiwaki, T. lchihara and T. Kasuya. Osteological note of a sperm whale. 35-45
lchihara, T. Prenatal dead foetus of baleen whales. 47-60
Nishiwaki, M. Mesoplodon bowdoini stranded at Akita Beach, Sea of Japan. 61-77
Nishiwaki, M. Observation on two mandibles of Mesoplodon. 79-82
Sinclair, John. An early dolphin embryo (Stenella caeruleoalbus) in serial sections. 83-87
Nemoto, T. Food of baleen whales collected in recent Japanese Antarctic whaling expeditions. 89-103
Uda, M. Subarctic oceanography in relation to whaling and salmon fisheries. 105-119

NUMBER 17, FEBRUARY 1963
Nishiwaki, M., S. Ohsumi and T. Maeda. Change of form in the sperm whale accompanied with growth.
1-14
Ohsumi, S., T. Kasuya and M. Nishiwaki. The accumulation rate of dentinal growth layers in the maxillary tooth of the sperm whale. 15-35
lchihara, T. Photometric method for counting laminae in ear plug of baleen whale. 37-48
Yoshikawa, T. and T. Suzuki. The lamination of the masseter of the humpback whale. 49-52
Fujino, K. Intra-uterine selection due to maternal-foetal in compatibility of blood type in the whales.
53-65
Cushing, John E., K. Fujino and N. CalapriC'e. The Ju blood typing system of the sperm whale and specificsoluble substances. 67-77
Nemoto, T. New records of sperm whales with protruded rudimentary hind limbs. 79-81
Nemoto, T. and K. Nasu. Stones and other aliens in the stomachs of sperm whales in the Bering Sea.
83-91
Nishiwaki, M. Taxonomical consideration on genera of Delphinidae. 93-103
Nasu, K. Oceanography and whaling ground in the subarctic region of the Pacific Ocean. 105-155

vii
Nemoto, T. Some aspects of the distribution ofCalanus cristatus and C. plumchrus in the Bering and its neighbouring waters, with reference to the feeding of baleen whales. 157-170
Tsuyuki, H. and U. Naruse. Studies on the oil of black right whale in the northern Pacific Ocean. 171190
Yagi, T., M. Nishiwaki and M. Nakajima. A preliminary study on the method of time marking withleadsalt and tetracycline on the teeth of northern fur seal. 191-195

NUMBER 18, MARCH 1964
Fujino, K. Fin whale subpopulations in the Antarctic whaling areas II, III and IV. 1-27
Ichihara, T. Prenatal development of ear plug in baleen whales. 29-48
Ohsumi, S. Examination on age determination of the whale. 49-88
Nemoto, T. School of badeen whales in the feeding areas. 89-110.
Okutani, T. and Nemoto, T. Squids as the food of sperm whales in the Bering Sea and Alaskan Gulf.
111-122
Ohsumi, S. Comparison of maturity and accumulation rate of corpora albicantia between the left andright ovaries in cetacea. 123-148
Omura, H. A systematic study of the hyoid bones in the baleen whales. 149-170
Nishiwaki, ?\I. Revision of the article "Taxonomical consideration on genera of Delphinidae" in No. 17.
171-172
Tsuyuki, H. and U. Naruse. Studies on the lipids in brain of black right whale in the northern Pacific
Ocean. 173-180

NUMBER 19, APRIL 1965
Ohsumi, S. Reproduction of the sperm whale in the north-west Pacific. 1-35
Kasuya, T. and T. Ichihara. Some informations on minke whales from the Antarctic. 37-43'Nemoto, T. and T. Kasuya. Foods of baleen whales in the Gulf of Alaska of the North Pacific. 45-51
Nishiwaki, M., M. Nakajima and T. Kamiya. A rare species of dolphin (Stene/la attenuata) from Arari,Japan. 53-64
Nishiwaki, M., T. Kasuya, T. Tobayama, T. Kamiya and M. Nakajima. Feresa attenuata captured at the
Pacific Coast of Japan in 1963. 65-90
Nakajima, M. and M. Nishiwaki. The first occurrence ofa porpoise (Electra electra) in Japan. 91-104
Hosokawa, H. and T. Kamiya. Sections of the dolphin's head (Stene/la caeruleoalba). 105-133
Ohsumi, S. A dolphin (Stene/la caeruleoalba) with protruded rudimentary hind limbs. 135-136

NUMBER 20, SEPTEMBER 1966
Ohsumi, S. Sexual segregation of the sperm whale in the North Pacific. 1-16
lchihara, T. Criterion for determining age of fin whale with reference to ear plug and baleen plate. 1782
Kasuya, T. Caryotype of a sei whale. 83-88
Kasuya, T. and S. Ohsumi. A secondary sexual character of the sperm whale. 89-94
Nishiwaki, M. and K. S. Norris. A new genus, Peponocephala, for the odontoceti cetacean species Electra
electra. 95-100
Nishiwaki, M., M. Nakajima and T. Tobayama. Preliminary experiments for dolphin marking. 101107
Nemoto, T. Thysanoessa euphausiids, comparative morphology, allomorphosis and ecology. 109-155
Nasu, K. Fishery oceanographic study on the baleen whaling grounds. 157-210
lchihara, T. and M. Nishiwaki. External measurements and weight of a southern elephant seal. 211-212

viii
Tsuyuki, H. and S. Itoh.

Studies on the oils contained in blubber of a southern elephant seal.

213-22 l

NUMBER 21, JUNE 1969
Omura, H., S. Ohsumi, T. Nemoto, K. Nasu and T. Kasuya. Black right whales in the North Pacific.
1-78
Nishiwaki, M. and Y. Hasegawa. The discovery of the right whale skull in the Kisagata shell bed. 79-84
Ohsumi, S. Occurrence and rupture of varginal band in the fin, sei, and blue whales. 85-94
Hosokawa, H., S. Igarashi, T. Kamiya and K. Hirosawa. Morphological characteristics and myelinization of acoustic system in the dolphins (Stene/la caeruleoalba). 95-123
Mo!, T. and P.J.H. van Bree. A ·short contribution to the history of whaling in Japan during the l 7th
century. 125-129
Tsuyuki, H. and S. Itoh. Fatty acid composition of finless porpoise oil. 131-135.
Tsuyuki, H. and S. Itoh. Fatty acid composition of many toothed pilot whale oil. 137-141

NUMBER 22, JUNE 1970
Omura, H., T. Ichihara and T. Kasuya. Osteology of pygmy blue whale with additional information on
external and other characteristics. 1-27
Nishiwaki, M. and T. Kasuya. Recent record of gray whale in the adjacent waters of Japan and a consideration on its migration. 29-37
Kasuya, T. and D. W. Rice. Note on baleen plates and on arrangement of parasitic barnacles of graywhale. 39-43
Nishiwaki, M. and T. Kasuya. A Greenland right whale caught at Osaka Bay. 45-62
Nasu, K. and Y. Masaki. Some biological parameters for stock assessment of the Antarctic sei whale.
63-74
Ohsumi, S., Y. Masaki and A. Kawamura, Stock of the Antarctic minke whale. 75-125
Kawamura, A. Food ofsei whale taken by Japanese whaling expeditions in the Antarctic season 1967/68.
127-152
Nemoto, T. and K. I. Yoo. An amphipod, Parathemisto gaudichaudii as a food of the Antarctic sei whale.
153-158
Tobayama, T., S. Uchida and M. Nishiwaki. Twin foetuses from a blue white dolphin. 159-162
Machida, S. A sword-fish sword found from a North Pacific sei whale. 163-164
Tsuyuki, H. and S. I toh. Fatty acid components of black right whale oil by gas chromatography. 165-170

NUMBER 23, SEPTEMBER 1971
Ohsumi, S. Some investigations on the school structure of sperm whale. 1-25
Kawamura, A. Influence of chasing time to stomach contents of baleen and sperm whales. 27-36
Kasuya, T. Consideration of distribution and migration of toothed whales off the Pacific coast of Japan
based upon aerial sighting record. 37-60
Omura, H. A comparison of the size of vertebrae among some species of the baleen whales with specialreference to whale movements. 61-69
Omura, H., M. Nishiwaki and T. Kasuya. Further studies on two skeletons of the black right whale in
the North Pacific. 71-81
Nishiwaki, M. and T. Kasuya. Osteological note of an Antarctic sei whale. 83-89
Hosokawa, H. and T. Kamiya. Some observations on the cetacean stomachs, with special considerations
on the feeding habits of whales. 91-101
Lugassy, A. A., E. Korostoff and J. L. Rabinowits. Influence of incremental lines upon the compressive
strength of sperm whale dentin. 103-110

ix
Nishiwaki, M. and N. Oguro. Baird's beaked whales caught on the coast of Japan in recent 10 years.
111-122
Mizue, K., M. Nishiwaki and A. Takemura. The underwater sound of Ganges river dolphins (Platanista
gangetica). 123-128
Kasuya, T. and M. Nishiwaki. First record of Mesoplodon densirostris from Formosa. 129-137
Kawamura, A. and K. Kashita. A rare double monster of dolphin, Stene/la caeruleoalba. 139-140
Tsuyuki, H. and S. Itoh. Fatty acid components of Ganges river dolphin oil. 141-147

NUMBER 24, NOVEMBER 1972
Omura, H. An osteological study of the Cuvier's beaked whale, -?,iphius cavirostris, in the northwest Pacific.
1-34
Nishiwaki, M. and N. Oguro. Catch of the Cuvier's beaked whales off Japan in recent years. 35-41
Nishiwaki, M., T. Kasuya, K. Kureha and N. Oguro. Further comments of Mesoplodor. gingkodens. 43-56
Kasuya, T. Growth and reproduction of Stene/la caeruleoalba based on the age determination by means ofdentinal growth layers. 57-79
Kasuya, T. and N. Oguro. A new tagging method of dolphins. 81-85
Kasuya, T. Some informations on the growth of the Ganges dolphin with a comment on the Ind us dolphin.
87-108Kasuya, T. and A.K.M. Aminul Haque. Some informations on the distribution and seasonal movementof the Ganges dolphin. 109-115
Tsuyuki, H. and S. Itoh. Fatty acid component of various blubber oil of Ganges River dolphin. 117-125
Naito, Y. and M. Nishiwaki. The growth of two species of the harbour seal in the adjacent waters of
Hokkaido. 127-144
Ichihara, T. and K. Yoshida. Diving depth of northern fur seals in the feeding time. 145-148

NUMBER 25, SEPTEMBER 1973
Kasuya, T. Systematic consideration of recent toothed whales based on the morphology of tympanoperiotic bone. 1-103
Omura, H. A review of pelagic whaling operations in the Antarctic based on the effort and catch data in
10° squares of latitude and longitude. 105-203
Nasu, K. Results of whale sighting by Chiyoda Maru No. 5 in the Pacific sector of the Antarctic andTasman Sea in the 1966/67 season. 205-217
Kawamura, A. Food and feeding of sei whale caught in the waters south of 40°N in the North Pacific.
219-236
Ohsumi, S. Find of marlin spear from the Antarctic minke whales. 237-239
Seki, Y. An anatomical study on the lower extension of the dorasl vagal nucleus to the upper cervical
cord in the sperm whale. 241-249
Tobayama, T., M. Nishiwaki and H. C. Yang. Records of the Fraser's Sarawak dolphin (Lagmodelphis
hosei) in the western North Pacific. 251-263
Miyazaki, N., T. Kusaya and M. Nishiwaki. Food of Stene/la caeruleoalba. 265-275
Nishiwaki, M. Possible vestigial teats of killer whale. 277-278
Williamson, G. R. Counting and measuring baleen and ventral grooves of whales. 279-292
Tsuyuki, H. and S. Itoh. Fatty acid component of blubber oil of Amazon River dolphin. 293-299
Naito, Y. Comparison in colour pattern of two species of harbour seal in adjacent waters of Hokkaido.
301-310x

NUMBER 26, NOVEMBER 1974
Omura, H. PoJSible migration route of the gray whale on the coast ofJapan. 1-14
Satake, Y. and H. Omura. A txonomic study of the minke whale in the Antarctic by means ofhyoid bone.
15-24
Kawamura, A. Food and feeding ecology in the southern sei whale. 25-144
McCann, C. Body scarring on cetacea-odontocetes. 145-155
Kasuya, T., N. Miyazaki and W. H. Dawbin. Growth and reproduction of Stene/la attenuata in the Pacificcoast of Japan. 157-226
Miyazaki, N., T. Kasuya and M. Nishiwaki. Distribution and migration of two species of Stene/la in the
Pacific coast of Japan. 227-243
Kamiya, T. and P. Pirlot. Brain morphogenesis in Stene/la coeruleoalba. 245-253
Castello, H.P., A. P. Torno and J. S. Panizza. First Antarctic record of a killer whale stranding. 255258
Kamiya, T. and N. Miyazaki. A malformed embryo of Stene/la coeruleoalba. 259-263
Kamiya, T. and F. Yamasaki. Organ weights of Pontoporia blainvillei and Platanista gangetica (Platanistidae).
265-270
Machida, S. Surface temperature field in the Crozet and Kerguelen whaling grounds. 271-287
Machida, S. The voyage of the Konan Maru No. 16 to the Antarctic whaling grounds. 289-302
Itoh, S. and H. Tsuyuki. Fatty acid component of different blubber oil of finless porpoise. 303-306
Itoh, S. and H. Tsuyuki. Fatty acid component of Senegal manatee fats. 309-311
Naito, Y. Thr hyoid bones of two kinds of harbour seals in the adjacent waters of Hokkaido. 313-320

NUMBER 27, SEPTEMBER 1975
Omura, H. Osteological study of the minke whale·from the Antarctic. 1-36
Williamson, G. R. Minke whales off Brazil. 37-59
Kawamura, A. A consideration on an available source of energy and its cost for locomotion in fin whales
with special reference to the seasonal migrations. 61-79
Kasuya, T. and M. Nishiwaki. Recent status of the population of Indus dolphin. 81-94
Kasuya, T. Past occurrence of Globicephala melaena in the western North Pacific. 95-108
McCann, C. A study of the genus Berardius Duvernoy. 111-137
Nishiwaki, M. and K. Kureha. Strange organ in the anal region of the finless porpoise. 139-140
Machida. S. Distribution of sperm whale catches in the southern Indian Ocean. 141-159

NUMBER 28, OCTOBER 1976
Kawamura, A. and Y. Satake. Preliminary report on the geographical distribution of the Bryde's whalein the North Pacific with special reference to the structure of the filtering apparatus. 1-35
Pivorunas, A. A mathematical consideration on t~e function of baleen plates and their fringes. 37-55
Omura, H. and T. Kasuya. Additional information on skeleton of the minke whale from the Antarctic.
57-68
Omura, H. A skull of the minke whale dug out from Osaka. 69-72
Kasuya, T. Reconsideration of life history parameters of the spotted and striped dolphins based on cementa! layers. 73-106
McCann, C. Notes on the foetal skull of Mesoplodon stejnegeri. 107-117
Gianuca, N. M. and H.P. Castello. First record of the southern bottlenose whale, Hyperoodon planifrons
from Brazil. 119-126
Brownell, R. L. Jr., L. A. Aguayo and N. D. Torres. A Shepherd's beaked whale, Tasmacetus shepherdi, fromthe eastern South Pacific. 127-128
Brownell, R. L. Jr. and R. Praderi. Records of the delphinid genus Stene/la in western South Atlantic

xiwaters. 129-135
Yamasaki, F., H. Satomi and T. Kamiya. An observation on the papillary projections at the lingual
margin in the striped dolphin. 137-140
Kasuya, T. and N. Miyazaki. An observation of epimeletic behavior of Lagenorhyncus obliquidens. 141143
Kawakami, T. Squids found in the stomach of sperm whales in the northwestern Pacific. 145-151
Leung, Y. M. Life cycle of C)amus scammoni (Amphipoda: Cyamidae), ectoparasite of gray whale, witha remark on the associated species. 153-160
Kagei, N., T. Tobayama and Y. Nagasaki. On the helminthum of Franciscana, Pontoporia blainvillei.
161-166
Tsuyuki, H. and S. Itoh. Fatty acid component of lipid of Euphausia superba. 167-174
Naito, Y. The occurrence of the phocid seals along the coast ofJapan and possible dispersal of pups. 175185
Naito, Y. and M. Oshima. The variation in the development of pelage of the ribbon seal with reference
to the systematics. 187-197

NUMBER 29, DECEMBER 1977
Kasuya, T. Age determination and growth of the Baird's beaked whale with a comment on the feta!
growth rate. 1-20
Miyazaki, N. On the growth and reproduction of Stenella coeruleoalba off the Pacific coast ofJapan. 21-48
Kawamura, A. On the food of Bryde's whales caught in the South Pacific and Indian Oceans. 49-58
Herman, L. M. and R. C. Antinoja. Humpback whales in the Hawaiian breeding waters: population andpod characteristics. 59-85
Aminul Haque, A.K.M., M. Nishiwaki, T. Kasuya and T. Tobayama. Observations on the behaviour
ai1d other biological aspects of the Ganges susu, Platanista gangetica. 87-94
Yamasaki, F., S. Komatsu and T. Kamiya. A comparative morphology of anal tonsils in Platanistidae.
95-100
Nemoto, T., R. L. Brownell, Jr. and T. Ishimaru. Coconeis diatom on the skin of Franciscana. 101-105
Castello, H.P. Food of a killer whale: Eagle sting-ray, Myliobatis found in the stomach of a stranded
Orcinus orca. 107-111
Nishiwaki, M. and A. Sasao. Human activities disturbing natural migration routes of whales. 113-120
Yoshida, K., N. Baba, M. Oya and K. Mizue. On the formation and regression of corpus luteum in thenorthern fur seal ovaries. 121-128
Abe, H., Y. Hasegawa and K. Wada. A note on the air-sac of ribbon seal. 129-135
Kawamura, A. and T. Furuno. On the northern extremes of pack ice observed by whaling vessels in thesummer of the Antarctic seasons 1957/58-1962/63. 137-141

NUMBER 30 DECEMBER 1978
Kasuya, T. The life history of Dall's porpoise with special reference to the stock off the Pacific coast ofJapan. 1-64
Miyazaki, N. and M. Nishiwaki. School structure of the striped dolphin off the Pacific coast of Japan.
65-116
Clarke, R., A. Aguayo L. and S. B. de! Campo. Whale observation and whale marking off the coast of
Chile in 1964. 117-178
Miyazaki, N. and S. Wada. Observation of cetacea during whale marking cruise in the western tropical
Pacific, 1976. 179-196
Goodall, R. N. P. Report on the small cetaceans stranded on the coasts of Tierra de! Fuego. 197-232
Miyazaki, N. and S. Wada. Fraser's dolphin, Lagenodelphis hosei in the western North Pacific. 231-244
Nemoto, T. Humpback whales observed within the continental shelf waters of the eastern Bering Sea.

xii

245-247
Yamamoto, Y. and H. Hiruta. Stranding of a black right whale at Kumomi, southwestern coast of Izu
Peninsula. 249-251
Klima, M. Comparison of early development of sternum and clavicle in striped dolphin and in humpback
whale. 253-269
Omura, H. Preliminary report on morphological study of pelvic bones of the minke whale from theAntarctic. 271-279
Kamiya, T., F. Yamasaki and S. Komatsu. A note on the parathyroid glands ol Ganges susu. 281-284
Yamasaki, F., S. Komatsu and T. Kamiya. Taste buds in the pits at the posterior dorsum of the tongueof Stenella coeruleoalba. 285-290
Kawamura, A. On the baleen filter area in the South Pacific Bryde's whales. 291-300
Kasuya, T. and M. Nishiwaki. On the age characteristics and anatomy of the tusk of Dugong dugo11.
301-310
Kagei, N., K. Asano and M. Kihata. On the examination against the parasites of Antarctic krill, Euphausia
superba. 311-313

NUMBER 31, DECEMBER 1979
Kasuya, T. and K. Kureha. The population of finless porpoise in the Inland Sea of Japan. 1-44
Kasuya, T. and R. L. Brownell Jr. Age determination, reproduction, and growth of Frnaciscana dolphin,
Po11toporia blainvillei. 45-67
Jurasz, C. M. and V. P. Jurasz. Feeding modes of the humpback whale, Megaptera novaeangliae, insoutheast Alaska. 69-83
Omura, H. and T. Kasuya. A skull of baleen whale dredged from the Inland Sea of Japan. 85-92
Kamiya, T., T. Tobayama and M. Nishiwaki. Epidermal cyst in the neck of a killer whale. 93-94
Major, P. F. An aggressive encounter between a pod of whales and billfish. 95-96
Kato, H. Carotenoid colored minke whale from the Antarctic. 97-99
Kato, H. Unusual minke whale with deformed jaw. 101-103
Naito, Y. and S. Konno. The post breeding distributions of ice-breeding harbour seal (Phoca largha)
and ribbon seal (Phoca fasciata) in the southern sea of Okhotsk. 105-119
Naito, Y. A record of the bearded seal wandering with special reference to the wandering speed.
121-123
Miyazaki, N., K. Itano, M. Fukushima, S. Kawai and K. Honda. Metals and organochlorine compounds in the muscle of dugong from Sulawesi Island. 125-128
Kamiya, T., S. Uchida and T. Kataoka. Organ weights of Dugong dugon. 129-132
Nishiwaki, M., T. Kasuya, N. Miyazaki, T. Tobayama and T. Kataoka. Present ditribution of the dugong
in the world. 133-141

NUMBER 32, DECEMBER 1980
Kawamura, A. Food habits of the Bryde's whales taken in the South Pacific and Indian oceans. 1-23
Omura, H. Morphological study of pelvic bones of the minke whale from the Antarctic. 25-37
Hohn, A. A. Age determination and age related factors in the teeth of western North Atlantic bottlenose
dolphins. 39-66
Yonekura, M., S. Matsui and T. Kasuya. On the external characters of Globicephala macrorhynchus off Taiji,
Pacific coast of Japan. 67-95
Nemoto, T., P. B. Best, K. Ishimaru and H. Takano. Diatom films on whales in South African waters.
97-103Kamiya, T. and P. Pirlot. Brain organization in Platanista gangetica. 105-126
Yamasaki, F., S. Komatsu and T. Kamiya. A comparative morphological study on the tongues ofmanatee and dugong (Sirenia). 127-144

xiii
Casinos, A. and J. Bou. On a massive stranding of short-finned pilot whale, Globicephala macrorhynchus
Gray, 1846, on Margarita Island (Venezuela). 145-148
Mermoz, J. F. A brief report on the behavior of commerson's dolphin, Cephalorhynchus commersonii, in
Patagonian shores. 149-154
Kawamura, A. A review of food of balaenopterid whales. 155-198
Kawakami, T. A review of sperm whale food. 199-218

NUMBER 33, DECEMBER 1981
Omura, H., T. Kasuya, H. Kato and S. Wada. Osteological study of the Bryde's whale from the central
South Pacific and eastern Indian Ocean. 1-26
Miyazaki, N., Y. Fujise and T. Fujiyama. Body and organ weight of striped and spotted dolphins off
the Pacific coast of Japan. 27-67
Yamasaki, F. and T. Kamiya. The stomach of the Boutu, Inia geoffrensis: comparison with those of other
Platanistids. 69-81
Watkins, W. A. Activities and underwater sounds of fin whales. 83-117
Omura, H. and Y. Takahashi. A pygmy sperm whale stranded at Tokaimura, Ibaragi, Japan. 119-124
Aguilar, A., L. Jover and E. Grau. Some anomalous dispositions of the Jacobson's organ in the fin
whale. 125-126
Kamiya, T., N. Miyazaki and S. Shiraga. First case of dicephaly in Odontoceti. 127-129
Ohtaishi, N. and M. Yoneda. A thirty four years old male Kuril seal from Shiretoko Pen., Hokkaido.
131-135

NUMBER 34, DECEMBER 1982
Sergeant, D. E. Mass strandings of toothed whales (Odontoceti) as a population phenomenon. 1-47
Nishiwaki, M. The mandible of bowhead in Kathmandu. 49-57
Kawamura, A. Food habits and prey distributions of three rorqual species in the North Pacific Ocean.
59-91
Zhou, K. Classification and phylogeny of the superfamily Platanistoidea, with notes on evidence of themonophyly of the cetacea. 93-108
Nishiwaki, M. and T. Tobayama. Morphological study of the hybrid between tursiops and pseudorca.
109-121
Kato, H. Food habits of largha seal pups in the pack ice area. 123-136
Nishiwaki, M., M. Yamaguchi, S. Shakita, S. Uchida and T. Kataoka. Recent survey on the distributionof the African manatee. 137-147

NUMBER 35, MARCH 1984
Lowry, L. F. and K.J. Frost. Foods and feeding ofbowhead whales in western and northern Alaska. 1-16
Singarajah, K. V. Observations on the occurrence and behaviour of minke whales off the coast of Brazil.
17-38
Kato, H. Observation of tooth scars on the head of male sprem whale, as an indication of intra-sexual
fightings. 39-46
Seki, Y. Anatomical studies on the cell column located closely medial to the nucleus of the spinal root of thetrigeminal nerve in the sperm and the pygmy sperm whales. 47-56
Kasuya, T. and S. Matsui. Age determination and growth of the short-finned pilot whale off the Pacificcoast of Japan. 57-91 ·Miyazaki, N., .L. L. Jones and R. Beach. Some observations on the schools of dalli- and truei-type Dall's
porpoise in the northwestern Pacific. 93-105

xiv
Kasuya, T. and L. L. Jones. Behaviour and segregation of the Dall's porpoise in the northwestern North
Pacific. 107-128
Leatherwood, S., R. R. Reeves, A. E. Bowles, B. S. Stewart and K. R. Goodrich. Distribution, seasonal
movements and abundance of Pacific white-sided dolphins in the eastern North Pacific. 129-157
Fordyce, R. E., R.H. Mattlin and J.M. Dixon. Second record of spectacled porpoise from subantarctic
Southwest Pacific. 159-164
Yamasaki, F. and K. Kito. A morphological note of the intestine of the Boutu, with emphasis on its lengthand ileo-colic transition compared with other Platanistids. 165-172
Zhou, K., M. Zhou and Z. Zhao. First discovery of a tertiary Platanistoid fossil from Asia. 173-181
Omura, H., M. Shirakihara and H. Ito. A pygmy sperm whale accidentally taken by drift net in the North
Pacific. 183-193
Furuta, M. Note on a gray whale found in the Ise Bay on the Pacific coast of Japan. 195-197
Appendix
Measurements of body proportion of the pygmy blue whale, left by The Late Dr Tadayoshi
Ichihara. 199-203

NUMBER 36, MARCH 1985
Best, P. B. External characters of southern minke whales and the existence of a diminutive form. 1-33
Marsh, H. Observations on the ovaries of an isolated minke whale: evidence for spontaneous sterile ovulation and structure of the resultant corpus. 35-39
D'Vincent, C. G., R. M. Nilson and R. E. Hanna. Vocalization and coordinated feeding behavior of the
humpback whale in southeastern Alaska. 41-47
Seki, Y. Anatomical observations on the lower brain stem of the right whale. 49-87
Kito, K. and F. Yamasaki. Duodenal portion of the hepato-pancreatic duct of the Boutu, lnia geoffrensis.
89-95
Crespo, E. A., G. Pagnoni and S. N. Pedraza. Structure of a long-finned pilot whale school stranded in
Patagonia. 97-106
Kasuya, T. Effect of exploitation on reproductive parameters of the spotted and striped dolphins off the
Pacific coast of Japan. 107-138
Kasuya, T. and S. Shiraga. Growth ofDall's porpoise in the western north Pacific and suggested geographical growth differentiation. 139-152
Brownell, R. L. Jr. and R. Praderi. Distribution of Commerson's dolphin, Cephalorhynchus commersonii, andthe rediscovery of the type of Lagenorhynchus floweri. 153-164
Pinedo, M. C. A note on a stranding of the humpback whale on the southern coast of Brazil. 165-168

NUMBER 37, MARCH 1986
Ohsumi, S. Yearly change in age and body length at sexual maturity of a fin whale stock in the eastern
North Pacific. 1-16.
Ohsumi, S. Earplug transition phase as an indicator of sexual maturity in female Antarctic minke whales.
17-30.
Simmons, M. L. and H. Marsh. Sightings of humpback whales in Great Barrier Reef waters. 31-46.
Horwood,J. W. The lengths and distribution of Antarctic sei whales. 47-60.
Kasuya, T. Distribution and behavior of Baird's beaked whales off the Pacific coast of Japan. 61-83.
Kasuya, T., T. Tobayama, T. Saiga and T. Kataoka. Perinatal growth of delphinoids: information fromaquarium reared bottlenose dolphins and finless porpoises. 85-97.
Yabu, H. and H. Ogi. Chromosome number of two color types of the Dall's porpoise. 99-102.
Reiner, F. First record of Sowerby's beaked whale from Azores. 103-107.
Lichter, A. A. Records of beaked whales (Ziphiidae) from the western South Atlantic. 109-127.
Scarff,]. E. Occurrence of the barnacles Coronula diadema, C. reginae and Cetopirus complanatus (Cirripedia) onright whales. 129-153.

xv
Horwood, J. W. The distribution of the southern blue whale in relation to recent estimates of abundance.
155-165.
Paterson, R. A. An analysis of four large accumulations of sperm whales observed in the modern whalingera. 167-172.
Hayama, S., M. Suzuki, H. Uno and T. Yamashita. Female sexual maturity and delayed implantation
period of the Kuril seal. 173-178.

NUMBER 38, MARCH 1987
Arnold, P., H. Marsh and G. Heinsohn. The occurrence of two forms of minke whales in east Australianwaters with a description of external characters and skeleton of the diminutive or dwarf form. 1-46.
Kato, H. Density dependent changes in growth parameters of the southern minke whale. 47-73.
Lockyer, C. Observations on the ovary of the southern minke whale. 75-89.
Miyazaki, N ., I. Nakamura, S. Tanabe and R. Tatsukawa. A stranding of Mesoplodon stejnegeri in the Maizuru
Bay, Sea of Japan. 91-105.
Delhon, G. A., E. A. Crespo and G. Pagnoni. Stranding of a specimen of Gray's beaked whale at Puerto
Piramides (Chubut, Argentina) and its gonadal appra'isal. 107-115.
Guiler, E. R., H. Burton and N. Gales. On three odontocete skulls from Heard Island. 117-124.
Kasuya, T. and H. Ogi. Distribution of mother-calf Dall's porpoise pairs as an indication of calving grounds
and stock identity. 125-140.
Shimura, E. and K. Numachi. Genetic variability and differentiation in the toothed whales. 141-163.
Zinchenko, V. L. and M. V. Ivashin. Siamese twins of minke whales of the southern hemisphere. 165-169.
Pinedo, M. C. First record of a dwarf sperm whale from southwest Atlantic, with reference to osteology,
food habits and reproduction. 171- 186.
Aguayo L., A. and S. T. Rafael. Sighting records of Fraser's dolphin in the Mexican Pacific waters. 187-188.

SUBJECT INDEX

Taxonomy, Body proportionand Osteology
Balaena mysticelus 22: 45-62, 34 :49-57
Eubalaenaglacialis 13: 1-52, 21: 1-78, 21: 79-84,

23: 71-81, 30: 249-251
22: 29-37, 26: 1-14, 35: 195197
Balaenopteramusculus 7: 125-183
B. musculus brevicauda 22: 1-27, 35: 199-203
B. physalus 7: 125-183, 9: 121-163, 12: 127-189,
15: 17-84, 16: 29-34
B. borealis 9: 89-103, 14: 1-33, 23: 83-89
B. edeni 9: 89-103, 14: 1-33, 16: 1-5, 16: 7-18,
31: 85-92, 33: 1-26
B.acutorostrata 11: 1-37, 12: 1-21, 19:37-43,22:75-125,27: 1-36,28:57-68,28:69-72,36: 1-33
38: 1-46
Megaptera novaeangliae 7: 125-183, 14: 49-87,
36: 165-168
odontocete 38: 117-124
Physetercatodon 7: 125-183, 11: 47-83, 16: 35-45,
17: 1-14
Kogia sp. 9: 37-58
K. breviceps 33: 119-124, 35: 183-193
K. simus 38: 171-186
Tasmacelus shepherdi 28: 127-128
Mesoplodon ginkgodens 13: 53-83, 24: 43-56
M. densirostris 23: 129-137
M. stejnegeri 14: 35-48, 28: 107-117, 38: 91-105
M. bowdoini 16: 61-77
M. grayi 38: 107-115
M. sp. 16: 79-82, 37: 103-107
Ziphius sp. 37: 109-127
Ziphius cavirostris 24: 1-34
Berardius 27: 111-137
B. bairdii 10: 89-132
Hyperoodon planifrons 2 8: 119-126
Peponocephala electra 19: 91-104, 20: 95-100
Feressa attenuata 9: 59-88, 19: 65-90
Orcinus orca 26: 255-258
Globicephala macrorhynchus and G. melaena 27: 95110
Globicephala macrorhynchus 32: 67-95, 32: 145-148
Lagenodelphis hosei 25: 251-263, 30: 231-244
Stenella attenuata 19: 53-64
S. spp. 28: 129-135
Phocoena dioptrica 35: 159-164
Platanistoidea 34: 93-108, 35: 173-181
Platanisla gangetica 24: 87-108
Eschrichtius robustus

Small cetaceans; Tierra de! Fuego 30: 197-230
20: 211-212
Systematic study
Pelvic bone 5: 5-15, 30: 271-279, 32:25-37
Hyoid bone, baleen whales 18: 149-170
Balaenoptera acutorostrata 26: 15-24
Phoca 26: 313-320
Sternum and clevicle
Stenella coruleoalba 30: 253-269
Megaptera novaeangliae 30: 253-269
Tympano-periotic bone, toothed whales 25: 1-103
Vertebrae, baleen whales 23: 61-69
Skull and other characteristics, delphinidae 17:
93-103, 18: 171-172
Secondary sexual character
Balaenoptera physalus 16: 29-34
Physeter catodon 20: 89-94
Karyotype
Balaenoptera borealis 20: 83-88

Mirounga leonina

Anatomical and Histological study
Brain, Physeter

6: 49-72

Stenella 26: 245-253
Platanista 32: 105-126
Eubalaena 36: 49-87
Spinal cord, Eubalaena 13: 231-251

Physeteridae 35: 47-56
Trigeminal nerve, Physeteridae 35: 47-56
Dorsal vagal nucleus, Physeter 25: 241-249
Acoustic system 2: 1-20, 21: 95-123
Organ of hearing 2: 21-30, 8: 1-79
Labyrinth 14: 291-304
Sinus hair, Balaenoptera borealis 1: 41-47
Sensory tubercle, lip 3: 1-16
Lingual margin 28: 137-140
Taste buds, Stenella 30: 285-290
Tongue, Sirenia 32: 127-144
Head section, Stenella 19: 105-133
Extrinsic eye muscle 6: 1-33
Masseter, Megaptera 17: 49-52
Heart, conducting system 9: 11-35
cardiac nerve, Berardius 7: 1-22
Larynx 3: 23-62
Air-sac, Histriophoca and Phoca 29: 129-135
Lung 6: 35-47
Parathyroid, Platanista 30: 281-284
Abdominal cavity, iconography 5: 17-39
Hepato-pancreatic, Inia 36: 89-95
Stomach 23: 91-101, Inia 33: 69-81
Renculi 13: 253-267

ii
Anal tonssil, Platanistidae 29: 95-100
Ovary 38: 75-89
Corpus luteum, Callorhinus 29: 121-128
Red bone marrow, B. physalus 3: 17-22
Embryo, Stenella 10: 1-68, 16: 83-87
Size of cell 13 : 269-30 I
Epidermal cyst 31: 93-94

Body and organ weight
Eubalaena glacwlis 13: 1-52, 21: 1-78
Balaenoptera musculus 3: 132-190, 4: 184-209,

125-183
B. musculus brevicauda 22: 1-27
B. physalus 3: 132-190, 4: 184-209, 7: 125-183
B. borealis 4: 1-13
B. edeni 10: 133-141
B. acutorostrata 22: 75-125
Megaptera noveangliae 7: 125-183, 14: 49-87
Physeter catodon 4: 1-13, 7: 125-183
Mesoplodon ginkgodens 24: 43-56
Lagenodelphis hosei 25: 251-263
Stene/la attenuata 26: 157-226
S. coruleoalba 33: 27-67
Platanista gangetica 24: 87-108, 26: 265-270
Pontoporm blainvillei 26: 265-270
Mirounga leomina 20: 211-212
Dugong dugon 31: 129-132

Age determination
Crystalline lens 3: 132-190, 4: 115-161
Baleen plates 4: 162-183, 6: 133-152
Earplug 12: 23-32, 14: 107-135, 17: 37-48, 18:
29-48
Baleen whales 7: 87-119
Balaenopteraphysalus 13: 155-169, 18: 49-88, 20:
17-82
B. acutrostrata 37: 17-30
Physetercatodon 13: 135-153, 17: 15-35, 20: 1-16
Berardius bairdii 29: 1-20
Globicephala macrorhynchus 35: 57-91
Tursiops truncatus 32: 39-66
Stenella caeruleoalba 8: 133-146, 24: 57-79, 28:
73-106,29:21-48
S. attenuata 26: 157-226, 28: 73-106
Platanista gangetica 24: 87-108
Pontoporm blainvillei 31 : 45-67
Collorhinus ursinus 17: 191-195
Dugong dugon 30: 301-310
Phoca kurilensis 33: 131-135

Population study
Balaena mysticetus 35: 1-16
Eubalaenaglacwlis 13: 1-52, 21: 1-78
Eschrichtius robustus 5: 71-79, 13: 201-205, 22:

29-37,22: 39-43, 26: 1-14
3: 132-190, 4: 27-113, 5:
91-167,6:73-131,7: 125-183,8; 147-213,37:
155-165
B.physalus 3: 119-131,3: 132-190,4:27-113,5:
91-167, 6: 73-131, 7: 125-183, 8: 147-213, 11:85-98, 12: 103-125, 13: 97-133, 13: 145-169,
15: 85-142, 17:53-65, 18: 1-27, 18:49-88,34:
59-91, 37: 1-16
B. borealis 3: 119-131, 4: 27-113, 9: 89-103, 22:
63-74,34: 59-91, 37: 47-60
B. edeni 3: 106-118, 3: 119-131, 9: 89-103, 9:
165-177, 10: 79-87, 14: 1-33, 16: 7-18, 28: 135, 30: 291-300, 34: 59-91
B. acutorostrata 11: 1-37, 11: 181-189, 19: 37-43,
22: 75-125, 37-59, 35: 17-38, 36: 1-34, 36:
35-39,38: 47-73
Megaptera novaeanglwe 4: 27-113, 6: 73-131, 7:
125-183,8: 81-102,8: 147-213, 14:49-87, 15:
1-16, 16: 19-28, 29: 59-85, 30: 245-247, 37:
31-46
Physeter catodon 3: 106-118, 3: 119-131, 4: 27113, 6: 153-165, 7: 121-124, 7: 125-183, 8:
147-213, 10: 143-149, 11: 39-46, 13: 135-153,
17: 15-35, 19: 1-35, 20: 1-16, 23: 1-25, 35:
39-46, 37: 167-172
Ziphius cavirostris 10: 89-132, 24: 35-41
Berardius 27: 111-137
B. bairdii 10: 89-132, 13: 213-214, 23: 111-122,
29: 1-20, 37: 61-83
Mesoplodon grayi 38: 107-115
Odontoceti 34: 1-47
Oreinus orca 13: 85-96
Globicephala macrorhynchus 35: 57-91
Globicephala macrorhynchus and G. melaena 27: 95110, 36: 97-106
Stenella coeruleoalba 12: 191-192, 22: 159-162,
24: 57-79,26:227-243,28:73-106,29:21-48,
30: 65-115, 36: 107-138
S. attenuata 26: 157-226, 26: 226-243, 28: 73106, 36: 107-138
Lagenorhynchus obliquidens 35: 129-15 7
Lagenodelphis hosei 30: 231-244
Phocoenoides dalli 30: 1-64, 35: 93-105, 35: 107128, 36: 139-152, 37: 99-102, 38: 125-140
Neophocaena phocaenoides 31: 1-44
Cephalorhynchus commersonii 32: 149-154, 36:
153-164
Platanista gangetica 24: 87-108, 24: 109-115, 27:
81-94, 29: 87-94
Genetic, toothed whale 38: 141-163
Pontoporw blainvillei 31 : 45-67
School, baleen whales 18: 89-110
Corpora albicantia 18: 123-148

Balaenoptera musculus

iii
Virginal band 21 : 85-94
Counting and measuring, baleen and ventral grooves
25: 279-292
Baleen, function 28: 37-55
Underwater sound 23: 123-128, 33: 83-117
Epimeletic behavior 28: 141-143
Marking dolphin 20: 101-107, 24: 81-85
Human activity disturbing whales 29: 113-120
History, whaling 21: 125-129
Color pattern, Phoca 25: 301-310
Growth, Phoca 24: 127-144
Tursiops 37: 85-97
Neophocaena 37: 85-97
Foods, Phoca 34: 123-136
Maturity, Phoca 37: 173-178
Pelage, Historiophoca 28: 187-197
Occurrence, phocid seals 28: 17 5-185
Distribution, Phoca 31 : l 05-119
Dugong 31: 133-141
Trichechus 34: 137-147
Diving depth, Callorhinus 24: 145-148
Wandering speed, Erignathus 31: 121-123
Gerology 7: 69-77, 8: 103-125, 9: 105-120, 11:85-98, 13: 171-184, 14: 89-100, 14: 101-106,
15: 85-142, 17: 53-65, 17: 67-77, 18: 1-27

Food and feeding(See also population study)
Baleen whales 5: 81-90, 12: 33-89, 13: 193-199,
14: 149-290, 16: 89-103, 17: 157-17~ 19:4551,20: 109-155,34: 59-91
Balaena mysticetus 35: 1-16
Balaenoptera borealis 22: 127-152, 22: 153-158,
25: 219-236,25-144
B. edeni 7: 79-85, 29: 49-58, 32: 1-23
Megaptera novaeangliae 31: 69-83, 36: 41-47
Eschrichtius robustus 22: 39-43
Physeter catodon 5: 81-90, 11: 139-151, 11: 153161, 18: 111-122, 28: 145-151, 32: 199-218
Kogia simus 38: 171-186
Orcinus orca 29: 107-111
Stene/la coeruleoalba 25: 265-275
Balaenopterids 32: 155-198, 34: 59-91
Largha Seal 34: 123-136
Antarctic fish from stomach 12: 225-233
Stone and alien from stomach 17: 83-91
Stomach content in relation to chasing time 23:
27-36
Energy budge 27: 61-79

Whaling ground, environmental
9: 179-187, 11: 163-179, 12: 91-101, 12: 209224, 13: 215-229, 14: 137-143, 15: 143-158,
16: 105-119, 17: 105-155, 20: 157-210, 26:

271-287, 27: 141-157
Statistical review 25: l 05-203
Pack-ice limit 29: 137-141
Sighting
By boat 25: 205-217, 26: 289-302, 30: 117178, 30: 179-195
By air 23: 37-60

Parasite, scar and skin disease
Diatom 4: 14-26, 11: 99-132, 13: 185-191, 29:
101-105,32: 97-103
Cyamus 28: 153-160
Barnacle 22: 39-43, 37: 129-153
White scar 10: 69-77, 26: 145-155
Skin disease 11: 133-138
Helminthes 11: 133-138, 28: 161-166
Marlin spear 14: 149-290 (p.252), 22: 163-164,
25: 237-239
Aggressive encounter 31 : 95-96
Parasite, Euphausia 30: 311-313

Chemical study
Enzyme, stomach l: 3-7
pancreas 1: 8-10, 1: 11-14, 2: 55-60,
3: 71-78
Whale meat, peptone l : 15-16
freshness l : 17-26, l: 28-30, 2: 3134, 3: 63-70, 5: 1-4, 6: 167-176,
7: 23-30, 7: 31-36, 9: 1-10
tryptophane 2: 51-54
digestion 2: 61-66
nutrition: 7: 51-67
amino acid 13: 303-317, 14: 305-326
methionine 3: 102-105
Whale blood 1: 38-40, 3: 96-101, 5: 41-47
Whale milk 10: 151-167
Vitamin 1: 31-37, 2: 35-41, 5: 53-59, 6: 187191, 7: 47-50
Kitol 3: 85-88, 3: 89-91, 3: 92-95, 5: 49-51, 5:
61-69,6: 193-198,7:47-50
Oil, gas absorption 11 : 191-213, 13: 309-321
molecular distillation 2: 42-45, 2: 46-50
Oil, Eubalaena 17: 171-190
Physeter 3: 79-84, 7: 37-46
Mirounga 12: 235-240, 13: 323-332, 20: 213221
Lipid, Eubalaena 18: 173-180
Fatty acid composition of oil,
Eubalaena 22: 165-170
Neopocaena 21: 131-135, 26: 303-306
Peponocephala 21: 137-141
Platanista 23: 141-147, 24: 117-125
Inia 25: 293-299
Trichechus 26: 307-311

iv
Krill 28: 167-174
Metal, Dugong 31: 125-128
Organochlorine corn pounds, Dugong 31 : 12 5-126
Mesoplodon 38: 91-105

MiscellaneousHybrid 34: 109-121
Hind limb 8: 127-132, 12: 197-208, 17: 79-81,
19: 135-136
Hermaphroditism 8: 215-218
Siamese twins 38: 165-169
Prenatal dead fetus 16: 4 7-60
Malformed fetus 12: 193-195, 14: 145-147, 23:

139-140, 26: 259-263
Jacobson's organ 33: 125-126
Dicephaly fetus 33: 127-129
Albino 13: 207-209
Carotinoid body color 31: 97-99
Deformedjaw 13: 211-212, 31: 101-103
Vestigial teat 25: 277-278
Strange organ 27: 139-140
Electrocardiogram, Tursiops 15: 159-165
Electric shock 6: 177-185
Compressive strength, dentin 23: 103-110
Flattened head harpoon 6: 199-207
Sighting, Fraser's dolphin 38: 187-188

AUTHOR INDEXAF

Abe, H. 29: 129-135
Abe, T. 12: 225-233
Aguayo L., A. 28: 127-128, 30: 117-177, 38:
187-188
Aguilar, A. 33: 125-126
Akiba, T. 3: 63-70, 5: 1-4
Akikusa, S. 10: 151-167
Akiya, S. 1: 3-7, 1: 8-10, 1: 11-14, 1: 15-16, 2:
51-54,5: 41-47,7: 23-30, 7: 31-36
Aminul Haque, A.K.M. 24: 109-115, 29: 87-94
Antinoja, R. C. 29: 59-85
Arai, Y. 7: 51-67
Arifuku, S. 2: 1-20
Arnold, P. 38: 1-46
Asano, K. 30: 311-313

Fordyce, R. E. 35: 159-164
Frost, K. J. 35: 1-16
Fujino, K. 7: 67-77, 7: 125-183, 8: 103-125, 9:
89-103, 9: 105-120, 9: 121-163, 10: 89-132,
10: 133-141, 11: 47-83, 11: 85-98, 13: 171-184,
14:89-100,14: 101-106,15:85-142,17:53-65,
17: 67-77, 18: 1-27
Fujise, Y. 33: 27-67
Fujiyama, T. 33: 27-67
Fukazawa, R. 3: 85-88, 3: 89-91, 3: 92-95, 5:
49-51
Furuta, M. 35: 195-197

BBaba, N. 29: 121-128
Beach, R. 35: 93-105
Best, P. B. 32: 97-103, 36: 1-33
Bou, J. 32: 145-148
Bowles, A. E. 35: 129-157
Brownell, R. L.Jr. 28: 127-128, 28: 129-135, 29:
101-105, 31: 45-67, 36: 153-164
Burton, H. 38: 117-124c
Calaprice, N. 17: 67-77
Casinos, A. 32: 145-148
Castello, H. P. 26: 255-258, 28: 119-126, 29:
107-111
Clarke, R. 30: 117-177
Crespo, E. A. 38: 107-115
Cushing, John E. 14: 89-100, 14: 101-106, 17:
67-77

DDairokuno, A. 12: 209-224
Dawbin, W. H. 26: 157-226
delCampo,S.B. 30: 117-177
Delhon, G. A. 38: 107-115
Dixon, J. M. 35: 159-164
D'Vincent, C. G. 36: 41-47

E
ECG Research Group

15: 159-165

G
Gales, N. 38: 117-124
Gianuca, N. M. 28: 119-126
Goodall, R.N.P. 30: 197-232
Goodrich, K. R. 35: 129-157
Grau, E. 33: 125-126
Guiler, E. R. 38: 117-124

H
Handa,C. 13: 85-96
Hanna,R.E. 36:41-47
Hasegawa, Y. 21: 79-84, 29: 129-135
Hayama, S. 37: 173-178
Hayashi, K. 3: 132-190
Heinsohn, H. 38: 1-46
Herman, L. M. 29: 59-85
Hibiya~ T. 6: 153-165, 7: 121-124, 9: 165-177,
22: 39-46, 13: 97-133, 13: 135-136
Hirata, M. 6: 199-207
Hirosawa, K. 21: 95-123
Hirose, S. 10: 151-167
Hiruta, H. 30: 249-251
Hohn, A.A. 32: 39-66
Honda,K. 31: 125-128
Horwood,]. W. 37: 47-60, 37: 155-165
Hoshina, T. 11: 133-138
Hoshino, 0. 5: 41-47, 7: 23-30, 9: 1-10
Hosokawa, H. 3: 23-62, 5: 5-15, 6: 1-33, 10: 168, 13: 269-301, 19: 105-133, 21: 95-123, 23:
91-101Ilchihara, T. 12: 127-189, 13: 155-169, 13: 201205, 14: 107-135,16:47-60, 17:37-48, 18:2948, 19: 37-43, 20: 17-82, 20: 211-212, 22: l-v

VI27, 24: 145-148, (35: 199-203)
Igarashi, S. 21: 95-123
Iguchi, K. 8: 147-213
Ishikawa, S. 1: 11-14, 2: 35-41, 2: 42-45, 2: 5560, 3: 71-78, 5: 53-59, 5: 61-69, 11: 191-213,
13: 309-321
Ishimaru, K. 32: 97-103
Ishimaru, T. 29: 101-105
Itano, K. 31: 125-128
Ito, H. 35: 183-193
Itoh, S. 20: 213-221, 21: 131-135, 22: 165-170,
23: 141-147,24: 117-125,25:293-299,26:303306, 26: 307-311, 28: 167-174
Ivashin, M. V. 38: 165-169
Iwai, E. 11: 139-151, 11: 153-161

J
Jimbo, H. 3: 119-131
Jones, L. L. 35: 93-105, 35: 107-128
Jover, L. 33: 125-126
Jurasz, C. M. 31: 69-83
Jurasz, V. P. 31: 69-83

K
Kagei, N. 28: 161-166, 30: 311-313
Kakuwa, Z. 8: 147-213
Kamiya, T. 12: 197-208, 13: 53-83, 13: 253-267,
14: 35-48, 19:53-64, 19: 105-133,21:95-123,
23:91-101,26:245-253,26:259-263,26:265270,28: 137-140,29:95-100,30:281-284,30:
285-29~31:93-94,31: 129-132,32: 105-126,
32: 127-144, 33: 69-81, 33: 127-129
Kaneko, A. 2: 46-50
Kanno, H. 2: 42-45
Kashita, K. 23: 139-140
Kasuya, T. 16: 35-45, 17: 15-35, 19: 37-43, 19:45-51, 19: 65-90, 20: 83-88, 20: 89-94, 21: 127, 22: 1-27,22: 29-37,22: 39-43,22:45-62,
23: 37-60, 23: 71-81, 23: 83-89, 23: 129-137,
24: 43-56, 24: 57-79, 24: 81-85, 24: 87-108,
24: 109-115,25: 1-10~25: 265-275,26: 157226,26:227-243,27:81-94,27:95-108,28:5768,28:73-106,28: 141-143,29: 1-20,29:8794,30: 1-63,30:301-310,31: 1-44,31:45-67,
31: 85-92, 31: 133-141, 32: 67-95, 33: 1-26,
35: 57-91, 35: 107-128, 36: 107-138, 36: 139152, 37: 61-83, 37: 85-97, 38: 125-140
Kataoka, T. 31: 129-132, 31: 133-141, 34: 137147, 37: 85-97
Kato, H. 31: 97-99, 31: 101-103, 33: 1-26, 34:
123-136, 35: 39-46,38: 47-73
Kawai, S. 31: 125-128
Kawakami,T. 7:79-85,8: 147-213,28: 145-151,
32: 199-218

Kawamura, A. 22: 75-125, 22: 127-152, 23: 2736, 23: 139-140, 25: 219-236, 26: 25-144, 27:
61-79, 28: 1-35, 29: 49-58, 29: 137-141, 30:
291-303, 32: 1-23, 32: 155-198, 34: 59-91
Kihata, M. 30: 311-313
Kimura, S. 9: 165-177, 10: 89-132, 11: 39-46,
11: 181-189, 12: 103-125
Kijima, M. 5: 61-69
Kito, K. 35: 165-172, 36: 89-95
Klima, M. 30: 253-269
Kobo, F. 1: 15-16
Kojima, T. 6: 49-72
Komatsu, S. 29: 95-100, 30: 281-284, 30: 285290, 32: 127-144
Konno, S. 31: 105-109
Korostoff, E. 23: 103-110
Kureha, K. 24: 43-56, 27: 139-140, 31 : 1-44

L
Leatherwood, S. 35: 129-157
Leung, Y. M. 28: 153-160
Lichter, A. A. 37: 109-127
Lockyer, C. 38: 75-89
Lowry, L. F. 35: 1-16

M
Machida, S. 22: 163-164, 26: 271-187, 26: 289302, 27: 141-159
Maeda, T. 17: 1-14
Major, P. F. 31: 95-96
Marsh, H. 36: 35-39, 37: 31-46, 38: 1-46
Masaki, Y. 22: 63-74, 22: 75-125
Matsui, S. 32: 67-95, 35: 57-91
Mattlin, R. H. 35: 159-164
McCann, C. 26: 145-155, 27: 111-137, 28: 107117
Mermoz,J. F. 32: 149-154
Mizue, K. 3: 106-118, 3: 119-131, 5: 71-79, 5:
81-90, 6: 73-131, 23: 123-128, 29: 121-128
Miyazaki, N. 25: 265-275, 26: 157-226, 26: 227243, 26: 259-263, 28: 141-143, 29: 21-48, 30:
65-115,30: 179-195,30: 231-244,31: 125-128,
31: 133-141,33:27-67,33: 127-129,35:93-105,
38: 91-105
Mo!, T. 21-125-129
Mori, T. 3: 79-84
Motohashi, N. 7: 23-30, 9: 1-10
Murata, T. 6: 35-47, 6: 73-131

N
Nagasaki, Y. 28: 161-166
Naito, Y. 24: 127-144, 25: 301-310, 26: 313-320,
28: 175-185, 28: 187-197, 31: 105-119, 31:
121-123

vii
Nakai,]. 1: 41-47
Nakai, T. 1: 17-26, 1: 27-40, 2: 31-34, 6: 167176, 6: 177-185, 14: 305-326
Nakajima, M. 17: 191-195, 19: 65-90, 19: 91104, 20: 101-107
Nakamura, S. 38: 91-105
Naruse, U. 17: 171-190, 18: 173-180
Nasu, K. 11: 163-179, 12: 91-101, 13: 193-199,
13: 211-212, 14: 137-143, 15: 143-158, 17: 8391, 17: 105-155, 20: 157-270, 22: 63-74, 25:
205-217
Natsume, Y. 3: 63-70, 5: 1-4
Nemoto, T. 10: 67-77, 10: 79-87, 11: 132, 11:
181-189, 12: 33-89, 13: 97-133, 13: 185-191,
13: 193-199, 14: 149-290, 16: 29-34, 16: 89103, 17: 79-81, 17: 83-91, 17: 191-195, 18: 89110, 18: 111-122, 19: 45-51, 20: 109-155, 21:
1-78, 22: 153-158, 23: 129-137, 27: 81-94, 29:
101-105,30: 245-247, 32: 97-103
Nilson, R. M. 36: 41-47
Nishimoto, S. 7: 79-85
Nishiwaki, M. 3: 132-190, 4: 115-161, 4: 162183, 4: 184-209,5:91-167,6: 133-152,6: 153165, 7: 87-119, 7: 121-124, 8: 133-146, 8: 215218,9: 165-177,10: 143-149,11:39-46,12:2332,12: 191-192,12: 193-195,13:53-83,13:8596, 13: 97-133, 13: 135-153, 13: 155-169, 14:35-48, 14:49-87, 15: 1-1~ 16: 19-28, 16:3546, 16: 61-77, 16: 79-82, 17: 1-14, 17: 15-35,
17:93-103, 17: 191-195, 18: 171-172, 19:53-64,
19:65-90,19:91-104,20:95-100,20: 101-107,
20: 211-212,21: 79-84, 22: 29-37, 22: 45-62,
22: 159-162,23:71-81,23:83-89,23:111-122,
23: 123-128,23: 129-137,24:35-41,24:43-56,
24: 127-144,25:251-263,25:265-275,25:277278, 26: 227-243, 27: 81-94, 27: 139-140, 29:
87-94, 29: 113-120, 30: 65-115, 30: 301-310,
31: 93-94, 31: 133-141, 34: 49-57, 34: 109121, 34: 137-147
Norris, K. S. 20: 95-100
Numachi, K. 38: 141-163

0
Ogawa, T. 2: 1-20, 3: 1-16, 7: 1-22, 8: 127-132,
9: 11-35, 12: 197-208, 13: 303-307
Ogi, H. 37: 99-102, 38: 125-140
Oguro, N. 23: 111-122, 24: 43-56, 24: 81-85
Ohe, T. 3: 17-22, 5: 17-39, 5: 91-107
Ohno, M. 7: 125-183
Oshima, M. 28: 187-197
Ohsumi, S. (Kimura) 13: 97-133, 13: 135-153,
13: 155-169, 13:207-209, 14: 145-147,15: 1784,17: 1-14,17: 15-35,18:49-88,18: 123-148,
19: 1-35, 19: 135-136, 20: 1-16, 20: 89-94, 21:

1-78,21:85-94,22:75-125,23: 1-25,25:237239, 37: 1-16, 37: 17-30
Ohta, K. 10: 151-167
Ohtaishi, N. 33: 131-135
Oishi, Y. 10: 151-167
Okano, K. 10: 151-167
Okuda, H. 5: 53-59
Okutani, T. 18: 111-122
Omote, Y. 2: 35-41, 2: 42-45, 5: 53-59, 5: 616~ 6: 187-191,6: 193-198, 7: 47-50
Omura, H. 4: 1-13, 4: 14-26, 4: 27-113, 8: 81102, 9: 89-103, 10: 79-87, 10: 89-132, ll: 1-37,
12: 1-21, 13: 1-52, 13: 213-214, 14: 1-33, 16:
1-5, 16: 7-18, 16: 35-45, 18: 149-170, 21: 1-78,
22: 1-27, 23: 61-69, 23: 71-81, 24: 1-34, 25:
105-203,26: 1-14,26: 15-24,27: 1-36,28:5768, 28: 69-72,30: 271-279,31: 85-92,32:2537, 33: 1-26, 33: 119-124, 35: 183-193
Ono, H. 6: 177-185
Osawa, M. 13: 303-307
Oya, M. 29: 121-128pPagnoni, G. 38: 107-115
Panizza, J. S. 26: 255-258
Paterson, R. A. 37: 167-172
Pinedo, M. C. 36: 165-168, 38: 171-186
Pirlot, P. 26: 245-253, 32: 105-126
Pivorunas, A. 28: 37-55
Praderi, R. 28: 129-135, 36: 153-164

R
Rabinowits, J. L. 23: 103-110
Rafael, S. T. 38: 187-188
Reeves, R. R. 35: 129-157
Reiner, F. 37: 103-107
Rice, D. W. 22: 39-43

s
Saiga, T. 37: 85-97
Saiki, M. 3: 79-84
Sakai, S. 7: 51-67
Sakiura, H. 11: 1-37
Sasao, A. 29: 113-120
Satake, Y. 26: 15-24, 28: 1-35
Sato, M. 10: 151-167
Satomi, M. 28: 137-140
Sawamura, R. 7: 31-36
Scarff, J.E. 37: 129-153
Seki, Y. 13: 231-251, 25: 241-249, 35: 47-57,
36: 49-87
Sekino, T. 13: 269-301
Sergeant, D. E. 34: 1-47
Shida, T. 1: 41-47, 3: 1-16

viii
Shimura, E. 38: 141-163
Shiraga, S. 33: 127-129, 36: 139-152
Shirakihara, M. 35: 183-193
Shakita, S. 34: 137-147
Simmons, M. L. 37: 31-46
Singarajah, K. V. 35: 17-38
Soma, Y. 2: 35-41
Stewart, B. S. 35: 129-157
Sugiura, Y. 11: 133-138
Suzuki, M. 37: 173-178
Suzuki, T. 13: 215-229, 17: 49-52

T
Takahashi, K. 2: 51-54, 14: 89-100
Takahashi, Y. (Satake) 33: 119-124
Takano, H. 32: 97-103
Takao, M. 7: 37-46
Takemura, A. 23: 123-128
Tanabe, S. 38: 91-105
Tanzawa, T. 1: 8-10
Tatsukawa, R. 38: 91-105
Tawara, T. 1: 31-37, 1: 38-40,3: 85-88,3: 8991,3: 92-95,3: 96-101, 5: 49-51
Tejima, S. 1: 3-7, 1: 8-10, 1: 11-14, 2: 55-60
Tobayama, T. 19: 65-90, 20: 101-107, 22: 159162, 25: 251-263, 28: 161-166, 29: 87-94, 31:
93-94,31: 113-141, 34: 109-121, 37: 85-97
Tokita, K. 15: 159-165
Tomo,A.P. 26: 255-258
Torres, N. D. 28: 127-128
Tozawa, H. 7: 79-85
Tsuchiya, T. 3: 63-70
Tsukamoto, S. 2: 61-66
Tsunoda, T. 13: 303-307
Tsuyuki, H. 12: 235-240, 13: 323-332, 17: 171190, 18: 173-180,20:213-221,21: 131-135,21:
137-141, 22: 165-170, 23: 141-147, 24: 117125,25: 293-299,26: 303-306,26: 307-311,28:
167-174uUchida, S.

22: 159-162, 31: 129-132, 34: 137-147

Ueshiba, Y. 10: 151-167
Uda, M. 9: 179-187, 11: 163-179, 12: 209-224,
13: 215-229, 16: 105-119
Umehara, M. 3: 63-70, 5: 1-4
Uno, H. 37: 173-178v
van Bree, P.J.H.

21: 125-129

w
Wada, K. 29: 129-135
Wada, S. 30: 179-195, 30: 233-246, 33: 1-26
Watar, T. 10: 151-167
Watkins, W. A. 33: 83-117
Williamson, G. R. 25: 279-292, 27: 37-59

yYabu, H. 37: 99-102
Yagi, T. 8: 133-146, 17: 191-195, 32: 127-144
Yamada, M. 2: 21-30, 8: 1-79, 9: 37-58, 9: 5988, 14: 291-304
Yamaguchi, K. 7: 69-77
Yamaguchi, M. 34: 137-147
Yamamoto, Y. 30: 249-251
Yamasaki, F. 26: 265-270, 28: 137-140, 29: 95100, 30: 283-286, 30: 289-292, 32: 127-144,
33: 69-81, 35: 165-172, 36: 89-95
Yamashita, T. 37: 173-178
Yang, H. C. 25: 251-263
Yoneda, M. 33: 131-135
Yonekura, M. 32: 67-95
Yoo, Y. I. 22: 153-158
Yoshida, K. 24: 145-148, 29: 121-128
Yoshida, M. 3: 102-105
Yoshizaki, F. 14: 291-304
Yoshikawa, T. 10: 151-167, 17: 49-52zZhao, Z. 35: 173-181
Zhou, K. 34: 93-108, 35: 173-181
Zhou, M. 35: 173-181
Zinchenko, V. L. 38: 165-169

THE SCIENTIFIC REPORTS OF THE WHALESRESEARCH INSTITUTE

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HrnEo OMURA; Editorial Director
SEIJI OHSUMITAKAHISA NEMOTO
Tosmo KASUYA
TosttrRo KAMIYAy ASUHIKO NAITO
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HIDEHIRO KATO
Tosttrn SHIRAI

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