ISSN 0083-9086

THE

SCIENTIFIC REPORTS
OF.
THE WHALES RESEARCH INSTITUTE
No. 39THE )VHALES RESEARCH INSTITUTETOKYO· JAPANI.. Whales.
i~~
Res,IJf};., No. 39~

MARCH 1988

THE
SCIENTIFIC REPORTS
OF
THE WHALES RESEARCH INSTITUTE

No. 39THE WHALES RESEARCH INSTITUTETOKYO, JAPANMARCH, 1988

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

After 41 years of operation, the Whales Research Institute (WRI) closed in
October 1987 while this volume was in press. This volume was completed by the
Editorial Board, using the remaining funds in the WRI budget and with the cooperation of the new Institute of Cetacean Research, which was established to replace the
WRI. The present Editorial Board will be dissolved upon the publication of thisvolume. We hope that the Director of the Institute of Cetacean Research will establish
a new journal to replace the Scientific Reports of the Whales Research Institute(SRWRI).
The Editorial Board, SRWRI

THE SCIENTIFIC REPORTS OF THE WHALESRESEARCH INSTITUTE
CONTENTS OF NUMBER 39Page

OMURA, H.
Distribution and migration of the western Pacificstock of the Gray whale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
KATO, H.
Ossification pattern of the vertebral epiphyses in the southernminke whale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
PATERSON, R.A. and S.VAN DYCK.
Bryde's whale in the coastal waters of eastern Australia . . . . . . . . . 21
KASUYA, T. and T. MIYASHITA
Distribution of sperm whale stocks in the North Pacific . . . . . . . . . 31
KASUYA, T., T. MIYASHITA and F. KASAMATSU
Segregation of two forms of short-finned pilot whales
off the Pacific coast of Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
WADA, s.
Genetic differentiation between two forms of short-finned
pilot whales off the Pacific coast of Japan . . . . . . . . . . . . . . . . . . . . 91
KASUYA, T., D.E. SERGEANT and K. TANAKA
Re-examination of life history parameters of long-finned
pilot whales in the Newfoundland waters . . . . . . . . . . . . . . . . . . . . 103
MIYASHITA, T. and T. KASUYADistribution and abundance of Dall's porpoises off Japan . . . . . . . 121
WILLIAMSON, G. R.
Seals in Loch Ness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

目 次

大村秀雄
アジア系コククジラの分布と回遊径路．．．．．．．．．．．．．．．．．．．．．．．．．．．．

1

加藤秀弘

南半球産ミンククジラにおける脊椎骨骨端板の化骨様式．．

............. 1
1

PATERSON, R.A.andS.VAN DYCK

東オーストラリア沿惇水域におけるニタリクジラ．．．．．．．．．．．．．．．．．．．．．

21

粕谷俊雄・宮下富夫

北太平洋におけるマッコウクジラ系統群の分布．．．．．．．．．．．．．．．．．．．．．．

31

粕谷俊雄・宮下富夫・笠松不二男

我国太平洋岸域におけるコビレゴンドウ地方型の棲み分け．．．．．．．．．．．．．．．

77

和田志郎
日本沿岸産コビレゴンドウの 2地方型聞の遺伝的差異．．．．．．．．．．．．．．．．．．

91

粕谷俊雄・ D.E
.SERGEANT・田中健士

ニューファウンドランド海域ゴンドウクジラの生物学的特性値の再検討...... 103
宮下富夫・粕谷俊雄

日本周辺におけるイシイルカ類の分布と資源量...................... 1
2
1
WILLIAMSON, G.R.

ネス湖のアザラシ......................................... 1
5
1

DISTRIBUTION AND MIGRATION OF
THE WESTERN PACIFIC STOCKOF THE GRAY WHALE*HIDEO OMURA**
ABSTRACT

There are two geographically isolated stocks of gray whales in the
North Pacific. One is the eastern stock which migrates between the Beringand Chukchi Seas and Baja California, or California stock, and the other isthe western stock which has been thought to migrate between Okhotsk Sea
and south coast of Korean Peninsula. This stock was called Korean stock
because south coast of Korean Peninsula has long been thought to be its
calving ground.
In recent years papers from China reported that in the past graywhales also occurred in the Yellow Sea and East and South China Seas. In
the light of these information the Japanese catch and other materials werestudied and these supported these information.
In relation to the migration of these gray whales the difference of theocean structure between the eastern and western North Pacific was noted.
In the latter the continental shelf is well developed. The gray whale isthought to have lived in shallow water and migrated directly across the East
China Sea between Kyushu and South China, from east to west or reverse
way, while some whales have migrated along the coast of the Yellow Sea.
INTRODUCTION

The gray whale, Eschrichtius robustus (Lilljeborg, 1861), is the sole member ofthe family Eschrichtiidae and is considered to be the most primitive surviving
baleen whale. There are presently two geographically isolated stocks: aneastern Pacific stock, which migrates between Baja California and the Beringand Chukchi Seas, and a western Pacific stock, which migrates between South
Korea and the Okhotsk Sea. These may be designated the California stockand the Korean stock, respectively, on the basis of their breeding grounds(Rice and Wolman, 1971).
The California stock was once reduced heavily by whaling in the 1850s as
well as by the operation of floating factories after the turn of the century.
Even so this stock made remarkable recoveries. Since it was afforded protec• This paper was read at a symposium of the XVI Pacific Science Congress held in Seoul, 20-30 August I987.
•• Whales Research Institute, 3-32-11, Ohjima, Koto-ku, Tokyo 136, Japan. Retired in October, 1987.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 1-9

OMURA2

TOTAL CATCH
1,362 WHALES

150

z

w
i.:

et

....
VJ

w

...J

et

:r
~

100 .....

LL.

0

cc
w

....

al

:?!
:::i

....

z

50 -·

0

nnnnnn.nn_

I

I

I

1910

1915

1920

1925

1930

I

1935

YEAR

Fig. 1. Catches of gray whales in the western North Pacific region.

tion from commercial whaling in 1946 by the International Convention for
the Regulation of Whaling, the population has recovered steadily. The stock
has been classified as a Sustained Management Stock since 1978, based on theunderstanding that it had remained stable at about 11,000 whales over an 11
years period with approximately constant catches (IWC, 1986).
The western Pacific stock of the gray whale was hunted twice in the history of whaling. Prior to the turn of the century whales were taken in Japan
using hand harpoon and net (net whaling). This whaling was conducted in
two regions of Japan, one the Pacific side and the other on the coasts ofsouthern Sea of Japan and eastern East China Sea (off Kyushu andYamaguchi prefecture). Right whale (Eubalaena glacialis), humpback whale(Bal,aenoptera novaeangliae) and fin whale (B. physalus) were the major targetsof this whaling, but the gray whale and other species of whales were also
taken (Omura, 1984).
Gray whales in the above two regions may represent different populations. The gray whales coming to the Pacific side is thought to have followed amigration route along the east coast of Japan (Nishiwaki and Kasuya, 1970;
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GRAY WHALE MIGRATION

3

Omura, 1974, 1984; Bowen, 1974). Bowen (1974) describes further that thosegray whales should be regarded as strays from the Bering Sea. Migration ofthese whales, however, is not discussed in detail in the present paper. The
gray whales coming to the coasts of Kyushu and Yamaguchi prefecture are
portion of those whales migrating in the waters adjacent to Korea (Omura,1984).
After the turn of the century (in the years 1911 - 1933) gray whales were
hunted heavily by modern catchers on the coast of Korea, and once the stock
was thought to be exterminated (Mizue, 1951; Bowen, 1974), but this was not
the case and some still survive (Brownell and Chun, 1977; Yablokov andBogoslovskaya, 1984) (Fig. 1).
The calving ground of the western Pacific stock was once believed to be
the southern coast of South Korea (Andrews, 1914; Mizue, 1951; Rice and
Wolman, 1971; Omura, 1984; Yablokov and Bogoslovskaya, 1984). Wang
(1984), however, noted the occurrence of gray whales in the Yellow Sea, theEast and South China Seas and described that the calving grounds of thesewhales are possibly in Baya Bay and Wailuo Harbour. In the light of thesereports I have tried to make clear their migration route using data in hand.
MIGRATION OF GRAY WHALES ALONG THE KOREAN PENINSULA
Andrews (1914) who firstly investigated gray whales at Ulsan, Korea, during aperiod in January and February 1912 states as follows:"In November and December, when the females are taken, almost every
individual will be found to be carrying young nearly for birth. As these would
necessarily be delivered within two or three weeks after passing Ulsan, thebirth must occur in the bays among the numerous small islands at the extreme
southern end of the peninsula."
In fact he examined 24 gray whales during his stay at Ulsan, in which 21
whales were males and 3 were females. One of the females contained a fetus
476cm long. The mean body length at birth of the gray whale fetus is 4.9
meters for the California stock whales (Rice and Wolman, 1971). This fetus,
therefore, can be regarded as near term. This is, however, the only fetal record
he had. It is clear, therefore, that the statement was based largely on information supplied from others, especially a Norwegian whaling gunner H. G.
Melsom, who worked with him.
As already stated a portion of the Korean stock had migrated to thenorth coast of Kyushu, where they were taken by net whaling prior to thiscentury. No catch statistics by species in Kyushu are available (Omura, 1984),
but it is clear that gray whales (Ko-kujira) were also taken at Ikitsuki Island in
addition to right, humpback and fin whales (Yamada, 1983)*. There the* An English translation from a Japanese old book entitled 'Isanatori-ekotoba', which means "Whaling,
explained with pictures". In the translation this was erroneously written as 'Yogiotoru eshi'.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

4

OMURA
TABLE !. CATCHES OF GRAY WHALES BY JAPANESEWHALE CATCHER (AFTER KASAHARA, 1950)
Area
Year

XII

XIII

XI

13

106

2

XIV

Total

1910
I

2
3
4

30

109

15

5
6
7
8
9

130
36
53
91
35

9

41
13
10
11

52 3)
23
19
4

2
2

1920
I

2
3
4
5
6
7
8
9

J43)
53
19
23
13
I

3

1930
I

2
3
Total

244

2
2

2

F. and W. 1)

6
121

121
1922)
131 2)
154

193
131
155

139
77
68
103
46

139
78 3)
69
104
46

68 3)
78
40
27
13

68
78
40
27
17

10
9
6
9
11

10

10

10
9
9
12

II

30
10
7

30
10
7

30
11
7
2

1,362

1,374

750

38

7

10
9
12

(I) Cited from Rice and Wolman (1971) which includes catches of gray whales in other areas, e.g. Okhotsk Sea.
(2) Cited from other sources kept at the Japan Whaling Association.
(3) Corrected in this table.
For the areas see text and Fig. 2.

whale migrating from north to south was called as the Down-going whale andthat coming from south to north as the Up-going whale. This is applied toabove four species of whales, including the gray whale. Hence the island wason the route of the southward and northward migration of the gray whale,
while it is situated more southerly than the south coast of Korea.
Kasahara (1950) analyzed the catch statistics of Japanese coastal whaling
between 1911 and 1949. A total of 83 land stations were operated by Japaneseindustry during the period in the western Pacific. He grouped these land
stations into 16 areas and made clear the yearly catches of each species in eacharea in his Table 10.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GRAY WHALE MIGRATION

5

130

Fig. 2. Positions of land stations concerned with catches of gray whales(after Kasahara, 1950).

Table 1 was rearranged from his Table 10, extracting areas where graywhales were mostly taken during this period.
As to the Kasahara's area some explanation may be needed here (Fig. 2).
Area XII means northeast Korea and includes land stations at Chongjin,
Shinpo and Changjun. Area XIII means southeast Korea and includes Uljin,
Kuryongpo and Ulsan. Area XI means North Kyushu and includes Senzaki,
Okochi, Izumi, Nishidomari, Hidakatsu, Iki, Katashima, Yobuko, Ukishima
and Arikawa. Area XIV means Yellow Sea and includes Cheju Island, Taihuksan, Uchong Island, Taechong Island and Changshan Island (Kantoshu).
As seen in Table 1 gray whales were mostly taken in Area XIII or southeast coast of Korean Peninsula and Ulsan was the center. This was followedby the Area XII or northeast coast of Korean Peninsula, and then North
Kyushu. It is noted, however, some gray whales were taken in the Yellow Sea.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

6

OMURA

This supports the recent reports of Wang ( 1978, 1984) that gray whales occur
in the Yellow Sea.
In this connection I recall a whale observed by Professor K. Uchida of
the Kyushu University. He was a famous ichthyologist who studied fish larvae.
Prior to 1945 he worked at the Fisheries Research Laboratory at Pusan, Korea
and made an expedition to collect fish larvae in May 1930 in the Yellow Sea.
He positively identified a gray whale during this expedition near Inchon, an
island locally called "Chanchangon" and situated at northwest of 60 nautical
miles from Inchon. His observation of the whale is well described in his book(1964). He observed clearly the fluke-lifting behaviour of a gray whale. He
also writes that the area was said to be a gathering place of whales.
Andrews (1914) writes that Captain H.G. Melsom has often observed
them (gray whales) in this vicinity, but because of the abundance of other andmore valuable species, they are not killed at this time by the Japanese. Thiswas written about the whaling off the south coast of Korean Peninsula, but itis thought this was applicable also to the Yellow Sea, because the main catches
in this area were fin whales.
It is possible, therefore, that the so-called Korean stock of gray whales, orat least a portion of them, entered into the Yellow Sea and hence migrated
south along the east coast of China, as shown in Fig. 2 of Wang (1984). It isalso possible that some whale went westwards from south coast of Korean
Peninsula to the east coast of China, across the southern border of the Yellow
Sea.
MIGRATION ROUTE OF GRAY WHALES THROUGHTHE COAST OF NORTHERN KYUSHU
Gray whales migrating to the northern Kyushu is a part of the Korean stock
and its migration past Ikitsuki Island was noted above. However, the migration of these individuals are very difficult to be understood. Fig. 7 of Omura( 1984) shows only the distribution of gray whales then known to him. In thecase of humpback, fin and right whales it is possible that they migrated
further south through the west coast of Kyushu. At Kasasa, a fishing village
on the west of Kagoshima prefecture, these three species of whales weresometimes taken accidentally entangled in fishing nets (Nasu, 1974; Anon.,1978).
Gray whales, on the other hand, have never been noticed by villagers of
Kasasa. It is possible, therefore, that gray whales took different course of
migration from the above three species.
In this connection this problem should be considered in relation to thedepth of the ocean. It is well known that the gray whale relies upon thebenthic animals for food, though peripheral areas and pelagic resources arealso exploited (N erini, 1984). This does not mean, however, that they also livein pelagic seas. The California stock of gray whales migrates along the coastal
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GRAY WHALE MIGRATION

120E

130E

7

140E

Fig. 3. Migration of the western Pacific stock of gray whales. (Excludes those occurringon the Pacific side of Japan).
1. Ikitsuki Island
2. Goto Island
3. Kasasa, Kagoshima prefecture

waters, and even in the eastern Bering Sea they travel within 2km from shore
to Nuvivak Island after passing through Unimak Pass in the northboundmigration. They migrated offshore only from that island to waters aroundSt. Lawrence Island (Braham, 1984).
In comparing the migration of the eastern and western stocks of the graywhale we should consider the difference of the ocean structure between theeastern and western North Pacific. In the eastern North Pacific the continental shelf is less developed and the deep sea is close to the continent. On thecontrary in the western North Pacific the continental shelf is well developed,
and the Yellow Sea and most parts of the East China Sea are shallower than
200 meters.
The gray whale is thought to have evaluated to live in shallow water. In
Fig. 3 the continental shelf or 200 meter depth line is shown by dotted line.
As seen in this figure most part of the East China Sea is shallower than 200
meters, and the 200 meters line extends from east side of Formosa to thesouth side of Kyushu, but a tongue of deep water projects along southwest
Kyushu as far north as it reaches westside of the Goto Islands, a group ofsmall islands situated southwest of Ikitsuki Island. The gray whale, therefore,
is thought to travel westwards, instead of southwards, avoiding this deep
water, from Ikitsuki until it reaches to the coast of China. Such migrations
directly crossing the East China Sea, from east to west or reverse way can not
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

8

OMURA

be denied. In this case they travel about 400 nautical miles of offshore.
Wang ( 1984) speculated that the western Pacific stock of the gray whale
migrated in the former times through the waters off the east coast of China,
and entered the calving grounds in the coastal waters of Guangdong Province. He also extended the speculation that these calving grounds are possibly in Baya Bay and Wailuo Harbour and that a few individuals probably
reached occasionally as far south as 20°N in the adjacent waters of the east
coast of Hainan Island.
In the light of the above knowledge of the distribution of the two graywhale stocks the names of "California" and "Korean" stocks seem to be inappropriate. The better expression will be "eastern Pacific" and "western
Pacific" stocks of the gray whale.
Present size of the western Pacific stock of the gray whale, however, hasbeen reduced to such a low level that it can no longer function as a significant
part of its ecosystem (Brownell, 1977). Yablokov and Bogoslovskaya (1984)
referred to a statement of Berzin ( 1978) that they were not recovering andthe number continuing to decline.
ACKNOWLEDGEMENTS

I am much indebted to Dr R. L. Brownell, Jr. of the U.S. Fish and Wildlife
Service, San Simeon, California for his critical comments and correction of
languages of earlier draft of this manuscript. Dr Toshio Kasuya of the Far
Seas Fisheries Research Laboratory and Dr Akito Kawamura of the Faculty ofFisheries, Hokkaido University kindly reviewed the manuscript and offered
many useful comments.
REFERENCES
ANDREWS, R. C., 1914. Monographs of the Pacific cetacea. 1. The California gray whale (Rhachianecteds
glaucus Cope). Mem. Am. Nat. Hist. (N.S.) 1: 227-287
ANON., 1978. Kujira-tori no Hanashi (Tale of catching whales). Geiken Tsushin, 312: 57-58. (in Japanese).
BowEN, S. L., 1974. Possible extinction of the Korean stock of gray whale (Eschrichtius robustus).]. Mamm.,
55: 208-209.
BRAHAM, H. W., 1984. Distribution and migration of gray whales in Alaska. pp. 249-266. In: M.L. Jones,
S. L. Swartz and S. Leatherwood (ed.) The gray whale, Eschrichtius robustus. Academic Press,
Orlando, Florida. 600 pp.
BROWNELL, R.L. Jr., 1977. Current status of gray whale. Rep. int. Whal. Commn, 27: 209-211.
BROWNELL, L. Jr. and C. Chun, 1977. Probable existence of the Korean stock of the gray whale (Eschrichtius
robustus).j. Mamm., 58: 237-239.
INTERNATIONAL WHALING COMMITTION, 1986. Thirty Sixth Report of the Commission.
KASAHARA, A., 1950. Nihonkinkai no Hogeigyo to sono Shigen [Whaling in the seas around Japan and its resources].
Nihonsuisan K. K. Kenkyujo Hokoku, Tokyo. No.4. 103 pp. with 95 Figs. (in Japanese).
MIZUE, K., 1951. Gray whales in the east sea area of Korea. Sci. Rep. Whales Res. Inst., 5: 71-79.
NASU, K., 1974. Satsuma-hanto ye agatta Zato-kujira no Hanashi. [Tale of a humpback whale landed at
Satsuma Peninsula]. Geiken Tsushin, 275: 54-57. (in Japanese).
Sci. Rep. Whales Res. Inst.,
No. 39, I988

GRAY WHALE MIGRATION

9NERINI, M., 1984. A review of gray whale feeding ecology. pp. 423-450. In: M.L.Jones, S.L. Swartz and S.
Leatherwood (ed.) The gray whale, Eschrichtius robustus. Academic Press, Orlando, Florida. 600 pp.
NrsHIWAKI, M. and T. KASUYA, 1970. Recent record of gray whale in the adjacent waters of Japan. Sci. Rep.
Whales Res. Inst., 22: 29-37.
OMURA, H., 1974. Possible migration route of the gray whale on the coast of Japan. Sci. Rep. Whales Res.
Inst., 26: 1-14.
OMURA, H., 1984. History of gray whales in Japan. pp. 57 - 77. In: M. L.Jones, S. L. Swartz and S. Leatherwood(ed.) The gray whale, Eschrichtius robustus. Academic Press, Inc., Orlando, Florida. 600 pp.
RICE, D. W. and A.A. Wolman, 1971. The life history of the gray whale (Eschrichtius robustus). Spee. Puhl.
Am. Soc. Mamm., 3: 1-142.
UCHIDA, K., 1964. Chigyo wo motomete. (Collecting fish larvae). lwanami Shoten (lwanami Shinsho No. 535),
Tokyo. 206 pp.
YABLOKOV, A. V. and L. S. Bogoslovskaya, 1984. A review of Russian research on the biology and commercial
whaling of the gray whale. pp. 465-485. In: M.L. Jones, S.L. Swartz and S. Leatherwood (ed.) The
gray whale, Eschrichtius robustus. Academic Press, Orlando, Florida. 600 pp.
YAMADA, Y., 1983. Yogiotoru eshi. Investigation on Cetacea. (ed. G. Pilleri). XIV. Supplementam. Berne,
Switzerland. 199 pp.
WANG, P., 1978. Studies on the baleen whales in the Yellow Sea. Acta Zoologica Sinica, 24(3): 269-277.
WANG, P., 1984. Distribution of the gray whale (Eschrichtius robustus) off the coast of China. Acta Theriologica
Sinica, 4(1): 21-26.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

OSSIFICATION PATTERN OF THE VERTEBRAL EPIPHYSESIN THE SOUTHERN MINKE WHALE

HIDEHIRO KATO*

ABSTRACTThe pattern of fusion of the vertebral epiphyses to the centrum in thesouthern minke whale was examined using materials collected during the1978179 and 1979/80 Antarctic whaling expeditions. The fusion of the vertebral epiphysis to the centrum proceeds from the center of epiphysis tothe peripheral on each vertebra regardless of the position on the vertebral
column. On a vertebral column, epiphyseal fusion starts at anterior cervical then at posterior caudal vertebra, and is completed on the middle orposterior dorsal vertebrae. The fusion is completed on the entire vertebral
column at ages of 23-36 years (males) or 28-36 years (females), and it has
little correlation with the body length.
INTRODUCTION

The southern minke whale (Balaenoptera acutorostrata Lacepede, 1804) is the
only species which is currently exploited by the pelagic whaling in the
Antarctic. Because of its importance in the stock management and study of
the antarctic ecosystem, various studies attempted to clarify historical changes
in their growth. For example, the decline of age at sexual maturity with timeprior to the full exploitation started in 1971172 has been suggested (Masaki,
1979; Best, 1982; Kato, 1983, 1987), which was thought to have resulted fromthe decline of possible competitative whale stocks such as blue (B. musculus(Linnaeus, 1758)) and fin whale (B. physalus (Linnaeus, 1758)).
Recently Kato (1987) compared growth curves between year classes ofthe southern minke whale and found the recent year-classes grew faster thanthe earlier ones. He analysed and suggested a possible change in the bodylength at the attainment of physical maturity with year-class. Although theexamination of epiphyseal fusion to centrum is essential for the identificationof physical maturity of whales, our information has been very fragmental onage, body length and progression of such change on the vertebral column.
Kato (1987) analysed some of these aspects of southern minke whales using
only the middle dorsal vertebrae, but he didn't present technical bases that
this vertebral part can be used as a mark of the physical maturity. This study
presents such basic information missing from the study of Kato (1987).
• Whales Research Institute, 3-32-Il, Ohjima, Koto-ku, Tokyo 136 Japan
Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 11-19

2
1

KATO

・
s
.
i
edeckofN
h
dont
e
t
c
se
i
nminkewhaleb
r
e
h
t
ou
hes
lcolumnoft
a
r
b
e
t
r
e
.V
.I
g
i
F
.
y
d
u
t
epresemshrtouNo.3f
r
a
m
‑
n
i
h
s

MATERIALANDMETHOD
9and
7
1
8
7
9
tby1
augh
sc
e
l
a
m
e
om45malesand51f
r
df
e
ct
ecole
r
swe
l
a
i
r
e
t
a
M
uth
o
s
e
h
t
o
t
3
.
o
uN
r
α
m
・
n
i
h
s
s
i
N
e
h
ionsoft
t
i
ped
gex
n
i
icwhalct
80Antar
/
1979
ned
i
m
r
e
t
e
d
s
a
w
e
g
.A
)
V
IandI
I
sI
a
e
r
A
30°E(
o1
en 0°t° Sandbetwe
0
of6
e
h
n oft
o
i
t
i
s
o
p
e
suming annualdsug andanearplsi
ayerhl
countinggrowt
h
t
i
dw
e
ecount
swer
r
e
y
a
.Thel
)
d
e
h
is
,unpubl
t
s
e
oandB
t
;Ka
2
,198
t
s
e
B
r(
e
y
a
l
ywasdetermined
t
i
r
u
t
a
em
.Femal
f
l
e
s
y
ym
） b
0×
6〜 1
ope(
c
s
o
r
cmic
i
p
o
c
s
o
e
r
e
t
s
tofwhichweredonebymyselfandsomebyDrsS.
,mos
s
e
i
byexaminingovar.
hs‑EastRegionalFi
h
t
ou
S
i(
.Masak
)andY
.
b
a
.L
s
.Re
h
s
i
sF
a
e
rS
a
F
Ohsumi(
.
y
d
u
t
s
t
n
e
s
e
r
p
e
h
t
n
i
d
e
s
y
l
a
n
a
t
o
n
s
a
w
y
t
i
r
u
t
a
m
e
l
Ma
.
)
.
b
a
L
.
s
e
R
h wereic
swh
l columns ofanimal
a
r
b
e
t
r
e
he v
yt
d
u
t
ts
n
e
s
e
r
he p
For t
h
t
i
sw
t
n
e
m
g
e
s
r
u
o
f
r
o
e
e
r
h
t
o
t
n
i
t
u
c
e
r
e
w
h
c
t
a
c
e
h
t
dfrom
e
t
c
e
el
randomlys
,
s
e
l
c
s
u
m
e
h
t
f
f
o
g
n
i
p
p
i
r
t
s
r
e
t
f
a
)
m
5
.
2
th =
eng
dl
i
al
v
nsaw(
hai
cc
i
r
t
c
e
an el
e
h
t
g
n
i
s
.U
)
.1
g
i
F
esamesaw(
h
tht
i
sw
eaxi
h
ngt
o
l
da
e
t
c
e
s
i
eywereb
h
thent
l
i
a
et
h
weent
dbet
e
i
r
r
u
eb
a
r
b
e
t
r
e
lv
a
d
u
a
oexaminesmalc
etmethodIwasabl
our
of
t
n
di
e
i
f
i
s
s
a
l
sandc
e
y
edbynakedevreewasobs
c
a
f
r
u
ts
u
.Thec
s
e
k
u
l
f
:
)
g.2
Fi
)(
1
6
9
1
rLaws(
e
t
f
sa
e
g
a
t
s
t
en
lagepres
i
t
r
a
ckc
i
h
UTC; unfused,t
t
n
e
s
e
r
lagep
ti
r
a
nc
i
h
,t
d
e
s
UFC; unfu
le
b
i
s
nvi
i
o
j
ed,
us
ヴ V; f
le
b
i
s
i
v
n
i
n
i
o
j
,
d
η1; fuse
αandA
eofN，η，sohot，りVandりfareequivalentteofUTC,UFC
g
a
t
Thes
y.
l
e
v
ti
c
e
p
s
e
)r
8
5
19
iya(
b
i
iandH
ak
hiw
ofOhsumi,Nis
,
.
山 t
.I
s
sRe
.Whale
p
e
.R
i
c
S
8
,198
9
.3
o
N

EPIPHYSEALFUSIO NINMINKEWHALES

1
3

F
i
g
.2 Typicalexample
soft
hee
p
iphy
s
e
a
lf
us
i
ons
t
a
g
e
susedint
hepres
en
ts
tudy
UFT
,unfus
edw
i
t
ht
h
i
ckc
a
r
t
i
l
a
g
e
; UTC,unfus
edwi
t
ht
hi
nc
a
r
t
i
lag
e：
，
円fV,fused
w
i
t
hj
o
i
nvi
日i
b
l
e；り人 f
u
s
e
dwi
t
h
o
u
tvi
s
i
b
lej
o
in

Thee
p
i
p
h
y
s
e
a
lf
u
s
i
o
nwasexaminedonbothc
e
n
t
e
randv
e
n
t
r
a
lmargin
oft
h
ep
o
s
t
e
r
i
o
re
p
i
p
h
y
s
i
s
. Sucho
b
s
e
r
v
a
t
i
o
nwasi
n
i
t
i
a
l
l
y madeona
l
lt
h
e
v
er
t
e
b
r
a
eoft
h
esampl
eda
n
i
m
a
l
sandrecordedont
h
ef
a
c
t
o
r
ys
h
i
p
.However
r
e
s
u
l
t
sont
h
e1
2s
e
l
e
c
t
e
dv
er
t
e
b
r
a
ea
r
eusedi
nt
h
ef
o
l
l
o
w
i
n
ga
n
a
l
y
s
e
s
.These
v
er
t
e
b
r
a
ea
r
e
:
1
s
t
,4thand7
t
hc
e
r
v
i
c
a
lv
e
r
t
eb
r
a
e
;
2nd,6
t
hand1
0
t
hdor
s
a
lv
e
r
t
e
br
a
e;
2nd,6
t
hand 10thlumbe
rv
e
r
t
e
b
r
a
e;
3
r
d
,1
0
t
hand1
7
t
hcaudalv
e
r
t
e
b
r
a
e
.
P
h
y
s
i
c
a
l
l
ymaturei
n
d
i
v
i
d
ual
swered
e
f
i
n
e
da
st
h
o
s
ewhereepiphysealf
u
s
i
o
n
)
.A
l
lt
h
eo
t
h
e
rs
t
a
g
ewere
wascompletedontheabove1
2v
e
r
t
e
b
r
a
e(
s
t
a
g
eりI
defineda
sp
h
y
s
i
c
a
l
l
yimma
t
u
r
e
.
RESULTFirstlyIcomparedepiphy
s
e
alf
u
s
i
o
nbetweenc
e
n
t
e
randv
e
n
t
r
a
lmarginofthesameepiphysi
s
.Ther
e
s
u
l
ti
sgroupedf
o
rt
h
et
h
r
e
ev
e
r
t
e
b
r
a
lsegmentsof
o
r
i
t
y
c
e
r
v
i
c
a
l,d
o
r
s
a
l,lumb
e
randc
a
u
d
a
lv
e
r
t
e
b
r
a
eands
howni
nTable1
.M弓j
S
c
i
.R
e
p
.Whal
e
sRe
s
.I
n
s
t
.
,
N
o
.39
,1988

KATO

14

TABLE 1. COMPARISON OF EPIPHYSEAL FUSION STAGES* BETWEEN THE CENTER
AND PERIPHERAL OF A EPIPHYSIS.
fusion at epiphyseal peripheral*

Vertebralsegment

fusion at
epiphyseal center

Cervical

UTC
UFC
FJV
FJI

25
4

UTC
UFC
FJV
Fjl

436
6

UTC
UFC
FJV
FJI

402
28

UTC
UFC
FJV
FJI

269
53
4

DorsalLumberCaudal

UTC

UFC

FJV

70
5

118

FJI

415

169
85

128
59

116
46

123
59

107

123
98

260

140
184

811

• UTC, unfused with thick cartilage; UFC, unfused with thin cartilage; FJV, fused with join visible; FJI,

fused with join invisible.

of the vertebrae showed the equal stage of fusion between the center andperipheral (ventral). Such vertebrae comprised 85.5% of the total data sets
(4,344) or 77% of 2,751 vertebrae excluding those with fully fused epiphyses.
However, 14.5% of them showed more advanced stage of fusion at the epiphyseal center and none of them showed the opposite case. Agreement of thetwo observations was lower on the posterior vertebral column; 95.5% in cervical vertebrae, 82.9% in dorsal vertebrae, 77.5% in lumbar vertebrae, and64.7% in caudal vertebrae (excluding observations on vertebrae with fully
fused epiphyses).
It is important to note that if the two observations disagreed the fusionnear the peripheral of epiphysis was always less advanced. This indicates thatthe fusion of the vertebral epiphysis proceeds from its center to theperipheral, and that the progress is slower on the posterior vertebrae. Epiphyseal fusion completes at the marginal of each epiphysis. In the following
analyses, I used only the status of epiphyseal fusion at the peripheral part.
Table 2 shows the progress of epiphyseal fusion with increasing bodylength. The fusion begins at the anterior cervical vertebrae in both sexes, andcervical epiphyses were completely fused to the centrum even on the smallest
male sample (22ft in body length). Epiphyseal fusion on the posterior caudal
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

EPIPHYSEAL FUSION IN MINKE WHALES

15

vertebrae starts at a body length of about 27ft for both sexes. After then, thefusion proceeds with increase of body length towards the middle vertebral
column. However, there are considerable individual variations in the stage ofthe epiphyseal fusion among the individuals of the same body length and sex.
For example, some individuals almost completed fusion while others had only
started the process on the dorsal and lumber vertebrae at the body lengthclasses between 27ft and 29ft in males, and between 28ft and 3 lft in females.
However the ossification is usually advanced on older individuals of the bodylength classes above.
Then, the individual data were rearranged according to their age to
produce Table 3 (individuals without sufficient age information were
excluded). It was confirmed again that the fusion of epiphyses begins firstly at
the anterior cervical at about age two years, and subsequently at the posteriorcaudal at about age 10 years in both sexes. The fusion proceeds with age fromthe both ends toward the middle region of the vertebral column and havebeen completed at the middle or posterior parts of the dorsal region. The
youngest physically mature animals appeared at 23 years and 28 years inmales and females respectively, while the oldest physically immature animals
were 36 years in both sexes. However, the differences between sexes may not
be significant.
DISCUSSION

Although histological technique will be desirable for the observation of
epiphyseal fusion as by Wheeler (1930), it was not applicable in the present
study. I cannot deny, therefore, misclassification of some stages of fusion,
especially between later stage of UFC (unfused, thin cartilage present) andbeginning of FJV (fused, join visible). However, as shown in Fig. 2, the presence or the absence of cartilage on the joining line can be easily recognizedwithout histological section if observed carefully. Thus I consider the present
method is adequate for the present study.
Mackintosh and Wheeler (1921) had preliminarily examined the physicalmaturity status of blue and fin whales by the epiphyseal fusion on some partsof the vertebral column, based on the suggestion given by an earlier work
(Flower, 1864). Wheeler (1930) examined further the nature of the ossification pattern on column in southern fin whale, and found in female that theepiphyseal fusion starts from both ends of the column and is completed at theanterior dorsal vertebrae. Later Ohsumi et al. (1958) confirmed similar pattern of ossification in the North Pacific fin whale using a larger sample sizeand detailed observation.
The present study compared ossification pattern with absolute age by
earplug growth layer counts, though both Wheeler (1930) and Ohsumi et al.
( 1958) used number of ovulation, and confirmed, for the southern minke
whales, similar pattern of the ossification of the vertebral column to that in fin
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

KATO

16

TABLE 2. RELATIONSHIP BETWEEN EPIPHYSEAL FUSION STAGES AND BODY LENGTH
MALE
BL
(ft)
22
24
25

FEMALE

Position on vertebral column*LcDCa
1 4 7 2 6 10 2 6 10 3 1017

·--

BL
(ft)
24
25

•••
.ALL
eLL

26

27

e.AL
.A.AL L-eeL L-eeL L--

eLL
eeL

26

-LL

·--·-- --·
-LJ..

LJ..L
-LL
LLL

27
28

.A.AL Lee

28

eeL
e.AL
--L
e.AL L-L --L
eeL L--LA.
A.LL LJ..Ji..

eA.L
e.AL
eeL

29

L.Ae

--·
--· ··-

•••
•••
••••
•••
LLL •••••••••••••• •••eLL-LL-•••
LLL
•••
.ALL
•••
•••
••••
••
•••
•••
••• •••••• •••
•••
•••
•••
•••
••••
•• •••
•••
•••
•••
•••
• ••
•••
•••
•••
•••
•••
•••
••••
••
•••
•••
•••
•••
•••
••• ••••••••• •••
A.LL LLJ..
•••
.AL.A

29

-··••••••

30

32

LLL

--L

•••
--L
LLJ..
LJ..-

•••
--L •••
LLJ.. ••••••••• •• ••
•••
•••
•••
••
• ••
e.AL
--L LJ..Ji..
eL--L •••
LLL
LLJ..
••••
•• A.LL LLL ••••••
A.LL A.LA. •••
•••
.ALA.
• ••
•••
•••
.AL.A
•••
•
••
e.AL
••• ••• ••• •••.AL-Ji..L·--••• ·-- -··-··
• ••
•••
• ••
•••
•••
-.AL

L-LL- -LL
L-- LLe
LLL
A.LL
.ALL

LA.e

Ji..L- LJ..A.
A.LA

•••
.ALL

-LL
-LL
-LL
--L
--L

eA.L L--

.ALA.

30

.ALeLeLeeL L-e.AL
Ji..-L LLJ..

.A.AL-Ji..L.A.AL
e.AL L--

Lee
L.Ae
L.Ae

•••
L-- --L
•••
•• ••
•••
•••
••
•••
•••
•
••
•••
••• •••
•••
••
•••
•••
•••
•••
•
-L••• L--

Position on vertebral column
No.
OvulacD
LCa----1 4 7 2 6 10 2 6 10 3 1017 tions

30

.ALL

•••
•••
•••
•••
•••
• ••
•••
•••
•
••
•••
•••
•
••
•••
•• •••••• •••
•••
•
••
•••••
•••
•••
•••
•••
••
••• ••• • •• • ••••• L-- -LL
-LL
•• ••
•••
••
•••
•
••
LLA.
•
••
•••
•••
••• • ••••• •••
•••
•••
••••
••••
•••
•••
••
••
•••
•••
•
••
•
••
••• •••••• •• ••••••• •• ••
••

··-

eeL

·-·--

-A.L
Lee

LA.e
LA.e

0
0
0
0
20
0
0
1
9
12
5
23
16
7
2+
23
12
21
18
17
17
17
6
4
4+
9
10
28
19
13
19
26
30
28
36
29
9
10
13
22
24
14
28
30
28
21
33

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

17

EPIPHYSEAL FUSION IN MINKE WHALES
32
33
34

••• •••••• ••••••• ••••••••• ••• ••• • ••
••

41
32

* Symbols used are; C, crevical; D, dorsal; and Ca, caudal vertebrae. Hyphen indicates stage unfused withthick cartilage (UTC), open circle unfused thin cartilage (UFC), closed triangle fused join visible (FJV),
closed circle fused join invisible (Fjl).
TABLE 3. RELATIONSHIP BETWEEN EPIPHYSEAL FUSION STAGES AND AGE.
MALE
Age BL
(ft)

2
4
5
7
8
9
12
14
16
17
19

21
23
26
29
30
36

25
25
26
29
26
28
26
29
29
28
27
27
28
30
29
28
29
32
30
30
27
29
30
27

FEMALE

Position on vertebral column*cDLCa
I 4 7 2 6 10 2 6 10 3 1017
eL'.L'.
•AL'.
• • ,!\,- ,!\, ,!\,

L'.--- ,!\, ,!\,

eL'.L'.
• • ,!\,-

L'.--,!\, ,!\,,!\,

•••
•••
•••

L'.--

-

AL'.L'.

L'.AA,!\, ,!\,

L'.AL'.

··-•••--A •••L'.Ae
L'.Ae
A-AAA ••••••••A AL'.A AA• •••--A•AA AL'.A AA••••••A AAA ••• ••A••••••
LAA A•••••••••••••• •••
AAL'. A•• ••A•••
AAA A • •
•••
•••
•••
•••
•••
•••
eAA AA• •••
•••
•AL'.

• • ,!\,

•AL'.

(ft)

4
5
7
10
11

-AA

• • ,!\,

AAL'.

,!\, ,!\,

Age BL

L'.-L'.--,!\, ,!\,,!\,

L'.--

AL'.L'.
AL-

A•L'.

13
14
15
16
17
18
19
21

L'.LA

22
24
25
26
28

29
30
31
32
34
35
36
38
41
42
* For symbols see Table 2.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

25
27
30
28
31
30
30
31
30
28
29
28
28
30
31
29
30
28
31
30
29
29
30
29
31
30
30
34
26
31
30
30
28
30
30
31
33

Position on vertebral column*
DLcCa--1 4 7 2 6 10 2 6 10 3 1017·,!\,-

AL'.L'.

••A A-AAL'.
•A-

··-

•AL'.

-,!\,·

L'.A-AL'.

L'.--

-A•
-AL'.

•AA

L'.--

-

AL'.•AL'.

L'.--

L'.L'.A,!\,,!\,

L'.••
-AL'.

• • ,!\,A••- - ,!\, AA•--L'. AAA
AA•
A••
-A•

•AL'.

-

•L'.-

AAL'.
-AL'.

•••

••A

AL'.L'.

-

,!\,

L'.--

•••
•••

L'.AL'.
AL'.L'.

•A• • •• •••
•••
AA•
••A
•••
•••
•••
AA•
••A A
ALA A••••• ••A A • • •••
•••
•••
A.6.A
••••
•• A-- .6.Ae
•••
•••
•AA
AA• •••
•••
•••
•••
•••
•••
•••
•••
•••
••• ••• ••• •••••••••••A AAA AA• •A•••••• ••••••••A A•• •••
•••
•AA
•••
•••
•••
•••
•••
•••
•••
•••
•••
•••
•••
••• ••• ••• •••
LL'.A

LL.6.

.6. L L'.

.6. .6.

LLL'.

A.6.L

.6. .6. L

A-L'.

.6. .6. •

18

KATO

whale above. Some differences exist, however, between fin and minke whale;in the fin whale the epiphyseal fusion firstly commences at posterior parts of
caudal vertebrae while it firstly starts at the anterior of the cervical in minke
whales; the fusion is completed among the anterior dorsal vertebrae for fin
whale rather than the posterior dorsal as in minke whale.
As stated by Wheeler (1930) and Mackintosh (1942) the completion of
epiphyseal fusion bears relation to number of ovulation and little to the bodylength. It was considered, in fin whale, that the ossification was completed at
13-16 ovulations (Wheeler, 1930; Peters, 1939; Nishiwaki and Oye, 1939;
Brinkman, 1948; Ohsumi, et al., 1958); based on the evidence of ossification at
the particular vertebrae. By converting these values of ovulation to absolute
age by average annual ovulation rate reported (0.67-0. 71; Laws, 1961;
Lockyer, 1971; Gambell, 1973) and assuming average age at sexual maturity
in the 1930-1950s to be age 11-12 years (from studies by Lockyer (1984) and
Ohsumi ( 1986)), the values can be roughly calculated to be age 28-36 years.
These ages for fin whale is similar to those in the present study for minke
whale (age 23-26 years), though the maximum life span for the former isabout twofold to the latter (Ohsumi, 1979).
However, it is still not clear whether completion of epiphyseal fusion ofindividual depend on time after sexual maturation or absolute age. Moreover,another aspect should be considered; the relationship between the physicalmaturity and changes in density. For example, Kato (1987) found that density
dependent changes in growth parameters such as age at sexual maturity andgrowth rate and suggested increase in body length at physical maturity withdensity in the southern minke whale stocks. These aspects are desired to be
examined further in the future study.
ACKNOWLEDGEMENTS

My sincere thanks are due to Dr T. Kasuya, Far Seas Fisheries ResearchLaboratory (FSFRL), for his critical and helpful review of this manuscript. I
would like also express my thanks to Dr S. Ohsumi (FSFRL) who kindly andcritically reviewed the manuscript. The suggestion of Dr P. B. Best, Universityof Pretoria, Republic of South Africa, at the field researches on the factory
ship was great assistance to the present study. Ms T. Shirai and Ms E. Shimuraof my institute kindly assisted in making the manuscript. I was not able tocarry out the field researches without cooperation of the staff and crew of Nisshin-maru No. 3, especially Messers K. Yamaguchi, M. Sato, S. Tabata,K. Maeda, T. Kaneda and S. Ohnaga.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

EPIPHYSEAL FUSION IN MINKE WHALES

19

REFERENCESBRINKMANN, A., 1948. Studies on female fin and blue whale. Hvalradets Skrifter, 31: 1-38.
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: 759-786.
FLOWER, W. H., 1864. Notes on the skeletons of whales in the principal museums of Holland and Belgium,with descriptions of two species apparently new to science. Proc. Zool. Soc. Lond., 1864: 384-420.
GAMBELL, R., 1973. Some effects of exploitation on reproduction in whales.]. Repord. Fert., Suppl., 19:533-553.
KATO, H., 1983. Some consideration on the decline in age at sexual maturity of the Antarctic minke whale.
Rep. int. Whal. Commn, 33: 393-399.
KATO, H., 1987. Density dependent changes in growth parameters of the southern minke whale. Sci. Rep.
Whal. Res. Inst., 38: 47-73.
LAWS, R.M., 1961. Reproduction, growth and age of southern hemisphere fin whales. Discovery Rep., 31:
327-486.
LocKYER, C., 1972. The age at sexual maturity of the southern fin whale (Balaenoptera physalus) using
annual layer counts in the ear plug.]. Cons. int. Explor. mer, 34(2): 276-294.
MACKINTOSH, N.A., 1942. The southern stocks of whalebone whales. Discovery Rep., 22: 197-300.
MACKINTOSH, N.A. and]. F.G. Wheeler, 1929. Southern blue and fin whales. Discovery Rep., 1: 257-540.
MASAKI, Y., 1979. Yearly change of the biological parameters for the Antarctic minke whale. Rep. int. Whal.
Commn, 29: 375-396.
NISHIWAKI, M. and T. OvE, 1951. Biological investigation on blue whales and fin whales caught by Japanese
Antarctic Whaling fleets. Sci. Rep. Whales Res. Inst., 5: 91-167.
0HSUMI, S., 1979. Interspecies relationships among some biological parameters in cetaceans and estimationof the natural mortality coefficient of the southern hemisphere minke whale. Rep. int. Whal. Commn,
29: 397-406.
0HSUMI, S., 1986. Yearly changes in age and body length at sexual maturity of a fin whale stock in theeastern North Pacific. Sci. Rep. Whales Res. Inst., 37: 1-16.
0HSUMI, S., M. NISHIWAKI and T. HrnIYA 1958. Growth of fin whale in the North Pacific. Sci. Rep. Whales
Res. Inst., 13: 97-133.
OMURA, H. and T. KASUYA, 1976. Additional information on skeleton of the minke whale from the Antarctic Sci. Rep. Whales Res. Inst., 28: 57-68.
PETERS, N., 1939. Uber Grosse, Wachstum and alter des Blauwales und Finwales. Zoologicher Anzeiger, Vol.
127.
WHEELER, ]. F. G., 1930. The age of fin whales at physical maturity. Discovery Rep., 2: 403-434.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

BRYDE'S WHALE IN THE COASTAL WATERSOF EASTERN AUSTRALIAROBERT A. PATERSON* AND STEPHEN VAN DYCK*ABSTRACT

While documented capture of B. edeni in eastern Australian waters islimited to only a few records, inshore observations suggest that the species
is not uncommon. Aspects of osteology and baleen morphology in twolarge stranded whales now housed in the Queensland Museum confirm
their identity as Bryde's whales. Breaching behaviour and the "working" offish schools is discussed.

INTRODUCTION

Bryde's whale (Balaenoptera edeni Anderson, 1878) is widely distributed
between latitudes 40°N and 40°S (Omura, 1959). Although Bryde's whale has
been captured in the south-west Pacific Ocean to the east of Australia(Kawamura, 1980) very few captures have been reported from the waters
adjacent to the east Australian mainland which lies between latitudes 11°37'S
and 39°04'S (Fig. 1). Information will be presented in this paper detailing
Bryde's whale captures, strandings and field observations in the coastal watersof eastern Australia. Specimens mentioned in this paper are lodged in thefollowing collections: Queensland Museum O or JM), Victorian Museum (C).
CAPTURES

Between 1952 and 1962 shore stations at Tangalooma (27°11 'S, 153°23'£)and Byron Bay (28°37'S, 153°38'£) processed 7423 humpback whales(Paterson and Paterson, 1984) and the industry was based almost exclusively
on that species. However, Bryden (1978) noted that on 14 September 1962 a
42 foot 3 inch [12.87 m] male sei or Bryde's whale was captured by the chaser
Norfolk Whaler five miles north of Cape Byron and Best (1977) noted that hehad received data concerning two Bryde's whales captured from the east
Australian shore stations in the early 1960s. Those captures and the small
numbers captured from the shore station at Carnarvon in Western Australia(Chittleborough, 1959) occurred during the decline in humpback whale
stocks in Australian waters and may have been associated with attempts to*Queensland Museum, PO Box 300, South Brisbane, Queensland 4101 Australia

Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 21-29

22

PATERSON AND VAN DYCK

152·

146"

140"E

12s

18"

QUEENSLAND

1- - - - - - - - - -/-~~

Ir-·\\.r.J

Cape Byron

I

I

I

30°

NEW SOUTH WALES

I
I

r-~,,"

III' "-,_,~---1

<.

I

',

35•

Corio Bay

Fig. 1. Eastern Australian mainland showing localities mentioned in text.

diversify the operations of the shore stations. No systematic survey of Bryde's
whale abundance was conducted and in 1962, when humpback whale stocks
were commercially exhausted, the east Australian shore stations ceased all
whaling activity.
STRAND IN GS

Skeletal elements of two whales, positively identified as Bryde's whales at thetime of stranding by the characteristic three longitudinal ridges on the dorsal
aspects of their heads (Omura, 1962) have been deposited in the Victorianand Queensland Museums (Table 1 and Figs 2 and 3). The two specimens are
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

、

23

AUSTRALIANBRYDE'S NHALES

F
i
g
.2
. Brydesw
h
a
l
e
ss
trandedont
h
ee
a
s
tA
u
s
t
r
a
li
anc
o
a
s
t
.
A
. SpecimenC884I,fromV叫 01ia.B.SpecimenJM4386,fromQueens
l
a
n
d
.
SeeTab
l
eIf
o
rl
o
c
a
l
i
t
yd
e
t
a
i
l
s
.

. BRYDESWHALESSTRANDEDO NTHEEASTAUSTRALIANCOAST
TABLEI

R
e
g
i
s
t
r
a
t
i
o
n
Number

Dat
eandl
o
c
a
t
i
o
n
ofs
t
r
an
d
i
ng

Spec
imen
de
t
ai
l
s

Refe
r
ence

C8841

2
5
.
v
i
i
.1
968
LimeburnerC
r
e
e
k
,
Cor
i
oBay
,V
i
c
t
o
r
i
a
。
04S
,1
4
4
。
24E
)
(
3
8

M
a
l
e
,6
.1m
l
o
n
g
,Po
s
t
c
r
a
n
i
a
ls
k
e
l
e
t
o
n
n
o
tc
o
le
c
t
e
d
.

Dixon
(
1
9
7
0
)

JM4
386

3
0
.
x
.
1
9
8
2
S
t
e
w
a
1tI
s
l
and,
Great
Sand
yS
t
r
a
i
t
,
Queensland
,1
52
。
57E
)
(
2
5°
3
8S

Sexunknown,
1
4
.
3
5m l
o
n
g
.
,
Almostcomp
l
e
t
e
s
ke
l
e
t
o
nbut
s
omec
au
d
a
l
v
e1
t
e
b
1aem
i
s
s
i
n
g
.

P
a
t
e
r
s
o
n
(
1
9
8
4
)

froma
n
i
m
a
l
sofd
i
s
p
a
r
a
t
ep
h
y
s
i
c
a
lm
a
t
u
r
i
t
y.Watson(1
981)notedt
h
a
tt
h
e
r
e1
4
.3and 14.
6m
maximumlengthsofmaleandfemaleBrydeswhalesa
e
s
r
e
s
p
e
c
t
i
v
e
l
ybutt
h
emaximumlengthsofmaleandfemaleBrydeswhal
S口.Rep. WJ
凶l
e
sRe
s
.I
n
s
t
.
,
，

N
o
.3
9
,1988

24

PATERSONANDVANDYCK

F
i
g
.3
. Brydes whaleJM438
6
,s
t
r
a
n
d
e
da
tS
t
e
w
a
1
tI
s
l
an
d
, Great Sandy S
t
r
a
i
t
,
Queensland.

capturedfromtheGreatB
a
r
r
i
e
rI
s
l
a
n
ds
h
o
r
es
t
a
t
i
o
ni
nNewZealandbetween
1956and 1
9
6
1 wer
e1
4
.
6and 1
4.
9m r
e
s
p
e
c
t
i
v
e
l
y(
G
a
s
k
i
n
,1
9
6
8
).C8841
measured6
.
1m i
nl
e
n
g
t
handt
h
eincompletef
u
s
i
o
nofi
t
sc
r
a
n
i
a
ls
u
t
u
r
e
si
n
‑
叫 w
asj
u
v
e
n
i
l
ewhereasJM4386measured 1
4
.
3
5m i
n
d
i
c
a
t
e
st
h
a
tt
h
ea
n
i
n
l
e
n
g
t
h and the Jumbo‑caudal p
o
r
t
i
o
nofi
t
sv
e
r
t
e
b
r
a
lcolumnshowsgrosschangeofs
p
o
n
d
y
l
i
t
i
sdeformansw
i
t
ha
s
s
o
c
i
a
t
e
ds
p
i
n
a
lc
a
n
a
ls
t
e
n
o
s
i
s
.Thosepathologicalchangesa
r
ec
o
n
s
i
d
e
r
e
dt
obeamainfe
s
t
a
t
i
o
nofadvancedage
(
P
a
t
e
r
s
o
n
,1
9
8
4
)anda
r
ep
r
o
b
a
b
l
ycausedbyr
e
p
e
t
i
t
i
v
ev
e
r
t
e
b
r
a
lligamentous
t
r
a
c
t
i
o
n(
L
a
g
i
e
r
,1
9
7
7
).
Omura(
1
9
5
9)andOmura,Kasuya,KatoandWada(
1
9
8
1
)a
f
t
e
rd
e
t
a
i
l
e
d
s
t
u
d
i
e
so
fBrydeswhalesfromthenorthandsouthP
a
c
i
f
i
cOceanandt
h
eI
n
‑
d
i
a
nOceanc
o
n
s
i
d
e
r
e
dt
h
a
tt
h
eappearancesoft
h
ea
n
t
e
r
i
o
ra
s
p
e
c
t
soft
h
e
n
a
s
a
lboneswere themostd
i
s
t
i
nc
t
i
v
eo
s
t
e
o
l
o
g
i
c
a
lc
h
a
r
a
c
t
e
r
i
s
t
i
cofBrydes
whaleswithregard t
od
i
f
f
e
r
e
n
t
i
a
t
i
o
nfromseiwhales(
B
αl
a
e
n
o
p
t
e
r
ab
o
r
e
a
l
i
s
L
e
s
s
o
n
,1
8
2
8
)
.Thea
n
t
e
r
i
o
rmarginsoft
h
en
a
s
a
lbonesareconcaveandin‑dined forw
ards on t
h
e
i
ro
u
t
e
ra
s
p
e
c
t
si
na
l
l specimensofBrydeswhales
examinedbyOmurawhereast
h
o
s
eofs
e
iwhalesareconvexors
t
r
a
i
g
h
tand
neverincl
inedforwardsontheiroutera
s
p
e
c
t
s
.Thes
k
u
l
lofJM4386,showing
t
h
ec
h
a
r
a
c
t
e
r
i
s
t
i
cn
a
s
a
lb
o
n
e
s
,i
si
l
l
u
s
t
r
a
t
e
di
nF
i
g
.4
.Thes
k
u
l
lofC8441hasbeenexaminedandi
t
sn
a
s
a
lbonesa
r
ec
o
n
s
i
s
t
e
n
tw
i
t
hOmurasd
e
s
c
r
i
p
t
i
o
nof
Brydesw
h
a
l
e
.
P
a
r
tofab
a
l
e
e
np
l
a
t
efromJM4386i
sshowni
nF
ig.5.Theincomplete
S
c
i
.Rep
.W
h
a
l
e
sRe
s
.I
n
s
t
.
,
N
o
.3
9
, 1988s

AUSTRALIANBRYDE WHALES

号︑

r
l
−
F
Il
﹂
−

ι

0・
5町
、

F
i
g
.4
. Dor
s
alv
i
e
woft
h
es
k
ulofBr
yd
凸 wh
a
l
eJM4
3
8
6
.
目 R
e
s
.I
n
s
t
.
,
S
c
i
.R
e
p
.W，／回 l

No.3
9
,1988

25

26

PATERSONANDVANDYCK

El占
ω
F

圃
11

．
．
︒
に
﹂O
Fi
g.5
.B
a
l
e
ens
amplefromBry
deswhaleJM438
6
.
S
c
i
.Re
p
.Whal
e
sRe
s
.I
出 t
.
,
N
o
.39
,1988

AUSTRALIANBRYDESWHALES

27

SOm m

Fi
g
.6.Dors
a
lv
i
e
woft
h
ena
s
albonesofBr
ydeswhal
eJ2I
7l
3(
t
hes
kulhadbeen
saw
nl
ongi
t
u
d
i
nalyl
oa
l
owi
t
sw
a
l
lmounting
)
.

n
a
t
u
r
eo
ft
h
i
ssamplep
r
e
c
l
u
d
e
dadetermina
ti
onoft
hea
f
f
i
ni
t
ie
sofJM4386
w
i
t
hBe
sts(
1
977） inshore and of
f
s
hor
ef
orms
.
Specimen]21713i
nt
heQueensl
and Museum isfromawhal
ewh
ic
h
s
t
r
a
n
d
e
da
tTinCanBayI
n
le
t(
2
5
。
5
1S
,1
53
。
02E
)i
n196
5
.Nob
a
l
e
e
nsamp
le
s
ord
i
a
g
n
o
s
t
icphotographsoft
h
es
t
r
a
n
d
e
dani
m
a
la
r
ea
v
a
il
ab
lef
o
rs
t
ud
y
.The
specimen wasc
o
n
si
de
r
e
dt
obet
h
a
tofas
eiwhaleandwasmountedanddisplayedi
nt
h
eQue
en
s
l
andMuseum.Th
eMuseumha
sr
ec
en
t
lybeenr
e
‑
l
oc
a
t
edandtheopportuni
tyha
sa
r
i
sent
oexaminethespecimeni
nde
t
ai
l
.The
n
a
s
a
l bone
sa
r
ei
l
l
us
t
r
a
t
e
di
n Fi
g
. 6 and theirappear
anc
ei
st
y
pi
c
alo
fa
Br
ydeswhale.Omurae
ta
l
.(
1
981
)notedt
h
a
tt
h
ev
e
r
t
eb
r
alc
ountofBr
y
des
w
h
a
l
e
si
s54‑55andt
ha
tofs
eiwhales56‑57.
Somev
er
t
e
b
r
a
eofJM4386and
]21
713a
r
em
i
s
si
ng,t
hev
er
t
e
b
r
alcountbei
ng49i
neachs
p
e
ci
men.S
p
e
c
i
‑
mensofbot
hBrydesands
e
iwh
a
l
e
sexaminedbyoneo
fu
s(
S
.
V.
D
.)i
n1
98
7
,
i
nt
heRijksmuseumVanN
a
t
u
u
r
lり
k
eHis
t
oi
r
e
,L
e
i
d
e
n
,！、~ ederland (
i
n
c
l
u
di
r
】
t
h
eP
a
l
a
uS
u
g
ispecimenr
ef
e
r
r
e
dt
obyOmura, 195
9)haveconfirmedt
h
e
S
c
i
.Re
p
.Whal
e
sRe
s
.I
悶 t
.
,

No
.39
,1988

28

PATERSON AND VAN DYCK

identity of JM4386 and J21713 as Bryde's whales.
FIELD OBSERVATIONS

One of us (R.A.P.) has monitored the annual migration of humpback whales
from Point Lookout (27°26'S, 153°33'E) and Cape Moreton (27°02'S,
153°28'E) during the months of June to October yearly since 1978 (Paterson,
1987). During this period (an approximate total of 320 watching days) incidental sightings of minke and Bryde's whales were recorded. The latter werepositively identified when the characteristic rostral ridges, described above,were seen. It was not uncommon for Bryde's whales to be seen close inshorenear the headland at Point Lookout and in the surf-lines along adjacentbeaches.
Kawamura (1980) noted that Bryde's whales have peak feeding periods
during early morning and late afternoon and the Point Lookout observations
appeared to support those findings but if schooling fish were present at othertimes during the day behaviour considered characteristic of feeding wasobserved. The behaviour included surface rushes, lunging and circling. On
occasions fish were seen leaping as the whales swam quickly through densely
packed schools.
Watson (1981) noted that Bryde's whales seldom show their flukes andfluke raising was not observed during any of the Point Lookout sightings.
Breaching was occasionally seen but it was not acrobatic, as is that of
humpback whales. When a Bryde's whale breached it usually emerged partiallyfrom the water and returned in the reverse direction but on two occasions
Bryde's whales were seen to leap clear of the water in a horizontal position
and re-entered by a "belly-flop".
Singles and pairs were the most common groupings and pairs occasionally "worked" adjacent schools of fish. As mentioned above, observations wereconducted at Point Lookout from June to October and no assessment wasmade of Bryde's whale occurrence during the other months of the year. At
this latitude in eastern Australia the sea is warmest in February and coldest in
August. The average surface temperatures for February and August werereported as 24.3°C and 18.9°C (Paterson, 1986). Although Bryde's whales
were seen in all months from June to October they were most frequently seen
during August and September. Bryden (1978, pls 1-3) showed a photographof a Bryde's whale seen near Cape Moreton (27°02'S, 153°28'E) during aerial
observations in September 1976.
As Bryde's whales seen on successive days at Point Lookout may havebeen the same animals it was not possible to estimate their abundance. However, the observations indicate that Bryde's whales frequent the inshore watersof eastern Australia between latitudes 27°S and 28°S at least during the winterand spring months.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

AUSTRALIAN BRYDE'S WHALES29

ACKNOWLEDGEMENTS
Mr Malcolm Cox of Project Jonah, Brisbane initially identified specimen
JM4386 and kindly allowed reproduction of his original photographs. Dr Chris
Smeenk, Curator of Mammals at the Rijksmuseum van Natuurlijke Histoire,
Leiden, Holland is gratefully acknowledged for his hospitality and assistance
while examinations were made of specimens in his care. Miss Joan Dixon,
Curator of Mammalogy at the Museum of Victoria gave every assistance withregard to specimen C8841 and provided the relevant photograph. Mr Carlos
Picasso of the Queensland Museum photographed the specimens in that
Museum. Drs Hideo Omura and Seiji Ohsumi were most helpful with advice
in relation to our enquiries.

REFERENCES
BEST, P.B., 1977. Two allopatric forms of Bryde's whales off South Africa. Rep. int. Whal. Commn (special
issue 1): 10-38.
BRYDEN, M.M., 1978. Whales and whaling in Queensland waters. Proc. R. Soc. Qd, 88: v-xviii, pls 1-3. (Thisappears in vol. 89).
CHITTLEBOROUGH, R. G., 1959. Balaenoptera brydei Olsen on the west coast of Australia. Norsk HvalfangstTid., 48(2): 62-66.
DIXON, ]. M., 1970. Two new whale records from Victoria Mesoplodon bowdoini Andrews (Ziphiidae) and
Balaenoptera edeni Anderson (Balaenopteridae). Viet. Nat., 87(4): 88-93.
GASKIN, D. E., 1968. The New Zealand cetacea. Fish. Res. Bull., 1: 28.
KAWAMURA, A., 1980. Food habits of the Bryde's whales taken in the south Pacific and Indian Oceans. Sci.
Rep. Whales Res. Inst., 32: 1-23.
LAG!ER, R., 1977. Spondylosis in the whale - an anatomical study of an osteophyte. Scand.]. Rhuematol.,
6(4): 245-249.
OMURA, H., 1959. Bryde's whale from the coast of Japan. Sci. Rep. Whales Res. Inst., 14: 1-33.
OMURA, H., 1962. Further information on Bryde's whale from the coast of Japan. Sci. Rep. Whales Res. Inst.,
16: 7-18.
OMURA, H., T. KASUYA, H. KATO and S. WADA, 1981. Osteological study of the Bryde's whale from thecentral south Pacific and Indian Ocean. Sci. Rep. Whales Res. Inst., 33: 1-26.
PATERSON, R.A., 1984. Spondylitis deformans in a Bryde's whale (Balaenoptera edeni Anderson) stranded on
the southern coast of Queensland. jnl. Wild. Dis., 20(3): 250-252.
PATERSON, R., 1986. Shark prevention measures working well. Aust. Fish., 45(3): 12-18.
PATERSON, R., 1987. Recovery in the east Australian humpback whale stock. Aust. Fish., 46(8): 32-36.
PATERSON, R. and P. PATERSON, 1984. A study of the past and present status of humpback whales in east
Australian waters. Biol. Conserv., 29: 321-343.
WATSON, L., 1981. Sea guide to whales of the world. Hutchinson, London. 302 pp.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DISTRIBUTION OF SPERM WHALE STOCKSIN THE NORTH PACIFICTOSHIO KASUYA * AND TO MIO MIYASHITA*
ABSTRACTTwo contrary opinions on the segregation pattern of sperm whale
stocks in the North Pacific, i.e. longitudinal vs. latitudinal, were tested
using whaling operation data, results of recent sighting cruises, andmovements of marked whales.
While Japanese coastal sperm whaling was exploiting the breeding
schools, the operation gradually changed from summer to winter and from
north to south. In the late 1950s and 1960s most of the whales were taken
during summer in the cold Oyashio Current area. During the 1970s
whales were taken in the warm Kuroshio Current area in summer and in
the Oyashio area in other seasons. In the 1980s most of the whaling occurred in the Kuroshio Current area during the winter. The last phase iscertainly undesirable for the industry using whaling stations opened forthe northern ground. In recent years sperm whale sightings are rare insummer in the previous whaling grounds north of the Kuroshio Current
and its extension.
These changes in the whaling operation and the whale distribution are
explained by assuming two latitudinally segregating sperm whale stocks
and earlier depletion of the northern one. In the summer adult males
move to colder waters segregating from their breeding population as wellas adult males of different stocks. This is supported by additional information from blood types, movement of marked whales, operation of Japanesepelagic whaling, and recent whale sightings. We further deduced that theeastern North Pacific is probably inhabited by a single sperm whale stock,
although presence of some local stocks is not fully excluded.
The present study also indicates the importance of ocean currents andwater masses for the evolution of sperm whale stocks, and provided an
example that a habitat vacancy produced by the depletion of one stock is
not easily reoccupied by nearby stocks. The successive exploitation ofdifferent components of one stock or exploitation of more than one stockwith overlapping time period could have masked possible changes in the
population structure and some density dependent life history parameters.

* Far Seas Fisheries Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan
Sci. Rep. Whales Res. Inst.,!Vo.39,1988,31-75

32

KASUY A AND MIY AS HITA

Sea of Japan

Pacific Ocean•Bonin130°140°Fig. 1. Japanese whaling stations that have been used for processing sperm whales
during the 1955 to 1986 seasons.

INTRODUCTION

Two contradictory opinions have been published on the segregation of sperm
whale stocks in the North Pacific. One assumed that stocks were segregatedlongitudinally. The others believed that the stocks were segregated latitudinally, although recognizing the presence of some longitudinal segregation.
Although Kasahara (1950) did not clearly state about the stock identity
in his study on whale stocks and whaling in Japan, he drew a diagram ofsperm whale migration in the western North Pacific. It shows as if he believedthat most breeding schools of sperm whales winter in the Bonin Islands
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

NORTH PACIFIC SPERM WHALES

33

waters and summer off Sanriku/Hokkaido waters, but that some females
winter off Sanriku/Hokkaido waters and summer in the central and northern
Kuril Islands area. Then Klumov (1955) presented a hypothesis that there are
two breeding stocks one summering in the northern Kuril Islands and theother in the southern Kuril Islands, with similar latitudinal stock segregationin the eastern North Pacific. An exwhaler Watase (1963) published a similar
hypothesis. He thought that the breeding schools of the southern stock segregate to the south of the Kuroshio Front with a northern range reaching 40°N
in summer (off Sanriku, see Fig. 1) following the shift of the Kuroshio Front,
while those of the northern stock principally inhabit waters north of the
Oyashio Front. He thought the breeding schools of the two stocks intermingle
in the summer in latitudes between 39° and 40°N off the Pacific coast ofJapan, although the northern stock will move further south in winter. He also
reported an autumn migration of a limited number of singletons or groupsof large males to the coastal Oya~hio Current area, but its relationship tothese stocks was not explained. In the same year, Fujino (1963) found asignificant difference in the blood type composition between sperm whales
taken by Japanese coastal fishery (both sexes, taken from June to November)and males taken by the pelagic fishery in the central Aleutian Islands/Bering
Sea area (51°-53°N, 172°E-165°W) in May to August, and concluded that thewestern North Pacific is inhabited by two sperm whale stocks and the northernstock migrates in autumn to Japanese waters but the southern stock does not
migrate to the Aleutian waters. He also analyzed the movement of marked
whales and concluded that sperm whales in the Bonin Islands area belong to
the southern stock. Although he does not seem to have clearly mentioned thatthe northern stock migrating off the Pacific coast of northern Ja pan includes
both sexes, an important factor for the interpretation of the result, his data
support that case (see Discussion).
Other studies have proposed a single sperm whale stock in the entire
latitudinal range off the east coasts of Ja pan and Kuril Islands. Masaki (1970)
analyzed mark-recapture data, blood types, catch distribution, size composition,and density hiatus appearing in the whale sightings, and assumed threelongitudinally segregating stocks in the entire North Pacific, with boundaries
at around 170°E-180°E and 150°W-160°W. Later, Ohsumi and Masaki( 1977) recognized a hiatus in the female catch in Japanese pelagic whaling inlongitudes around 160°W-175°W, and considered it to represent a stockboundary. Although such information was not available to the west of 160°E,
they considered from mark recapture data that sperm whales migrating off
the Pacific coast of northern Japan and Kuril Islands represent a single stock(western North Pacific stock). They ignored an apparent density hiatus offemales appearing in their data at 35°-40°N and west of 165°W, and concluded
that there were two (eastern and western) sperm whale stocks in the entire
North Pacific. Bannister and Mitchell (1980) analyzed the catch of 19th century
whaling between 20° -40°N to find a density hiatus at l 45°E, and assumed
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

34

KASUYA AND MIYASHITA

three longitudinally segregated sperm whale stocks, i.e. to the west of l 45°E,
in 145°E-l 79°E, and in l 79°E-150°W. The current management of the
sperm whale population by the International Whaling Commission (IWC) isbased on the assumption of two whale stocks in the entire North Pacific, a
distribution which has been adopted since the 1979 season (IWC, 1979) andis close to Ohsumi and Masaki (1977).
Ohsumi ( l 980b) indicated historical changes in the season and fishingground of Japanese coastal whaling during the past 29 years and attributed
them firstly to oceanographic changes, but later to the combination of changes
in the oceanography, selectivity between whale species, and decline in sperm
whale availability due to the operation of USSR pelagic whaling off Japan(Ohsumi, 1981 b ). A major oceanographic factor known to affect the Japanese
coastal whaling is the fluctuation of the Kuroshio Current as indicated by Uda(1954) and Ohsumi (1980b). The cycle, however, is believed to be 8 to 10
years (Uda, 1954). Since the studies of Ohsumi (l 980b, l 98lb), sperm whaling
has continued in Japanese coastal waters and resulted in a further southward
shift of the fishing ground and delay of the peak season (USSR pelagic whaling
lasted till 1979, and exploitation of North Pacific sei whales till 1976). If suchan uni-directional long time change of the fishery is attributable to change insome oceanographic condition, the total of such change must have been
extremely large and should have caused a significant climatic change in theregion. Such a change has not been detected.
Under these circumstances, the present study attempts to examine ifeither of the above two groups of hypotheses on the sperm whale stock off the
Pacific coast of Japan can better explain the observed changes in the fisheryand in the distribution of sperm whales. In addition we use analogy with thewestern North Pacific to consider the sperm whale distribution in the eastern
North Pacific.
MATERIALS AND METHODS

Statistics of Japanese land based fishery
The position, number and date of sperm whale catch by the Japanese
coastal whaling are used to analyze the historical change in the distribution of
the species off Japan. Catch positions of individual whales are available forseasons 1973 to 1985/86, but the corresponding data for 1955 to 1972 seasons
are only available by months and by whaling stations (compiled by the Japan
Whaling Association). We quoted from Kasahara (1950) the sperm whale
catch statistics before World War II, when the species was hunted without
regulation of fishing season or of catch quota. These are used in Tables 2 to
11 and Figs 2 to 4. Catch was regulated by national quota in 1959 to 1966,
and by agreement between related nations or by IWC since 1970 (Ohsumi,
l 980c). The actual figure of the quota varied by the government policy,
agreement between countries, or allocation of IWC quota between coastal andSci. Rep. Whales Res. Inst.,
No. 39, 1988

NORTH PACIFIC SPERM WHALES

35

pelagic fisheries. The reported catch agreed with the quota with a small
number of differences. These statistics are used as an indicator of peak monthof sperm whale catch, although we believe (without documented evidence)that there has existed unknown number of significant under-reporting in the
postwar coastal operations under quota system. Sex ratio or body lengthcompositions are not analyzed in detail. The body length must have beenskewed by the misallocation of body length due to the body length regulation(:2:30 feet in 1938 to 1948, :2:3S feet in 1949-1972, and :2:30 feet since 1973,
Ohsumi ( l 980c)). Sex ratio of the catch will not represent the ratio in the
population in the whaling ground due to the size selection of the fishery orcatch quota by sex (Table 1).
Catch by Kuril Islands land based fishery
Sperm whale catches by the USSR land based fishery summarized bymonth and land station during five years (l 9SO, l 9S 1, and 1962 through1964) are used to see the difference of migration timing between sexes (Fig.
8). The IWC body length regulation was the same as for Japanese coastal
whaling during the period, although the selectivity for larger whales or between sexes could be different.
Catch by Japanese pelagic fishery
Catch of sperm whales by sex, year, and two degree squares of latitude
and longitude have been cited from Smith (1980) and Shimadzu (1987), andused to find density hiatus or geographical variation in sex ratio. These data
are used in Figs 9 and lS. The range of Japanese pelagic whaling was modified several times by the Government during the period (Ohsumi, 1973). The
limit was ( 1) north of 4S 0 N in l 9S2-1966, (2) north of S0°N (west of 1S9°E),
north of 4S 0 N (1S9°-l 70°E) and north of 40°N (east of 170°£) in 1967 to
1971, (3) north of S0°N (west of 1S9°E), north of 4S 0 N (1S9°-l6S 0 E), northof 20°N (16S 0 E-1S0°W), and north of 3S 0 N (east of 1S0°E) since 1972. In
addition to these regulations Japanese factory ship operation was prohibited,since 1972, after 1 August in a small area off Japan surrounded by 20°N,
4S 0 N, l 6S 0 E, and 170°£. The size limit was 3S feet in 1949-19S l, 38 feet in
1952-1972, and 30 feet since 1973 (Ohsumi, 1980c), but there are somedoubts on the reliability of the length statistics near the above size limits(Allen, 1980).
Mark-recapture data
Data include all the available records of whales marked by Canada,
Japan, USA or USSR and recovered before 1987 by these countries. The
female records were provided by Shimadzu (1987), and male records werecompiled from published records of Omura and Ohsumi (1964), lvashin andRovnin (1967), Ohsumi and Masaki (1975), lvashin (1983), and Japanese and
USSR progress reports to IWC. Only recoveries made on 11 th day or later
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

36

KASUY A AND MIY AS HITA

from the date of marking are used (Figs 10 to 14).
Whale sighting data
Sightings of sperm whales were recorded during eleven whale sighting
cruises conducted in early summer to autumn in 1983 to 1986 using charteredwhale catcher boats Toshimaru No. 15 (September to October in 1985 and1986), Toshimaru No. 18 (June to September in 1986), Toshimaru No. 25 (Juneto August in 1983, June to September in 1984 and 1985, May to June in1986), Shonanmaru (June to July in 1983, June to August in 1984, June to
September in 1985), and Kankimaru No. 58 (September to October in 1986).
The method of sighting is described in Kasuya (l 986a), and is identical to thatused in the Antarctic minke whale assessment cruises (Best and Butterworth,1980). The vessels surveyed 74,274 nautical miles of prefixed trackline spending a total charter period of 761 days. Only presence of sighting effort insquares of one degree longitude and latitude, position of sperm whale sighting
and the estimated body length are used in the present study.
RESULTS

Changes in the fishing season
Ohsumi (l 980c) summarized the history of legal regulation of the sperm
whaling season. Until 1951 season, there was no regulation of sperm whaling
season in the Japanese coastal waters. The season was set since 1952 at eightmonths of April to November, and then altered to May-December (19661975) or August-March (1976177 to present) (Table 1). The industry could
operate whaling in any particular period described above. Each whaling
company owned several land stations at different latitudes along the Pacificcoast of Japan, and operated simultaneously one or two of them according to
the seasonal movement of the whaling ground and target species. Althoughno sperm whales were landed at stations in Kii from 1964 to 1975 (Table 1),
the stations were used during the period for short Bryde's whale seasons.
Four land stations are currently in use for sperm whaling, i.e. at Ohsawa(Nitto Whaling), Ayukawa (Nihon Whaling), and Wadaura (Nitto Whaling
being lent by Gaibo Whaling), and Taiji (Nihon Whaling).
Annual trend in the season of the sperm whale catch from 1955 to 1972
is shown in Table 2 (data of several years are grouped according to the change
in the regulation of the fishing season) and that from 1973 to 1985/86 in Fig.
2. The peak catch gradually moved from August/September in 1955-1960 tci
October/November in 1970-1972 seasons. Even after 1973 season, when
detailed catch data became available including the positions of individual
whales, this trend in the annual shift of the fishing season further continued,
to reach a peak in March in recent years (Fig. 2). It is notable that such
uni-directional change of the peak season preceded the alteration of legal
regulation. Possibly the legal regulation followed the need of the industry.
Sci. Rep. Whqles Res. Inst.,
No. 39, 1988

37

NORTH PACIFIC SPERM WHALESTABLE 1. NUMBER OF WHALING STATIONS** THAT OPERATED SPERM WHALING OFF
THE PACIFIC COAST OF JAPAN AND RELATED WHALING REGULATIONS
Kii
33.5°N

Year
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976177
1977178
1978179
1979/80
1980/81
1981/82
1982/83
1983/84
1984/85
1985/86

Boso
35°N

Sanriku
38°-40.5°N

Hokkaido
43°-43.l 0 N

FishingseasonCatch*

8
8
8
8
8
8
8
8
6
5
4
4
4
4
4
4
4
4
4
4
4
4
2
2
2
2
2
2
2
2
2

4
5
5
5
5
5
5
5
5
5
4
2
2
2
2
1

Apr. -Nov.
Apr.-Nov.
Apr.-Nov.
Apr.-Nov.
Apr. -Nov.
Apr.-Nov.
Apr.-Nov.
Apr.-Nov.
Apr. -Nov.
Apr. -Nov.
Apr.-Nov.
May -Dec.
May -Dec.
May -Dec.
May -Dec.
May -Dec.
May -Dec.
May-Dec.
May -Dec.
May -Dec.
May -Dec.
Aug.-Mar.
Aug.-Mar.
Aug.-Mar.
Aug.- Mar.
Aug.- Mar.
Aug.-Mar.
Aug.- Mar.
Aug.-Mar.
Aug.-Mar.
Aug.-Mar.

1,506
2, 125
2,361
2,588
2,111
2, 121
2,110
1,685
1,715
1,800
1,800
2,101
2,635
3,747
3,667
3,484
3,328
3,020
2,436
2,361
2,307
2,487
2,017
1,730
1,269
1,192
869
439
393
400
400

2
2
I

2
2
2
3
3
2

l***

* Take of females exceeding 15% of the quota has been prohibited since 1979/80 season.
** Given for geographical regions.
*** Operated using a station in Bonin Islands (26.6°N) instead of the Taiji station on the Kii Peninsula.
TABLE 2. MONTHLY CATCH OF SPERM WHALES IN JAPANESE COASTAL
WHALING OFF THE PACIFIC COAST OF JAPAN, EXPRESSED AS THE
PERCENTAGE OF ANNUAL CATCH
Month
Year
1955-60
1961-65
1966-69
1970-72

Apr.

May

June

July

Aug.

Sep.

Oct.

Nov.

6.5
1.4

6.3
3.4
1.4
1.5

6.8
5.5
3.4
1.6

9.4
9.0
2.9
3.4

22.2
20.6
16.5
8.7

26.6
34.5
24.8
20.8

13.6
17.3
22.I
29.3

8.6
8.4
19.l
22.7

* In parentheses are total number of catch representing the monthly catch.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

Dec.

Total*

9.8
12.0

JOO (12,837)
JOO ( 9,099)
100 (12,150)
JOO ( 9,831)

38

KASUY A AND MIYAS HITA

20
10 1985/86

0 1-------------J---I
10 1984/85
01----------w:-----:---::-",~---;~

10 1983/84

Ot----l 0 1982183~

c 10 1981/82
QI~
QI

01-----a.

10 1980/81

c

0

:c 10

-----1

1979 /80

Ill

.c
~

.....

10 1978/79

0

0

0

10 1977178

zT

01------h1~~-1976/77_ _ _ __,

10 1975176

0~--------1

10 1974175

0 µ;:::::::;:::::.,==1::::__;
10 1973/74

M J

J

A S 0 N D J
Month

F M A

Fig. 2. Monthly distribution of sperm whale catch by .Japanese coastal whaling.

The shift of the peak fishing season continued even after the ban on catching
sei whales in 1977.

Whaling ground
The whaling companies gradually closed their stations in northern Japan
from 196_3-.through 1977, and several major companies ceased coastal whaling
during the period, although this change might not be attributable solely toavailability change of sperm whales but also to that of sei whales or to preferSci. Rep. Whales Res. Inst.,
No. 39, 1988

39

NORTH PACIFIC SPERM WHALESTABLE 3. NUMBER OF SPERM WHALE LANDINGS BY REGION AND WHALINGSEASONS, EXPRESSED AS THE PERCENTAGE OF THE ANNUAL CATCH(BASED ON THE SAME DATA AS TABLE 2)
Land stations
by region

Kii
33.5°N

Boso
35°N

Sanriku
38°-40.5°N

Hokkaido
43°-43.l 0 N

Total

1955-60
1961-65
1966-69
1970-72

1.9
0.7
0
0

0.4
0
0
0

32.l
46.3
71.4
88.5

65.6
53.0
28.6
11.5

100
100
100
100

ence of industry for pelagic whaling over land based operation. Since 1977,
coastal sperm whaling has been operated by two companies using four stations(Table 1).
Most of the sperm whale catch (65%) was landed at stations in Hokkaido(north of 43°N) during 1955-1960, but the proportion continued to decline
after this and landings in Sanriku (38°-40.5°N) increased to attain 88% of thetotal sperm whale catch in 1970-1972 seasons (Table 3). This trend further
continued in 1973 through 1985/86 seasons. In 1973 the major ground wasin the latitudes of 34°-39°N with a peak in 37°-38°N (Figs 3 and 4). In 1977/
78 season the catch occurred also in the additional latitudes of 32°-33°N or
between Boso and Bonin Islands. Then during 1978179 through 1982/83
seasons catch in the northern ground (34°-39°N) declined and became almost
negligible since 1983/84 season. The operation in 1981/82 season was exceptional because a station in the Bonin Islands was used only for one season.
Recent catches occur in winter and mostly in 29°-33°N and 130°-145°£,
which is quite different from the operation in the 1950s and 1960s done insummer and in higher latitudes.
The above change is hard to attribute to short cyclic fluctuations inoceanographic conditions because it lasted too long (over 30 years), nor to aselectivity change between whale species because the change continued both
before and after the ban on catching sei whales in 1977. If we consider thefact that the two whaling stations (Taiji and Wadaura) in the south can process
only meat, and that the other parts of the carcass (viscera, blubber and bone)
have to be transported for the final processing to the northern stations inSanriku (Ayukawa and Ohsawa), which in a straight line are 500 to 700km
apart from the corresponding southern ones, we can reasonably presume thatabove mentioned change in the fishing ground is due to a decline in availability of sperm whales in the northern ground.
Seasonal and latitudinal changes in the coastal operation
Latitudinal and monthly distributions of the catch are shown in Tables
5 to 11. Several fishing seasons are combined according to the above mentioned
changes in the regulation of whaling season and latitudinal range of operation.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

40

KASUYA AND MIYASHITA

30

1985/86

20
10
0
10

1984/85010

1983/840
101962183..... 0
c 10
Cl.I

u
....

0

Cl.I

a. 10 1980/81
c
0

l/I

Cl.I

ili
.!:.

10

~

0

0

1979/800
10 1978179

0

z 10 1977/78
0
10

1976/770
10

1975/760
10

1974/7501001973174

25

30

-'~
35

1~1:::::1::1,

40

Latitude in degree
Fig. 3. Latitudinal distribution of sperm whale catch by Japanese coastal whaling.

Some catches for research purposes are included.
Data from biologists indicate that the sperm whale catch was composed
mostly of females in summer off Hokkaido (>43°N) and Sanriku (38°-41°N)(Table 4) or in winter Qanuary and February) in 36°-40°N (Ohsumi and
Satake, 1980). These agree with the analysis of prewar statistics by Kasahara(1950; see Table 5) or postwar statistics by Ohsumi (l 980b), and indicate that
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

"[

?:

~
::i::i

Co ""

~~

_l.O~

\JJ

::i::i

<: ~
~·

?

"
"

...

--

-"'!~

~'to

-~

en

CD

'

~

CD

;:;;

---il~~~~~-+~~~~~~1-~~

-,.

~~

-

rn

0

0

0

w
0

0

....
0

Fig. 4. Position of sperm whale catch by Japanese coastal whaling in some selected years. Each mark represents one sperm
whale. Numerals (1 to 9) and alphabets (X, Y, Z) indicate month of the year Qanuary to September, October to December).
Every second individual has been plotted (being selected by the order of processing) for 1973 and 1976/77 seasons, but all
the catches are plotted for other seasons. Each mark represents one sperm whale.

....
0

0

w

Ill,.,...... ""'""'-"'Col ...

0

0

-

....

0

~

-

•,..-:J._.-:...., ... ~~-... ~-- ~-"""" ... -•~~~ ~-;,:.JP..J,

-~

0

mi-;~

.......-" it • ~·-t,•• 'dlE".
x

-

0

.::

-

0

w

0

&;1--+-~~~~~+-~~~~~+-~~~~~~1--~-;

0

~

w

<{:

0

w
~

-

0

w

CD
...,

.+:-

-

~
r:Jl

>

::c:

~

~

"'

r:Jl

c;

'-.j

~......

::c:

~

z
0

42

KASUYA AND MIYASHITA

the fishery exploited the breeding schools.
In the late 1950s, sperm whaling started in April and slightly over halfof the total catch was obtained off Sanriku (April to June), then the groundshifted to Hokkaido to the north Quly to October), but this pattern changed
from the late 1960s so that greater catches were made off Sanriku in any
month (Table 6). And in the three years of 1973 to 1975 when individual
catch positions became available, the season started in May at 34°-39°N, thenthe area of peak catch shifted in summer slightly to the south (33°-36°N), andagain returned to the north (37°-39°N) in autumn (Table 7). The last feature
was the same in the 1976177 and 1977178 seasons when the fishing season was
extended to March (Table 1). Most of the winter (December-March) catch
TABLE 4. PROPORTION OF FEMALES IN THE CATCH OF JAPANESE COASTALSPERM WHALING EXAMINED BY BIOLOGISTS, 1960 THROUGH 1965Land
stations

Sex

May

June

July

Aug.

Sep.

Oct.

Nov.

Hokkaido

malefemale

0
0

8
0
0

39
64
63

246
371
60

444
1345
75

200
691
78

20
73
79

957
2544
73

16
4
20

52
77
60

111
130
54

218
351
62

93
202
68

49
124
72

15
78
84

554
966
64

(%)
Sanrikumale
female(%)

Total

TABLE 5. PROPORTION OF FEMALES IN THE CATCH OF JAPANESE COASTAL SPERM
WHALING IN 1940 THROUGH 1948, WHEN THERE WAS NO REGULATION OF
SEASON OR QUOTA (EXTRACTED FROM TABLE 29 IN KASAHARA, 1950)
Month
Kuril Is

Jan.

Feb.

Mar.

M
F

%
Hokkaido

July

Aug.

Sep.

Oct.

Nov.

144

440
62
12

558
101
15

189

40
4
9

2
0

0

0

0
35
11
24

44
9
17

27
16
37

33
10
23

268
130
33

257
179
41

71
105
60

16
18
52

421
661
61

330
528
62

448
534
54

422
522

55

255
151
37

2

14

0

0

0

100
124
55

73
69
49

75
37
33

90
38
30

155
143
48

357
221
38

444
526
54

16
4
20

20
3
13

11
3
21

43
24
36

56
13
19

12
1
8

12
5
29

M
F

17

%

0

55
56
50

148
209
59

116
196
63

17
65
79

M
F
M
F

Dec.

338
11
3

14
13
48

%
Bonin Is

June

8

%
Boso
&Kii

May

6
3
33

M
F

%
Sanriku

Apr.

3
0

0

0

M: number of males, F: number of females, %: female proportion in %.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

43

NORTH PACIFIC SPERM WHALES

occurred at 36°-40°N (Table 8).
Off the Pacific coast of Japan the fronts of the cold Oyashio Current andwarm Kuroshio Current situates at around 35°N and 40°N, respectively, andthe surface water temperature in the intermediate area alternates seasonallyclose to either of the two currents with considerable annual and local variations
TABLE 6. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE
CATCH BY JAPANESE COASTAL WHALING IN THE PACIFIC,
1955 TO 1972 SEASONS
Wh~ling

stations

Apr.

May

June

July

Aug.

Sep.

Oct.

Nov.

1955 to 1960
Hokkaido
Sanriku
Boso
Kii

341
314
40
144

280
500
8
21

264
548

781
420

2211
625

2792
612

1419
332

334
770

66

8

7

8422
4121
48
246

1961 to 1965
Hokkaido
Sarn:iku
Kii

44
37
45

31
269
10

155
336
5

416
401
2

770
1103

1883
1255

1061
515

466
295

4826
4211
62

1966 to 1969
Hokkaido
Sanriku

5
161

81
330

52
306

235
1765

880
2138

1086
1603

896
1425

236
951

3471
8679

1970 to 1972
Hokkaido
Sanriku

17
128

51
109

53
283

65
792

126
1920

414
2458

376
1848

16
1163

1130
8701

Dec.

Jan.

Feb.

Total

TABLE 7. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE CATCH BY
JAPANESE COASTAL WHALING IN THE PACIFIC, 1973 TO 1975 SEASONS
Latitude

May

June

July

Aug.

Sep.

5
5

8
2
4

7
2

14
14
I

43°-44°N
42°-43°N
41°-42°N
40°-41°N4
2

39°-40°N
38°-39°N
37°-38°N
36°-37°N
35°-36°N

3
12
16
26
33

10
21
18
57

2
8
56

4
29
56

34°-35°N
33°-34°N
32°-33°N
31°-32°N

19
4

97
16

34
17

Total

120

231

133

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

Oct.

Nov.

Dec.

Jan.

7
8
3
23
151
297
867
184

40
14

127
28
5

37
19

154

496

1596

67
228
645
1036
75

98
283
861
1078

10
33
25

8

2051

2339

Mar.

Total
8
43
30
19

11

4
3
26
91
183

Feb.

196
688
1882
3186
669
362
98
6

68

7188

44

KASUY A AND MIYASHITA(Mizuno and White, 1983), and possibly with a cyclical fluctuation of 8 to 10
years (Uda, 1954). The boundary area probably corresponds to the westernpart of the Subarctic Boundary of Favorite, Dodimead and Nasu (1976). The
seasonal shift of the sperm whaling ground shown above is the reverse of theseasonal movement of the oceanography, and can be explained only by
assuming that there were two groups or stocks of female sperm whales mainly
inhabiting each in the Kuroshio and Oyashio Currents. The industry exploited
more northern stock individuals in summer and autumn in postwar period
TABLE 8. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE CATCH BY JAPANESE
COASTAL WHALING IN THE PACIFIC, 1976177 AND 1977178 SEASONS
Latitude

May

June

July

Aug.

Sep.

Oct.

Nov.

Dec.

0

40°-4l N
39°-40°N
38°-39°N
37°-38°N
36°-37°N
35°-36°N

63
3

34°-35°N
33°-34°N
32°-33°N
31°-32°N
30°-3l 0 N

3
11

43
7
25

116
270
18

51
23
18

18
34
20

7
38
385
647
3

Jan.

Feb.

Mar.

Total

51

6

9

66

315
146
95
416
53

75
182
213
562
8

26
129
203
216
8

429
498
1058
2118
115
95
83
49

26
22

2

2

29°-30°N
28°-29°N
27°-28°N
Total

7

14

173

478

1080

1124

1046

592

4514

TABLE 9. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE CATCH BY JAPANESE
COASTAL WHALING IN THE PACIFIC, 1978179 THROUGH 1980/81 SEASONS
Latitude

May

June

July

Aug.

Sep.

Oct.

Nov.

Dec.

Jan.

0

40°-4l N
39°-40°N
38°-39°N
37°-38°N
36°-37°N
35°-36°N
34°-35°N
33°-34°N
32°-33°N
31°-32°N
30°-3l 0 N
Total

7

Mar.

Total

77

15

92

27
83
251
57

41
91
113
101
102

60
130
244
131
34

102
276
531
652
309

2

l

3

4

25
43

23
86
143
66

3
5
4

47
61
13

41
112
86
15
3

26
71
37
9

188
150
87
6

118
441
161
l

497
949
497
57
26

575

561

956

1335

3988

4

2

Feb.

I

7

ll

4

16

74
109
109
6
3

28

155

371

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

45

NORTH PACIFIC SPERM WHALES

before the 1960s, and started in the early 1960s to take a significant catchfrom the southern stock on the summering ground and from the northernstock on the wintering ground. This interpretation have some agreement withTABLE 10. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE CATCH BY JAPANESE
COASTAL WHALING IN THE PACIFIC, 1981/82 AND 1982/83 SEASONS
Latitude

May

June

July

Aug.

Sep.

41°-42°N
40°-4l 0 N

Oct.

Nov.

Dec.

Jan.

Feb.

Mar.

Total

2

39°-40°N
38°-39°N
37°-38°N
36°-37°N
35°-36°N

2
12
8
11

4

4

34°-35°N
33°-34°N
32°-33°N
31°-32°N
30°-31°N

8
12
21
33
5

6
10
8
26
19

29°-30°N
28°-29°N
27°-28°N
26°-27°N
25°-26°N

2
7
17

113

19
5
35
21

16
41
8
24
11

21
3
4
10

10

9

3
2

107

96

3

32
42
25
30
13

43
60
36
34
22

55
72
47
34
27

35
79
24
2

97
203
91
150
69

22
36
10

22
47
34
17

50
48
6

41
27
133
147
38

177

298

439

1234

24°-25°N
Total

4

TABLE 11. LATITUDINAL DISTRIBUTION OF THE SPERM WHALE CATCH BY JAPANESE
COASTAL WHALING IN THE PACIFIC, 1983/84 TO 1985/86 SEASONS
Latitude

May

June

July

Aug.

Sep.

Oct.

Nov.

Dec.

Jan.

40°-41°N
39°-40°N
38°-39°N
37°-38°N
36°-37°N
35°-36°N

534°-35°N
33°-34°N
32°-33°N
31°-32°N
30°-31°N

2

20
14
12

12
31
21
33
29

3
22
8
47
75

23
25
4
46
30

29°-30°N

20

17

7

Total

151

175

181

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

53
18
29
35
31

166

Feb.

Mar.

To~al

7

34

41

19

19

3
5
5

7

30
21
23

7
65
42
36
42

67
60
28
49
41

165
221
132
246
248

2

46

307

1192

212

46

KASUYA AND MIYASHITA

the previous analyses of fishery oceanography. Uda (1954) states that sperm
whales are scarce in the middle of the Kuroshio Current System (Kuroshio
Current and Kuroshio Extension), but are dense on both sides of the current.
Several authors indicated bimodal catch of sperm whales off the Sanriku coast;
July-August and October-November (Kasahara, 1950), or July-early September
and early October-late November (Uda and Dairokuno, 1957). Although it isunclear if their ocean-ographical terminology accurately corresponds to ours,
there seems to be some similarity with the result of the present study.
In the 1978179 season the industry started operating both in the southern(32°-35°N, autumn) and northern (36°-39°N, winter) latitudes (Table 9), andthis pattern lasted till the 1980/81 season. Although this pattern was principally
retained in the 1981/82 season, the industry took sperm whales in autumn/
winter using a land station in the Bonin Islands with resultant catch in 25°300N only in this particular year (Table 10 and Fig. 4). Sperm whales takenfrom the northern stock on their wintering ground (35°-40°N) continued tillthe 1982/83 season, but it became negligible from the 1983/84 season when
the fishery expanded to the southwest (Table 11 and Fig. 4).
The above analysis is summarized as follows. Although both stocks had
been hunted by Japanese coastal whaling since before World War II, in the
postwar period before the early 1950s most of the sperm whales were caught
from the northern stock. A significant number of whales started to be takenfrom the southern stock probably in the late 1950s in the northern part ofits summer range, while operations in other seasons took mainly from thenorthern stock. However, the proportion of whales from the southern stockprobably did not show rapid increase till the 1978179 season, because the takefrom the northern stock on the wintering ground continued by extending thefishing season to March. Exploitation of the southern stock for the entire
whaling season started in late 1970s, and the hunting of the northern stock
became negligible since the early 1980s.
Other information on sperm whale distribution
Fig. 5 shows the distribution of sperm whales taken in Japanese waters
by American whaling operations during the middle 18th to early 20th centuries(Townsend, 1935). The catch off the Pacific coast of Japan occurred in thosedays in two isolated areas, one in 35°-40°N and west of 150°E, and the otherin an area extending from 28°N, 135°E to 30°N, 180°. The main season for
the former ground was May-July, and that for the latter was April-July (westof 143°E) or June-September (east of 143°E). The former ground probably
represents sperm whales of the northern stock which winter there and havebeen hunted by modern coastal whaling in the early summer of the 1973197 5 seasons and in the winter of the 1977-1983 seasons. However, there
remains a possibility that some individuals from the southern stock areincluded in the periphery of the main range. The hiatus in distribution
between the two fishing grounds roughly corresponds to the low density area
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

47

NORTH PACIFIC SPERM WHALES.

.--~~~~~~~~-.---r:=-~~~~-,,~-,50°N

o•Apr. to July
Aug. to Oct.

0 'Fig. 5. Distribution of sperm whale catches from the records of i 9th century American
whale fishery. Plots represent positions of vessels on days when one or more sperm
whales were taken (modified partial reproduction of Townsend, 1935).

in the middle of the Kuroshio Current System indicated by Uda (1954).
Although the northern range of the southern stock of females approximately
coincides with the Kuroshio Front, its primary habitat will be to the south of
the Kuroshio Current and its extension.
Recent whale sighting cruises in summer off the Pacific coast of Japan
indicate that most sperm whale sightings are limited to the south of the frontsof the Kuroshio Current System, and that the density is high to the south ofthese currents, which agrees with the feature observed in America whaling
and recent Japanese coastal whaling operations. Spending a considerable
sighting effort off the Pacific coast of northern Japan, we have confirmedthat recent sperm whale density is extremely low in summer to the northof 35°N (past coastal whaling grounds off Sanriku and Hokkaido) (Figs 4,
6 and 7).
In the northern North Pacific and Bering Sea only 15 sperm whales in
4 schools have been sighted during five Dall's porpoise sighting cruises witha total period of 202 days from May to October, i.e. 17 August to 19 September
1982 (Kasuya, l 982a; Kasuya and Ogi, 1987), 10 August to 11 September
1983 (Ogi, 1983; Kasuya and Ogi, 1987), 10 May to 20 June 1984 (Miyazaki,
Fujise, Komuro and Taketomi, 1984), 6 August to 16 September 1985 (Ogi,
Tanaka, Kuramochi and Yamamoto, 1986; Kasuya and Ogi, 1987), and 9
August to 6 October 1986 (Yoshioka, Ogura and Shikano, 1987). Because
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

48

KASUYA AND MIYASHITA

30°N

20°N

120°E

130°E

140°E

150°E

160°E

Fig. 6. Distribution of sperm whales observed during the whale sighting cruises in1983 to 1986, May to July. Star indicates school containing individuals 46 feet orover in body length, and closed circle school of smaller whales. Shaded area
represents one degree squares of latitude and longitude not surveyed.

Dall's porpoises are distributed to the north of the Subarctic Boundary(Kasuya and Jones, 1984), the survey area covered past grounds for sperm
whales to the north of 40°N. Although all the cruises had experienced whale
biologists on board, only the 1982 cruise had an observer with experience ofcommercial whaling. The target species of the cruise was the Dall's porpoise
which was usually sighted within 0.5 nautical miles from the trackline(Bouchet, Ferrero and Turnock, 1986; Kato and Miyazaki, 1986). These
factors could have caused a lower sperm whale sighting efficiency of thecruises compared with those off Japan (Figs 6 and 7). However, we still
consider that these data indicating low sperm whale density in the previous
whaling grounds are significant, because the number was less than one fourthof the sum of the blue, fin, sei and humpback whales identified to species (51individuals in 20 schools). The historical southward shift of the sperm whaling
ground (Ohsumi and Masaki, 1977) will therefore indicate the density decline
in the northern grounds.
It will be concluded from this that the sperm whales that once wintered
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

49

NORTH PACIFIC SPERM WHALES

Aug. to Oct.

30°N

20°N
120°E

13Q0 E

150°E

160°E

Fig. 7. Distribution of sperm whales observed during the whale sighting cruises in1983 to 1986, August to October. For marks see Fig. 6.

in the western North Pacific north of 35°N and were hunted by the Japaneseand USSR coastal and pelagic whaling operations have been extremely
depleted.
Segregation of adult males
Table 12 shows the frequency of estimated body lengths of sperm whales
listed in Figs 6 and 7. The majority of them were individuals below 40 feet(12.lm) and about 5% of the individuals with body length estimates werecalves (~20 feet), indicating that the North Pacific area south of the Kuroshio
Current System is inhabited in early summer to autumn season by breeding
schools of the sperm whale.
However, some sperm whales have been estimated at over 46 feet
(13.9m) in body length, which are expected to be mature males in the North
Pacific and Southern Hemisphere (Ohsumi, 1966; Best, 1979) (Table 13).
These individuals were singletons or found with relatively large individuals(over 42 feet or 12.7m), suggesting that adult males were solitary or formed
schools with pubertal males but they were not in breeding schools. Thisagrees with the observation of sperm whales off the Galapagos Islands thatthe mature males are associated with a particular group of females only fora periods of hours at a time (Whitehead, 1987). Although all six schools ofadult males in June and July were sighted in latitudes similar to that of thebreeding schools (Fig. 6), many of those in August tended to be segregatedSci. Rep. Whales Res. Inst.,
No. 39, 1988

50

KASUYA AND MIYASHITATABLE 12. COMPOSITION OF ESTIMATED BODY LENGTHS (IN FEET) AND NUMBER
OF CALVES IN THE SPERM WHALE SIGHTINGS IN FIGS 6 AND 7
Body
lengthMay toJuly

Augustto Oct.

Body
lengthMay toJuly

Augustto Oct.

:'513
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35

8

4

2

2

36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
Total
Calves*

40
40
45

6
8
8

42
8
27
5
3
4
5

8

I

3
3

5

13

2
7
2
3
18

2
2
17
3
31
16
24
25
19
35

40
15
32
57
34
78

3
1
2

543
62

3
6
2
4

6
5
8
2

256
34

* Number of calves, includes both those having body length estimation and listed in the frequency andthose without length estimation.

TABLE 13. POSITION AND SCHOOL STRUCTURE OF LARGE MALE SPERM WHALES(~46 FEET) IN TABLE 12, FIG. 6 AND FIG. 7
Date

Position

15 June '83
23 June '86
3 June '84
9 July '83
16 July '84
22 July '84
6 Aug. '86
13 Aug. '84
13 Aug. '84
18 Aug. '84
18 Aug. '84
18 Aug. '84

30°29'N, 137°32'E
24°59'N, 147°57'E
31°31'N, 143°26'E
22°33'N, 158°05'E
12°36'N, 147°4l'El5°5l'N, 158°47'E
26°37'N, 142°44'E
34°23'N, 152°36'E
34°29'N, 152°24'E
38°ll'N, 157°26'E
38°03'N, 157°15'E
37°57'N, 157°21'E

School
size

1
5
9

9
9

2

Body len~th
composition (ft)53
48
50
46X2, 48X2, 50
42X3, 44X3, 46X3
49
50X4, 51X3, 52X2
50X2, 51, 52X4, 54, 55
53
52
51, 52
53
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

51

NORTH PACIFIC SPERM WHALES

20

100

10

50

0

0

....0 20

200

CJ)
(b

.,,
E

....
(b

iU

<II

.,,Ol 10

-

100

(b

.....
(b

£
~

....0

c

u

CJ)
(b

0

0

Cl.

-

20

0

z
100

10

50

A

M

J

J

A

0

Month
Fig. 8 Catch of sperm whales by USSR coastal whaling off the Kuril Islands in 1950,
1951, and 1962 through 1964, expressed by sex, month and position of land stations(compiled from USSR IWC/NP Forms). Closed circle and solid line: proportion of
females in the catch; open circle and dotted line: number of female catches (actual
number); triangle and dotted line number of male catches (x0.25 for 46°-5G°N,
xo.5 for other areas).

to the north (34°-40°N) of the breeding schools (Fig. 7).
The breeding of sperm whales is seasonally diffuse, and in the northernhemisphere conceptions occur most frequently in April-May and least in
October-November (Ohsumi, l 96S; Shimadzu, 1987). The distribution of
adult males appearing in our sighting records suggests that adult males of thesouthern stock leave the breeding ground after the mating peak and migrate
to northern latitudes. However, we consider from their presence in 34°-40°N
in August that they may not migrate so far north as the Bering Sea/AleutianIslands waters (>S0°N) but probably remain during summer in the Oyashio
Current and its eastern extension (Subarctic Current) in 40° -S0°N, or just to
the north of the front of the Kuroshio Current System at 3S 0 -40°N.
Sexual segregation of sperm whales in the Oyashio Current area is seenin the operations of USSR coastal whaling off the Kuril Islands (Fig. 8). The
season of female catch was shorter, and the female proportion in the catch
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

52

KASUY A AND MIYAS HITA

was lower in the northern Kuril Islands. The peak of female catch in thenorthern Kuril Islands was slightly earlier than that of the males in the same
region (50°-51°N). Such features are expected when females are segregatedto the south and arrive later and return to the south earlier than the males.
The seasonal change in the sex ratio is apparent only in the northern part,suggesting that male density is probably higher off the northern Kuril Islands
than the south. Off the Pacific coast of northern Japan and during the same
period (early 1960s), the female proportion was slightly higher off the northern(Hokkaido) land stations than those off the southern (Sanriku) ones, and it
increased from summer to autumn/early winter in both areas (Table 4). The
similar seasonal trend is observed in the prewar catch in the 1940s (Table 5).
The absolute value of the sex ratio is not directly comparable between the
Kuril and Japanese coastal fishery, or between prewar and postwar operations
off Japan, because both the selectivity of sexes and availability of whales
might be different. However, the above feature suggests that one of theconcentrations of female sperm whales in the western North Pacific exists inthe summer season off the Kuril Islands area, and that it migrates off Hokkaido
and Sanriku waters in autumn/winter season. The period of high maleproportion was probably longer off Hokkaido (May to August) than off
Sanriku (March to April) during the 1940s (Table 5). This suggests that moremales were distributed off Hokkaido (and possibly to further north) than off
Sanriku.
Supporting evidence for this is found in the catch of sperm whales byJapanese pelagic whaling presented by Smith (1980). If the catch between
l 58°E and 180° is totalled latitudinally from his data, there appears in both
sexes two major latitudinal concentrations of the catch (Fig. 9). There is asmall hiatus in the catch, especially of females, in 50° -52°N and west ofl 72°E. We consider this relates to a local intrusion of cold water in the region(see below). Ignoring this small hiatus, we find larger hiatus in the catch inlatitudes 32°-44°N. The latitudes of low sperm whale catch correspond to avery distinct hiatus in whale sightings in 30°-40°N and 154°E- l 7 5°E apparent
in Ohsumi, Masaki and Wada (1977), and to the waters between the front of
the Kuroshio Extension (Mizuno and White, 1983) and the Subarctic Boundary(Favorite et al., 1976). The proportion of females in the catch is high on bothsides of these latitudes, or in 45° -55°N and south of 30°N.
The distribution of the catch of female sperm whales by the Japanesepelagic fishery (Smith, 1980; Shimadzu, 1987) also shows geographicalconcentrations, two in the western North Pacific and one in the eastern North
Pacific (Fig. 15). The two in the western North Pacific correspond to theabove mentioned latitudinal concentrations of female sperm whales. Although
the south western extension of the northern female concentration is unclear in
Smith ( 1980) and Shimadzu ( 1987) due to the prohibition of pelagic whaling
in the eastern area by the Japanese Government (see Materials and Method),the above analysis of the catch of USSR and Japanese coastal fisheries suggests
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

53

NORTH PACIFIC SPERM WHALES
2000

No. males

1500

1000

500

300
200

100

0~---.1.----'-~-'-~0El::"-----'-~-'-~-'-~~

60
40
20
OL-__JL--__i~--'-~-r-c:~-'-~--'-''---'-~'~

200

30°

40°

50°

60°

LatidudeFig. 9. Latitudinal distribution of sperm whale catch by Japanese pelagic whaling in
1966-1977, between l58°E and 180° longitude (compiled from Smith, 1980).

that it will have extended to the southern Aleutian Islands (Fig. 15).
From these analysis we conclude that there are two concentrations offemale sperm whales in the western North Pacific, one in the Western North
Pacific Gyre to the north of the Oyashio Front or Subarctic Boundary and theother to the south of the front of the Kuroshio Current System. Ohsumi andNasu (1970) indicated that the northern limit of summer range of the former
concentration coinsides with the surface water temperature of 9°C. Adult
males are segregated in non-mating season to the north of these female
concentrations. There is some overlap between the ranges of adult males andtheir breeding population even in the non-breeding season. The summer
ranges of adult males of the southwestern North Pacific stock and adultfemales of the north western North Pacific stock overlap considerably, althoughSci. Rep. Whales Res. Inst.,
No. 39, 1988

54

KASUY A AND MIYASHITA

150°£

160°£

Fig. 10. Movement of marked female sperm whales, USSR marks only. Includes only
marks recovered over 10 days after marking. Closed circle represents position ofmarking, open circle position of recovery, and numeral by the circle month ofmarking or recovery. For movement outside of this range see Table 14.

the overlap between individuals of the corresponding sex or growth stages
from different stocks seems to be less common. This segregation will befurther analyzed using information on movement of marked whales (seebelow).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

NORTH PACIFIC SPERM WHALES

55

Fig. 11. Movement of marked female sperm whales, Canadian, Japanese, USA and
USSR marks (excluding those listed in Fig. 10). Recoveries within 10 days or lessfrom marking or movement within the dotted area are excluded. For movement
outside this range see Table 14, and for symbols see Fig. 10.

Evidence from the movement of marked whales
If the widely accepted assumption of a single sperm whale stock in thewestern North Pacific is correct, there will be a significant number of marked
whales moving between north of 40°N and south of 30°N. However, if there
are two latitudinally segregated sperm whale stocks, we will see no mixing
between the two isolated latitudes. We do not consider the movement within
30°-40°N latitudes or between these latitudes (30° -40°N) and either of theranges of the two hypothetical stocks to be meaningful. The intermediate
latitudes can be seasonally inhabited by the two stocks, or simultaneously byschools of the two stocks. It is also important to note that since such marking
data have been collected over many years they exaggerate the intermingling
between stocks in a season of a particular year.
Large numbers of recaptures of marked females off Hokkaido andSanriku (Figs 10 and 11) are due to a high sperm whale catch in the area.
Their movement indicates that breeding schools taken off the Pacific coast ofJapan have a connection with those in the northwestern North Pacific orsouthwestern North Pacific including those in the Bonin Islands waters. The
females off Japan and the Kuril Islands waters migrate to 160°W-l 70°W,
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

56

KASUY A AND MIY AS HITA

while females from the eastern North Pacific waters migrate l 70°E-l80° in
higher latitudes (40°-50°N) or between 160°W-l 70°W in lower latitudes(20° -30°N). No direct connection of female sperm whales is indicated between
western and eastern North Pacific. This does not support the assumption of
two stocks in lower latitudes of the western North Pacific (Bannister and
Mitchell, 1980), but agrees rather well with the conclusion of Ohsumi and
Masaki (1977) that sperm whales in the western and eastern North Pacificintermingle in the central North Pacific, although their deduction of a single
stock in the entire latitudinal range of the western North Pacific disagrees
with ours.
Available data indicate no female movement between north of 40°N andsouth of 30°N. We consider that this is indirect support of the presence oflatitudinally segregated sperm whale stocks in the western North Pacific.
There is one female that was marked by Japan in May 1967 in 48°00'N,
177°49'E and recovered in August 1976 in 25°0l'N, 166°27'W. Although thismight appear to represent an example that violated this hypothesis, we interpreted this in another way. It was recovered with a female that was marked
by USSR in August 1960 in 43°40'N, l 37°44'W, thus the school could havebelonged to the eastern North Pacific stock of Ohsumi and Masaki (1977),
which might have a wider latitudinal range (see below).
Movement of female sperm whales from the summering ground off theKuril Islands to the wintering ground off Hokkaido and Sanriku (north western
North Pacific stock) is indicated by numerous whale mark recoveries. Movement of females of another stock (southwestern North Pacific stock), which
may winter in the Bonin Islands waters or further south, to Sanriku/Hokkaido
waters for summering is indicated by six females (Figs 10 and 11).
Ohsumi and Masaki (1975) considered a Japanese whale mark No. 7741
to indicate female movement between the Bering Sea and the Gulf of Alaska.
However, accepting that such a rare case may occur, we ignored this particularmark return and considered that there are currently no reliable evidence
supporting such movement. This mark was recorded to have been fired at afin whale but reportedly recovered from a female sperm whale by a USSR
factory ship which processed both fin and sperm whales on that day (Shimadzu,
1987). We also ignored another Japanese mark No. 8394 apparently indicating
movement of a sperm whale of unknown sex between the Bering Sea (52°15'N,
I 76°00'W) and the central North Pacific (37°11 'N, l 76°10'E). This was firedin the Bering Sea in 1961 at an 11 m sperm whale and recovered by a USSR
fleet in 1972, but no information was provided on the sex, body length, or
how it was recovered. It is possible that the mark was recovered from a cooker.
The movement of this mark, if it is accepted, does not change our conclusion.
Since the distribution of adult males is different from that of the pubertal
or juvenile males (Best, 1979; Ohsumi, 1966), we analyzed movement by
growth stages, roughly classifying the maturity from body length at recapture,i.e. 2::46 feet (13.9m) as mature and ~45 feet (13.6m) as immature. There are
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

57

NORTH PACIFIC SPERM WHALES

40°N

1500E

170°E

180°

1600W

Fig. 12. Movement of marked adult male sperm whales (~46 feet at recapture),using Canadian, Japanese and USSR marks recovered over 10 days after marking.
For symbols see Fig. 10.

20 whale marks recovered from adult male sperm whales, five from theBering Sea, 10 from the Kuril Islands and Pacific coast of Japan, and fivefrom the eastern North Pacific. And there are no mark returns indicating
movement between any of these areas (Fig. 12). We consider this significant
as an indication of segregation between adult males of different stocks.
Two concentrations of adult males identified in the summer season in
the western North Pacific and Bering Sea are located to the north of thesummer range of breeding schools of the corresponding female populations
mentioned above, i.e. the Bering Sea adult male concentration to the northof the females of the northwestern North Pacific stock summering in thewestern Aleutian/Kuril Islands area, and the Kuril Islands/Hokkaido/Sanriku
concentration to the north of the females of the southwestern North Pacificstock summering in the Kuroshio Current System (Fig: 15). This suggests that
adult males from each of the two western North Pacific stock migrates after
the mating season to the north of the female range. This will function to
decrease competition for food resources between adult males and breeding
schools of the same stock (Best, 1979).
The summer range of the adult males from the southwestern North
Pacific stock mostly overlaps with that of the females of the northwestern
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

58

KASUY A AND MIYAS HIT A

Fig. 13. Movement of marked immature male sperm whales (::=;45 feet at recovery),using Japanese marks recovered over JO days after marking. For movement outside
this range see Table 14, and for symbols see Fig. 10.

North Pacific stock. We do not consider that this will mean free interbreeding
between stocks (see Discussion).
The movement of immature males (:=;45 feet or 13.6m) in the western
North Pacific has characteristics of both females and adult males, or in otherwords it is intermediate of the two in many cases. Many of such male recaptures
show movement within the range inhabited by the females, i.e. between
Sanriku/Hokkaido area and south of the western Aleutian Islands area or
between Sanriku/Hokkaido area and Bonin Islands/western Taiwan area.
However, some of the immature males showed movement between the Bering
Sea and female range south of the western Aleutian Islands or movement
within the Bering Sea as seen in the adult males. Another seven immature
males probably of the northwestern North Pacific stock moved to waters
surrounding the eastern Aleutian Islands near to l 70°W. These indicate assuggested by Best ( 1979) that males leave the breeding school at the puberty
and tend to migrate to higher latitudes, and provides support for the assumption that the adult male sperm whales migrating into the Bering Sea are thosefrom the western North Pacific stock.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

59

NORTH PACIFIC SPERM WHALES

so•N

30°N
180°

Fig. 14. Movement of marked immature male sperm whales ($45 feet at recapture),using USSR marks recovered over 10 days after marking. For movement outside
this range see Table 14, and for symbols see Fig. 10.

Although further accumulation of data, which is unlikely given thecurrent situation of whaling, may show some adult or pubertal males migrating
between the Bering Sea and the Gulf of Alaska through the eastern AleutianIslands, currently available data do not indicate such movement.
Identity of eastern North Pacific sperm whales
This subject is analyzed using only the catch distribution of sperm whales
by Japanese pelagic whaling reported by Smith (1980) for 1966 to 1977 andShimadzu (1987) for 1966 to 1979, the movement of marked whales, and theanalogy with the stocks in the western North Pacific.
The female catch by Japanese pelagic whaling in the eastern North
Pacific (June to September in 1966-1979) concentrated in two latitudinalzones centered at 43°N and 52°N, which merged at the eastern part (Fig. 15).
The presence of two latitudinal concentrations does not seem to be theariifact of biased fishing season, because this pattern appears in July andAugust of the monthly total of the 14 years catch or yearly totals of the seven
whaling seasons when a considerable catch has been made in the eastern
North Pacific (Appendix Figs 1.1 to 2.15 of Shimadzu, 1987). Rather, weconsider that this female concentration relates to the relatively warm area of
the Alaskan Stream, and that the low catch of females in the western part ofSci. Rep. Whales Res. Inst.,
No. 39, 1988

60

KASUY A AND MIYASHITA

Fig. 15. Distribution of three sperm whale stocks in the North Pacific suggested in
the present study. Solid line: northwestern North Pacific stock; Dotted line:
southwestern North Pacific stock; Chain: eastern North Pacific stock. For eachstock, thick line indicates a total geographical range for the stock (based on markrecapture data), thin line northern or western limit of females in summer season(based on mark-recapture data), shaded area major concentration of adult males insummer after mating season (based on mark-recapture and sightings data), dotted
area high concentration of females in summer season (constructed from Smith,
1980, Shimadzu, 1987, USSR coastal fishery off Kuril Islands, and whale sightingdata).

the Alaskan Gyre relates to the low water temperature (Fig. 16). We find asimilar hiatus in female distribution in the western part of the Western North
Pacific Gyre (see above) and will interprete it in the same manner as the effectof the intrusion of cold water indicated by Favorite et al. (1976).
From analogy with the western North Pacific female concentrations, wepresume that the summer concentration of females in the Alaskan Gyre
represents the breeding population of a sperm whale stock in the eastern
North Pacific. Shimadzu (1987) reported a small scale concentrations offemale catch in July 1978 around 25°N, 130°W and 25°N, 152°W (Fig. 15).
We wondered if these female concentrations represent a breeding populationof another sperm whale stock in the eastern North Pacific. However, there isno supporting evidence at present for that assumption. Rather, the currently
available marking data of females and the movement of an immature malethat wintered in the southern Mexican waters ( l 7°N) and summered in the
Alaskan Gyre (46°N) (Table 14) suggest a single sperm whale stock distributed
widely in the eastern North Pacific, i.e. breeding schools moving between
Mexican waters, Hawaiian ground, Alaskan Gyre, and waters to the south of
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

61

NORTH PACIFIC SPERM WHALES

60°

50°

40°
30°
20°

60°

50°

40°
------26

30°
28

20°
140°

160°

180°

160°

140°

Fig. 16. Top. Major current systems in the North Pacific in July through September(based on Dodimead et al., 1963; Favorite et al., 1976; Maritime Safety Agency,1982). Keys: !=Okhotsk Sea Gyre, 2=Western North Pacific Gyre, 3=Bering Sea
Gyre, 4=Alaskan Gyre, A=Alaskan Stream, C=California Current, E=Kuroshio
Extension, K=Kuroshio Current, NE=North Equatorial Current, NP=North
Pacific Current, O=Oyashio Current, S=Subarctic Current, T=Tsugaru Current.
Bottom. Fifteen years (1966-1980) mean of the surface water temperature0( C) in the North Pacific in August (after Maritime Safety Agency,1982). The
surface water temperature in February will be about 10°C lower than that in Augustin the middle latitudes (30° -40°N).

the eastern Aleutian Islands.
Quite different from the two sperm whale stocks in the western North
Pacific, the movement of marked whales in the eastern North Pacific does notdemonstrate post-mating latitudinal segregation between adult males andbreeding population, but suggests segregation of adult males to the west of
the concentration of the breeding schools. This agrees with the fact that theSci. Rep. Whales Res. Inst.,
No. 39, 1988

KASUY A AND MIYASHITA

62

latitudinal segregation of males was unclear in the catch of the Japanese
Pelagic fishery in the eastern North Pacific but the proportion of males washigh in the western part of the Gulf of Alaska (Fig. 17). This segregation
pattern has been mentioned by Ohsumi and Nasu (1970). As mentioned
above, the western part of the Alaskan Gyre is covered, in July to September,by water which is a few degrees colder than the surrounding area of the Gulf
of Alaska (Fig. 16). We consider that the above adult male segregation relates
to the presence of this cold water area and has the same biological significanceas in the north/south segregation of sperm whales in the two western North
Pacific stocks (see above). The range of pubertal males of this stock probably
extends further to the west along the southern coast of Aleutian Islands(indicated by 44 feet and 35 feet males in Fig. 13). Although the AleutianIslands may not absolutely inhibit the migration of sperm whales (see above),the relatively shallow water depth (<500m) may decrease the chance of theirmigration between the Bering Sea and the North Pacific through the eastern
Aleutian Islands.
Two whales (a juvenile male and a female) marked in the northernhemisphere (< 10°N) in March and May were recovered in the southernhemisphere (4°-5°S) in November and March, respectively (Table 14). We do
not know the relationship between these individuals and the eastern North
Pacific sperm whale stock, but there may remain some possibility that there
is one sperm whale stock in equatorial waters or that the range of a southernhemisphere stock seasonally crosses the equator in the eastern Pacific.

TABLE 14. MOVEMENT OF MARKED SPERM WHALES IN THE EASTERNNORTH PACIFIC NOT LISTED IN FIGS 10 THROUGH 14
Marking

Recapture

Mark no.
date

position

date

positionbodylength29/05/1965
1011211965
10112/1965
19/08/1963
08/05/1963
07/05/1975

54°10'N, 141°50'W
35°58'N, 120°43'W
35°58'N, 120°43'W
40°00'N, 145°08'W
49°53'N, 129°20'W
02°52'N, 094°55'W

26/06/67
17/0717146°20'N, 134°26'W
48°35'N, 131°26'W

ll.6m
ll.6m

10/06/68
22/07/65
20/03176

43°37'N, 131°19'W
48°55'N, 127°57'W
04°40'S, 082°50'W

I0.5m
I0.7m
9.8m

18/08/1963
01/03/1966
29/03/1975

39°23'N, 144°27'W
17°1 I 'N, 102°32'W
09°07'N, 093°55'W

30/06/66
25/06/66
09/11175

44°ll'N, 142°22'W
46°43'N, 141°27'W
04°12'S, 083°20'W

ll.4m
I 1.2m9.8m

Ffmales

J9729
A439*
A444*
R610187
R610852
RE1725
Males

R610203
R6!0675
RE1885*: recovered from same individual. A: US mark. J: Japanese mark. R: USSR mark.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

63

NORTH PACIFIC SPERM WHALES

80

f\

60

!
j

40

:

'.

I

l

!\

:

1

800

\

R

1

\b. ..d' }' \ p'I \I/:!' "

f\

•

I ~

u.,n

/'r'
,'

600

'' '\

\..

'\ '

: \

\!

d

400
'

'

~

20

\

iii

E

....~

0

0

200

'o
170°

160°

150°

140°

130°

w

0

Longitude

0

z

40
20

40°

50°

LatitudeFig. 17. Sexual segregation of sperm whales in the eastern North Pacific appeared in
the catch of Japanese pelagic fishery from 1966 through 1977 (data are based on
Smith, 1980). Open circle and dotted line indicate total number of sperm whalescaught, closed circle and solid line percentage of females in the catch.
Top. Longitudinal segregation of female sperm whales in the eastern North
Pacific north of 40°N (Gulf of Alaska area).
Bottom. Latitudinal segregation of female sperm whales in the principal
range of the eastern North Pacific stock (Pacific areas east of l 70°W and north of
40°N, and east of 160°W and south of 40°N).

DISCUSSION

Stock boundaries
Klumov ( 1955) assumed two breeding stocks of sperm whales summering
off the northern and southern Kuril Islands, His southern stock might
correspond to some females of our southwestern North Pacific stock migrating
to southern Kuril Islands north of its ordinary summer range, and thenorthern stock to our northwestern North Pacific stock. However, it is also
possible to presume that he had just identified two latitudinal concentrationsof females of the northwestern North Pacific stock (Fig. 15). Our study failed
to find support for the two female stocks considered by Klumov (1955) to besegregated latitudinally in the eastern North Pacific.
In an isozyme analysis of North Pacific sperm whales, Wada (1980)
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

64

KASUY A AND MIYASHITA

compared the gene frequency of the North Pacific sample from the central
sectors with several subsamples extracted from it, and concluded that thecentral North Pacific sample represents more than one stock. This supports
our contention that the central North Pacific is a mixing area for eastern andwestern stocks.
Our conclusion on sperm whale stocks in the western North Pacificagrees with the hypothesis presented by Watase (1963). Although he did notpresent the basic data used to construct the hypothesis, he wrote that the sizeof breeding schools is larger in his "northern stock" than the "southern stock".
He told us that the southern stock schools were frequent in the protrusionof the Kuroshio Current into the Oyashio Front and that of the northernstock to the north of it. The southern individuals had light brown color whilenorthern ones dark brown body (he was uncertain if it reflected the real bodycolor difference or difference in the color of sea water). Such difference willappear even from different degree of diatom infection. He also stated that thenorthern stock schools were tighter than those of the southern stock whenchased by the catcher boat, although he was not sure if it reflects the real
behavior difference of whales or difference in the ocean structure and soundconductivity (S. Watase, pers. commn in 1987). After mentioning the loose
dispersed schools of the southern type which might correspond to the above
mentioned school difference of Watase, Mr K. Yamamura of the Japan
Whaling Association stated that it was the general belief of his colleagues(confirmed by his observations made while he was working at an Onagawa
land station on the Sanriku coast) that individuals of the southern type had
a greater number of healed or unhealed oval scars than the northern type
and the skin looked unclean (pers. commn in 1987). Mr Y. Yanagihara,gunner of the Sanyo Whaling, believed that the southern type has slenderbody and is hard to harpoon because of the smartness and/or the school
members that tend to scatter during the chase (pers. commn in 1987). Thiswas partially confirmed by Dr H. Kato, the Whales Research Institute, that an
adult male (16.8m) of the southern type identified by the station staff had
smaller mandibular teeth and much slender lower jaw (0.86 time in the absolute
diameter at mid-symphysis) than the northern type adult male (17.6m) takenfrom different herds and processed on a same day in November 1987 at the
Ohsawa Station (pers. commn in 1987).
We presume that their southern type corresponds to the southern stockof Watase (1963) and that the scars would be equivalent to bites of the cookiecutter shark, lsistius brasiliensis, known on various cetaceans in warm waters
Qones, 1971). The recognition of two stocks (or types) of sperm whales off the
Pacific coast of Japan was probably common among whalers, although it was
not always clear from their description if the characteristics were a valid basis
for separating the stocks. Yamamura also stated that the southern type arrived
off Sanriku in early summer but that the date was delayed about two weeks
every year in the early 1970s. This agrees with our analysis of catch statistics,
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

NORTH PACIFIC SPERM WHALES

65

and probably reflects a change in the timing of migration accompanied by thedensity decline in the peripheral habitat. We consider that the two sperm
whale types described by them represent two stocks identified by us in thewestern North Pacific. Adult males, solitary or in small schools, reported by
Watase (1963) to migrate off Hokkaido in autumn possibly represent adultmales from the southwestern North Pacific stock that summered in the cold
Oyashio Current area.
Blood type analysis by Fujino (1963) was probably the first to give ascientific basis for distinguishing two sperm whale stocks off Ja pan. Using 198
blood samples (all males) from the Bering Sea/Aleutian Islands waters (>51°N)
and 121 samples off the Hokkaido/Sanriku area (26% were males and 72%
were taken in August/September), he found that the former sample contained
no Ju2-positive individuals but the latter contained about 42% of such individuals. He further confirmed that blood type frequency did not significantly
differ between the sexes of the pooled Japanese coastal sample, and that the
proportion of Ju2-positive individuals in the Japanese coastal sample
decreased from 46/87 (53%) in August/September to 4/29 (14%) in October/
November. Finally he concluded after examining mark recapture data thatmembers (sex is not stated by him) of the stock in the Bering Sea/Aleutian
waters migrated in autumn to northern Japan, and that adult males of theJapanese coastal stock (with high Ju2-positive frequency) would migrate to
Kuril and Kamchatka waters but not to the central Aleutian waters.
Examination of data presented in Tables 4 and 6 of Fujino (1963) reveals
that his October/November sample contained a minimum number of 5 females
in 1959 and 14 in 1961 and 2 of these were Ju2-positive, i.e. the minimum
number of Ju2-negative females was 17 and the positive ones were actually 2
females. For safety we compared this minimum ratio (17:2) for females with
41 :46 (negative:positive) of the August/September sample (which includes
both sexes, and was collected in 1962 except for 2 in 1961) to find a highly
significant difference (Chi-square test, p<0.001). Thus we conclude that data
presehted by Fujino ( 1963) support our conclusion on the presence of two
breeding stocks of sperm whales off the Pacific coast of northern Japan.
We have concluded that many female sperm whales summering off theSanriku coast winter in the lower latitudes (20°-30°N) of the western North
Pacific and belong to the southwestern North Pacific stock, which contains ahigh proportion of Ju2-positive individuals (Fujino, 1963). If adult males
from this stock had migrated to the Aleutian Islands area, Fujino (1963)
should have detected some Ju2-positive individuals in the sample from theregion. The absence of such individuals in his sample must indicate thecorrectness of our conclusion on the segregation pattern of adult males of thetwo sperm whale stocks in the western North Pacific. At the same time thisindicates the presence of some yet unknown mechanism that inhibits freeinterbreeding between males of southwestern North Pacific stock and femalesof the northwestern North Pacific stock in their overlapping summer range
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

66

KASUY A AND MIYAS HIT A(small scale interbreeding may occur between stocks).
The first of the possible factors will be the timing of migration andbreeding peak. The northward migration of adult males and the overlap of
distribution between sexes of different stocks occurs after the conception peakof the species (see above). This alone can decrease the chance of interbreeding.
The second is the social barrier inhibiting the free interbreeding between
stocks. Killer whales, Orcinus orca, off Vancouver Island are known to havethree communities each consisting of 3 to 12 pods and having occasionallyoverlapping ranges (Bigg, 1982; Ford and Fisher, 1983). Although pods
within community regularly associate with one another and may interbreed(cows in a pod without bull produced calves), pods in different communities
do not presumably due to cultural or behavioral differences (Bigg, Ford andCraeme, 1985). If this happens to the sperm whale, it will contribute to inhibit
free interbreeding between different stocks. The third possibility relates to thesynchlonize of migration and the cycle of reproductive activity in individual
males. The social structure of elephants has some similarity to that of the
sperm whales (Best, 1979). Adult males of the Asiatic elephant, Elephas
maximus, live apart from matriarchal group of cows and calves, and join it only
when it passes his territory while he is in heat which is thought to comeannually or biannually (Eisenberg, 1981). Dugongs, Dugong dugon, haveno sharply defined breeding season, but the males are not continuously inbreeding condition and their reproductive activity in a population is notsynchronized (Marsh, Heinsohn and Marsh, 1984). Although nothing is known
on the reproductive cycle of individual males of sperm whales in the North
Pacific, these example will suggest a possibility that males migrating to thehigher latitudes are in cycle of lower reproductive activity, and that they may
return to the breeding ground at the arrival of the heat as suggested by oursighting data.
A possible ratio of the two stocks constituting the Japanese coastal catch
can be estimated using data from Fujino ( 1963) and with the unconfirmed
assumptions mentioned below. The proportion of Ju2-positive individuals in
his combined Hokkaido/Sanriku sample was 2/5 in June and July, 46/87 inAugust and September, and 4/29 in October and November. Assuming as
suggested from his sample that the northwestern North Pacific stock contains
no Ju2-positives, assuming as an unconfirmed extreme case that all the individuals from the southwestern North Pacific stock are Ju2-positive, and using
the monthly catch reported by the industry (Table 2), we roughly estimate thecontribution of the southwestern stock in the late 1950s as (0.065 + 0.063 +0.068 + 0.094) x 2/5 + (0.222 + 0.266) x 46/87 + (0.136 + 0.086) x 4/29
= 0.40, and that of the northeastern stock as 1 - 0.40 = 0.60. Since the blood
type composition was probably different between Hokkaido and Sanriku
samples, further improvement of above estimate requires larger sample andcalculation by each geographical area. If Ju2-negative individuals exist in thesouthern stock, the above calculation will underestimate its contribution to
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

NORTH PACIFIC SPERM WHALES

67

the catch. The proportion of the northwestern North Pacific stock in thecatch was probably higher in earlier years when the industry landed most of
the sperm whales in Hokkaido, and it could have increased again during the1976177 to 1977178 seasons when they hunted sperm whales wintering off
Sanriku coast. It must have become almost negligible since the 1983/84 seasons(see above).
Oceanographic factors
The effect of oceanography on migration and segregation of toothed
whale stocks has been demonstrated by several studies in the northwestern
North Pacific. With the exception of finless porpoises, N eophocaena phocaenoides,
which live in coastal waters of wide thermal range (Kasuya and Kureha,1979), most other toothed whales in the area inhabit either warm waters
under the influence of Kuroshio Current or cold waters such as the Oyashio
Current area (Kasuya, 1980; l 982b).
The Dall's porpoise, Phocoenoides dalli, is one of the best studied cold
water species. Its distribution is limited to north of the Subarctic Boundary,and the breeding population of each stock segregates into particular water
domains such as the Okhotsk Sea Gyre, Oyashio Current, Western North
Pacific Gyre, Bering Sea Gyre, and Alaskan Gyre (Kasuya and Ogi, 1987;
Miyashita and Kasuya, 1987; Yoshioka, Ogura and Shikano, 1987). One
population of the Dall's porpoise in the Oyashio Current has successfully
expanded its habitat to the Japanese coastal waters between the fronts of cold
Oyashio and warm Kuroshio Currents, but is still unable to intrude into theproper Kuroshio current area. The Baird's beaked whale, Berardius bairdii,
was considered from its breeding season probably to have evolved in higher
latitudes (Kasuya, 1977), which was supported by the distribution in thenorthern North Pacific. This cold water species in the North Pacific hasdeveloped a local stock in Japanese coastal waters near the southwestern
range, or between the fronts of Kuroshio and Oyashio Currents (Kasuya,
l 986a). Although these whales commonly occur in an area with high (>20°C)
surface water temperature in summer, they are still unable to expand theirhabitat in the main Kuroshio Cusrent area and their range is limited to thearea north of 35°N.
An opposite example is found with the short-finned pilot whales,
Globicephala macrorhynchus, inhabiting tropical and temperate waters of theworld. In the northwestern North Pacific, the majority of the individuals(southern form) live in a vast range to the south of the fronts of Kuroshio
Current and its extension. However the species has developed a morphologically distinct local form (northern form) in colder waters off Japan between
the fronts of Kuroshio and Oyashio Currents (Kasuya, l 986b; Kasuya,
Miyashita and Kasamatsu, 1988). Northern forms are not distributed in the
Oyashio Currents and its eastern extension. Although an apparently similar
form (having distinct saddle mark) has been sighted in the northeastern
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

68

KASUYA AND MIYASHITA

North Pacific from Washington coast to Baja California, the distribution isapparently discontinuous between the two sides of the North Pacific andfurther study is needed on the systematic relationship between them (Kasuya
et al., 1988).
These examples suggest that the Kuroshio and Oyashio Fronts haveacted as strong barriers to the distribution of toothed whales, and that it has
not been possible to cross both of the fronts and to enter into quite different
water masses even for species that succeeded to overcome one of the two
fronts. For this reason if such a boundary is once passed it could have contributed to the development of isolated whale populations.
Several gyres to the north of the Subarctic Boundary probably haveworked also in a similar, but weaker way. The distribution of three sperm
whale stocks in the North Pacific seems to be closely related to the gyres in
the North Pacific, i.e. the concentration of breeding populations of the three
sperm whale stocks has a tight connection each with the Western North PacificGyre, Alaskan Gyre, and with the wide circulation area centered at theKuroshio Counter Current area and surrounded by Kuroshio Current,
Kuroshio Extension, North Pacific Current, and presumably North Equatorial
Current. The presence of only one recognized sperm whale stock in most of
the latitudinal range of the eastern North Pacific probably relates to theabsence of distinct ocean fronts in the region. Although there seem to be no
distinct oceanographic barriers between female ranges of the southwestern
North Pacific stock and eastern North Pacific stock, a significant isolation
could probably have been maintained because (1) the major concentration of
the latter stock occurs in the Alaskan Gyre and the low sperm whale density
in the lower latitudes of the stock's range decreased the chances of mixing, (2)the segregation of eastern North Pacific stock females to the east of malerange decreased chances of mixing (this also apply to isolation from thenorthwestern North Pacific stock), and (3) the mixing was limited due tothe direction of seasonal migration that tended to be north/south rather thaneast/west.
The pantropical distribution of sperm whales suggests the tropical originof the species. We believe that the sperm whales in the Okhotsk Sea or Sea
of Japan can be excluded from the possible origin of the northwestern North
Pacific stock, because the species is uncommon in these waters (Berzin, 1972),
and they do not seem to have established their niche in the region. Thus, thenorthwestern North Pacific stock of the sperm whales could have probably
originated either from the southwestern North Pacific stock or the eastern
North Pacific stock. Since the north/south temperature boundaries seem tohave blocked the dispersal of toothed whales more effectively than theboundary between the Western North Pacific Gyre and Alaskan Gyre (seeabove), we consider that the eastern North Pacific stock is more plausible as
the origin of the sperm whale stock in the northwestern North Pacific.
There are two possibilities on the origin of the eastern North PacificSci. Rep. Whales Res. Inst.,

No. 39, 1988

NORTH PACIFIC SPERM WHALES

69

stock of the sperm whale. One is to assume that the sperm whales in the
Kuroshio Current System intruded into eastern North Pacific and establisheda niche in the Alaskan Gyre and the California Current possibly after the
Wurm Glacier Period which was the last glacier period ended about 10,000
years ago. Another possibility is that sperm whales immigrated in the cold
California Current area across the equator from the South Pacific. Southernhemisphere sperm whales could have immigrated to the northern hemisphere
more easily across the colder eastern equatorial waters during a period of cold
climate. Similar incidents have been suspected for several cetaceans (Davies,
1963; Kasuya, 1975; Brownell, 1983). Although the chance of such immigration could have certainly occurred during the Wurm Glacier Period, thechance probably lasted till the very recent time for such pantropical species assperm whales. The movement of two juvenile sperm whales that were marked
in the northern hemisphere in northern spring and recovered in the southernhemisphere in austral fall or spring provides an evidence of small scale (7° to
13° in latitude) transequatorial migration of breeding schools in the eastern
tropical Pacific (Table 14). Larger scale transequatorial movement (from 21°N
to 33°S in 4 years 3 months) of an immature male sperm whale was known
from the eastern Atlantic (lvashin, 1967), where the oceanographic structure
is comparable to eastern tropical Pacific. These indicate that the large scaletransequatorial immigration of sperm whales was possible in some geologicalage. Fujino (1963) indicated a highly distinct difference in blood type frequencies between two sperm whale stocks in the western North Pacific (noJu2-positives vs. 53% or more). This leaves a possibility for eastern South
Pacific sperm whales to be the origin of eastern North Pacific stock. Further
analysis of genetic similarity between sperm whale stocks in the North Pacificand those in the eastern South Pacific will throw some light on the evolutionof these stocks.
·
The niche previously occupied by the northwestern North Pacific stockof the sperm whale has become almost vacant after its depletion. However, so
far we do not find the niche being reoccupied by sperm whales from somenearby stocks, e.g. the southwestern North Pacific stock or stock in the eastern
North Pacific. This will be an example indicating that such vacancies are hardfor other nearby stocks to reoccupy, especially when the nearby stocks are also
depleted to some unknown degree. It can, however, reasonably be deduced
from the above analyses that the range of each sperm whale stock andmovement of the member whales are controlled by oceanographic conditions.
We have no data to indicate the possibility of a small local stock inJapanese coastal waters between the fronts of Kuroshio and Oyashio Currents
as observed for Baird's beaked whales and short-finned pilot whales. Development of such a local sperm whale stock could have been inhibited by theearlier establishment of a Baird's beaked whale stock in the near shore deep
waters or the current two sperm whale stocks partially overlapping off Japan.
However, even if such a small local stock had evolved in a geological age
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

70

KASUY A AND MIYAS HITA

either from the southwestern or northwestern North Pacific sperm whale
stock, it could have been exterminated by the intensive operation of Japanesemodern whaling in coastal waters.
Significance for management
IWC (1980) identified two human induced factors expected to cause
pregnancy rate change in the sperm whale population, i.e. a decrease in thenumber of adult males relative to that of adult females, and a decrease in thefemale density. The first effect, decrease in pregnancy rate accompanied bya decrease in the adult male density, has not been detected in any sperm
whale stocks, but the second has been detected in sperm whales off South
Africa.
Best (1980) reported an increase in the apparent pregnancy rate ofsperm whales that followed exploitation off Durban from about 17% in theearly 1960s to 21 % in the middle 1970s. Later, Best, Canham and Macleod(1984) further refined the analysis to reinforce the conclusion that the pregnancy rate increase was due to the improvement of reproductive potential of
females of wide age range and not to the increased proportion of young adultfemales of high reproductive potential.
In the North Pacific, however, several attempts to detect the historicalchange in the sperm whale pregnancy rate were unsuccessful (Beddington,
1980; Masaki, 1980; Ohsumi, l 980a; Ohsumi, 198 la; Shimadzu, 1987).
Several factors could have masked possible change in the pregnancy rate.
They include (1) a very slight change in the timing of the sampling period,
which included both mating and parturition seasons, could have easilychanged the proportion of females in early or late pregnancy, (2) the difficultyin distinguishing females in early pregnancy and those having corpus luteumof ovulation, and (3) the proportion of unrecorded take of lactating females
could have changed between years, fishing grounds and whaling fleets.
One of two additional factors could be that the whaling operation moved
from north to south and from west to east. Thus the proportion of females
from the more depleted stock gradually decreased in the catch and that of theless depleted one increased, and during this period the depletion of the latterstock could have progressed. Many authors have attempted to overcome thisproblem by dividing the female sample into 10 degree (or larger) cells oflatitude and longitude, without recognizing the latitudinal segregation of thestocks. If the sample was divided into small areas or short time periods(month), it inevitably decreased the sample size in each cell and caused low
precision, but too coarse cell divisions also could have masked the possible
change in the pregnancy rate. A similar kind of effect is expected in the analysis
of many population parameter changes expected to accompany exploitation(with exception of growth rate increase (Kasuya, unpub.)).
Another factor that could have caused an apparently stable pregnancy
rate would be the combined effect of adult male depletion and the depletion
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

NORTH PACIFIC SPERM WHALES

71

of females. Since adult males segregate, in summer, to the north or west of
the female range of the corresponding stock, and whaling commenced earlier
in the north/west and selectively hunted adult males which were larger inbody size, the availability of adult males for reproduction could have decreased
and the pregnancy rate could have declined before the large scale exploitationof females in the corresponding stock started. For example, hunting of adultmales of the southwestern stock segregating in summer off Hokkaido andKuril Islands continued from the start of Japanese coastal whaling in the
1910s (Table 5) to the end of pelagic whaling in the late 1970s (Ohsumi,
l 980c). Although the exploitation of breeding females of the stock started at
the same time off Sanriku (probably mainly in summer) and other Japanesewhaling station to the south of Sanriku region, most intensive exploitation
probably started in the late 1960s with the pelagic and coastal fisheries. The
pregnancy rate analyses for this stock used data collected since 1972 (Masaki,
1980; Ohsumi, l 980a). Therefore, the annual trend in pregnancy rate would
be hard to analyze without catch statistics by sex, maturity and stock, and thedetection or prediction of the change would be extremely hard due to the
opposite effects of the change in male availability and female density. The
similar change could have occurred on the eastern North Pacific stock.
If the present hypothesis on the range of North Pacific sperm whale
stocks is correct, the stock boundary currently in use for the management will
have to be adjusted. The boundary between the eastern North Pacific stockand two stocks in the western North Pacific will be the Aleutian Islands andline connecting points 52°30'N, l 75°E and 20°N, 160°W. The latter passes
middle of the overlapping area of the stocks. We have no data on the boundary
to the south of 20°N, but l 60°W longitude will probably be adequate. The
boundary between the breeding populations of two western North Pacificstocks will be at around 35°N in winter and 40°N in summer. Latitudinalboundary between the adult male populations of two western North Pacificstocks will be at about 50°N in summer and perhaps at around 35°N in winterto spring (mating season), but nothing is known on the boundary in theintermediate seasons. To make the problems more difficult is the range ofpubertal males, which are expected to be distributed in either of the adultmale or breeding female ranges and also in areas between the two ranges
depending on their age. Thus, if a sample is collected in summer in thewestern North Pacific between 40°N and 50°N, it will be mainly composed ofadult males of the southwestern North Pacific stock, and pubertal males andmembers of breeding schools (females and immature males) of the northwestern North Pacific stock. However, it will probably include also somemembers of breeding schools of the former stock in the southern part of thesampling area and some members of adult males from the latter stock in thenorthern part of the latitudes. Further study is needed for more precise
determination of stock boundaries and their seasonal movement.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

72

KASUYA AND MIYASHITAACKNOWLEDGEMENTS
We would like to thank many scientists who helped us in the preparation ofthis study. Drs R.L. Brownell Jr and P.B. Best critically read the manuscripts
and corrected English. Drs S. Ohsumi, N. Miyazaki, and I. Ikeda made usefulcomments at the various stage of preparation of this manuscript. Drs K.
Mizuno and S. Matsumura advised us in oceanography. We are grateful to
Dr Y. Shimadzu for providing data on marked whales in his unpublisheddoctorial thesis. Ms M. Ikeya and Ms Y. Yamamoto helped us in data analysis
and drawing.

REFERENCES
ALLEN, K.R., 1980. Size distribution of male sperm whales in the pelagic catches. Rep. int. Whal. Commn(special issue 2): 51-56.
BANNISTER, J. and E. MITCHELL, 1980. North Pacific sperm whale stock identity: distributional evidence
from Maury and Townsend chart. Rep. int. Whal. Commn (special issue 2): 219-230.
BEDDINGTON, J. R., 1980. Analysis of the pregnancy rate of sperm whales in the North Pacific. Rep. int.
Whal. Commn (special issue 2): 63-64.
BERZIN, A.A., 1972. The Sperm Whale. Israel Program for Scientific Translations, Jerusalem, 394 pp.
BEST, P. B., 1974. The biology of the sperm whale as it relates to stock management. pp. 257-293. In: W. E.
Schevill (ed) The Whale Problem a Status Report. Harvard Univ. Press, Cambridge and Massachusetts. 419 pp.
BEST, P.B., 1979. Social organization in sperm whales, Physeter macrocephalus. pp. 227-289. In: H.E. Winn
and B.L. Olla (eds) Behavior of Marine Mammals. Plenum Press, New York and London. 438 pp.
BEST, P.B., 1980. Pregnancy rate in sperm whales off Durban. Rep. int. Whal. Commn (special issue 2):
93-97.
BEST, P.B. and D.C. BUTTERWORTH, 1980. Report of the southern hemisphere minke whale assessment
cruise, 1978179. Rep. int. Whal. Commn, 30: 257-283.
BEST, P.B., A.S. CANHAM and N. MACLEOD, 1984. Pattern of reproduction in sperm whales, Physeter
macrocephalus. Rep. int. Whal. Commn (special issue 6): 51-79.
BIGG, M.A., 1982. An assessment of killer whale (Orcinus orca) stocks off Vancouver Island, British
Columbia. Rep. int. Whal. Commn, 32: 655-670.
BIGG, M.A., J.K.B. FORD and M.E. GRAEME, 1985. Two sympatric forms of killer whales off British
Columbia and Washington. Abstract of Sbcth Biennial Conf. Biol. Marine. Mamm. Vancouver, 22-26,
November, 1985.
BoucHET, C., R. C. FERRERO and B.J. TuRNOCK, 1986. Estimation of the abundance of Dall's porpoise(Phocoenoides dalli) by shipboard sighting surveys. Document submitted to the International North
Pacific Fisheries Commission, Tokyo, March. 50pp.
BROWNELL, R.L. ]R., 1983. Phocoena sinus. Mammalian Species, 198: 1-3.
DAVIES, L.J., 1963. The antitropical factor in cetacean speciation. Evolution, 17(1): 107-116.
DODIMEAD, A.J., F. FAVORITE and T. HIRANO, 1963. Review of oceanography of the Subarctic Pacific region.
Bull. Int. North Pac. Fish. Comm., 13: 1-195.
EISENBERG, J. F., 1981. The mammalian radiations, an analysis of trends in evolution, adaptation, andbehavior. Univ. Chicago Press, Chicago and London. 610 pp.
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.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

NORTH PACIFIC SPERM WHALES73

FORD, ]. K. B. and H. D. FISHER, 1983. Group specific dialects of killer whales (Orcinus orca) in British
Columbia. pp. 129-161. In: R. Payne (ed) Communication and Behavior of Whales. Westview Press,
Colorado. 643 pp.
FUJINO, K., 1963. Identification of breeding subpopulations of the sperm whales in the waters adjacent toJapan and around Aleutian Islands by means of blood typing investigations. Bull. jap. Soc. Sci. Fish.,29(12): 1057-1063.
IvASHIN, M. V., 1967. A sperm whale crosses the equator. Rybnoe Khozyaistvo, I :20. (English translation from
Russian by G.A. Thompson).
IvASHIN, M. V., 1983. Marking of sperm whales in the North Pacific under the Soviet marking programme.
Rep. int. Whal. Commn, 33: 295-304.
IvASHIN, M.V. and A.A. RovNIN, 1967. Some results of the Soviet whale marking in the waters of theNorth Pacific. Norsk Hvalfangst-Tid., 56(6): 123-135.
IWC, 1979. Chairman's report of the thirtieth annual meeting. Rep. int. Whal. Commn, 39: 21-37.
IWC, 1980. Report of the sub-committee on sperm whales, Cambridge, June, 1978. Rep. int. Whal. Commn(special issue 2): 65-74.
JoNES, E.C., 1971. Isistius brasiliensis, a squaloid shark, the probable cause of crater wounds on fish andcetaceans. Fish. Bull., U.S., 69(4): 791-798.
KASAHARA, A., 1950. [Whaling and whale stocks in the adjacent waters of Japan]. Bull. Nikon Suisan Res.
Inst., 4: 1-106+95 txt-figs. (in Japanese).
KASUYA, T., 1975. Past occurrence of Globicephala melaena in the western North Pacific. Sci. Rep. Whales Res.
Inst., 27: 95-108.
KASUYA, T., 1977. Age determination and growth of the Baird's beaked whale with a comment on the feta!
growth rate. Sci. Rep. Whales Res. Inst., 29: 1-20.
KASUYA, T., 1980. [Life history of dolphins]. Anima (Tokyo), 8(9): 13-23. (in Japanese).
KASUYA, T., 1982a. [Outline of marine mammal research during the second cruise of the Hoyomaru No. 12
in 1982 (17 August to 19 September)]. Far Seas Fisheries Res. Lab., Shimizu. 12 pp. (in Japanese).
KASUYA, T., l 982b. Preliminary report of the biology, catch and populations of Phocoenoides in the western
North Pacific. pp. 3-9. In: ].G. Clark, J. Goodman and G.A. Soave (eds) Mammals in the Seas. FAO
Fisheries series No. 5, Vol. IV. FAO, Rome. 531 pp.
KASUYA, T., 1986a. Distribution and behavior of Baird's beaked whales off the Pacific coast of Japan. Sci.
Rep. Whales Res. Inst., 37: 61-83.
KASUYA, T., l 986b. Comparison of life history parameters between two stocks of short-finned pilot whales
off the Pacific coast of Japan. IWC/SC38/SM10. 32 pp.
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 K. KuREHA, 1979. The population of finless porpoises in the Inland Sea of Japan. Sci. Rep.
Whales Res. Inst., 31: 1-44.
KASUYA, T., T. MIYAHITA and F. KASAMATSU, 1988. Segregation of two forms of short-finned pilot whales off
the Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 39: 77-90.
KASUYA, T. and H. OG1, 1987. Distribution of mother-calf Dall's porpoise pairs as an indication of calving
ground~ and stock identity. Sci. Rep. Whales Res. Inst., 38: 125-140.
KATO, M. and N. MIYAZAKI, 1986. Comparison of abundance estimation of Dall's porpoise by sighting
survey between salmon research vessels and a dedicated vessel for Dall's porpoise. Document
submitted to the International North Pacific Fisheries Commission, Tokyo, March. 8pp.
KLUMOV, S. K., 1955. [On the local character of whale herds]. Trudy IO AN SSSR, 18. (cited in Berzin, 1972).
MARITIME SAFETY AGENCY (Tokyo), 1982. Current Chart in the North Pacific Ocean. Ip.
MARSH, H., G. E. HEINSOHN and L. M. MARSH, 1984. Breeding cycle, life history and population dynamics ofthe dugong, Dugong dugon (Sirenia: Dugonidae). Aust.]. Zool., 32: 767-788.
MASAKI, Y., 1970 (ms). Study on the stock units of sperm whale in the North Pacific. (Paper submitted tothe special meeting on sperm biology and stock assessment, Honolulu, 1970. cited by Best, 1974).
MASAKI, Y., 1980. On the pregnancy rate of the North Pacific sperm whales. Rep. int. Whal. Commn (special
issue 2): 43-48.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

74

KASUY A AND MIY AS HIT AMIYASHITA, T. and T. KASUYA, 1988. Distribution and abundance of Dall's porpoise off Japan. Sci. Rep.
Whales Res. Inst., 39: 121-150.
MIYAZAKI, N., Y. FUJISE, T. KOMURO and H. TAKETOMI, 1984. [Outline of survey of dolphins and porpoises
during the Hoyomaru No. 53 Dall's porpoises cruise (10 May to 20 June 1984)]. Far Seas Fisheries
Res. Lab., Shimizu. 47 pp. (in Japanese).
MIZUNO, K. and W. WHITE, 1983. Annual and interannual variability in the Kuroshio Current system.].
Physical Ocean., 13(10): 1847-1867.
0GI, H., 1983. [Outline of the survey of marine mammals by the Hoyomaru No. 12 in 1985]. Far Seas
Fisheries Res. Lab., Shimizu. 14 pp. (in Japanese).
0GI, H., H. TANAKA, T. KURAMOCHI and Y. YAMAMOTO, 1986. [Outline of the research by the dedicatedvessel Hoyomaru No. 12 in 1983]. Document submitted to the International North Pacific FisheriesCommission. 26pp. (with English translation of text.)
0HSUMI, S., 1965. Reproduction of the sperm whale in the northwest Pacific. Sci. Rep. Whales Res. Inst.,
19: 1-35.
0HSUMI, S., 1966. Sexual segregation of the sperm whale in the North Pacific. Sci. Rep. Whales Res. Inst.,
19: 1-16.
0HSUMI, S., 1973. [Review of whaling area and whale stock management]. Bull. Soc. Fish. Oceanography,
22: 41-44. (in Japanese).
0HSUMI, S., l 980a. Examination of the pregnancy rate of the sperm whale in the North Pacific. Rep. int.
Whal. Commn (special issue 2): 169-176.
0HSUMI, S., 1980b. The sperm whale catch by Japanese coastal whaling in the Sanriku region. Rep. int.
Whal. Commn (special issue 2): 161-168.
0HSUMI, S., l 980c. Catches of sperm whales by modern whaling in the North Pacific. Rep. int. Whal. Commn(special issue 2): 11-18.
0HSUMI, S., l 98la. Pregnancy rate of the sperm whales caught by Japanese coastal whaling. Rep. int. Whal.
Commn, 31: 801-804.
0HSUMI, S., 198lb. Catches of sperm whales in the coastal waters of Japan. Rep. int. Whal. Commn, 31:
813-820.
0HSUMI, S. and Y. MASAKI, 1975. Japanese whale marking in the North Pacific, 1963-1972. Bull. Far. Seas.
Fish. Res. Lab., 12: 171-219.
0HSUMI, S. and Y. MASAKI, 1977. Stock and trends of abundance of the sperm whale in the North Pacific.
Rep. int. Whal. Commn, 27: 167-175.
0HSUMI, S., Y. MASAKI and S. WADA, 1977. Seasonal distribution of sperm whales sighted by scouting boats
in the North Pacific and Southern Hemisphere. Rep. int. Whal. Commn, 27: 308-323.
0HSUMI, S. and K. NAsu, 1970 (ms). Range of habitat of the female sperm whale with reference to theoceanographic structure. Paper presented to the meeting of sperm whale biology and stock assessment, Honolulu, March 1970. 7pp+l5txt-figs.
0HSUMI, S. and Y. SATAKE, 1980. Provisional report on investigation of sperm whales off the coast of Japan
under a special permit. Rep. int. Whal. Commn, 27: 324-332.
OMURA, H. and S. 0HSUMI, 1964. A review of Japanese whale marking in the North Pacific to the end of
1962, with some information on marking in the Antarctic. Norsk Hvalfangst-Tid., 53(4): 90-112.
SHIMADZU, Y., 1987. Studies on the reproduction of sperm whales in the North Pacific. Doctoral thesis submitted
to Faculty of Agriculture, University of Tokyo, 194 pp.
SMITH, T., 1980. Catch of male and female sperm whales by 2-degree square by Japanese pelagic whaling
fleet in the North pacific, 1966-77. Rep. int. Whal. Commn (special issue 2): 263-275.
TOWNSEND, C.H., 1935. The distribution of certain whales as shown by logbook records of American
whaleships. Sci. Contr. New York Zool. Soc., Zoologica, 19(1): 1-50+4 plates.
UDA, M., 1954. Studies of the relation between the whaling grounds and hydrographical conditions (I).
Sci. Rep. Whales Res. Inst., 9: 179-187.
UDA, M. and A. DAIROKUNO, 1957. Studies of the relation between the whaling grounds and hydro graphicalconditions (II). A study of the relation between the whaling grounds off Kinkazan and the boundaryof the water masses. Sci. Rep. Whales Res. Inst., 12: 209-224.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

NORTH PACIFIC SPERM WHALES75

WADA, S., 1980. On the genetic uniformity in the North Pacific sperm whale. Rep. int. Whal. Commn (special
issue 2): 205-211.
WATASE, S. 1963. [East-west migration hypothesis of whales]. Geiken Tsushin, 148: 1-12. (in Japanese)
WHITEHEAD, H., 1987. Social organization of sperm whales off the Galapagos: Implication for management
and conservation. Rep. int. Whal. Commn, 37: 195-199.
YosHIOKA, M., M. 0GURA 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.
22 pp.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OF TWO FORMS OF SHORT-FINNEDPILOT WHALES OFF THE PACIFIC COAST OF JAPAN*

TOSHIO KASUYA**, TOMIO MIYASHITA** AND FUJIO KASAMATSU***
ABSTRACTTwo forms of the short-finned pilot whale are known off the Pacificcoast of Japan. The northern form, having larger body size, distinct saddle
mark and round contour of the head seen from the top, inhabits the coastal
waters between fronts of the cold Oyashio Current and warm Kuroshio
Current, or l2°-24°C in surface water temperature and 35°-43°N inlatitude. The southern form, having smaller body size, indistinct saddle
mark and square shaped contour of adult male head, is known from wide
range of the coastal and offshore waters south of the Kuroshio Front (overl 8°C and south of 39°N) with some degree of possible density gap within
the range. Their geographical ranges may occasionally overlap in theboundary area, but mixed schools of two forms are believed to be very
rare. The geographical and social segregation, individually identifiablemorphological differentiation, and similarity in their life history characteristics suggest that they can be dealt as separate subspecies or local stocksof the short-finned pilot whale. Although north/south segregation of thecorresponding forms might exist in the eastern North Pacific, current
information is insufficient for further consideration.
INTRODUCTION

Yamase (1760) described two kinds of pilot whales off Taiji on the Pacificcoast of central Japan, the one Shiho goto was larger and had white dorsal
patch, and the other Naisa goto was smaller and had no dorsal mark. Grayreferred similar distinction for Japanese pilot whales, and named his Naisa
gota (appeared in his 1846 and 1866 papers) or Naisa goto (in his 1846 paper)as G. sieboldii Gray, 1846 and Shiba golo (in 1846, 1866 and 1871 papers) as G.
sibo Gray, 1871. The minor difference in the spelling is not important. The
Ohnan goto of Yamase (1760) and Gray (1866) is now considered to represent
the false killer whale Pseudorca crassidens (Owen, 1846). Recent Japanesewhalers who hunted pilot whales also distinguished two pilot whales Tappa* Early version of the manuscript was submitted to the 38th annual meeting of the Scientific Committee of theInternational Whaling Commission in Bournemouth in May 1986 with document no. IWCISC/38/SMJ2.
** Far Seas Fisheries Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan.
*** Japan Whaling Association, 3-2-4, Kasumigaseki, Chiyoda-ku, Tokyo, JOO Japan. Present address: The Instituteof Cetacean Research, 3-32-ll, Ohjima, Koto-ku, Tokyo, 136 Japan.
Sci. Rep. Whales Res. Inst.,!Vo.39,1988, 77-90

78

KASUYA, MIYASHITA AND KASAMATSU

naga (=having long flipper) off northern Japan and Ma-gondo (=common
pilot whale) off central and southern Japan. Since the last century this caused
confusion for Japanese whale taxonomists, and caused the use of various
scientific names as reviewed by Hawley (1960) and Kasuya (1975).
Nishiwaki, Kasuya, Brownell and Caldwell ( 1967) examined pilot whale
skulls taken off Izu coast (34°30'N) and Taiji (33°35'N) to find that the pilot
whales off the Pacific coast of central Japan which was called by the vernacularname of Ma-gondo and had been considered to represent Globicephala melaena(Traill, 1809) was actually G. macrorhynchus Gray, 1846. Kasuya (1975) examinedstatistics of pilot whale catch by Japanese small-type whaling and the skulls
taken by the fishery off the Pacific coast of northern Japan, found that all the
specimens examined by him possessed characteristics of rostral region of G.
macrorhynchus described by Bree ( 1971 ), and concluded, acknowledging thepossibility of presence of some local stocks, that G. macrorhynchus is the only
confirmed member of recent pilot whale fauna in the western North Pacific.
Although G. melaena survived in the northern Sea of Japan till the 12th
century and the current existence was not fully denied (Kasuya, 1975), no
supporting evidence was collected after the study and there was accumulated
indications suggesting the absence of G. melaena in the Bering Sea and northern
North Pacific (see below).
In 1982, some of the Japanese small-type whalers resumed harvesting
pilot whales off the southern part (38°N to 40°N) of the Sanriku region(Pacific coast of northern Japan between 38°N to 41°30'N) as reviewed by
Kasuya and Tai (1986), and some of the catch were examined by Miyazaki(1983). He reported that two kinds of pilot whales were taken in the season.
The one (southern form of this study) was a type that was common off the
Pacific coast of central and southern Japan (Izu and Taiji) and studied by
Nishiwaki et al. (1967), Yonekura, Matsui and Kasuya (1980), Kasuya andMatsui (1984), Kasuya and Marsh (1984) and Marsh and Kasuya (1984). The
other (northern form of this study) was new to him. Although, both forms
shared skull characteristics of G. macrorhynchus described by Bree (1971), thelatter was easily distinguished from the former by distinct saddle mark andlarger body size (Miyazaki, 1983; Kasuya, l 986b).
In the present study, we analyze distribution and segregation of the twoforms of short-finned pilot whales using sighting records in the western
North Pacific collected since the finding of Miyazaki (1983), and some additional records of previous sightings, some of which are identifiable to two
forms based on photographic or other records.
MATERIALS AND METHODS

Ident~fication of two forms
The short-finned pilot whale identified in this study as "northern form"
represents those being recognized by Japanese whalers as Tappa-naga, and its
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OFSHORT‑F
INNEDPILOTWHALE
S

79

F
i
g.I
.D
i
f
f
e
r
e
n
c
eofsaddl
emar
kbeLweenL
heLwof
o
rm
sofs
hon‑
f
i
n
n
e
dp
i
l
o
Lwhal
e
s
f
f
L
hePa
ci
f
i
cc
o
a
s
lof
Ja
p
a
n
.AandB:n川 thernform,
CandD:souLher
nf
o
1m.

。

c
ount
e
rpar
t southernform"r
epr
es
en
t
sMa‑gondoo
ft
h
ewhal
e
r
s.Compar
e
d
w
i
t
ht
h
esouthernform,t
h
enor
t
her
nformhaslargerbodybyabout 1m
(
f
emal
e)t
o 2m (m
al
e)(K
a
suy
a
,1
9
8
6
)androundc
ontourofheadviewed
f
rom t
h
ea
b
o
v
e
.Adultmale
soft
hes
ou
t
her
nformhass
q
u
a
r
es
hape
dhea
d
(Y
onekura,MatsuiandKa
suy
a
,1
980
)
.Thedor
s
a
lf
i
nofa
dul
tmale
soft
he
nor
t
hernformtendstobenarr
owert
hant
hatoft
hes
o
u
t
h
e
r
nform,butt
he
d
i
f
f
er
enc
ei
si
n
d
i
s
t
i
n
c
t
.Miy
a
z
ak
i(
1
9
8
3
)r
epor
t
e
ds
i
lgh
td
i
f
f
e
r
e
n
c
ei
nt
henipp
er
l
engt
h(
l
ong
eri
nt
henor
t
her
nf
orm)
.
Thes
ad
d
lemar
koft
henor
t
her
nf
ormi
sus
ualymorei
lgh
tv
ar
y
i
ngi
n
col
orf
r
om pur
ewh
i
t
et
ov
er
yl
igh
tg
r
e
y
,andt
hatoft
hes
o
u
t
h
e
r
nf
ormi
sgr
ey
ordark gr
ey andalmos
tunr
ecogn
iz
a
bl
eon t
hec
ar
c
a
s
s(
Yonekur
a
,e
ta
l
.
,
1
980)
.Howev
er
,t
hea
bs
ol
u
t
ebr
igh
tne
s
si
sani
n
f
e
r
i
o
rc
uee
spe
ci
alyf
ort
he
s
h
i
pboar
dob
s
e
r
v
e
r
sbec
aus
ei
t
sv
i
s
ualc
ha
r
a
ct
erc
hange
sbywe
a
t
herc
o
n
d
i
t
ion,
d
i
r
e
c
t
i
o
nofs
un,anddept
hofwhal
e
si
nt
hewa
t
er
.Theeyep
a
t
c
he
sar
es
i
lgh
t
ly
mor
eb
r
igh
ti
nt
hen
o
r
t
he
rnform,butt
he
yar
ei
n
d
is
t
i
nc
tandar
enots
u
i
t
abl
e
f
o
rt
hei
d
e
n
t
i
f
ic
at
i
o
n purp
o
s
e
.Thes
i
z
eofs
a
d
d
l
emarkisvariab
leamongnort
hernformi
n
d
i
v
i
d
u
a
l
s
.
Theb
e
s
tex
t
e
r
n
a
lc
har
a
ct
er
is
ti
c
st
hats
epar
a
t
et
hetwoformsar
en
o
tt
he
s
i
z
eorb
r
i
g
h
t
ne
ssoft
hes
ad
d
lemar
k,butt
hed
i
re
ct
i
o
nandd
is
t
i
nct
ne
s
soft
he
po
s
t
er
iorboundaryoft
hes
ad
d
lema
rk(
F
ig.1
)
.Ont
h
enor
t
h
e
r
n formt
he
po
s
t
er
iorboundar
yoft
hes
a
d
d
lemar
ki
sc
le
ar
lyboundedbyt
h
epo
st
er
ior
b
la
cka
r
e
aoft
hebodyandd
i
r
e
c
t
e
d an
t
er
io‑
v
e
n
t
r
a
l
ly
,anda
d
d
i
t
ionalyt
he
s
a
d
d
lemar
kdo
e
snotext
endpo
s
t
e
r
i
or
lybeyondthelevelofanusbutext
end
an
t
er
ior
lyus
ualybey
ondthelevelofpo
st
e
r
i
o
rmar
gi
noft
hedor
s
alf
i
n
.On
t
h
es
outhernform,however,itext
endspo
st
e
r
i
or
lyt
ot
h
em
i
d
‑
l
engthoft
ai
l
S
c
i
.Re
p
.W
h
a
l
e
sRe
s
.I
市 t
.
,
N
o
.3
9
,1
988

80

KASUYA, MIYASHITA AND KASAMATSU
TABLE 1. LIST OF CRUISES CONDUCTED BY THE JAPAN FISHERY AGENCY
AND USED TO COLLECT DATA IN FIG. 2 OF THIS STUDYName of vessel

Year

Month

Pilot whalesightings*

Reference for cruise
track line

Konanmaru No. 25
Toshimaru No. 15
Toshimaru No. 15
Toshimaru No. 15
Toshimaru No. 25
Shonanmaru
Toshimaru No. 25
Shonanmaru

1982
1983
1984
1985
1986
1983
1983
1984

1-3
1-3
1-3
1-3
5-6
6-7
6-8
6-8

present
absentpresent
absentpresent
present
present
absentToshimaru No. 25

1984

6-9

present

Toshimaru No. 25
Toshimaru No. 18
Shonanmaru
Toshimaru No. 15
Toshimaru No. 15
Kankimaru No. 58

1985
1986
1985
1985
1986
1986

6-9
6-9
7-9
9-10
9-10
9-10

present
present
present
absentpresent
present

Miyashita (l 986b)
Miyashita (l 986b)
Miyashita (l 986b)
Miyashita (I 986b)
Miyashita and Kasuya ( 1987)
Miyashita (1985)
Miyashita (1985)
Miyashita (I 986a,b)
Kasuya (I 986a)
Miyashita (I 986a,b)
Kasuya (I 986a)
Miyashita (1986b)
Miyashita and Kasuya ( 1987)
Miyashita (I 986b)
Miyashita (l 986b)
Miyashita and Kasuya ( 1987)
Miyashita and Kasuya (1987)• Pilot whale sightings in the area indicated in Fig. 2.

peduncle. The posterior and ventral boundaries of the saddle mark of thesouthern form gradually fades into the black body color making it difficult todefine the boundary. The saddle marks of live pilot whales in Figs 1 and 2 ofPlate I in Yonekura et al. ( 1980) are now clear to represent those of northern
forms, but other photographs of the carcasses and a drawing in text-Fig. 2 of
their study represent the southern form.
Using above criteria, Kasuya (1986b) could identify all the postnatal
northern forms used in his study (about 300 individuals over 1.5 years old),and found no individuals that could be considered as intermediate of the twoforms of the short-finned pilot whale. However, none of the four full term
fetuses of northern form (165 to 185 cm in body length) had recognizablesaddle mark (Kasuya, unpublished) and the distinction of the two forms
appeared to be difficult except for the larger body size of the northern form
(Kasuya, l 986b). This suggests that the distinction of two forms by the saddle
mark becomes possible at an age between 0 and 1.5 years or well before themean age at weaning 2.4-3.1 years (Kasuya, l 986b), which causes no difficultyin the identification of northern form schools.
Source of sighting data
Main body of the data used in this study was the results of whale sighting
cruises conducted by Ja pan Fishery Agency in 1982 through 1986 (Table 1).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OF SHORT-FINNED PILOT WHALES

81

TABLE 2. DALL'S PORPOISE SIGHTINGS AND HARPOONING CRUISES IN THE WESTERNNORTH PACIFIC AND BERING SEA, WHICH PROVIDED INFORMATIONON PILOT WHALE DISTRIBUTION FOR THE PRESENT STUDYName of vessel

Year

Month

Hoyomaru No. 67
Hoyomaru No. 12

1979
1982

6-8
8-9

Hoyomaru No. 12
Hoyomaru No. 53
Hoyomaru No. 12
Hoyomaru No. 12

1983
1984
1985
1986

8-9
5-6
8-9
8-10

Pilot whalesightings

Reference for cruise
track linenone*
2 schools
off Japan
none
none
none
present

Miyazaki, Jones and Beach (1984)
Kasuya and Ogi ( 1987)
Kasuya and Ogi (1987)
Miyazaki and Fujise (1985)
Kasuya and Ogi (1987)
Yoshioka et al. (1987)• Personal communication of Dr N. Miyazaki.

In these cruises the sighting of whales was conducted along pre-fixed trackline using the method that had been used in the Antarctic minke whale
assessment cruise (Best and Butterworth, I 980), and all the marine mammalsightings were recorded. The trackline was designed systematically to coverevenly the survey area. Instruction was given since I 984 to biologist on board
or to captain of the vessel to distinguish the two forms of short-finned pilot
whales and to take photographs of those individuals for later confirmation.
Some additional photographs or sketches were left by observers of earlier
cruises at voluntary base.
Additional information was available from published reports of five cruises
conducted by Japan Fishery Agency for Dall's porpoise sightings and harpooning in the western North Pacific (Table 2). Among these cruises pilot
whales were sighted only during the I 982 and I 986 cruises, but information
obtained from other cruises was also valuable as the indication of absence ofpilot whales in the surveyed area. Biologists were on board of these five cruises.
In addition to above cruises, sightings data collected during 4 cruises ofthe Hakuhomaru and 4 cruises of the Tanseimaru (both were conducted by
the Ocean Research Institute, University of Tokyo), and each cruise of the
Hayachinemaru and Koeimaru were used. These cruises (conducted in I 967 toI 985) were selected from many other similar kind of cruises by the presenceof at least one pilot whale sighting. Kasuya or some trained observers were on
board of these cruises to collect records of whale sightings. Two schools of thenorthern form and one school of unidentified form were cited from Ogi(pers. commn in 1985) and Kuroda (1956), respectively. Some of these sightings
were identified to the whale types using photographs.
Catch of drive fisheries or of small-type whaling in Kasuya and Marsh(I 984) or in Kasuya and Tai (I 986) were used as well as a stranding in Kasuya
and Marsh (1984) as the indication of occurrence of the species.
The surface water temperature was recorded at the position of sighting
for many of the above records.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

82

KASUY A, MIY AS HITA AND KASAMATSU

140"E

ISO"E

1600E

140°E

150"E

160"E

Fig. 2. Sightings of short-finned pilot whales and surveyed area (inside of the shaded
area indicated by one degree squares). Open triangle: school of northern form,
Closed triangle: school of southern form, Star: school of unidentified form. Marksinside the coast line represent catch or stranding. The isotherms indicate ten years
mean of surface water temperature in March, .July, September, and December(Japan Oceanographic Data Center, 1978).

RESULTS

Geographical segregation

The surveyed area and sightings of pilot whales are indicated by seasonsin Fig. 2. In winter Qanuary to March), the sighting effort was limited to thesouth of 37°N. Northern forms were sighted twice off the Boso Peninsula at
between 35°N and 36°N. In spite of extended sighting effort no southern
forms were sighted to the north of 30°N, but several sightings were recorded
to the south of the latitude (Table 4, for further details of these sightings see
Miyashita (1986b)). In this season the drive fishery off Taiji (33°35'N) captured
schools of the southern form, indicating their presence in the coastal waters
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OF SHORT-FINNED PILOT WHALES

83

of the latitude.
In spring (April to June), the sighting effort expanded to wider geographicalarea, although the total surveyed areas was still limited. Northern forms weresighted off northern Japan at latitudes between 40°N and 41°N. A school ofsouthern form was sighted at about 34°N. Several additional sightings of theform were recorded to the south of 30°N (Miyashita, l 986b). Drive fishery at
Taiji (33°35'N) and at Arari (34°50'N) on the Izu coast captured schools of
the southern form in this season. These suggest a northward expansion of theconcentration of southern form whales in the spring season. A school ofunidentified form in Fig. 2 (5th May 1986) in the coastal waters in 36°-37°N
and 141°-142°£ was recorded by the captain of the Toshimaru No.25 as thesouthern form. Although the surface water temperature at the position(8.6°C) appeared to be too low for the southern form, this position was justto the inshore colder side of a very distinct water front (surface water temperature decline of 12.3°C in 24 n.m.), and both forms could have been present
at the spot. Since the correctness of the identification could not be supportedby photographs or subsequent sightings (the cruise had only one sighting ofpilot whales), we tentatively dealt the school as unidentified.
In summer months (July to September), the sighting effort expandedwidest. Northern forms were sighted in the Japanese coastal waters between
36°N and 43°N, and west of l 49°E longitude. Most of these sightings wereconcentrated within about I 00 nautical miles from the coast. In spite ofconsiderable amount of sighting effort (three 40 to 45 days cruises in Augustthrough September, and two similar cruises in May through August), there
were no sightings of pilot whales in the Bering Sea and western North Pacificwest of l 75°E in the Subarctic Convergence Zone and north of it (Table 2).
Pilot whales of unidentified form were sighted south of the Subarctic Convergence in the central North Pacific in August (Table 3). These data suggestthat short-finned pilot whales do not usually enter into the Subarctic Convergence Zone in the North Pacific and the long-finned pilot whale does notexists in the Bering Sea and northern North Pacific.
In the same season, southern forms were sighted to the south of 37°N.
Segregation between the two forms is clear (Fig. 2). At Taiji (33°35'N), thedrive fishery captured southern form schools. Although density seemed to be
low south of 25°N or east of 152°E suggesting the maximum range of the
population in the western North Pacific (IWC, 1987), firm conclusion was
hard to be drawn due to the limited sighting effort in the offshore waters. In
addition to this, there is an apparent density hiatus in the Kuroshio Current
area and the distribution seems to be discontinuous between coastal area andoffshore Kuroshio Counter Current area. The sighting trackline was arranged
systematically for even coverage of the area, so the density hiatus does notseem to be an artifact of uneven sighting effort (for details see Miyashita,
l 986b). Further study is needed to confirm more than one stocks of thesouthern form short-finned pilot whales in the western North Pacific.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

84

KASUYA, MIYASHITA AND KASAMATSU

TABLE 3. SIGHTINGS OF PILOT WHALES DURING THE CRUISES DEALT IN THE PRESENTSTUDY, OUTSIDE OF THE RANGE IN FIG. 2 AND NORTH OF 35°N.
NONE OF THE WHALE TYPES WERE IDENTIFIED
Date ofsighting
2 Aug. 1967
2 Aug. 1967
3 Aug. 1967
28 Aug. 1971

Position ofsighting
42°04'N,
41°57'N,
41°56'N,
39°04'N,

175°00'E
171°54'E
165°17'£134°36'E

Area
w. N. Pac.
w. N. Pac.
w. N. Pac.

S.ofJapan

Water
temp.

Name ofvessel19.6°C
22.9°C
19.9°C
24.5°C

Hakuhomaru
Hakuhomaru
Hakuhomaru
Hakuhomaru

In autumn months (October to December), sighting effort was limited to
the Pacific coast between 34°N and 39°N, and there were sighted three schoolsof northern forms (to the north of 36°N). Northern forms were caught byJapanese small-type whaling off the Pacific coast in October and November
in latitudes between 37°N and 40°N (Miyazaki, 1983; Kasuya and Tai, 1986).
Southern forms were not sighted in the coastal waters south of 36°N in thisseason, but the presence was indicated by the stranding of a school at Choshi(35°43'N), and frequent catch by the drive fishery on Izu coasts (34°40'N) andat Taiji (33°35'N) (Kasuya and Marsh, 1984). Miyazaki (1983) reported catchof the southern form by small-type whaling off Sanriku (38°N to 40°N) in
October 1982. However, this was possibly a rare incident for the region in thisseason, because such case did not occur during the following four pilot
whaling seasons (Kasuya, 1986; unpublished; Kasuya and Tai, 1986) andbecause it was the first case for the gunner to hunt such short whales of adultshape (Mr Y. Toba, pers. commn in 1983).
There are reasons to believe that northern forms may occasionally occur
off Taiji (33°35'N) on the Pacific coast of central Japan (see Discussion).
In the Sea of Japan, we have only one record of sighting of pilot whalesof unknown form (Table 3). The species seems to be uncommon in the area
as already mentioned by Kasuya (1975). We do not have data to indicate
which form of pilot whales are distributed in the Sea of Japan.
Thermal segregation
Table 4 shows number of short-finned pilot whale sightings by surface
water temperature, type of whales and season. Southern forms were sighted
at the water temperature between 24° and 31°C in summer, and between 20°
and 24°C in winter. The observed seasonal difference of the low temperature
limit was 4°C (lower in winter), while the geographical northern range shiftedto the south by about 9° in latitude. The actual thermal difference in the
ha_bitat between winter and summer must have been larger, because there
were frequent winter drives of this form at Taiji (33° 35'N) where surface
water temperature could be below 20°C (Fig. 2). This indicates that theseasonal change of the geographical range of southern form short-finned
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

85

SEGREGATION OF SHORT-FINNED PILOT WHALESTABLE 4. MONTHLY SURFACE WATER TEMPERATURE ATTHE POSITION OF SHORT-FINNEDPILOT WHALE SIGHTING IN FIG. 2 (WITHOUT PARENTHESIS) AND
THOSE IN THE WATERS SOUTH OF 30°N LATITUDE MADE
BY CRUISES LISTED IN TABLE I (IN PARENTHESES)
Northern form

W.T.*
(oC)

1-3

4-6

7-9

Unidentified

Southern form

10-12

1-3

7-9

10-12

4-6

7-9

10-12

I**

8
14
15
16

17
18
19

6

20
21
22

23
24
25

(2)
(3)

4
4

2

(2)

(I)

4
I

26

2(2)

27
28

5(7)

4(1)

29

(2)

30

(I)

(I)

(2)

• Water temperatures between n° and n+ l°C indicated by n (n being integer).

* * Captain of the research vessel (Toshimaru No. 25 cruise in I 986) recorded this as a southern form school(see text).

pilot whales is not large enough to retain a constant surface water temperatureenvironment for the stock. In other words, some additional factors such as
basithermo structure or food availability is also controlling the distribution
and their distribution does not always cover the whole geographical range
permitted by their thermal tolerance.
Northern forms, on the other hand, were sighted at the surface watertemperature between l9°C and 24°C in summer, and at between 15°C andl8°C in other seasons (Table 4). Accumulation of more data may give wider
thermal range, especially for the lower limit. Kasuya and Tai (1986) reported
that the water temperature at the position of northern form catch (38°N to40°N) in October and November ranged from 12°C to 21°C with a peakfrequency of catch at l6°-l 7°C. The surface water temperature of 10°-l5°C
corresponds to the front of the cold Oyashio Current in the area. The summer
sightings of three pilot whale schools of unidentified form at 41° -43°N will
represent the northern form. We consider that northern forms move in thefall to the southern wintering ground (north of 35°N and south of the Oyashio
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

86

KASUY A, MIY AS HITA AND KASAMATSU

Front) from their summering range expanded probably up to 43°N accompanying the seasonal shift of the Oyashio Front. Their southern range does
not change seasonally so much as the northern range, and they endure theseasonal change of the surface water temperature between 12° and 24 °C(Fig. 2).
The segregation between the northern and southern forms of short-finned
pilot whales is usually distinct geographically and thermally. Although there
exist some examples of geographical or possible social intermingling, suchcases seem to be rare and unusual as discussed below.
DISCUSSION

The characteristics that we have used in the present study to separate twoforms of short-finned pilot whales off the Pacific coast of Japan are similar to
those used by Yamase (1760) to describe two kinds of pilot whales off Taiji(33°35'N) on the Pacific coast of Japan. Cray's (1846; 1866) description of thepilot whales off Japan is almost identical to that of Yamase (1760). This lead
us to consider that our "southern form" is equivalent to their Naisa goto or
Naisa gota which was named as G. sieboldii Gray, 1846, and our "northernform" is equivalent to their Shiho goto or Shibo golo named as G. sibo Gray,
1871. Both of these scientific names have been correctly considered by Bree
(I 971) to be junior synonyms of G. macrorhynchus Gray, 1846.
The next question will be if the northern form individuals still occur off
Taiji which situates further south of the ordinally range of the northern form
confirmed in the present study. There are evidences supporting this. In
winter, a belt of cold coastal water below l 8°C extends from 35°N (the ordinary
southern range of the northern form in both summer and winter) to 33°N
(south of Taiji at 33°35'N) along the Pacific coast of Japan. Thus it is expected
for some northern form individuals to stray to the waters off Taiji. An exwhaler and a present dolphin meat dealer Mr M. Mizutani of Taiji Town and
Mr Y. Seko of the Taiji Fish Market gave us the description of the northern
form correctly and told their belief that one of the small-type whaling vessels
at Taiji caught the northern form pilot whale (their tappa-naga) once (Mizutani)or several times (Seko) after World War II. Since the meat of southern forms
is esteemed over that of northern forms, their identification can be trusted.
As the small-type whaling ceased operation off Taiji since 1978, the catch
could have been before the date.
In their sample of more than 500 southern form short-finned pilot whales,
Kasuya and Marsh (1984) found only one male of putative northern formand excluded it from their analysis. This male was found in an aggregationof about 230 southern form individuals caught at Taiji in June 1975, andexamined by their colleague. It was 5.8 m in body length, or 0.6 m larger thanthe largest southern form in their sample. The testis (1.7 kg) was at the lower
limit of the testis weight (l.7-3.0 kg) of southern forms measuring over 5 m
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OF SHORT-FINNED PILOT WHALES

87

in body length, but it was of reasonable weight for the northern form of thatbody size (Kasuya, I 986b). The lack of observation of saddle mark or age
estimate inhibited reliable classification of the whale type. Yonekura et al.
( 1980) did not recognize among their sample of 211 individuals (most of themwere not included in Kasuya and Marsh (1984)) any individuals which could
be classified to the northern form.
Only confirmed records of southern forms off the Sanriku coast (33°-37°N)
were seven individuals taken by a small-type whaling vessel at Ayukawa(38°15'N) on 5th November 1982, examined by Dr N. Miyazaki (1983) andaged by Kasuya (1986b). These individuals were apparently taken from aschool of the same form (Y. Toba, pers. commn in 1984). These were no
additional records of such incidence during the five years operation of thewhaling in October and November, 1982 to 1986. Kasuya (1986b) identified
about 300 individuals taken by the small-type whaling off Sanriku during
the period as the northern form based on the pigmentation, and confirmed
it using body length on age relationship. These suggest that the two formsof short-finned pilot whales rarely form a common school even though
their range of distribution may occasionally situate close or overlap in theboundary area.
Although there exist opinions to consider that the saddle mark of theshort-finned pilot whale may change brightness or shape by growth orphysiological conditions (see below), currently available data indicate that thefeature of saddle mark we have described above is a stable characteristics toidentify individually two forms of short-finned pilot whales off Japan withpossible exception of newborn individuals. The whale type of newborns is
identifiable only by body size assisted by the age information (Kasuya, 1986b).
The life history of northern form short-finned pilot whales off Japan differsfrom that of the southern form (Kasuya and Marsh, 1984) only in the larger
body size and later mating peak (May vs. September), and all the life history
characteristics that were found by them to be peculiar to the short-finned
pilot whale are shared by both northern and southern forms (Kasuya, 1986b).
Kasuya (I 986b) speculated from these some ecological mechanisms whichmight inhibit free interbreeding between the two forms, and considered thatthe degree of differentiation between the two forms will be at the level ofsubspecies or local stocks. Wada ( 1988) arrived at the similar conclusion
through the analysis of isoenzymes.
Two types of short-finned pilot whales have been distinguished in theeastern North Pacific using various independent characteristics, e.g. bodysize and head shape (Mitchell, 1975) and skull morphology (Polisini, 1980).
Published studies on the pigmentation of short-finned pilot whales in thesewarters are confusing. Yablokov and Evans (1981) described individual variation of the saddle mark of short-finned pilot whales in the southern California
Bight, and Leatherwood, Reeves, Perrin and Evans (1982) and Evans, Thomas
and Kent (1984) questioned its stability and the usefulness for stock identifiSci. Rep. Whales Res. Inst.,
No. 39, 1988

88

KASUYA, MIYASHITA AND KASAMATSU

cation. The latter authors, however, suggested in the same study a possibilityof geographical variation of the pigmentation pattern, indicating that the
short-finned pilot whales in the eastern tropical Pacific usually have no or
only faint markings on the dorsal surface. The apparent disagreement of
opinions probably came from the mixing of some minor individual variationof pigmentation in a single population and more stable difference between
stocks.
A short-finned pilot whale photographed off Baja California and the Gulf
of California by T. Amborn (pers. commn in 1986) and Leatherwood et al.
(1982) had saddle mark similar to that of the present northern form, and aschool of 35 pilot whales sighted off Seattle (48°28'N, 133°5l'W) in August
had apparently similar saddle mark with the northern form sighted off Japan(39°50'N, 145°42'E) in August during the same cruise (Yoshioka, Ogura andShikano, 1987). We confirmed the photographic records of these sightings.
While describing the external morphology of G. scammonii, which was identified
by Bree (1971) as a junior synonym of G. macrorhynchus, Scammon (1874)
made no comment on the saddle mark of the type specimen taken by him off
Baja California (31°N). His detailed description of the variation of killer whale
saddle mark in the same book suggests that he would have mentioned thesaddle mark of the type specimen if it had such clear one as found on shortfinned pilot whales off northern Japan or off the coast of North America.
These suggest, as well as a comment in Evans et al. (1984), the presence ofgeographical segregation of two forms of the short-finned pilot whale in theeastern North Pacific. Although information on other biological feature ofthese individuals is needed for further consideration, there is a possibility thateach of them corresponds to the southern and northern forms off Japan.
The short-finned pilot whale in the North Pacific could have evolved two
geographical forms (or subspecies), one in the tropical waters and the otherin the temperate waters north of it.
We do not have information on the morphology of pilot whales sighted
in the central northern North Pacific (Table 3). The latitudes of sightings(39°-42°N), which were just to the south of the Subarctic Convergence Zone,
leave possibility for them being either of the two forms of the present study.
However, in view of the concentration of northern forms in the Japanese
coastal waters and tht; apparent discontinuity of distribution in the offshore
waters, we consider that the Japanese coastal individuals of the northern form
will constitute a local stock of relatively small population size. Miyashita (l 986b)
estimated the population as about 5,000 individuals.
ACKNOWLEDGEMENTS

Thanks are due to many anonymous scientists and crew on board of theresearch vessels who cooperated in collecting sighting records of pilot whales.
Drs T. Amborn, H. Ogi, C. Shikano, M. Yoshioka provided photographs andSci. Rep. Whales Res. Inst.,
No. 39, 1988

SEGREGATION OF SHORT-FINNED PILOT WHALES

89

records of sightings of short-finned pilot whales for the present study. Dr N.
Miyazaki critically read the manuscript. Mr S. Matsui helped us in collecting
information on the historical records of the northern form catch in Taiji. Dr
A.A. Hohn advised us in references. Mrs Y. Yamamoto and Mrs M. Ikeya
helped us in data analysis and drawings.
REFERENCES
BEST, P.B. and D.S. BUTTERWORTH, 1980. Report of the southern hemisphere minke whale assessment
cruise. 1978/79. Rep. int. Whal. Commn, 30: 257-283.
BREE, P.J. H. VAN, 1971. On Globicephala sieboldii Gray, 1846, and other species of pilot whales. Beaufortia,
19(247): 79-87.
EVANS, W. E.,]. A. THOMAS and D. B. KENT, 1984. A study of pilot whales (Globicephala macrorhynchus) in thesouthern California Bight. National Marine Fisheries Ser. Administrative Rep. LJ-84-38C, 47 pp.
GRAY, J.E., 1846. The Zoology of the voyage of H.M.S. Erebus and Terror. 1: 13-53, 37 pls.
GRAY, J.E., 1866. Catalogue of Seals and Whales in the British Museum. Trustees British Museum, London. 402 pp.
GRAY, ]. E., 1871. Supplement to the Catalogue of Seals and Whales in the British Museum. Trustees British
Museum, London. 99 pp.
HAWLEY, F. 1960. Miscellanea Japonica II, Whales and Whaling in Japan, vol.l, part 1. 354 + Xpp. Publishedby the author.
IWC, 1987. Report of the sub-committee on small cetaceans. Rep. int. Whal. Commn, 37: 121-128.
JAPAN OCEANOGRAPHIC DATA CENTER, 1978. Marine Environmental Atlas, Northwestern Pacific Ocean II (Seasonal,
Monthly). Japan Hydrogr. Ass., Tokyo. 157 pp.
KASUYA, T. 1975. Past occurrence of Globicephala melaena in the western North Pacific. Sci. Rep. Whales Res.
Inst., 27: 95-110.
KASUYA, T. l 986a. Distribution and behavior of Baird's beaked whales off the Pacific coast of Japan. Sci.
Rep. Whales Res. Inst., 37: 61-83.
KASUYA, T. l 986b. Comparison of life history parameters between two stocks of short-finned pilot whales
off the Pacific coast of Japan. IWC/SC38/SM10. 32 pp.
KASUYA, T. and H. MARSH, 1984. Life history and reproductive biology of the short-finned pilot whale,
Globicephala macrorhynchus, off the Pacific coast of Japan. Rep. int. Whal. Commn, (special issue 6):259-310.
KASUYA, T. and S. MATSUI, 1984. Age determination and growth of the short-finned pilot whale off the
Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 35: 57-91.
KASUYA, T. and H. 0GI, 1987. Distribution of mother-calf Dall's porpoise pairs as an indication of calving
grounds and stock identity. Sci. Rep. Whales Res. Inst., 38: 125-140.
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.
KASUYA, T. and S. TAI, 1986. Operation of Japanese small-type whaling on the short-finned pilot whale off
the northeastern Japan. IWC/SC38/SM16. 16 pp.
KURODA, N. 1956. Records of marine mammals in the northern North Pacific.]. Mamm. Soc. Japan, 1(3):35-39. (in Japanese with English summary)
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 Tech. Rep.
NMFS. Circular 444. 245 pp.
MARSH, H. and T. KAsUYA, 1984. Change in the ovaries of the short-finned pilot whale, Globicephalamacrorhynchus, with age and reproductive activity. Rep. int. Whal. Commn, (special issue 6): 311-335.
MITCHELL, E.D. 1975. Report of the meeting of smaller cetaceans, Montreal April 1-11, 1974, Subcommittee
on Small Cetaceans, Scientific Committee, International Whaling Commission.]. Fish. Res. Bd Can.,32(7): 889-983.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

90

KASUYA, MIYASHITA AND KASAMATSUMIYASHITA, T. 1986a. Sighting estimate for the Bryde's whale stock in the western North Pacific. Rep. int.
Whal. Commn, 36: 249-252.
MIYASHITA, T. 1986b. Abundance of some globicephalid cetaceans in the adjacent waters of Japan.
IWC/SC38/SM17. 18 pp.
MIYASHITA, T. and F. KASAMATSU, 1985. Population assessment of the western North Pacific stock of Bryde's
whales. Rep. int. Whal. Commn, 35: 363-368.
MIYASHITA, T. and T. KASUYA, 1988. Distribution and abundance of Dall's porpoises off Japan. Sci. Rep.
Whales Res. Inst., 39: 121-150.
MIYAZAKI, N. 1983. On pilot whales off Kinkazan Island. Abstracts of Papers Read in the Autumn Meeting
Japanese Soc. Sci. Fisheries. p. 55. (in Japanese).
MIYAZAKI, N. and Y. FUJISE, 1985. Outline of the survey of dolphins and porpoises by the Hoyomaru No. 53
dedicated for Dall's porpoise study (JO May to 20 June 1984). Far Seas Fisheries Res. Laboratory.
Shimizu. 47 pp. (in Japanese).
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.
N1sHIWAKI, M., T. KASUYA, R.L. BROWNELL and D.K. CALDWELL, 1967. On the taxonomy of Globicephala in
the Japanese coastal waters. Abstracts of Papers Read in the Annual Meeting ofJapanese Soc. Sci. Fisheries,
p. 15. (in Japanese)
OG1, H., H. TANAKA, T. KuRAMOCHI and Y. YAMAMOTO, 1986. Outline of the research by the dedicated vessel
Hoya Maru No. 12 in 1985. Document submitted to the meeting of Scientific Subcommittee of the
Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo,
March 1986. 26 pp. (in Japanese with English translation of text).
PousINI, 1980. A comparison of Globicephala macrorhyncha (Gray, 1846) with the pilot whale of the North
Pacific Ocean: An analysis of the skull of the broad-rostrum pilot whales of the genus Globicephala.
Doctoral thesis presented to Fae. Graduate School, Univ. Southern Cali[., 299 pp.
SCAMMON, C.M., 1874. The Marine Mammals of the North-western Coast of North America. Carmany, San Francisco.
319 pp.
WADA, S., 1988. Genetic differentiation between two forms of short-finned pilot whales off the Pacific coastof Japan. Sci. Rep. Whales Res. Inst., 39: 91-102
YABLOKov, A. V. and W. E. EVANS, 1981. On the benefit of external appearance. Science and Life, 3: 76-81.
(in Russian).
YAMASE, H. 1760. Geishi [Natural History of Whales]. Osakashorin, Osaka. 70 pp. (in Japanese).
YoNEKURA, M., S. MATSUI and T. KASUYA, 1980. On the external characters of Globicephala macrorhynchus off
Taiji, Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 32: 67-95.
YOSHIOKA, M., M. 0GURA 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,
March 1987. 22 pp.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GENETIC DIFFERENTIATION BETWEEN TWO FORMS
OF SHORT-FINNED PILOT WHALES OFF
THE PACIFIC COAST OF JAPAN*

SHIRO WADA**ABSTRACTThe northern and southern forms of the short-finned pilot whale off
the Pacific coast of Ja pan were examined by horizontal starch gel electrophoresis on 36 enzyme loci using 371 specimens. Two and five loci werevariable in the northern and southern forms, respectively. The proportionof polymorphic loci under the 0.95 criterion and the value of the average
heterozygosity per locus were 0.028 and 0.009 in the northern form and0.056 and 0.008 in the southern form, respectively. No significant deviationin genotype frequencies from the Hardy-Weinberg expectations was seenin either form. Significant between-form difference in genie proportions
revealed that the northern form is genetically isolated from the southern
form. From the value of Nei's genetic distance, 0.0004, the degree ofgenetic differentiation between two forms was considered to be of the local
population level.
INTRODUCTION

The short-finned pilot whale, Globicephala macrorhynchus Gray, 1846, is one of
the important objective species for the coastal whaling in Japan, which has
been harvested in two different fisheries. Two forms segregate geographicallyand thermally off the Pacific coast of Japan (Kasuya, Miyashita and Kasama~su,
1987). The northern form, tappanaga, having been harvested by the small-typewhaling (Kasuya and Tai, 1986), distributes off the Pacific coast of northern
Japan between 35°N and 42°N in the surface water temperature range of
12-24°C, while the southern form, magondo, having been harvested by thesmall-type whaling and the drive fishery at Taiji (Kasuya, l 986b), distributes
in the waters south of the major range of the northern form and waters over
18°C.
Form-identification is easy from the difference of external characteristics.
The northern form has a larger body size, a distinct saddle mark and a roundcontour of the head, while the southern form has a smaller body size, an* An earlier version of this manuscript was submitted to the Scientific Committee of the International Whaling
Commission, Bournemouth, May 1986 (Document No. SC/38/SM18).

** Far Seas Fisheries Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan
Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 91-101

92

WADA

indistinct saddle mark and a square contour of adult male head (Kasuya et al.,1987). However, the life history parameters of the two forms differ significantly
only in those concerning to body size and to breeding season (Kasuya, l 986a).
Both forms share the skull characteristics of G. macrorhynchus described byBree (1971 ). From these, Kasuya (l 986a) suggested that they can be dealt
with as separate geographical forms or subspecies.
Electrophoretic survey on a large number of loci for genetic variability or
genetic differentiation in cetacea have been reported on rather limited numberof species; on minke whale by Wada and Numachi (1979), Simonsen, Kapeland Larsen (1982), and Wada (1982; 1983a; 1984); on fin and sei whales by
Danielsd6ttir and Amason (1987); on fin, sei, Bryde's and minke whales by
Wada ( 1987); on striped dolphin by Wada ( l 983b); on Dall's porpoise by
Winans and Jones (in press); on long-finned pilot whale by Andersen (1987);
on 12 species of toothed. whale by Shimura and Numachi (1987).
The aim of the present study is to evaluate the magnitude of genetic
differentiation between two forms of short-finned pilot whales and to consider
their taxonomic relationship from the viewpoint of biochemical genetics.
MATERIALS AND METHODS

Tissue samples, liver and skeletal muscle, of 204 northern forms werecollected by Dr T. Kasuya and his co-workers as a part of their biologicalsamplings from the whales caught by the small-type whaling off the Sanriku
region and landed at Ayukawa in October and November 1983 ( 105 specimens)
and 1984 (99 specimens).
Tissue samples of 167 southern forms were collected by myself from thewhales driven at Taiji and flensed on 7-8 October 1984 (68 specimens fromfour schools in a single drive of 92 whales) and 11-12 November 1985 (99specimens from a single drive of about 120 whales which might have been
mixed with a few members of a previous drive). Form-identification for the
specimens in 1984 was done by Dr N. Miyazaki and for those in 1985 bymyself. All tissue samples were stored at - 20°C until use.
Methods of sample and gel preparations, and electrophoresis followed
the procedures described in Numachi (1974), and Shimura and Numachi( 1987), and that of gel preservation in N umachi ( 1981 ). Of the 32 enzymes
examined, the following three loci and five enzymes showed an indistinct
electrophoretic pattern, and therefore I didn't use them in the present study
though the last three enzymes were found to be variable; Adh-2, Ak-1,
Pgm-2, Aconitase, Fumarase, Peptidases B, C and D. Table 1 shows buffers
and tissues used for 36 loci on which reliable genotyping was possible. Recipes
for the 100 ml reaction mixture for staining enzymes, prepared according toHarris and Hopkinson (1976) in principle are listed in Table 2.
In case of multi-loci enzymes, a most anodally migrating locus wasnamed as 1, lesser anodal locus as 2, and so on. At a variable locus, alleles
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GENETICS OF SHORT-FINNED PILOT WHALES

93

were named alphabetically as c, s, n andf from cathode to anode. Then allele
denotes the most frequent allele in a variable locus, or denotes the single one
in a monomorphic locus.
Genotype and allele frequencies were analysed using the G-test (Sokal
and Rohlf, 1969) for a deviation in genotype frequencies from the HardyWeinberg expectations within a form (Gn), and for between-form heterogeneity
in gene frequencies (CH) based on the R (number of alleles) x C (number offorms) contingency table format. G-values were compared with the criticalvalues of Chi-square under (number of genotypes)-(number of alleles)
degrees of freedom for Gn, and under (R-1) x (C-1) degrees of freedom for
CH.

RESULTS

Genetic variability
Genetic variation was found at two loci, Ada and Sod-I, in the northern
form and at five loci, Ada, Mdh-1, 6Pgd, Pgm-3 and Sod-I, in the southern
form. These loci were all biallelic. The northern form had the same alleles as
the southern form at all loci except Ada, where a variant allele in the former(Adas gene) was different from that in the latter (Adac gene). Heterozygotes at
Ada and Pgm-3 showed a two-banded pattern and those at Mdh-1, 6Pgd andSod-I showed a three-banded pattern, suggesting that the enzymes controlled
by the former two and the latter three loci are monomer and dimer, respectively (Fig. 1). The remaining 31 loci were fixed for a single allele in bothforms, so that the subunit structure of enzymes controlled by these loci was
unknown. These results on the southern form agreed substantially with thosein Shimura and Numachi (1987) except a considerable gene frequency
difference at Ldh-A (their Ldh-1) and Pgm-2, probably due to difference ofsample size between the two studies.
The observed genotype frequencies at five variable loci agreed well with
the Hardy-Weinberg expectations. Although the expectations for rare
genotypes were less than five, the Gn values for 7 cases, ranged from 0.01 to
0. 97, were all less than the critical values of Chi-square at the 5% level ofsignificance (Table 3). This suggests that each sample is homogeneous.
Number of polymorphic loci under the 0.95 criterion (P.95: loci on which
the most frequent allele is less than or equal to 0.95) was very small, only one(Ada) in the northern form and two (Ada and Sod-I) in the southern form,
though Sod-I of the former was nearly polymorphic. The P.95 values were
therefore 0.028 and 0.056 in the northern and southern forms, respectively.
The level of average heterozygosity per locus (H) was also low due to low
frequencies of variant genes. The estimates of H value calculated in thenorthern and southern forms were 0.009 ± 0.007 (SE) and 0.008 ± 0.005(SE), respectively. Standard error (SE) of H was calculated using a formula of
Nei and Roychoudhury (1974).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

94

WADA
TABLE I. LOCI EXAMINED AND ELECTROPHRETIC CONDITIONSFOR THE SHORT-FINNED PILOT WHALES
Enzyme (abbreviation)

Adenosine deaminase (ADA)
Alcohol dehydrogenase (ADH)
Adenylate kinase (AK)
Aldolase (ALD)
Creatine kinase (CK)
Glyceraldehyde-3-phosphate
dehydrogenase (GAPDH)
a-Glycerophosphate dehydrogenase (GDH)
Glutamate dehydrogenase (GLUDH)
Glutamate oxaloacetate transaminase (GOT)
Glucosephophate isomerase (GPI)
Hexokinase (HK)Isocitrate dehydrogenase (IDH)
Lactate dehydrogenase (LDH)
Malate dehydrogenase (MDH)
Malic enzyme (ME)
Mannosephosphate isomerase (MPI)
NADP-dependent dehydrogenase (NDH)
Peptidase-A (PEPA)
Peptidase-E (PEPE)
Peptidase-S (PEPS)
6-Phophogluconate dehydrogenase (6PGD)
Phophoglucomutase (PGM)
Pyruvate kinase (PK)Sorbitol dehydrogenase (SDH)Superoxide dismutase (SOD)

Xantine oxidase (XOD)
Xylulose reductase (XR)

Locus

Tissueusedbuffer

Ada
Adh-1
Ak-2
Aid
Ck-1
Ck-2
Gapdh

Liver
Liver
MuscleMuscleLiver
MuscleLiver

AC70
AC70, Mg, NAD
AC70
AC70, Mg
TEB87
TC86
TC86, EDTA, NAD

Gdh
Gludh
Got-I
Got-2
Gpi
Hk
Idh-1
Idh-2
Ldh-A
Ldh-B
Mdh-1
Mdh-2
Me
Mpi
Ndh
Pep A
PepE
Peps
6Pgd
Pgm-1
Pgm-3
Pk
Sdh
Sod-1
Sod-2
Sod-3
Sod-4
Xod
Xr

Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Liver
Muscle
Liver
Liver
Liver
Liver
Muscle
Liver
Liver
Liver
Liver
MuscleLiver
Liver

AC70, Mg, NAD
TEB87
TC80
AC70
TCSO
TC86
AC70, Mg
AC70
AC60
AC60
AC60
AC60
AC60
AC70
AC70, NADP
AC60
AC60
TCSO, Mg
AC70, NADP
AC70
TC80
AC60, Mg
AC70, Mg, NAD
AC60
AC60
AC60
AC60
TEB87
AC70, Mg, NADP

AC: amine-citrate buffers originally used in Clayton annd Tretiak (1972), slightly modified by Numachi,
Nagahora and Iwata (1979).
Gel: 0.002 M citric acid. Electrode: 0.04 M citric acid.
AC60: adjusted with N-(3-Aminopropyl)-morpholine to pH 6.0.
AC70: adjusted with N-(3-Aminopropyl)-diethanolamine to pH 7.0.
TC: tris-citrate buffers.
TC80: originally used in Clayton and Tretiak (1972). Gel: 0.002 M citric acid. Electrode: 0.04 M citricacid. Both solutions were adjusted with Tris (hydroxymethyl) aminomethane to pH 8.0.
TC86: described in Harris and Hopkinson (1976). Electrode: 0.083 M citric acid adjusted with 0.661 M
Tris (hydroxymethyl) amino-methane to pH 8.6. Gel: 27 .5 times dilution of electrode buffer.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GENETICS OF SHORT-FINNED PILOT WHALES

®

..
®

Mdh-1

--

sn

6Pgd

®

..

:

- -- SS

sn

nf

nn

8

Ada

en

Pgm-3

-- - r~:
nn

nn

95

nn

EB

Sod-1

-SS

sn

nn

..
Fig. I. Electrophoretic patterns at five variable loci in the short-finned pilot whales
off the Pacific coast of Japan. The genotype of each phenotype is shown in italic.
~: sample origin, (±): anode, 8: cathode

Genetic differentiation
A significant difference in gene frequencies between the two forms wasfound in the following three loci, Ada; CH = 48.03, d.f. = 2, P<0.001,
Mdh-1; CH = 10.55, d.f. = 1, P<0.01, 6Pgd; CH = 4.80, d.f. = 1, P<0.05,
but the differences at Pgm-3 and Sod-1 were not significant. An overall Gttvalue for the five variable loci was 66.96 (d.f. = 6, P<0.001), which indicatesthat the two forms are genetically isolated stocks.
The extent of genetic differntiation between two forms was measured by
Nei's (1972) genetic distance (D), which represents the average number ofelectrophoretically detectable allelic substitutions per locus. It ranges from 0(all populations share the same alleles in the same frequencies at all loci) to
infinite (each population is fixed for an unique allele at all loci). The estimate
of D value calculated using 36 loci was 0.0004.

(Footnote continued)
TEB:

described in Harris and Hopkinson (1976). Stock: 0.9 M Tris (hydroxymethyl) aminomethane0.02 M ethylenediamine tetraacetic acid disodium salt (EDTA-2Na)-0.5 M boric acid, pH 8.7.
Anodal electrode: 7 times dilution of stock; cathodal electrode: 5 times dilution of stock. Gel: 20
times dilution of stock.
EDTA: gel contains 0.242 mM or 9 mg/100 ml EDTA-2Na.
gel contains 10 mM magnesium chloride.
Mg:
NAD: gel and electrode buffers contain 4 mg/200 ml nicotinamide adenine dinucleotide. For GAPDH
only, 15 mg/200 ml was used.
NADP: gel and electrode buffers contain 4 mg/200 ml nicotinamide adenine dinucleotide phosphate.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

96

WADA
TABLE 2. STAIN RECIPIES FOR THE IOOml REACTION MIXTURE

Enzyme 6>

Substrate(s) I)

ADA

40mg Adenosine

ADH!ml 1-octanol
9ml 95% ethanol
500mg D-glucose
IOOmg ADP
200mg Fructose-1,6di phosphate
I OOmg Creatine
phosphate
500mg D-glucose
IOOmgADP
400mg Fructose-1,6diphosphate
2g a-glycerophosphate

AK
ALD
CK

GAPDH
GDH
GLUDH

2g L-glutamate

GOT

75mg 2-oxoglutaric acid
225mg L-aspartic acidGP!

IOOmg Fructose-6phosphate
2g D-glucose
200mgATP200mg DL-isocitrate

HK
IDH
LDH
MDH
ME
MPI
NDH
PEPA
PEPE
PEPS
6PGD
PGM
PK

SDH
SOD
XOD
XR

Buffer
0.05M Phosphate,
pH7.4
O.IM Tris-HCl,
pH8.7
O.IM Tris-HCl,
pH8.0
O.IMTris-HCl,
pH8.0
O.IMTris-HCl,
pH8.0
O. IM Tris-HGl,
pH8.0
O.IM Tris-HCl,
pH8.7
O.IM Tris-HCl,
pH8.0
adjusted to pH7.5
with2MKOH

Coenzyme andcoupling dye 2)

Iron 3)

NBT,PMS

Linking
enzyme4)

Other
components 5)

luXOD
Ju NP

2g Agar

IOOu HK
60u G6PD
IOOuGAPDH

2g Agar

NAD*, NBT, PMS
NADP, NBT, PMS+

NAD, NBT, PMS

500mg
Na arsenate

NADP, NBT, PMS

NAD*, NBT, PMS+

lOOu HK
60u G6PD

2g Agar

25u ALD

500mg
Na arsenate

NAD, NBT, PMS

lgEDTA-2Na

NAD, NBT, PMS
500mg Fast blue BB

O.IM Tris-HCl,
NADP, NBT, PMS
60u G6PD
pH7.4
O.IMTris-HCl,
NADP, NBT, PMS+ 60u G6PD
pH8.0
O.IM Tris-HCl,
NADP, NBT, PMS+
pH8.0
O.IM Tris-HCl,
NAD, NBT, PMS
2ml 50% DL-lactate
pH8.7
NAD, NBT, PMS
2g DL-malate
O.IM Tris-HCl,
pH8.7
2g DL-malate
O.IM Tris-HCl,
NADP, NBT, PMS+
pH8.0
IOOmg D-mannose-6O.IM Tris-HCl,
NADP, NBT, PMS
60u G6PD
phosphate
pH7.4
50u GP!
O.IMTris-HCl,
NADP, NBT, PMS+
pH8.0
I OOmg Glycyl-DL0.05M Phosphate,
75mg Dianisidine-HCl
IOuAAO+IOOu POD
pH7.4
glycine
IOOmg L-leucyl-~-naphtyl-amide as substrate in the same buffer and reagent mixture as PEPA
IOOmg L-leucyl-1-leucine as substrate in the same buffer and reagent mixture as PEPA
IOOmg 6-phosphoO.IMTris-HCl,
NADP, NBT, PMS+
gluconate
pH8.0
200mg D-glucose-1O.IM Tris-HCl,
NADP, NBT, PMS+ 60u G6PD
phosphate*
pH8.0
O.IM Tris-HCI,
NADP, NBT, PMS
I OOmg Phosphoenol++ IOOu HK
pH8.0
pyruvate
60u G6PD
500mg D-glucose
IOOmg ADP
O.IM Tris-HCl,
NAD, NBT, PMS
3g D-sorbitol
pH8.0
NBT,PMS
O. IM Tris-HCl,
pH8.7
O.IMTris-HCI,
NBT,PMS
250mg Hypoxanthine
pH8.0
3g D-xylitol
O.IM Tris-HCl,
NADP, NBT, PMS+
pH8.0

IOOmg EDTA-2Na
3g Na phosphatemonobasic
2g Agar
2g Agar

2g Agar

2g Agar

500mg EDTA-2NaI) ADP: Adenosine-5'-diphosphate; ATP: Adenosine-5'-triphosphate; *:containing D-glucose-1,6-diphosphate. Ca. 1%.
2) NAD: 30mg Nicotinamide adenine dinucleotide; NAO*: 90mg; NADP: Nicotinamide adenine dinucleotide phosphate;
NBT: 20mg Nitroblue tetrazolium; PMS: 5mg Phenazine methosulfate.
3) +: IOmM MgCl2; ++: !OmM MgCh, 150mg KC!.
4) NP: Nucleoside phospholylase; G6PD: Glucose-6-phosphate dehydrogenase; AAO: Amino acid oxidase; POD: Peroxidase.
5) EDTA: Ethylenediaminetetraacetic acid.
6) see Table I

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

97

GENETICS OF SHORT-FINNED PILOT WHALESTABLE 3. GENOTYPE AND ALLELE FREQUENCIES FOR FIVE VARIABLE LOCIIN THE NORTHERN AND SOUTHERN FORMS OF THE SHORT-FINNEDPILOT WHALE OFF THE PACIFIC COAST OF JAPAN
Locus

Form

Ada

N

s

en
0
13

sn
17
0

nn
51
86

Total
69
99

0
0

sn
0
8

nn
154
159

nn
204
164

nf
0
3

SS

SS

0
SS

Mdh-1

N

s
6Pgd

N

s
Pgm-3

N

s

0
0
SS

Sod-I

Allelefrequencies

Genotypes

N

s

0

Gn
value

.138
.OOO

n
.862
.934

0.64
0.91

Total
154
167

.OOO
.024

n
I.OOO
.976

0.20

ff
0
0

Total
204
167

n
I.OOO
.991

.OOO
.009

0.03

sn
0
2

nn
204
165

Total
204
167

.OOO
.006

n
I.OOO
.994

0.01

sn
18
16

nn
186
150

Total
204
167

.044
.054

n
.956
.946

0.83
0.97

.OOO
.066

f

S: southern form. N: northern form. Gn: G-value for deviation in genotype frequencies from the HardyWeinberg expectations within a form.

DISCUSSION

Reliable estimates of average heterozygosity for marine mammals have beenreported from nine species of pinniped, four species of baleen whale and 12
species of toothed whale. Table 4 summarises the level of their genetic
variabilities. Mean H value for pinnipeds is 0.019, ranging from 0 in northernelephant seal, Mirounga angustirostris (Bonnell and Selander, 1974) to 0.047 in
ribbon seal, Phoca fasciata (Fujio and Saito, 1986). Wada (1987) calculated H
values for three stocks of fin whale, Balaenoptera physalus, two stocks of sei
whale, B. borealis, five stocks of Bryde's whale, B. edeni, and three stocks ofminke whale, B. acutorostrata, which allowed to calculate the mean values of
H for fin, sei, Bryde's and minke whales as 0.017, 0.021, 0.022 and 0.051,
respectively. Simonsen et al. (1982) reported H = 0.046 for the Atlantic minke
whales. Using these values, the mean H values for four stocks of minke whales
and four baleen whale species have been calculated as 0.050 and 0.028,
respectively.
On toothed whales, Wada (l 983b) reported the H value in striped dolphin,
Stenella coeruleoalba, off the Pacific coast of Japan as 0.021. Shimura andNumachi (1987) calculated H values on 12 species in 11 genera from 4 families,
which ranged from 0 in finless porpoise, Neophocaena phocaenoides, to 0.154 in
Dall's porpoise, Phocoenoides dalli (dalli-type). Winans and Jones (in press) also
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

98

WADA
TABLE 4. SUMMARY OF THE GENETIC VARIABILITY IN MARINE MAMMALS
No. loci
examined

P.95

Seals
Mirounga angustirostrisM.
leonina
Odobenus rosmarus rosmarus
Pagophilus groenlandicus
Cystophora cristata
Pusa hispida
Phoea f asciata
P.
viturina stejnegeriP.
largha

24
18
32
21
21
21
34
34
34

0.000
0.278
0.094*
0.048*
0.048*
0.095*
0.147
0.059
0.059

0.000 Bonnell and Selander (1974)
0.030 McDermid, Ananthakrishnan and Agar (1972)
0.026 Simonsen, Born and Kristensen (1982)
0.007 Simonsen, Allendorf, Eanes and Kapel (1982)
0.009 Simonsen, et al. (1982)
0.009 Simonsen, et al. (1982)
0.047 Fujio and Saito (1986)
0.023 Fujio and Saito (1986)
0.017 Fujio and Saito ( 1986)

Baleen whales
Balaenoptera physalus 1l
B.
borealis 2l
edeni 3lB.
acutorostrata 1l
B.
acutorostrata
B.

45
45
45
45
21

0.138*
0.158*
0.114*
0.207*
0.095*

0.017 Wada(l987)
0.021 Wada (1987)
0.022 Wada (1987)
0.051 Wada (1987)
0. 046 Simonsen, et al. (1982)

Toothed whales
Berardius bairdii
Globicephala macrorhynchus (N. F.)
G.
macrorhynchus ( S.F.)
macrorhynchus ( S.F.)
G.
Peponocephala electra
Pseudorca crassidens
Stenella coeruleoalba
S.
coeruleoalbas.
attenuataTursiops truncatus
Lagenorhynchus obliquidens
Steno bredanensis
Phocoena phocoena
Phocoenoides dalli (dalli-type)dalli (dalli-type)P.
P.
dalli (truei-type)
Neophocaena phocaenoides

18
36
36
19
19
19
15
19
19
19
19
19
18
26
19
19
18

0.056
0.028
0.056
0.263
0.105
0.211
0.130
0.263
0.263
0.105
0.316
0.053
0.167
0.231
0.421
0.474
0.000

0.016 Shimura and Numachi (1987)
0.009 Present study
0.008 Present study
0.054 Shimura and Numachi (1987)
0.035 Shimura and Numachi (1987)
0.051 Shimura and Numachi (1987)
0.021 Wada (1983b)
0.089 Shimura and Numachi (1987)
0.089 Shimura and Numachi (1987)
0.039 Shimura and Numachi (1987)
0.093 Shimura and Numachi (1987)
0.007 Shimura and Numachi (1987)
0.047 Shimura and Numachi (1987)
0.058 Winans and Jones (in press)
0.154 Shimura and Numachi (1987)
0.147 Shimura and Numachi (1987)
0.000 Shimura and Numachi (1987)

SpeciesH

Reference* under the 0.99 criterion
1) mean value for three stocks. 2) mean value for two stocks. 3) mean value for five stocks.
N.F. = the northern form. S.F. = the southern form.

examined other specimens of the latter species from three areas in the North
Pacific and Bering Sea, and calculated H value as 0.058. However, there arelarge differences in the reported values of P.95 and H for S. coeruleoalba, P.
dalli (dalli-type) and G. macrorhynchus between authors (Table 4). However,comparing the common loci only, these studies show very similar results apartfrom a few loci where sample size is small. The mean of the above 17 H values
for 13 toothed whale species (Table 4) is 0.054, which is higher than that for
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GENETICS OF SHORT-FINNED PILOT WHALES

99

pinnipeds (H0.019), baleen whales (H = 0.028) and 184 mammalian
species (H = 0.041; Nevo, Beiles and Ben-Shlomo, 1984).
Selander and Kaufman (1973) suggested that large, mobile animals
generally have lower levels of genetic variability than smaller, less mobile
ones. However, both forms of the short-finned pilot whale showed almost thelowest levels of genetic variability among cetacean species, which were lower
than Baird's beaked (Berardius bairdii), Bryde's, sei and fin whales that have alarger body size thereby a lower level of genetic variability than the pilot
whales is predicted.
Nei (1975) showed the D values to correlate with the systematic distance,i.e., 0-0.058 of interpopulation 'level, 0.004-0.351 (mainly 0.1-0.2) of intersubspecies level and 0.05-2.73 (mainly 0.5-2.0) of interspecies level. However,Avise and Aquadro ( 1982) showed that the degree of genetic differentiationdiffer considerably from species to species, and that the mean D value between
species was 1.75 in amphibia, 0.67 in reptilia, 0.41 in mammalia and 0.08
in Aves.
In cetacea, however, much smaller D values have been reported between
populations. Among five stocks_of Bryde's whale in the Indian and Pacific
Oceans, Wada (1987) obtained D = 0.0029, ranging from 0.0003 to 0.0050.
The D value between two color types of the Dall's porpoise was 0.004 (Shimura
and Numachi, 1987). Andersen (1987) calculated the genetic distance amongnine schools of the long-finned pilot whale, Globicephala melaena, around theFaroe Islands. The largest D value estimated from her gene frequency data
is 0.0032. The D value of 0.0004 calculated in the present study was in thelower range of above values.
Nei and Roychoudhury (1974) and Nei (1978) studied on the sampling
variance of D, and decomposed a total variance into the intralocus andinterlocus variances. The former is due to a restricted number of genes
sampled for each locus, and is almost negligible when the sample size is morethan 50. The latter is due to a restricted number of loci sampled from thegenome. Therefore, the reliability of the estimate of D mainly depends on thenumber of loci or chance of sampling particular loci.
In cetacea examined to date, the most frequent allele at each locus wascommon in all populations within a species except in minke whales. This
yielded a small value of a single-locus distance; the largest ones between
populations were 0.0034 at Me in fin whale, 0.0150 at Ada in short-finned
pilot whale, 0.0211 at Pgm-3 in Dall's porpoise, 0.1164 at Sdh in sei whale and0.1316 at Pgm-1 in Bryde's whale. If a hypothetical Dis calculated between
the two forms of the short-finned pilot whales off Japan assuming an additional
37th locus with a single-locus distance value of 0.15, tenfold of the actuallyobserved value, the estimate of D over all loci increases from 0.0004 to
0.0040. Even under this extreme assumption, the D value is still smaller than
the smallest ones obtained from species comparison; D = 0.026 between
striped dolphin, Stenella coeruleoalba and spotted dolphin, S. attenuata, and D
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

100

WADA

= 0.04 7 between sei and Bryde's whales. From this, I conclude that the extent
of genetic differentiation between the two forms of the short-finned pilot
whale is nothing more than the level of interpopulation. It is quite reasonable
to say that their current taxonomic relationship is the two local forms withina species. This conclusion coincides with the results of the comparative studies
on life history parameters (Kasuya, l 986a) and on morphology and segregation(Kasuya et al., 1987) between the two forms.
ACKNOWLEDGEMENTS

I wish to thank the following three persons: Dr T. Kasuya, who identified thewhales at Ayukawa as northern form, collected tissue samples from them, andread the manuscript critically. Dr N. Miyazaki, who identified the whales at
Taiji in 1984 as southern form and helped me in collecting tissue samples
from them. Miss T. Kohno, who helped me in eletrophoresis.
REFERENCES
ANDERSEN, L. W. 1987. An investigation of the population structure of the long-finned pilot whales,
Globicephala melaena, around the Faroe Islands on basis of isozymes. IWC/SC/39/SM13. 14pp.
Av1sE,]. C. and C. F. AQUADRO, 1982. A comparative summary of genetic distances in the vertebrates. Evol.
Biol., 15: 151-185.
BONNELL, M.L. and R.K. SELANDER, 1974. Elephant seals: genetic variation and near extinction. Science,
184: 908-909.
BREE, P.J.H. VAN, 1971. On Globicephala sieboldii Gray, 1946, and other species of pilot whales. Beaufortia,
19(247): 79-87.
CLAYTON,]. W. and D. N. TRETIAK, 1972. Amine-citrate buffers for pH controls in starch gel electrophoresis.
]. Fish. Res. Bd. Can., 29: 1169-1172.
DANIELSDOTTIR, A. K. and A. ARNASON, 1987. Progress report on the study of genetic variation at enzymeloci in fin whales (Balaenoptera physalus) and sei whales (Balaenoptera borealis). IWC/SC/39/Ba8. 15 pp.
FUJIO, Y. and Y. SAITO, 1986. Population genetics in harbor seal, Phoca vitulina, spotted seal, Phoca largha andribbon seal, Phocafasciata. pp. 195-213. Jn: K. WADA, T. lTo, A. NnzvMA, S. HAYAMA, and M. SUZUKI,(eds.) Ecology and Conservation for Harbor Seals. Tokai Univ. Press, Tokyo. 418 pp. (in Japanese)
HARRIS, H. and D.A. HOPKINSON, 1976. Handbook of Enzyme Electrophoresis in Human Genetics. North-Holland,
Amsterdam.
KASUYA, T. 1986a. Comparison of life history parameters between two stock of short-finned pilot whales
off the Pacific coast of Japan. IWC/SC/38/SMIO. 32 pp.
KAsuYA, T. 1986b. Japanese fisheries exploiting southern form short-finned pilot whales. IWC/SC/38/SM19.
12 PP·KASUYA, T., T. MIYASHITA and F. KASAMATSU, 1988. Segregation of two forms of short-finned pilot whales
off the Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 39: 77-90.
KASUYA, T. and S. TAI, 1986. Operation of Japanese small-type whaling on the short-finned pilot whale off
the northeastern Japan. IWC/SC/38/SM16. 16 pp.
McDERMID, E.M., R. ANANTHAKRISHNAN and N.S. AGAR, 1972. Electrophoretic investigation of plasma andred cell proteins and enzymes of Macquarie Island elephant seals. Anim. Blood Grps. Biochem. Genet.,
3: 85-94.
NEI, M. 1972. Genetic distance between populations. Amer. Natur., 106: 282-292.
NEI, M. 1975. Molecular Population Genetics and Evolution. North-Holland, Amsterdam, 288 pp.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

GENETICS OF SHORT-FINNED PILOT WHALES

101

NE!, M. 1978. Estimation of average heterozygosity and genetic distance from a small number of individuals.
Genetics, 89: 583-590.
NEI, M. and A. K. ROYCHOUDHURY, 1974. Sampling variances of heterozygosity and genetic distance. Genetics,
76: 379-390.
NEvo, E., A. BEILES and R. BEN-SHLOMO, 1984. The evolutionary significance of genetic diversity:
ecological, demographic and life history correlates. pp. 13-213. In: G.S. MANI (ed.) Lecture Notes in
Biomathematics, 53. Springer-Verlag, Berlin. 312 pp.
NuMACHI, K. 1974. Genetic characteristics of fish population. pp. 5-36. In: M. N1smwAKI (ed.) Shigenseibutsuron. Tokyo University Press, Tokyo, 214 pp. (in Japanese).
NuMACHI, K. 1981. A simple method for preservation and scanning of starch gel. Biochem. Genet., 19: 233-236.
NuMACHI, K., S. NAGAHORA and M. lwATA, 1979. Genetic demonstration of hybrids between chum and pinksalmon in the northwest Pacific. Otsuchi Mar. Res. Cent. Rep., 5: 87-102.
SELANDER, R. K. and D. W. KAUFMAN, 1973. Genetic variability and strategies of adaptation in animals. Proc.
Nat. Acad. Sci. USA, 70: 1875-1877.
SIMONSEN, v., F.W. ALLENDORF, W.F. EANES and F.O. KAPEL, 1982. Electrophoretic variation in large
mammals. III. The ringed seal, Pusa hispida, the harp seal, Pagophilus groenlandicus, and the hooded
seal, Cystophora cristata. Hereditas, 97: 87-90.
SIMONSEN, V., E.W. BORN and T. KRISTENSEN, 1982. Electrophoretic variation in large mammals. IV. The
Atlantic walrus, Odobenus rosmarus rosmarus (L.). Hereditas, 97: 91-94.
SIMONSEN, V., F. KAPEL and F. LARSEN, 1982. Electrophoretic variation in the minke whale, Balaenoptera
acutorostrata Lacepede. Rep. int. Whal. Commn, 32: 275-278.
SHIMURA, E. and K. NuMACHI, 1987. Genetic variability and differentiation in the toothed whales. Sci. Rep.
Whales Res. Inst., 38: 141-163.
SOKAL, R.R. and F.J. ROHLF, 1969. Biometry. W. H. FREEMAN and Co., San Francisco. 859 pp.
WADA, S. l 983a. Genetic structure and taxonomic status of minke whales in the coastal waters of Ja pan.
Rep. int. Whal. Commn, 33: 361-363.
WADA, S. l 983b. Genetic heterozygosity in the striped dolphin off Japan. Rep. int. Whal. Commn, 33:
617-619.
WADA, S. 1987. biochemical analyses of genetic differentiation among the populations and species in
Balaenoptera. Doctoral thesis submitted to Faculty of Agriculture, University of Tokyo, 145 pp. (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. JONES (in press). Electrophoretic variability in the Dall's porpoise (Phocoenoides dalli)in the North Pacific Ocean and Bering Sea.]. Mamm.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

RE-EXAMINATION OF LIFE HISTORY PARAMETERS
OF LONG-FINNED PILOT WHALES IN
THE NEWFOUNDLAND WATERS*TOSHIO KASUYA**, DAVID E. SERGEANT*** AND KENJI TANAKA****
ABSTRACTAge dependent life history parameters of the long-finned pilot whale
were analyzed using recent technique of aging which allowed accurate age
estimate for old individuals and materials taken in 1954 from the drive
fishery off Newfoundland and once used by Sergeant (1962). In both sexes
mean growth ceases at ages between 21 and 25 years, when natural mortality increases. Males live to age 36 years or about 10 years shorter thanfemales. Natural mortality is dependent on age in both sexes, and malemortality exceeds that of females of the same age, thus causing age related
decline of male proportion in the population. Pregnancy rate is notapparently dependent on age of females and the possibility of a large
proportion of postreproductive females is rejected, which is different fromfeature known on the short-finned pilot whale. Additionally, long-finned
pilot whales differ from short-finned pilot whales in the younger age atmaturation, shorter longevity and higher proportion of adult males,suggesting less specialized reproductive strategy and difference in thesocial structure.
INTRODUCTION

A study on life history and reproductive biology of the long-finned pilot
whale, Globicephala melaena (Traill, 1809), was published by Sergeant (1962)
using materials obtained from the drive fishery off Newfoundland. This was
the first delphinid biology based on reliable age determination. However, as
recognized by himself, the age of older individuals tended to be under
estimated due to the decrease of readability of dentine layers or cessation of
the deposition at an age between 8 and 16 years, and reliable life history
parameters were not available for older individuals. Recent study of Martin(1987) on long-finned pilot whales mass stranded on the British coast probably retained similar problem (IWC, 1987).
• Early version of this manuscript was submitted to the 38th annual meeting of the Scientific Committee of theInternational Whaling Commission in Bournmouth in May 1986 with document no. IWCISC/38/SMll•• Far Seas Fisheries Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan••• Arctic Biological Station, 555 St. Pierre Blvd. Ste. Anne de Bellevue, Quebec, H9X 2W1 Canada•••• Faculty of Oceanography, Takai University, 3-20-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan
Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 103-119

104

KASUYA, SERGEANT AND TANAKA

After Sergeant (1962), there was a progress in age determination
technique of toothed whales (Perrin and Myrick, 1981), and Kasuya andMatsui (1984) established age determination method for the short-finned
pilot whale, G. macrorhynchus Gray, 1846, using annual growth layers in dentine
and cementum apparent in decalcified and haematoxylin stained longitudinal
section of the tooth. Based on this aging technique, Kasuya and Marsh (1984),
Marsh and Kasuya ( 1984) and Kasuya ( 1986) analyzed the life history andreproductive biology of short-finned pilot whales taken by the drive fishery or
small-type whaling with harpoon gun off the Pacific coast of Japan. Thesestudies showed that the short-finned pilot whale exhibits a large longevity
difference between males (46 years) and females (63 years), age dependentchange in the pregnancy rate, and post-reproductive life time of females
extending over 20 years. Marsh and Kasuya (1986) indicated further need to
examine the presence of postreproductive females in g. melaena.
We reanalyzed in the present study some of the life history parameters of
the long-finned pilot whale using materials of Sergeant (1962) and age determination method of Kasuya and Matsui (1984), and compared them with theresults of short-finned pilot whales off Japan to find difference of the reproductive strategy between the two pilot whale species.
MATERIALS AND METHODSThis study is based on teeth of 437 long-finned pilot whales obtained fromthe drive fishery off Newfoundland and some accompanying biological data
(Table 1). They were collected in June to October 1954 and were the major
portion of the materials used by Sergeant ( 1962) for the study of age andgrowth. The teeth had been preserved in glycerin with a tag having specimen
number, body length (measured to a nearest inch), sex and date on it.
Information was not available for male maturity. The reproductive status
data of females (usually pregnancy and lactation only) were available for some
limitted number of individuals. Although these data did not seem to be biased
to certain body length classes (Fig. 2), our data contained high proportion of
females of unknown reproductive status and very low number of restingfemales (adult females neither pregnant nor lactating), the former being close
to the sum of the females in pregnancy or in lactation, and the latter amounts
only 16% of the pregnant females (Table 2). This was because only females
which were obviously pregnant or lactating were fully recorded and mature
females of another reproductive status (resting) were underrecorded in thesample (Sergeant, 1962: p.56). Therefore mature females of unknown reproductive status were more likely to be in the resting status rather than pregnant
or lactating.
The teeth had been cut transversely near the cingulum for the previous
age determination. For the present age determination, we usually used only
the root portion of the tooth. The crown side of old individuals did not usually
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

105

LONG-FINNED PILOT WHALESTABLE 1. MATERIALS USED IN THE PRESENT STUDY

Sex

Month*

With ageandbody lengthWith age
but without
body length**

Male

July
August
Sept.
Oct.
Total
July
August
Sept.
Total

43
101
8
0
152
67
200
8
275

0
1
0
0

Female

1
6
2
9

Total

43
102
8
0
153
68
206
10
284

* All the materials were collected in 1954.

** Used for only age composition and age dependent sex ratio analysis.

have the most recent layers due to sawing off. The few exceptions were for 0
to 2 years old young tooth where the crown side of the tooth was used because
the root was too short and thin. Either root or crown portion of the tooth was
firstly rinsed in running water for one to two nights to remove the glycerin,
longitudinally half sectioned, glued on a plastic plate, polished to a thicknessof about 30 to 40 µ,m, decalcified in 5% formic acid for several hours, stainedwith Mayer's haematoxylin and mounted with Canadian balsam (Kasuya andMatsui, 1984).
Kasuya aged all the individuals without referring to any data of thespecimen (including the date of sampling) and using method of Kasuya andMatsui (1984) outlined below:(1) To have three independent counts for both cementum and dentine.
(2) To choose the middle figure as the best for each tissue.
(3) To use the best dentinal count if the pulp cavity is wide and the deposition of dentine was considered to be continuing on the entire
pulp wall (open pulp cavity) or on part of the wall (closing one), or to
use the best cemental count if the pulp cavity was narrow and linedby thin uniformly stainable dentine suggesting cease of the deposition (closed pulp cavity).
(4) A pair of stainable and unstainable layer was assumed to represent
one year as deduced by Sergeant (1962), and any age between n and
n+l year was expressed by n+0.5 (n being an integer).
After aging all the individuals, the body length was plotted on age, andfive individuals (two females and three males, see Figs 3 and 4) were found in
the body length/age relationship to be apart from rest of the individuals.
These individuals were excluded from the subsequent analyses, but ages ofrest of the individuals were accepted as they stand (including 10 individuals
having no body length data).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

106

KASUYA, SERGEANT AND TANAKA

Males• OpenoIii,/

Femalesc

Closing• Closed

20

:;::;

~ 30

cloo

"'C

•

/.

• 0/0

.....

• •o/ •• ••• • .:Cl.I

o o..f ~

.D 20

E

• • •
o "" •
eo •ce

~

o.

:I

0

z

o

-

o

o ./o~

a.I..::..

• .t• ..

•

•

•

•

•

•

.

•
•

•

•

•

• o
o

-5(••

:-:;/:"~

.~7-=

.

,..
:.;,t.-

10.. 9/•... 6"•.

• g'
•• 7"

-· ./{
10

20

30

40

50

Number of cementa! growth layers
Fig. I. Scatter plot of number of dentinal growth layers on that of cementa! layers inthe same tooth slide. Symbols distinguish the condition of pulp cavity. Numerals
represent the number of individuals having open pulp cavity, and each of othermark represents one individual. The solid line represent equal deposition of layers
in both issues.

RESULTS

Comparison between dentinal and cemental layer counts
Fig. 1 compares the number of growth layers in cementum and that in
dentine of the same teeth. Since these tooth had been cut transversely toremove a piece of thin section for the previous age determination (Sergeant,1962), we could not confirm on most of the present preparations if all thecementa! or postnatal dentine layers were present (neonatal line in dentine
could be identified only on the slide of juveniles prepared from the crownportion of the tooth). Although this did not necessarily imply loss of the first
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

LONG-FINNED PILOT WHALES

107

postnatal growth layer in either of the tissues, we were uncertain on tooth
showing disagreement of counts in the two tissues if it came from the error ofreading or from the deficit of the preparation. The readability of cemental
and dentinal layers was slightly inferior to that of the short-finned pilot
whales studied by Kasuya (1986) and Kasuya and Matsui (1984).
Admitting possible minor disagreement expected from the above deficit,
we considered that growth layer counts in the two different tissues in a toothslide were similar on most of the teeth having open or closing pulp cavity, but
the correlation was lost on teeth with closed pulp cavity. The number of
cemental layers exceeded that of the dentinal layers after ages between 15 to
20 years, and the magnitude of the disagreement increased with increasingage (Fig. 1).
We conclude therefore that growth layers in the two dental tissues aredeposited at a same rate on young individuals, but on older individuals only
the cemental layers continue deposition. And we assumed without direct
evidence that the rate of cemental layer deposition stays same (annual) for theentire lifetime after the start of its deposition in early postnatal time (Kasuya
and Matsui, 1984).
Body length composition and neonatal length
Body lengths of the 152 males ranged between the half-foot length
groups of 5.5-6.0 feet (l.68-l.83m) and 19.5-20.0 feet (5.94-6.lOm) (Fig. 2).
A peak of large individuals was present between 17 .5 and 19.0 feet (5.33 to
5.79m)
Body lengths of the 275 females were found between length groups of
6.0-6.5 feet (l.83-l.98m) and 16.0-16.5 feet (4.88-5.03m). A peak of larger
individuals was present at lengths between 14.0 and 15.0 feet (4.27 to 4.57m),
which was about 1 m smaller than that of the male. These features are similar
to the body length frequencies presented by Sergeant (1962).
We had five (three female and two male) postnatal individuals having no
neonatal layer in dentine, an indication of newborn calves (Kasuya andMarsh, 1984). Their body lengths were 175 and 198cm in males, and 173,
183, and 183cm in females (Figs 3 and 4). Mean of the five body lengths was
182.4cm. The range was nearly within the range of neonatal lengths of both
sexes (165 to 191 cm) reported by Sergeant (1962), and the mean was close to
the mean neonatal lengths (174 cm in females and 178 cm in males) estimatedby him. We found no reason to change the neonatal length estimate ofSergeant (1962).
Male growth
The correlation between body length and age was very good before age
20 years, with most of the plots within the range of 70 cm, but it was apparently lost after an age between 21 and 25 years (Fig. 3). The male growth is
rapid till the age of 2.5 years, or the body length of 2.7 to 3.3 m. After thisSci. Rep. Whales Res. Inst.,
No. 39, 1988

108

KASUYA, SERGEANT AND TANAKA
2
20

3

5

/,

6

Males

15
10
5
0
5

1!!.

r1J
:J

:2
>

'ii
c

0
.....
Cl.I

0
10
5
0
20
15

.0

E 10

:J

z

5
0
5
0
20

Unknown

15
10
5
0

5

10

15

20

Body length in feetFig. 2 Body length frequency of materials used in the present study. Scale at the top
indicates body length in meter.

age, males grew at a slower but almost constant rate till the age of about 20
years. The inconspicuous secondary growth spurt probably started at about
12-13 years.
Although the mean body length seemed to stop increasing at an age
between 21 and 25 years, and the mean body length of males over 25 years
was 557 cm (n=5), we were unable to consider this figure as a reliable estimate of the mean asymptotic length of males due to the small sample size
(Appendix Table 1).
The age at the start of secondary growth spurt (12-13 years) probably
corresponds to the mean age at the attainment of breeding maturity 12 years
estimated by Sergeant ( 1962). Due to the lack of adequate number of samples
on age and maturity, Sergeant (1962) firstly estimated the mean age of breeding maturity (12 years) from a limited number of samples with good age
estimate, then he read the mean body length of 4.88 mat breeding maturity
on his mean growth curve corresponding to the age at the attainment of
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

109

LONG-FINNED PILOT WHALES
6
(•)

..
I•

.: .
E
c

A•

••I•

-

£. 4
OI

I•
y

c

~
:>.

(•)

u

0

(•)

ID

. ~:
t'
I

0

10

20

30

40

Age in years
Fig. 3. Scatter plot of body length on age, males. Each mark represents one individual. Marks in parentheses indicate ages that were not used in the present
alalyses.

breeding maturity. If the same method was adopted to the growth curve
constructed in the present study, males were estimated to attain the length of
4.3 to 4.9 m at the mean age of breeding maturity (12 years). The middle
value of this range, 4.6 m, was about 30 cm smaller than the estimate ofSergeant (1962). We consider that the difference is significant in view of thenarrow individual variation of body length (see above).
This disagreement probably came from the overestimation of malegrowth by Sergeant ( 1962) due to the underestimation of age of many individuals over 8 to 16 years. Therefore, the present estimate of 4.6 m can be abetter estimate of the mean male length at age 12 years (age at breeding
maturity estimated by Sergeant (1962)). However, in view of slow and complicated procedure of maturation of males of the short-finned pilot whale(Kasuya and Marsh, 1984) and rather limited number of samples available forthe long-finned pilot whale study (Sergeant, 1962), we feel that parameters
relating to male maturity of the latter species require further investigation.
Female growth curve
Female body length increased almost at the same rate as that of theSci. Rep. Whales Res. Inst.,
No. 39, 1988

110

KASUYA, SERGEANT AND TANAKA.. .. ... ··i. :.
:

..

., .

•.

·.··i
. ........
• . • ?:=:.•··
. I
:• •.

fll

•

Me

•

• •
• • .f • • • •··-·1•.:.·.
:! , ....

I •

E 4

•

,.

.

-=' j -· .

• ; .i. .•. .

c~~r?l·~·
i ~i

>i 3
-0
0

: ....
T

CD•:Matureo: Immature•:Unknown
(•)

0

10

20

30

40

50

60

Age in years
Fig. 4 Scatter plot of body length on age, females. Each mark represents one individual. Marks in parentheses indicate ages that were not used in the present
analyses.

males till the age of 6 years (mean age of females at sexual maturity, see
below) as indicated by Sergeant ( 1962) (Fig. 4), then the growth rate declined
rapidly with increasing age, and the mean body length apparently ceased toincrease at an age between 21 and 25 years. The mean body length of females
over 25 years was 488.8cm (n=53, sd= 18.6). This is the mean asymptotic
length of females of this population.
Both mature and immature females were present at the body lengths
between 11.0 and 13.0 feet (3.35 and 3.96m), and at the ages between 4 and 8
years (Figs 4 and 5). These ranges did not differ from corresponding figures
estimated by Sergeant (1962). His estimation of the mean age and bodylength of females at the attainment of sexual maturity were 6 years and 12
feet (3.66m), respectively.
Age related change in female reproductive activity
Three resting females identified as senile by Sergeant ( 1962) were agedby us at 22.5, 30.5, and 41.5 years, and they were not always old. Marsh andKasuya ( 1984) indicated the difficulty of identifying postreproductive females
by macroscopic observation of ovaries. The oldest females of the present
study at the pregnant, lactating, or resting status were aged at 39.5, 39.5 and41.5 years, respectively (Fig. 5), which were close each other. Ages of three
resting femals having corpus luteum of ovulation were 4.5, 24.5, and 25.5
years, and the age of a lactating female having corpus luteum of ovulation
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

111

LONG-FINNED PILOT WHALES

Males

20
15
10
I/)

Iii

:J
"'O

>
"'O

.£

5
5
Immature

05Prngnant

0

.....

0

Cll

Lactating

.D

E 5
:J

z

0
5

Resting0
Unknown

10

5

10

20

30

40

50

Age in years
Fig. 5. Age composition and reproductive status of the long-finned pilot whale sample. White square at the bottom indicates sum of the females of known reproductive status.

was 31.5 years. These ages are younger than that of the oldest confirmed
pregnancy.
Table 2 lists two kinds of pregnancy rates; (1) proportion of pregnant
females in sexually mature females of known reproductive status, and (2)proportion of pregnant females in all the females including both immatureand unknown reproductive status. Since females of unknown reproductive
status in our sample probably tended to include more resting females thanthe pregnant or lactating ones (see above), the former figure will overestimatelevel of the apparent pregnancy rate of the sample, and this underrepresent,
if it exists, the age dependent decline in the pregnancy rate. To the contrary,
the latter will underestimate the apparent pregnancy rate (the degree of
which will depend on the number of pregnant females classified to the unknown category), but will better reflect the age dependent change in the
pregnancy rate if it exists.
None of the two pregnancy rate series in Table 2 showed significant age
dependent change (Chi-square tests for ages over 10 years, p > 0.5). Thus, wewere unable to conclude that the females of long-finned pilot whales off
Newfoundland exhibit age dependent decline of reproductive activity, which
was very distinct in the short-finned pilot whale populations off Japan andSci. Rep. Whales Res. Inst.,
No. 39, 1988

112

KASUYA, SERGEANT AND TANAKATABLE 2. AGE DEPENDENT CHANGE IN APPARENT PREGNANCY RATE INGLOBICEPHALA MELAENA.
Age(years)Immatu re

0-10
10-20
20-30
30-40
40-50
50-60
Total

No.
data

Pregnancy rate(%) **
(1)

(2)

1
0

15
55
36
16
1
0

75
28
20
10
4

53.3
30.9
38.9
37.5
0

8.8
20.5
25.0
23.l
0
0

7

123

138

36.6

16.5

Mature*
p

L

11
0
0
0
0
0

8
17
14
6
0
0

6
37
19
9
0
0

11

45

71

R

3

T

• P=pregnant, L=lactating, R=resting, T=total.
** (1) indicates proportion of pregnant females in mature females of known reproductive status, and (2)that in total females including females of immature and unknown maturity.

was an indication of the presence of postreproductive females (Kasuya andMarsh, 1984; Marsh and Kasuya, 1984; Kasuya, 1986).
The uncertainty that surrounds above analysis comes from the adultfemales of unknown reproductive status. If a 39.5 years old pregnant female
is excluded, then all the 18 females over 33.5 years are non-pregnant or of
unknown reproductive status (Appendix Table 2). Females of the latter category has high probability of not being pregnant, and might leave a possibility
for postreproductive females. However, even under extreme assumption thatthey were all in the resting status, the number of pregnant females in the total
females over 35 years (1/15) was not significantly different from that at 10-35
years (36/119) (Chi-square test, 0.2>p>O.l), making it impossible to conclude
the presence of significant number of postreproductive females in the population.
From the above analyses we conclude that the population of long-finned
pilot whales has high reproductive capacity till the observed oldest age,although a larger sample may perhaps prove the presence of some postreproductive females among old females.
Sex ratio, age composition and mortality rate
The proportion of females in the sample increased from parity at ages
below 10 years to 100% at age over 36 years (Table 3 and Appendix Table 2),
or about 5 years earlier than the corresponding age for the short-finned pilot
whale populations off Japan (Kasuya and Marsh, 1984; Kasuya, 1986). The
decline of male proportion with increasing age will reflect the sexual difference of mortality rates and longevity (see below).
Sergeant ( 1962), using cementum age of limited number of selected individuals, showed that males lived to age of only 36 to 40 years while females
did to age of 46 to 50 years. Ages of the oldest individuals of the present
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

113

LONG-FINNED PILOT WHALESTABLE 3. AGE RELATED CHANGE OF THE SEX RATIO INGLOBICEPHALA MELAENA.
Age(years)No. females

0- 5
5-10
10-15
15-20
20-25
25-30
30-35
35-40
40-45
45-50
50-55
55-60

55
51
46
44
34
22
16
10
5
0
0

Total

284

No. males

Total

Females
(%)

56
37
23
19
13
2
2
I

0
0
0
0
153

Ill

88
69
63
47
24
18
11
5
0
0

49.5
58.0
66.7
69.8
72.3
91.7
88.9
90.9
100.0

100.0
437

65.0

material were 35.5 years in males and 56.5 years in females. However, the ageof the oldest female seemed to be an outlier, and the ages of the next oldest
male and female were 33.5 and 42.5 years, respectively (Appendix Table 2).
Thus reasonable longevity difference between sexes of the long-finned pilot
whale will be about 10 years as suggested by Sergeant ( 1962).
Age frequencies plotted on a logarithmic scale (Fig. 6) showed an apparent gradient change in both sexes at an age between 21 and 25 years. Additionally, there was observed in the male age composition a slight depression atages between 8 and 17 years or at the age of puberty, suggesting a possible
segregation of some pubertal males from the breeding schools. The similarfeature was indicated for short-finned pilot whales off Japan (Kasuya andMarsh, 1984).
Ignoring the slight underrepresentation of pubertal males indicatedabove, we estimated the apparent annual mortality rate of males as about 0.07
at ages below 25 years (Table 4). The corresponding figure for ages between
21 and 36 years (the oldest male age) was calculated to be about 0.15 using
very limited number of samples. For females, we estimated the corresponding
figure of the mortality rates to be slightly over 0.02 (< 25 years) and about 0.1(from 21 to the oldest individual). The male apparent mortalities are always
higher than that of the females of the same age, as observed on the short-finned
pilot whale off Japan (Kasuya and Marsh, 1984; Kasuya, 1986).
DISCUSSION

We re-examined several biological parameters of long-finned pilot whales off
the Newfoundland waters using materials once used by Sergeant (1962) and
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

114

KASUYA, SERGEANT AND TANAKA
30r-~~~~~~~~~~~~~~~~--,

Males

20
10

5

3
2
1.___~'---~'---~'---~'---~'---~+--~'---~+--~
40
30
0
10
20

Age in years
Fig. 6. Age frequency of long-finned pilot whale samples plotted on logarithmic
scale. Straight line indicate linear regression of the frequency on age (see Table 4).

recently improved age determination method, which could give higher ages
for many of individuals aged over 10 years by the previous method of aging
using only dentinal layers. Among biological parameters examined, we foundno reason to alter the previous estimate of Sergeant ( 1962) on neonatal bodylength, longevity, female age at the attainment of sexual maturity, andjuvenile sex ratio. The growth curves of both sexes were altered slightly, andthe mean asymptotic length of females and the age at the length were newly
estimated in the present study.
In particular, we obtained new estimate of age composition of the catchand biological parameters derived from it. These allowed us to compare somelife history parameters of long-finned pilot whales in the Newfoundlandwaters and those of short-finned pilot whales off Japan studied by Kasuya andMarsh (1984), Marsh and Kasuya (1984) and Kasuya (1986).
Apparent mortality rates calculated above are sums of natural mortality
rate, fishing mortality rate and annual change in recruitment. Effect of thefishery on the latter two components is probably significant in the populationof long-finned pilot whales, which had long history of hunting of relatively
small scale (probably less than 500 individuals per year) by highly selective
harpoon fishery and 3 years large scale harvest just prior to the commencement of present sampling (about 3,000 individuals per year) by less selective
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

115

LONG-FINNED PILOT WHALESTABLE 4. APPARENT ANNUAL MORTALITY RATES OF GLOBICEPHALA MELAENAESTIMATED FROM AGE COMPOSITION.
MethodFemaleMale

0-25 years
21-43 years
21-57 years
0-25 years
21-36 years

AB

0.0231
0.06960.0201 ±0.0090
0.0682 ±0.0160
0.0985 ±0.0122
0.0716 ±0.0115
0.1497 ±0.0507

0.0683

A: From the gradient of the linear regression in Fig. 6.
B: By segment analysis (Robson and Champman, 1961), best point estimate and standard error.

(Kasuya and Marsh, 1984) drive fishery (Sergeant, 1953; 1962; Mercer,1975).
We consider that the drive fishery could have decreased absolute numberof recruitment in the last 2 years preceding the sampling, but did not cause
severe change in the age composition of older individuals. Thus we feel thatthe present age composition data are not suitable for the analysis of age dependent change in juvenile mortality rate.
To the contrary, the history of harpoon fishery over 7 years could haveselectively killed larger individuals and changed the age composition and sex
ratio of older individuals as observed on the short-finned pilot whales off
Japan (Kasuya and Marsh, 1984). This causes difficulty to make meaningfulcomparison of apparent age dependent mortality rates between sexes. However, we consider that the present sample size is probably large enough togive a rough estimate of the maximum age which is allowed physiologicallyfor the species, and that our finding of the shorter longevity of males allows
our deduction of above result that males will have natural mortality rate
exceeding that of the females of same age.
Ages of the oldest individuals in the sample of long-finned pilot whales
were younger than those of short-finned pilot whale populations off Japan by
6 (including an outlier) or 20 years (excluding an outlier) in females or by 10
years in males, and were close to those of less specialized delphinid species
such as striped dolphin, Stenella coeruleoalba, and spotted dolphin, S. attenuata,studied by Kasuya (1985). The difference of longevity between the two pilot
whale species was in parallel with that of the age at sexual maturity (G.
melaena of shorter life matures younger). Although reliable estimates ofnatural mortality rate are not available for either of the two pilot whale
species, above longevity difference suggests a higher natural mortality of thelong-finned pilot whale.
Although there remains a possibility that a larger sample may find somepostreproductive females in old age classes, we have been unable to confirm
age dependent decline of pregnancy rate in the long-finned pilot whale. This
is in clear contrast with the life history observed on the short-finned pilot
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

116

KASUYA, SERGEANT AND TANAKA

whale populations off Ja pan, where the confirmed pregnancy occurred below
age of 36 years and lactation below 51 years while females lived for 63 years,
and additionally their pregnancy rate declined with increasing age for all theage range over 8 years (Kasuya and Marsh, 1984; Marsh and Kasuya, 1984;
Kasuya, 1986). We conclude therefore that female long-finned pilot whales
have a shorter lifespan and breed till older age at a more constant rate than
the short-finned pilot whale. We do not have data to compare the absoluteannual pregnancy rates of the two species. Not denying the possibility that theabove features of reproduction of long-finned pilot whale could have beenenhanced in some degree by the continued expolitation, we suggest that thedifferences indicated between the two pilot whale species are principally
species specific.
In a short-finned pilot whale population off Japan, individuals become
reproductive at the mean ages of 9 years (female) and 17 years (male), andthe sex ratio of adult individuals is 0.27 (adult males/adult females) (Kasuya
and Marsh, 1984). In the population oflong-finned pilot whales, males mature
at a lower age (probably at 12 years) relative to the age of female maturity (6years), and the natural mortality rate of both sexes appear to increase at asimilar age (21-25 years) while there is large difference in the short-finned
pilot whale off Japan (28 years in males and 46 years in females). These resulted in the higher adult male ratio of 153/220=0.70 (estimated from the age
composition), which is closer to those of more generalized delphinids, e.g.
0.77 of Stenella attenuata (Perrin, Coe and Zweifel, 1976), 0.91 of S. longirostris(Perrin, Holts and Miller, 1977) and 1.1 (=1278/1191) of S. coeruleoalba(Miyazaki and Nishiwaki, 1978)
Above analyses indicate that the long-finned pilot whale has life history
parameters which are apparently less specialized than those of the shortfinned pilot whale, and that its reproductive strategy and social structure will
not be the same with those of the short-finned pilot whale. The cohesive
matrilineal school structure and long maternal care of the latter species(Kasuya and Marsh, 1984) may not be so pronounced in the long-finned pilot
whale population off Newfoundland.
ACKNOWLEDGEMENTS

We thank Dr S. Ohsumi for reviewing manuscript, and Mr T. Miyashita andMrs M. Ikeya for the help in statistics and drawings.
REFERENCES
IWC, 1987. Report of the sub-committee on small cetaceans. Rep. int. Whal. Commn, 37: 121-128.
KsuvA, T., 1985. Effect of exploitation on reproductive parameters of the spotted and striped dolphins off
the Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 36: 107-138.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

LONG-FINNED PILOT WHALES

117

KsuvA, T., 1986. Comparison of life history parameters between two stocks of short-finned pilot whales off
the Pacific coast of Japan. IWC/SC38/SMIO. 32 pp.
KASUYA, T. and H. MARSH, 1984. Life history and reproductive biology of the short-finned pilot whale,
Globicephala macrorhynchus, off the Pacific coast of Japan. Rep. int. Whal. Commn (special issue 6):259-310.
KASUYA, T. and S. MATSUI, 1984. Age determination and growth of the short-finned pilot whale off the
Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 35: 57-91.
MARSH, H. and T. KASUYA, 1984. Change in the ovaries of the short-finned pilot whale, Globicephalamacrorhynchus, with age and reproductive activity. Rep. Int. Whal. Commn (special issue 6): 311-335.
MARSH, H. and T. KASUYA, 1986. Evidence for reproductive senescence in female cetaceans. Rep. int. Whal.
Commn (special issue 8): 57 - 74.
MARTIN, A. R., P. REJTBIKDS and M. G. RICHARDSON, 1987. Aspect of the biology of pilot whale (Globicephalamelaena) in recent mass strandings on the British coast.]. Zool., Land., 211: 11-23.
MERCER, M. C., 197 5. Modified Leslie-DeLury population models of the long-finned pilot whale (Globicephalamelaena) and the annual production of the short-finned squid (Illex illecebrosus) based upon their interaction at Newfoundland.]. Fish. Res. Bd Can., 32 (7): 1145-1154.
MIYAZAKI, N. and M. NISHIWAKI, 1978. School structure of the striped dolphin off the Pacific coast ofJapan. Sci. Rep. Whales. Res. Inst., 30: 65-115.
PERRIN, W. F., J.M. COE and J. R. ZWEIFEL, 1975. Growth and reproduction of the spotted porpoise, Stenella
attenuata, in the offshore eastern tropical Pacific. Fish. Bull., 74(2): 229-269.
PERRIN, W.F., D.B. HoLTs and R.B. MILLAR, 1977. Growth and reproduction of the eastern spinner
dolphin, a geographical from of Stenella longirostris in the eastern tropical Pacific. Fish. Bull., 75(4):725-750.
PERRIN, W. F. and A. C. MYRICKJR (eds), 1981. Age determination of toothed whales and sirenians. Rep. int.
Whal. Commn (special issue 3). 229 pp.
ROBSON, D.C. and D.G. CHAPMAN, 1961. Catch curves and mortality rates. trans. Am. Fish. Soc., 90: 181-189.
SERGEANT, D.E., 1953. Whaling in Newfoundland and Labrador waters. Norsk Hvalfangst-Tid., 12: 687-695.
SEGREANT, D. E., 1962. The biology of the pilot or pothead whale Globicephala melaena (Traill) in Newfoundland waters. Bull. Fish. Res. Bd. Can., 132: 1-84 +I-VII.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

118

KASUYA, SERGEANT AND TANAKAAPPENDIX TABLE 1. AGE-LENGTH KEY OF GLOBICEPHALA MELAENA (CM).
Age(years)
0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
11.5
12.5
13.5
14.5
15.5
16.5
17.5
18.5
19.5
20.5
21.5
22.5
23.5
24.5
2'.25.5

safliples
4
13
23
9
7
10
13
7
2
5
4
2
6
4
6
4
5
5
3
2
3
4
1
4
5

Males
mean
207.8
264.3
303.0
319.7
332.9
360.1
387.7
393.l
405.0
416.8
425.0
471.5
448.3
474.3
481.8
495.3
508.2
544.4
559.3
553.5
560.3
554.0
561.0
582.3
556.0
557.2

sd

no.
samples

23.0
11.4
17.<:J
12.3
10.6
15.0
17.9
11.7
14.0
26.9
6.3
6.5
12.1
22.8
23.0
41.8
16. l
19.7
4.7
15.5
13.8
15.6

10
11
8
10
15
8
4
14
13
9
10
10
8
9
5
6
14
12
7
4
6
5
9
4
10
53

15.8
19.8

Females
mean

sd

199.3
270.6
302.0
327.1
333.5
358.9
376.5
379.5
398.4
389.4
401.1
422.2
421.9
413.4
415.0
426.2
436.4
435.9
441.7
434.5
445.3
464.6
451.2
444.0
444.8
448.8

21.4
16.7
15.4
11.9
17.9
14.5
19.4
19.4
22.2
11.2
11.0
21.9
18.4
12.3
18.0
17.2
21.4
18.0
13.6
16.5
13.3
18.3
18.0
12.3
18.9
18.6

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

119

LONG-FINNED PILOT WHALESAPPENDIX TABLE 2. AGE AND REPRODUCTIVE STATUS OF GLOBICEPHALA MELAENA.
Age(year)

immat.
preg.

0.5
1.5
2.5
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
11.5
12.5
13.5
14.5
I5.5
16.5
17.5
18.5
19.5
20.5
21.5
22.5
23.5
24.5
25.5
26.5
27.5
28.5
29.5
30.5
31.5
32.5
33.5
34.5
35.5
36.5
37.5
38.5
39.5
40.5
41.5
42.5
56.5
Total

Femalesmature
!act.
rest.

4

2
2
2

I*

3
3
2
I
2
3
3
3
2

I
2
I
3
2
3

I
2
3
3
5
5
6
4
6
4
4
2
2
I**
4

6
II
9
8
11
7
3
8
10
6
8
4

10
II
9
10
15
9
4
14
13
11
12
II
9
9
5
6
14
12
8
4
6
5
9
4
10
2
3
6
7
4
3
6
3

I
2
6
7
3
3
2
2
4
2
2

2*

I
2

2
2

I**
I
3

total

l
2
3
2
I
3

4
3

2

11

46

71

• Includes one female having corpus luteum of ovulation.
** Classified as "senile" by Sergeant (1962).

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

l*
l*

Males
unknown

4
I3
23
9
7
10
I3
7
2
5
4
2
6
4
7
4
5
5
3
2
3
4
4

2

3
4

4
I**

I
2

3

7

l
I49

I
284

153

DISTRIBUTION AND ABUNDANCE OF
DALL'S PORPOISES OFF JAPAN*

TOMIO MIYASHITA** AND TOSHIO KASUYA**ABSTRACT

Results of nine whale sighting cruises in the Japanese coastal waters in1983 through 1986 and some additional cruises provided following
conclusion. Dall's porpoises inhabit waters below 24°C, but the upper
temperature limit is lower in winter: Dalli-type individuals occur throughout the range of the species, but the majority of them winter in the Sea ofJapan, and summer in the Okhotsk Sea and Pacific coast of Japan. Trueitype individuals inhabit only waters off the Pacific coast of northern Japanand southern Kuril Islands. They winter off the Pacific coast of Japan, andsummer mainly in the waters between 40° and 45°N and west of I 55°E. A
minimum estimate of the number of dalli-type that winter in the eastern
Sea of Japan is about 46,000 individuals, of these about 15,000 migrate
through the Tsugaru Strait to the Pacific coast of Japan with the major
portion of the stock summering in the Okhotsk Sea and northern Sea ofJapan. The number of truei-types in the nearshore surveyed area is estimated at about 26,000, and the extraporation of the density to the offshore
range of the .type provides an estimation of total truei-type population of
about 58,000 individuals. The continuation of current Japanese harpoon
fishery will further deplete the stock(s) of Dall's porpoises.
INTRODUCTION

The Dall's porpoise, Phocoenoides dalli (True, 1885), includes two major color
morphs designated as dalli-type and truei-type (Houck, 1976; Kasuya, 1978),the former being mainly distributed in the cold waters of the North Pacificand the latter in a limited area of the northwestern North Pacific (Nishiwaki,
1972; Ohsumi, 1975; Kasuya, 1978, 1982). Considering distribution of thesecolor types and their seasonal movement, Kasuya (1978) suggested thepresence of at least three local stocks of the Dall's porpoise in the north western
North Pacific and the adjacent seas, i.e. I) off the Pacific coast of northern
Japan and southern Kuril Islands, 2) offshore northwestern North Pacific and
the Bering Sea, and 3) in the Sea ofJapan and the Okhotsk Sea. He considered* An earlier version of this manuscript was submitted to the Scientific Committee of the International Whaling
Commission, Bournemouth, June 1987 (Document no. SC/39/SMI 1).

** Far Seas Fisherifs Research Laboratory, 5-7-1, Orido, Shimizu-ski, Shizuoka-ken, 424 Japan
Sci. Rep. Whales Res. Inst.,
No.39,1988,121-150

122

MIY AS HITA AND KASUY A

that all the dalli-type individuals in the truei-type range off the Pacific coast ofJapan would not be the members of Japanese east coast stock, but that at least
some of them, especially those in the schools containing no truei-types, would
be migrants from the offshore stock in the northwestern North Pacific and
the Bering Sea or from the Sea of Japan-Okhotsk Sea stock. A similar view
was presented by Miyazaki and Fujise (1985).
Recent data on the distribution of mother-calf pairs, parasite load, electrophoretic analysis of isoenzymes and pollutant levels in Dall's porpoisesuggest that the hypothetical stock of Kasuya ( 1978) in the north western
North Pacific and the Bering Sea probably includes two or more stocks, each
breeding in the Bering Sea, south of the western Aleutian Islands, and perhaps
off the east coast of northern Kuril Islands, respectively (Kasuya and Ogi,
1987; Subramanian, Tanabe, Fujise and Tatsukawa, 1986; Walker, 1987;
Winans and Jones, in press). Additionally, Yoshioka, Ogura and Shikano( 1987) presented data suggesting another apparently isolated breeding
ground in the Gulf of Alaska.
Subramanian, Tanabe, Fujise and Tatsukawa (1986) found that the PCB/
DDE ratio in the dalli-types taken in summer off the Pacific coast of Hokkaido
was closer to those in the Sea of Japan than the truei-types in the same region,and considered that the dalli-types in the two locations could have shared acommon feeding area. This suggests that the dalli-types migrate seasonally
between the Sea of Japan and the Pacific coast of northern Japan.
The number of Dall's porpoises in the principal area of truei-type distribution has been estimated, using sightings data pooled for the months
April to August since 1980, as about 64,000 (Kato, 1986) or about 125,000
individuals (Kato, 1987).
The present study analyzes the distribution and segregation of two typesof Dall's porpoises in the Japanese waters using data obtained through nine
whale sighting cruises in the western North Pacific, Sea of Japan and the
Okhotsk Sea. The population of the two types of Dall's porpoises in the area
is estimated using line transect methodology.
MATERIALS AND METHODS

The main body of data was obtained from the nine whale sighting cruises
conducted using two whale catcherboats (Toshimaru No. 15, 647.3 gross tons,
3,480 HP; Toshimaru No. 25, 739.9 gross tons, 3,600HP) chartered by theJapan Fisheries Agency in 1983 through 1986 (Table 1). Other sighting
cruises in which no Dall's porpoises were observed were excluded. The
seasons covered were nine months of the year, excluding April, November
and December.
In these cruises, survey was conducted along predetermined track line
placed systematically perpendicular to the coast line. Two mast-top observers
and three to six upper wheel-deck observers conducted sightings during
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

123

DALL'S PORPOISES OFF JAPANTABLE 1. WHALES SIGHTING CRUISES USED IN THE PRESENT STUDY
Cruiseno.

Period*Year

Name of vessel

2
3
4
5
6
7

12 Jan. - 24 Mar.
11 Jan. - 10 Mar.
10 Jan. - 10 Mar.
2 May - 30 June
9 June - 4 Sep.
10 June - 5Aug.
8June- 5 Sep.

1983
1984
1985
1986
1984
1983
1985

8
9

I Sep. - 30 Oct.
1 Sep. - 30 Oct.

1985 Toshimaru No. 15
1986 Toshimaru No. 15

Toshimaru No. 15
Toshimaru No. 15
Toshimaru No. 15
Toshimaru No. 25
Toshimaru No. 25
Toshimaru No. 25
Toshimaru No. 25

Biologists
on board
S. Shiraga
S. Nishiwaki
H. Shimada
T. Kasuya (7 July-6 Aug.)Y. Fujise (88 June-8 July),
F. Kasamatsu (6-20 Aug.),
H. Kishino (6-20 Aug.)
T. Miyashita (1-30 Sep.)
H. Shimada,
M. Ichihara (2 Sep.-8 Oct.)

Number of schools sighted
D

T

M

u

0
24

0
0
0

85
9
9
47

0
0
0
71
47
38
24

2
0
I

3
3
0
0
5
0
9

24
34

5
16

0
4

0
6

D: dalli-type Dall's porpoise. T: truei-type Dall's porpoise. M: mixed school of the two color types.
U: school of unknown color type. *: Total period of the cruise including the period that cruised out side theranges of Figs 2 to 7 and had no Dall's porpoise sightings.

daytime from 15 minutes after sunrise to 15 minutes before sunset except
during poor weather condition (Kasuya, 1986). The method of sighting wasbasically the same with that used for the Southern Hemisphere minke whale
assessment cruises and described by Best and Butterworth (1980).
Sighting effort has usually been discontinued when visibility is less than
1.0 nautical mile (n. m.) or the sea state is Beaufort 5 or over. The vessel
remained at the termination position until the weather changed, as far as time
permitted. Only sighting effort during searching mode under good weather
conditions and with mast-top observers was used as the primary sighting
effort, and sightings made under these condition are designated as primarysightings. We used only primary sightings and accompanying effort data forthe estimation of abundance. Any sightings other than primary sightings weredealt as secondary sightings and used only for the analyses of distributional
ranges.
All the marine mammals sighted were attempted to approach for
identification of species, color types of Dall's porpoise and school composition.
The following data were collected by the biologist and the captain for eachsighting; sighting time, sighting cue, angle from the bow of the vessel to theschool, radial distance, position and swimming direction of the school when
first seen, and estimated size composition. Surface water temperature at theposition of school was recorded, except for the 1983 and part of the 1984
cruises of Toshimaru No. 25. Radial distance between the vessel and Dall's
porpoise school was estimated usually when school was within about 0.5 n. m.,
but when school was apart for over the distance it was estimated from thevessel speed (15 knot for closure) and the time required for closure to a certain
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

124

MIYASHITA AND KASUYATABLE 2. NUMBER OF DALL'S PORPOISE SIGHTINGS IN THE JAPANESE
COASTAL WATERS BY AREA, MONTH AND COLOR TYPE
MADE DURING THE NINE CRUISES IN TABLE I
dalli-type

u

mixed

truei-type

Total*

Area & Month
no.

%

no.

%

no.

%

Pacific
March
May
July
AugustSeptember
October

4
18
21
18
35

5.3
15.3
63.3
64.3
77.7

70
98
II
6
10

93.3
83.I
33.3
21.4
22.2

l
2

1.3
1.7
3.0
14.3

Sea ofJapan
March
May
June
July
October

25
22
56
8
2

100.0
100.0
100.0
100.0
100.0

Okhotsk Sea
May
July
October

3
18
3

75.0
100.0
37.5

Total

233

no.

no.

%

75
Jl8
33
28
45

100
100
100
100
JOO

25
22
56
8
2

100
100
100
100
100

6

4
18
8

100
100
JOO

26

442

3

4

5
I
2
4
3

2

25.0
5
20J

62.5
8

U: school of unidentified color type. mixed: school of the two color types.
*: excluding school of unidentified color type.

position from the school where the rest of distance could be estimated visually.
However, the majority of the Dall's porpoise sightings occurred within theformer range.
School size was estimated by the two mast-top observers. Calves wereidentified by their small size and close association with a larger individual(presumably the mother). Color type of the porpoise was identified by the
biologist on board or by the captain. When color type was not recorded for
all the members of a Dall's porpoise school, we considered that all individuals
in the school were of the same color type. This could have underestimated the
proportion of mixed schools composed of both col or types. Since 1983 summer
cruise, an attempt was made to photograph all the marine mammal sightings
for later confirmation of the species identificaiton.
The surface isotherm was drawn based on surface water temperaturehourly recorded. Although this does not reflect the actual isotherm at any
particular moment, it is useful to indicate the relationship between the distribution of Dall's porpoise and surface water temperature.
Additional data recorded by the officers of research vessels include
position of the vessel and hourly meteorological records from 4 a.m. to 8 p.m.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

125

DALL'S PORPOISES OFF JAPANTABLE 3. OCCURRENCE OF DALL'S PORPOISE SCHOOLS OFF THE PACIFIC COAST OF
JAPAN IN RELATION TO THE SURFACE WATER TEMPERATURE AT THE POSITION
OF SIGHTING. NOON POSITIONS INCLUDE ALL RECORDS FOR DAYS WITH
ORDINARY SIGHTING EFFORT DURING THE CRUISES IN TABLE I*
Surfacewatertemperature(OC)

3.0- 3.9
4.0- 4.9
5.0- 5.9
6.0- 6.9
7.0- 7.9
8.0- 8.9
9.0- 9.9
10.0-10.9
11.0-11.9
12.0-12.9
13.0-13.9
14.0-14.9
15.0-15.9
16.0-16.9
17.0-17.9
18.0-18.9
19.0-19.9
20.0-20.9
21.0-21.9
22.0-22.9
23.0-23.9
24.0-24.9
25.0-25.9
26.0-26.9
27.0-27.9
Total

May
N

August

July

D

T

2

3

N

D

T

N

D

September
T

N

D

T

October
N

D

T

1

2

10
8
12
9

2
5

2

7
7
2
5
5

2

3
2

10

2

2

7

1
3
5

2

1
2

2

2
7
7

3
3
3
3
3
4

4

3
9
3

22

5

71

36

4 31

1
5
5
3
3
3
2
6
29

3
4

9

1
2

2
1

4
1

3

2

2
3

8
7

11
13
2

l
2

7
10
10
4

2
2

3

55

35

9

11

6
6
1
3
4

2
20

2

54

22

10

N: number of noon positions, D: number of dalli-type schools, T: number of truei-type schools.
*: mixed schools are included into schools of each color type.

in local time during steaming, and when the activity of the vessel changed.
The northeastern range of truei-type porpoise was determined using
information recorded by biologists on board several Dall's porpoise research
vessels operated by the Japan Fisheries Agency during transits to the northwestern North Pacific and Bering Sea. These cruises and the referenceswhere details of the cruise including track lines and sightings are available areas follows;
May to June, 1984: Miyazaki, Fujise, Komuro and Taketomi (1984)
June to August, 1978: Miyazaki, Jones and Beach (1984), Kasuya andOgi (1987)
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

126

MIYASHITA AND KASUYATABLE 4. OCCURRENCE OF DALL'S PORPOISE SCHOOLS IN THE SEA OF JAPAN IN
RELATION TO THE SURFACE WATER TEMPERATURE AT THE POSITION OF
SIGHTING. NOON POSITIONS INCLUDE ALL RECORDS FOR DAYS WITH
ORDINARY SIGHTING EFFORT DURING THE CRUISES IN TABLE I
Surfacewatertemperature(oC)

2.0- 2.9
3.0- 3.9
4.0- 4.9
5.0- 5.9
6.0- 6.9
7.0- 7.9
8.0- 8.9
9.0- 9.9
10.0-10.9
11.0-11.9
12.0-12.9
13.0-13.9
14.0-14.9
15.0-15.9
16.0-16.9
17.0-17.9
18.0-18.9
19.0-19.9
20.0-20.9
21.0-21.9
22.0-22.9
23.0-23.9
24.0-24.9
Total

March

N

May

D

N

D

N

2

2

15

3

7
3
1
3

June

7

October

July
D

N

D

1

3
3

N

D

6
12
10
18

14

7
2

2

2

2

1
4

5
2

2

4
6
4

9

25

4

23

29

3
1
3
4
56

5

8

22

2

N: number of noon positions, D: number of dalli-type schools.

August to September, 1982: Kasuya and Jones (1984), Kasuya and Ogi(1987)
August to September, 1983: Ogi and Fujise (1984), Kasuya and Ogi(1987)
August to September, 1985: Ogi, Tanaka, Kuramochi and Yamamoto(1986), Kasuya and Ogi (1987).
SURFACE WATER TEMPERATURE

Sea of Japan-Okhotsk Sea dalli-types
Only dalli-type individuals were sighted in the Sea of Japan. Althoughtruei-types were sighted in summer months near the southeastern border ofSci. Rep. Whales Res. Inst.,
No. 39, 1988

127

DALL'S PORPOISES OFF JAPANTABLE 5. OCCURRENCE OF DALL'S PORPOISE SCHOOLS IN THE OKHOTSK SEA
IN RELATION TO THE SURFACE WATER TEMPERATURE AT THE POSITION
OF SIGHTING. NOON POSITIONS INCLUDE ALL DAYS WITH ORDINARY
SIGHTING EFFORT DURING THE CRUISES IN TABLE I*
Surfacewatertemperature

May

(oC)

N

2.0- 2.9
3.0- 3.9
4.0- 4.9
5.0- 5.9
6.0- 6.92

7.0- 7.9

2

D

T

N

D

T

N

D

T

3

8.0- 8.9
9.0- 9.9
10.0-10.9
11.0-I l.9
I2.0-I2.9
I3.0-I3.9
Total

October

July

3

5

3

I

I

2

II
5

3

3

I8

3

3

5

N: number of noon positions, D: number of dalli-type schools, T: number of truei-type schools.
*: mixed school of the two color types are included into schools of each color type.

the Okhotsk Sea (Figs 2 and 6), the primary color morphs of the Dall's
porpoise inhabiting the sea was considered to be dalli-type. In these twowaters, the survey was conducted in surface water temperature between 2°(May) and 25°C (October), and the Dall's porpoise occurred in the temperature
range of 6° (May) to 20°C (October) (Tables 4 and 5).
Sighting effort below 6°C was about 6 hours (one day) in the Sea ofJapan and 18 hours (three days) in the Okhotsk Sea resulting in a survey
distance of about 290 n. m. The absence of Dall's porpoise during the period
suggests that dalli-type Dall's porpoises in the Sea of Japan and Okhotsk Sea
may be uncommon in the waters below 6°C. Further definition of the lower
temperature bound of the species is not possible due to the limited survey
effort near the northern limits of the species.
The comparison between distribution of surface water temperature at
the noon position (indication of effort distribution) and the temperature atthe position of the Dall's porpoise sightings suggests that dalli-type Dall's
porpoises are rare in waters over l6°C in the Sea of Japan and in the Okhotsk
Sea (Tables 4 and 5). If one exceptional October record between 19° and·
19.9°C is excluded, the upper bound of surface water temperature for the
distribuion of the species in the Sea of Japan varied from about l3°C in
March, l4°C in June, and to l6°C in July and October (Table 4 and 5, andFig. 1). This change will be more enhanced if an exceptional record in OctoberSci. Rep. Whales Res. Inst.,
No. 39, 1988

128

MIYASHITA AND KASUYA

is taken into consideration. Thus we consider that Dall's porpoises do notchange the geographical distribution seasonally so much as expected from thechange in the surface water temperature, but they tend to live in higher watertemperature in the summer season than in the winter.
The number of dalli-type sightings relative to the quantity of survey
effort in certain water temperature range (represented by the number ofnoon position at certain surface temperature) was high in the temperature
ranges of 7° -11°C in March, 8°-l 3°C in June, and 12°-l 6°C in July, indicatinga temperature increase of 3°-5°C during the three months. Although data
were scanty in May and October, the feature was probably close to March andJuly, respectively.
Pacific coast truei-types
Although six schools of truei-types were sighted in May and October inthe southern Okhotsk Sea (Figs 2 and 6, and Table 5), they were very close
to the boundary to the Pacific Ocean. Therefore we consider they have notaltered our general concept that the southern Okhotsk Sea is primarily
inhabited by dalli-types (Kasuya, 1978).
Off the Pacific coast survey was conducted within the surface watertemperature of 3° to 28°C (May to October), and truei-type individuals weresighted at temperature below 25°C (Tables 3 and 5). The lower bound of
distribution was not detected, because the surveyed area was limited well tothe south of the northern range of distribution of truei-types indicated inFig. 8.
The upper bound of the temperature range in May ( l 9°C) increased to
25°C in July, and this was followed by a gradual decline to 24°C in August,
20°C in September, and to l9°C in October (Table 3). Three schools of Dall's
porpoise of unknown color type were sighted in March at about 35°N off the
Pacific coast of Japan (Fig. 1). Surface water temperatures for these sightings
were between 12° and l3°C. Thus it is suggested that seasonal migration oftruei-type Dall's porpoises is less than the magnitude of seasonal change of
surface water temperature, and that they inhabit waters of relatively hightemperature in summer season. A similar trend was indicated on dalli-types
in the Sea of Japan-Okhotsk Sea (see above), but the absolute temperature
ranges were several degrees higher in the Pacific truei-types.
The water temperature range of high sighting frequency was between 5°
and l 4°C in May and did not seem to fluctuate seasonally, which appeared tobe different from feature in the Sea of Japan-Okhotsk Sea stock.
Pacific coast dalli-types
Although, upper bounds of the temperature range of Pacific dalli-typesightings in July through October did not significantly differ from that oftruei-types in the same area, it was considerably lower in May and the rangeof the most preferred temperature seemed to be lower than that of truei-type
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN129

in August through October (Table 3).
This will reflect the distribution of dalli-types in the northern part of thesurveyed area. The factors controlling this geographical segregation were
unclear.
GEOGRAPHICAL RANGE

Sea of Japan-Okhotsk Sea dalli-types
Data are available for February/March (Fig. 1), May (Fig. 2), June (Figs
2 and 5), July (Fig. 5), and October (Fig. 6) to indicate seasonal change of
Dall's porpoise distribution in the Sea of Japan and Okhotsk Sea.
The currently confirmed southern limit of the distribution in the Sea ofJapan has been between 35° and 36°N. A small number of individuals wasrecorded in winter from northern Kyushu at latitude of about 34°N during
the extensive sighting survey of dolphins in the Iki Island area between
southern Sea of Japan and the East China Sea (Kirishima, 1986). Thus, weconsider that the southern limit of Dall's porpoise in the Sea of Japan is in the
Tsushima Strait between Korea and Kyushu in western Japan, and that they
do not migrate to the East China Sea. Dall's porpoises have not been recorded
from China (Zhou, 1986).
The southern limit moved with the progress of season from the Tsushima
Strait to 40°N in early June (Fig. 2), and to 43°N in early July (Fig. 5). In
October some sporadic sightings of the dalli-type were recorded in thenortheastern part of the Sea of Japan between 41° and 43°N (Fig. 6). Noguchi(1946) reported past records of dolphin fishery off Tajima (35°30'N) in thesouthern Sea of Japan. The records indicated that the season of Dall's porpoise
hunting ended while the Pacific white-sided dolphin started in early May. No
data are available to indicate southward movement in the autumn/winterseason.
Although the majority of Dall's porpoise in the Sea of Japan leave there
in summer months and enter the Okhotsk Sea (Kasuya, 1978; 1982), someindividuals may summer in the Tatarskii Strait region where the surface watertemperature remains below 17°C.
Pacific coast truei-types
Data on the seasonal change of Dall's porpoise distribution off the Pacificcoast of Japan were available in March (Fig. 1), May (Fig. 2), July (Figs 3, 4
and 5), August (Figs 3, 4 and 5), September (Figs 6 and 7), and October(Fig. 7).
Truei-types were not observed in the Sea of Japan (Table 2), and thewestern limit observed in the present study was about 30 n. m. northeast of
the eastern entrance of the Tsugaru Strait (Fig. 3). Kawamura, Nakano,Tanaka, Sato, Fujise and Nishida (1983) reported the occurrence of truei-types
in the Tsugaru Strait area at 41°30'N, 141°00'E in June and December. This
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

130

MIYASHITA AND KASUY A
Cruise No.1
0

12 Jan-2~MarJ3°
1983, ",: -150

7

130°E

·._~ ___'./ ~
,

~

360 N

34°N

140°E

Fig. 1. Southern limits of Dall's porpoises in winter season observed during threewhale sighting cruises of the Toshimaru No. 15 Qanuary, February and March in
1983, 1984 and 1985). Solid line indicates track line cruised with ordinary sighting
effort, dotted line the surface water isotherm in centigrade, open circle sighting of
dalli-types, and star that of type unidentified Dall's porpoises. Dall's porpoiseschools of secondary sighting included.

Fig. 2. Dall's porpoise sightings, surface water isotherms (dotted lines, in centigrade),and the track lines of the Toshimaru No. 25 cruised with ordinary sighting effort in
May through June, 1986 (solid line and arrow head). Open circle indicates schoolof dalli-types, closed circle that of truei-types, open triangle that containing twocolor types, and star that of unidentified color types. Secondary sightings of Dall's
porpoise schools included.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

131

DALL'S PORPOISES OFF JAPANPacific OceanJ)

1

14 Aug.

20 Aug.(350N

Fig. 3. Dall's porpoise sightings, surface water isotherms (dotted lines in centigrade),and the track lines of the Toshimaru No. 25 cruised with ordinary sighting effort inJuly through August, 1984 (solid line and arrow head). Open circle indicates schoolof dalli-types, closed circle that of truei-types, open triangle that containing twocolor types, and star that of unidentified color types. Secondary sightings of Dall's
porpoise schools included.

019Jul~'

jFig. 4. Dall's porpoise sightings, surface water isotherms (dotted lines in centigrade),and the track lines of the Toshimaru No. 25 cruised with ordinary sighting effort inJuly through August, 1983 (solid line and arrow head). Open circle indicates schoolof dalli-types, closed circle that of truei-types, open triangle that containing twocolor types, and star that of unidentified color types. Secondary sightings of Dall's
porpoise schools included.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

MIYASHITA AND KASUYA

132
Cruise No.7···16

Fig. 5. Dall's porpoise sightings, surface water isotherms (dotted lines in centigrade),and the track lines of the Toshirnaru No. 25 cruised with ordinary sighting effort inJuly through August, 1985 (solid line and arrow head). Open circle indicates schoolof dalli-types, closed circle that of truei-types, open triangle that containing twocolor types, and star that of unidentified color types. Secondary sightings of Dall's
porpoise schools included.

130°E
140°E
Fig. 6. Dall's porpoise sightings, surface water isotherms (dotted lines, in centigrade),and the track lines of the Toshimaru No. 15 cruised with ordinary sighting effort in
September through October, 1985 (solid line and arrow head). Open circle indicatesschool of dalli-types, closed circle that of truei-types, open triangle that containing
two color types, and star that of unidentified color types. Secondary sightings of
Dall's porpoise schools included.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN133

Fig. 7. Dall's porpoise sightings, surface water isotherm (dotted lines in centigrade),and the track lines of the Toshimaru No. 15 cruised with ordinary sighting effort in
September through October, 1986 (solid line and arrow head). Open circle indicatesschool of dalli-types, closed circle that of truei-types, open triangle that containing
two color types, and star that of unidentified color types. Secondary sightings of
Dall's porpoise schools included.

is the confirmed western limit of the color type in the Tsugaru Strait area.
The southernmost sighting of truei-types was recorded in May at about
34°N and at the water temperature of about 24°C (Fig. 2 and Table 3). This
was an isolated southern record for the season and we do not consider it torepresent the ordinary range of the color type in the season (Fig. 2). The next
southern records (three schools of unknown ·color type) were obtained in
March in between 35° and 36°N (Fig. 1) and this agreed with the previously
reported range of the species off the Pacific coast of Japan (Kasuya, 1978).
The sourthern range of truei-types in the Japanese coastal Pacific waters
moved from around 35°N in March to around 36°N in early May and earlySci. Rep. Whales Res. Inst.,
No. 39, 1988

134

MIYASHITA AND KASUYA
"\)

i I

-

\

'
lr~

-

_!
I

I

Tl

~

[/

"""-- -~ I? -t1,,,_!:12-" Ul , ,

,

~

Tl'

T1

T3

D3Ul

f_.19'<
7' 1,
UlO ::.- ',/TG=
TS T3 T2 ' T4 T1
.D3Dl
Dl
~
U2'- u:iT 12~-::: =\- - Ul
'J
D3
T3- Ul TG- J4', Tri
Dl
D3
Dl
\
I~
,
; Ul
I 1i
D2 / /
I--,,-""-...
~

LJ

jY

Ul

/

~~

-

-/

,OJ

Ul,, T17 Ul D4'/ / D2
U9
U2/
Dl J>3 D21'y7/£_ ,,. .... ~1/

~ ~/
'.fl'
-:) Dly ~(DB.
--- l1/

DB', D8
UG

45°N

~

Ul

-- '

~

/

//

--- --T3_ --- -- - T2_ >----- J2- --TL T4- --U6
Ul~+- Dl D3

J-

D2;;P~ U4

U2, U2Dl_
D1- Tl-- _!].;:' TS"- Tly DG:.. ~5Ul ~Ul
D3 B~ lJ 1,
U4,.. 6'
I
T4
D4 y.2"- Dl...._
T2'
Tl,~
Ul
D)/ D2u//lJ4 U3 , I
J4/
T1
Tl~ 'Tll ,
B~/
~ Ul
/

sv
-y.;y- -- 7- ----....... 6f~
A- -- -- /
,-

/,/

/
//

D2,, .()2

D}/ DV Dl

,

U2

//,

/

tr
T4

~

.

Dl
U2

A

/'~

]

.

,

T1

,,

DJ'

v

U2

Fig. 8. Number of Dall's porpoise sightings off the Pacific coast of northern Japanand southern Kuril Islands in May through September appeared in the publishedrecords of the Dall's porpoise research cruises (Kasuya and Jones, 1984; Miyazaki
et al. l 984a; Miyazaki et al., l 984b; Ogi and Fujise, 1984; Ogi et al., 1986). Secondarysightings included. Color type code: T, truei-type school; D, dalli-type school; U,
school of unidentified type. Mixed schools of two color types are included into eachtype.

July (Figs 2 and 4), to 40°N in early August (Fig. 4). The southern limit ofdalli-type in the coastal waters tended to be to the south of their range in theoffshore waters (Figs 5 and 7). This reflects the presence of cold water in the
coastal area.
Kasuya (1978) indicated that although the proportion of dalli-type catch
increased with month the majority (about 96%) of Dall's porpoise catches off
Sanriku Region between 37°30'N and 40°00'N were truei-types in January to
March. The feature is similar in principle to our sighting data during May
through July (Figs 2 to 4), but the predominance probably changes in August
as seen in Figs 4 and 5.
In August, truei-types were absent in the coastal Pacific waters during thecruise no. 7 in 1985 (Fig. 5), but present during the cruise no. 6 in 1983 (Fig.
4) suggesting some annual fluctuation in the timing of seasonal movements
and predominance change. Truei-types were almost totally absent fromJapanese coastal waters in September of 1985 (cruise no. 8) and 1986 (cruise
no. 9) (Figs 6 and 7). However, a survey in September and October 1986
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN

135(cruise no. 9) suggested that the porpoise had probably moved in summer tothe offshore waters between 144° and 14 7°E and returned to coastal waters in
October (Fig. 7). Some truei-types were sighted in late October in the boundary
area between the southern Okhotsk Sea and Pacific Ocean at latitudes around
44°N (Fig. 6). We conclude therefore that truei-types predominates over dallitypes in the coastal waters along the Pacific coast of northern Japan during
winter and spring seasons (probably, from November to July) but the
predominance alters during a short summer/autumn period (September toearly October) with possible annual fluctuation.
Information on the northern range of truei-types has been reported bybiologists on board of five Dall's porpoise research cruises in the north western
North Pacific and the Bering Sea (Fig. 8). Although Dall's porpoises weresighted almost continuously during the cruises in the area, the dominantcolor type altered rather sharply. The approximate positions of the change inthe predominant color types of the Dall's porpoise are as follows (truei-type
predominating on the southwestern side of the designated points);
1. May38°30'N, 152°00'E (Miyazaki, Fujise, Komuro, Taketomi,1984).
42°30'N, 153°00'E (Miyazaki, Fujise, Komuro, Taketomi,
2. June1984).
45°00'N, 150°00'E (Miyazaki, Jones and Beach, 1984).
3. June42°00'N, 143°30'E (Ogi, Tanaka, Kuramochi and
4. AugustYamamoto, 1986).
43°00'N, 154°00'E (Miyazaki, et al., 1984).
5. August
6. August
43°30'N, 152°00'E (Ogi and Fujise, 1984).
7. August
44°00'N, 157°00'E (Kasuya and Jones, 1984).
8. September 43°00'N, 145°00'E (Kasuya and Jones, 1984).
9. September 43°00'N, 151°00'E (Ogi and Fujise, 1984).
10. September 43°00'N, 153°30'E (Ogi et al., 1986).
Two coastal points (nos 4 and 8 in the above list) reflect the local concentrationof dalli-types mentioned below and may not be a good indicator of the eastern
limit of the range of truei-types. The point no. 1 will possibly represent theeastern range of truei-types in May.
In other months (June to September), the observed northern boundaryof distribution of truei-types was located between 42° and 45°N, and showedno north/south movement. This is in good contrast with the disappearance ofmost of truei-types from the Japanese coastal waters in September andOctober (see above).
The above analysis indicates that truei-type Dall's porpoise has seasonal
northeast to southwest movement within their ·range between 35° and 45°N,
and in late summer they almost disappear from a narrow Japanese coastal
waters south of 43°N to concentrate in the northern and presumably slightly
offshore waters. Northern limit of truei-types in the winter season is still to be
examined.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

136

MIY AS HITA AND KASUY A

Pacific coast dalli-types
Data on the distribution of dalli-type Dall's porpoise off the Pacific coastof northern Japan were obtained during cruises in March (no color typeidentification available, Fig. 1), May (Fig. 2), July (Figs 3, 4 and 5), August(Figs 4 and 5), September (Figs 6 and 7), and in October (Fig. 7).
About 4% of the catch of the winter operation of harpoon fishery off
Sanriku were dalli-types (Kasuya, 1978), and there was no difference detectedin the temperature preference between the two color types off the Pacificcoast of Japan (see above). Therefore, we consider that the southern limit of
the normal distribution of dalli-types would be at about 35°N as in the case forthe truei-types.
Our data recorded small local concentrations of dalli-types to the east of
the Tsugaru Strait as already indicated by Kasuya ( 1978) and Miyazaki andFujise (1985). This concentration occurred in May along the southern coastof Hokkaido from the east of the Tsugaru Strait to 41°N, l 45°E (Fig. 2). The
feature was similar in July 1984, when we observed a concentration in 42°N,
l 43°30'E close to the southern coast of Hokkaido (Fig. 3). Such concentration
possibly existed in August 1983 in the southeastern area of the Tsugaru Strait(Fig. 4).
The abundance and distribution of dalli-type individuals off the Pacificcoast of Japan was high during the months when truei-types were becoming
scarce in August (Fig. 5), almost absent (September, Figs 6 and 7), or probably
just starting to reappear (October, Fig. 7). Among Dall's porpoise sightings in
Fig. 5, all the 24 truei-type sightings occurred in July, 2 dalli-type sightings in
the Pacific area in July, and 19 dalli-type sightings in August.
Our data confirmed that the distribution of dalli-types in the Pacificwaters was continuous through the Tsugaru Strait to the Sea of Japan at leastin May (Fig. 2), September (Fig. 7) and October (Fig. 6). However the density
in the strait area appeared to be low. Similar observations have been made by
Kawamura et al. (1983) in the Tsugaru Strait area. They recorded moredalli-types in the strait area in April through July than truei-types, but they
considered that the frequency was low compared with that of other dolphin
species.
We consider therefore that the distribution of dalli-type Dall's porpoises
is continuous between the Sea of Japan and Pacific waters during spring andautumn season, and that most of the dalli-types in the latter area are probably
migrants from the former waters. Thus, we presume that a portion of theputative Sea of Japan-Okhotsk Sea stock of Kasuya (1978) passes the Tsugaru
Strait in spring to migrate to the Pacific coast of Japan and summer there
while the majority of truei-types summer further offshore in the northernarea. Dalli-types will return to the Sea of Japan in autumn preceding thearrival of truei-types. The bases for the above conclusion are summerized asfollows;( 1) A small local concentration of dalli-types occurred in the waters east
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN137

of the Tsugaru Strait in May when the distribution of dalli-types wascontinuous through the strait between the Sea of Japan and Pacificcoast of Japan (Fig. 2).
(2) The dalli-type range extended east/south before summer when the
distribution of the species became discontinuous between the twoseas (Fig. 5).
(3) The distribution of dalli-types was continuous through the Tsugaru
Strait in September and October, when the migration of dalli-types
in the southern Okhotsk Sea did not apparently reach to the west
coast of Hokkaido (Fig. 6).
This migration pattern of the Dall's porpoise is similar to schematic drawing
by Noguchi (1946), which has not received the attention of biologists, presumably due to the lack of presentation of basic data for the hypothesis.
Data are not available to determine whether dalli-types summering off
the Pacific coast of northern Japan and in the southern Okho.tsk Sea (they are
considered to belong to Sea of Japan/Okhotsk Sea stock) intermingle in thewaters adjacent to the southern Kuril Islands and eastern Hokkaido.

ABUNDANCE
Mathematical methodology
Population size (N) was estimated for the two color types and sub-areas
defined below using following equation,
N=n"f(O)·A·s

2·L

where n represents number of primary sightings, A size of surveyed area
(n. m. 2), L length of transect line (n. m.),j(O) probability density function of
the perpendicular distances evaluated at the origin, and s mean school size.
The coefficient of variation (c. v.) for n, s and f(O) were estimated by theequations of Anon. (1985a), then that of N by following equation,c.v.(N)2 = c.v.(n)2 + c.v.(f(0)) 2 + c.v.(s) 2
assuming each factor was independent statistics.
In this study we firstly fitted both Fourier series (FS) and negative
exponential models (NE) to estimate j(O) value, then chose the model with
better fit for each data using the Chi-square goodness of fit test (Table 7). The
probability of seeing a Dall's porpoise school on the track line was assumed
as one. No smearing was done to eliminate the rounding error of sighting
angle and radial distance estimate.
Sub-area definition
We used only data obtained through six spring/summer cruises (cruisenos 2, 4, 6, 8 and 9) which had relatively good coverage of the Dall's porpoise
range of distribution and had a large number of sightings. Five sub-areas (twoSci. Rep. Whales Res. Inst.,
No. 39, 1988

MIYASHITA AND KASUYA

138

45°N

T3

40°N
/

I

i

,-T2--/---·

/

'

I

/

'

I

I

/

I

I

I
I

'

Tl

140°E

35°N

145°E

150°E

1ss E
0

Fig. 9. Sub-areas defined to estimate the population of Dall's porpoises off Japan.
DI, observed range of dalli-types in the Sea of Japan; D2, observed range of dallitypes off the Pacific coast of Japan; TI and T2, observed ranges of truei-types off
the Pacific coast of Japan; T3, known range of truei-type predominance but
unsurveyed in the present study.

for dalli-type range and three for truei-type range) (Fig. 9 and Table 6) were
defined to cover the whole range of Dall's porpoise sighting. Of these fivesub-areas, four (DI, D2, TI and T2) are areas covered by our sightings effort,
but the remaining one (T3) is the unsurveyed area known to be inhabited bytruei-types (see above). A minor modification is done for T3 to meet theboundary difference of TI and T2. We have extrapolated the truei-type
densities in the two surveyed sub-areas (TI and T2) into the unsurveyed
sub-area (T3) in order to obtain a rough estimate of the total population oftruei-types. The methodological problem that surrounds this procedure will
be discussed later.
School size
We used primary sightings of I 43 dalli-type schools and I 36 truei-type
schools for the population estimate, but school size estimate was not available
for one dalli-type school. There were three mixed schools of the two color
types, and we regarded them as separate school for each color type.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

139

DALL'S PORPOISES OFF JAPANTABLE 6. PARAMETERS FOR THE ESTIMATION OF DALL'S PORPOISE
POPULATION IN THE SURVEYED AREA
Area(n. mile) 2

Transectlength(n. mile)

no.ofsightings**

Meanschoolsize (c.v.)

Sighting
rate***(c.v.)

1986
1985
1985
1986

48,80225,36525,36525,36525,365

1,296
1,003
1,398
1,756
3,154

75
14
17
32
49

6.7 (0.07)
13.3 (0.19)
9.6 (0.19)
7.5 (0.16)
8.4 (0.13)

3.75 (0.19)
1.40 (0.40)
1.36 (0.65)
1.65 (0.33)
1.48 (0.30)

2 May - 23 May 1986
8 July - 3 Aug. 1984
3 Aug. 1983
14 July 8 July - 3 Aug.

93,71874,31 I74,3 I I
74,31 I

2,296
1,124
836
1,960

68
35
33
68

6.4 (0.08)
3.5 (0.10)
9.7(0.15)
6.5 (0.13)

2.92 (0.22)
2.94 (0.32)
3.95 (0.34)
3.42 (0.24)

Periodofdata

Cruise Subnumber* area
dalli-type
4
7
8
9
8+9
truei-type
4
5
6
5+6

DI

D2
D2
D2
D2
TI

T2
T2
T2

26 May 7 July 16 Sep. 11 Sep. I I Sep. -11 June26 Aug.
30 Oct.
30 Oct.
30 Oct.

*: see Table 1. **: number of primary sightings; ***: number of primary sightings per JOO n. miles.

The size of 142 dalli-type schools ranged from one to 34 individuals, withthe modal school size at four to six individuals in the three sub-area/cruises(Fig. 10). Mode was unclear in the Pacific sightings in sub-area D2. Mean
school sizes of dalli-type were from 7.5 to 13.3 individuals in the Pacificsub-area D2 and 6.7 in the Sea of Japan sub-area Dl. The first and last
figures were significantly smaller than the largest figure for the Pacific subarea (Mann-Whitney U-test, p<0.04), but other means were not significantly
different each other (p>0.19).
The 136 primary sightings of truei-types ranged from one to 70 individuals(the second largest school was composed of 34 individuals). We excluded
from the following analysis this largest school of 70 individuals recorded
during the cruise no. 6 in sub-area T2, because we were uncertain if it was areal large school or included some nearby schools that should have beenclassified as secondary sightings. This exclusion decreased the mean school
size from 11.5 (with the largest school) to 9.7 (used here). It could have also
caused small degree of underbias in the population estimate (Tables 7 and 8)
through the under representation of school density. However, we do notconsider this effect very important, because the population estimate thus
calculated still had extraordinarily large coefficient of variation (see below).
The modal figures of the truei-type school sizes varied between three to
10 individuals in the three sub-area/cruises (Fig. 10), and the mean values
between 3.5 and 9. 7 individuals (Table 6). Only the smallest mean school size
(3.5 individuals) for cruise no. 5 in sub-area T2 was significantly smaller thanany other values (Mann-Whitney U-test, p<0.01).

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

140

MIYASHITA AND KASUYA
A. dalli - typesub-area 01
cruise no. 4

15

E.

truei-typesub-area T 1
cruise no.4

G.

truei-typesub-area T 2
cruise no. 6

15

10

10

5
Ul

0

0

-5Ul 0+------.-----'--"-r----'-'-T"-----'-r'--..... 20~

~ 0 +---'---'-rL-1......__....,...__.___'-T"--__......._

E

5

i. 2

lJO
34

5

0
5

5

-0-D

10

15

20 30

nD-0

0
0

5

10

15

20 26 30 70

School size
Fig. 10. School size composition of primary sightings of Dall's porpoises.

Sighting rate
The sighting rate (number of primary sightings per I 00 n. m. of transectline) of the dalli-type schools was between 1.36 and 1.65 in the Pacific sub-area
D2 (cruise nos 7, 8 and 9) and 3.75 in the Sea of Japan sub-area DI (cruise
no. 4) (Table 6). The figure for the Sea of Japan sub-area was significantly
larger than any of the three corresponding figures of the dalli-type in the
Pacific (Mann-Whitney U-test, p<0.0 I).
The three sighting rates for truei-type in the Pacific sub-area TI and T2
ranged from 2.92 to 3.95 (Table 6), and the difference was not statisticallysignificant (Mann-Whitney U-test, p>0.14).
Perpendicular distanceThe distribution of perpendicular distances of dalli-type (Sea of Japan)
and truei-type (Pacific) sightings during the cruise no. 4 (Toshimaru No. 25)
had clear shoulder at 0.2 to 0.3 n. m. (Fig. 11 A and E), but different cruises
by one vessel often had different distribution pattern as seen in the contrast
between A or E and For Gin Fig. 11 (Toshimaru No. 25 cruise). This suggeststhat the distribution pattern of the perpendicular distances is not dependent
on the vessel but varies between cruises (presumably affected by observer orweather).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

141

DALL'S PORPOISES OFF JAPAN

25 •

~

20

A. dalli-typesub- area 01
cruise no.4

E.

t ruei-typesub-area T 1
cruise no.4

15

''

10

\

''

5

-E 0

+---~,.........__._-~_.___ _...,

o
..C

u

'

'

dalli-typesub-area 02
cruise no.7

5

I/)

F.
,,

truei-typesub-area T2
cruise no.5

.....
0

.... 0 +-~"-'"--+---'-'"-T---.....
CIJ

~ 10

C.

::J

~

z

I

\

dalli-typesub-area 02
cruise no.8+--~-'-----'--+'---==~

3.2
G.

5

D.
~

10

'

_q

truei-typesub-area T2
cruise no.6

dalli- typesub-area 02
cruise no.9
I

~\

'

\

5

~\

O+----~-'-~T-=---~-~''--.-,

0

0.5

1.0

1.5

+-~--l-.........._~~...._~.Q
0
0.5
1.0
2.8

Perpendicular distance(n. m.)
Fig. 11. Perpendicular distances of primary sightings of Dall's porpoises (whitesquares) and Fourier or negative exponential model fitted to them (closed circles anddotted line). For models used see Table 7.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

142

MIYASHITA AND KASUY A

20\ dalli-type, sub- area 02, cruises 8+9
'

10

0
l/l

0
0

.c.
u
l/l

0.5

0
30

1.0

~[b
0

5

y

10

15

20

10

15

20

truei-type, sub-area T2, cruises 5+6

....0

~

Q.I

.a
E

20

~\

::J

z

''

~'
'

10

\

0 +---....-----'----l..::\'"'~o.L-~
0

0.5

1.0

Perpendicular d ist. (n. m.)

05School size

Fig. 12. Distribution of school size and perpendicular distance for d.alli-types (sum of
the cruise nos 8 and 9) and truei-types (sum of the cruise nos 5 and 6) off the Pacificcoast of Japan. For marks see Fig. 11 and Table 7.

Population estimate
Either Fourier series or negative exponential model was selected forindividual data set based on Chi-square goodness of fit test (Table 7). The
Fourier series model showed better fit for dalli-type sightings in all sub-area/
cruises and one truei-type data set (cruise no. 4, sub-area TI). Anothertruei-type data set (cruise no. 5, sub-area T2) showed better fit to the negative
exponential model. And only negative exponential model could be successfully
fitted to a truei-type data set in the Pacific sub-area T2 (cruise no. 6). The
Fourier series model could not be fitted to this data set, because the terms of
the Fourier series fit exceeded the number to satisfy the 'stopping rule' of
Burnham, Anderson and Laake. (I980).
Population of dalli-types in the Sea of Japan (for sub-area DI) was
estimated at 3 I,789 individuals (with 95% confidence interval of I 7,770 to
45,808) using data in May to June, I986 (cruise no. 4) (Table 7). This value
represents only a portion of the Sea of Japan-Okhotsk Sea stock of the Dall's
porpoise (dalli-type), because it does not include individuals in the whole
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

143

DALL'S PORPOISES OFF JAPANTABLE 7. POPULATION ESTIMATE OF DALL'S PORPOISES IN THE SURVEYED
AREA. f(O) WAS CHOSEN BY THE CHI-SQUARE FITNESS TEST
Cruiseno. m
Table I

f(O) (c.v.
andmodel used)*

Chi-squ.
goodnessof fit**Population
size(c.v.)

Subarea

Periodofdata

dalli-type
4
7
8
9
8+9

DI
D2
D2
D2
D2

May -June 1986
July - Aug. 1985
Sep. - Oct. 1985
Sep. - Oct. 1986
Sep. - Oct.

3.36 (0.09, FS)
6.19 (0. 24, FS)
5.69 (0.25, FS)
3.31 (0.21, FS)
4.91 (0.19, FS)

0.816
0.600
0.082
0.430
0.247

31,789 (0.23)
14,579 (0.50)
8,424 (0. 72)
5,737 (0.42)
8,126 (0.38)

truei-type
4
5
6
5+6

TI
T2
T2
T2

May
July July July -1968
Aug. 1984
Aug. 1983
Aug.

2.94 (0.06, FS)
2.88 (0.24, NE)
3.87 (0.25, NE)
3.36 (0.17, NE)

0.452
0.522
0.004
0.018

26,113 (0.25)
11,662 (0.41)
55,057 (0.45)***27,844 (0.32)****: FS, Fourier series model. NE, Negative exponential model.
**: probability of obtaining a deviation as great or greater than calculated Chi-square value.
***: low reliability due to poor model fit.

range of the stock considered to extend during the survey period to the
Okhotsk Sea (Kasuya, 1978) and western part of the Sea of Japan (see Fig. 2)
or to the Pacific coast of northern Japan (see above). At the time of the cruise(early June) the southern limit of distribution has already moved to 40°N
from the southernmost limit at 35°N in winter season. The cruise (no. 4)
proceeded from north to south against the seasonal movement of the Dall's
porpoise (Fig. 2). This also could have caused some degree of underbias in
the estimate of population size.
Three population estimates of dalli-types in the Pacific sub-area (D2)ranged from 5,737 to 14,579 individuals (Table 7), but none of these figures
were statistically different (p>0.33). Since none of the parameters of dalli-typesightings during the two cruises of no. 8 and no. 9 in the Pacific sub-area D2
and in September and October, we combined the data to increase sample size
and to decrease the confidence interval. The procedure gave dalli-type
population of 8,126 with 95% confidence interval of 2,105 to 14,146 (Tables
6 and 7). This was not significantly different still from 14,579 estimated forJuly-August data of the same area. However, the September/October figure
was only half of the July/August figure, and it is suggested that the difference
may reflect in some degree the migration of the dalli-type individuals to the
Sea of Japan in autumn (see above). Therefore, we considered that about
15,000 individuals of dalli-types in the Sea. of Japan migrate through the
Tsugaru Strait and spend summer off the Pacific coast of Japan. The rest of
individuals in the stock will summer in the northern Sea of Japan or in the
Okhotsk Sea (Kasuya, 1978).
The above population estimates of dalli-types in the Sea of Japan (DI)Sci. Rep. Whales Res. Inst.,
No. 39, 1988

144

MIY AS HITA AND KASUY A

and Pacific (D2) area were made using data obtained in slightly different
seasons of the year (late May to early June in the Sea of Japan, and early Julyto late August in the Pacific). Although there is some possibility that individuals
counted in the Sea of Japan were again included in the population estimate
for the Pacific area, we consider that the effect may not be very large comparedwith the individuals distributed in the western Sea of Japan or in the Okhotsk
Sea far from the Hokkaido Qapanese) coast and excluded from the calculation.
We note that the southern boundary of the Dall's porpoise in the Sea of Japan
has almost passed the latitude of the Tsugaru Strait at the survey time in early
June (Fig. 2). We have excluded some dalli-types found in the offshore
unsurveyed truei-type area (T3), which belonging is still uncertain to us. Thus
we consider that the currently available best figure of the minimum estimateof Sea of Japan-Okhotsk Sea stock of Dall's porpoises is about 46,000(=3I,789+ I4,579) individuals with 95% confidence interval of 26,290 to
66,445.
We obtained primarily three population estimates for truei-types in thesurveyed area, one for May and two for July/August. Although their range
was wide (I I,662 to 55,057 individuals, Table 7), none of them were statisticallydifferent from others (p>O. I 4). Although the mean school sizes were different
between the two cruises (nos 5 and 6) conducted in the same season Quly/
August) and in the some sub-area T2, we combined these data as in the dallitype case (cruise nos 8 and 9) to improve the estimate of truei-type population
size. This procedure provided an estimate of 27 ,844 individuals with 95%
confidence interval of 10,380 to 45,308 (Tables 6 and 7). This figure Quly/
August, sub-area T2) is not significantly different from 26, I I 3 (with 95%
confidence interval of I3,522 to 38,704) estimated using May data in the
sub-area TI.
Above estimates of truei-type population do not include individuals
known to be distributed in their summering ground outside the present
survey area. Extrapolation of the density data corresponding to the above
three estimates to the unsurveyed area almost doubles the estimation oftruei-type population (Table 8). This procedure assumes equal Dall's porpoisedensity in any particular moment for both surveyed and unsurveyed part ofthe sea. Table 9 compares, using data listed in Fig. 12, Dall's porpoise density
between offshore and inshore Pacific areas off the northern Japan, whichroughly correspond to T3 and TI or T2 of this study, respectively. The ratiosof truei-types: dalli-types in each of the area are I 90:59 (northern offshorearea), I86:5I (northern inshore) and 52:II (southern inshore), and the trueitype proportion ranged from 76 to 82% showing no significant difference
between the three areas. The density of Dall's porpoises were almost same
between two northern areas while that in the southern area was lower than
the two.
These suggest that the Dall's porpoise density in the present surveyed
areas (TI and T2) is almost same with that in unsurveyed area (T3) if averaged
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

145

DALL'S PORPOISES OFF JAPANTABLE 8. TRUEI-TYPE POPULATION ESTIMATES EXTRAPORATED TO UNSURVEYEDAREA OF THE NORTHEASTERN PORTION OF THE RANGE (T3*)

surveyedarea

Unsurveyed
area ofdistribution(n. mile 2)

Populationin
unsurveyed
area

Total
population

26,113
11,66255,057
27,844

113,834
112,852
112,852
112,852

31,71817,71083,612**
42,235**57,831
29,372
138,669**
69,779**Population
Cruise
no.

Month

4
5
6
5+6

May
July - Aug.
July - Aug.
July - Aug.

m*: see Fig. 9 for range.

**: low reliability due to poor model fit.

over months (May through September) and years (5 seasons). However, thisdoes not necessarily imply that the densities of truei-types in the northern
inshore and offshore areas are same in any particular month or year. Rather,
we consider that the number of truei-types in the inshore area and that in theoffshore area are negatively correlated, and that the densities are also
dependent each other. Therefore, the estimates of truei-type population in
the unsurveyed area thus extrapolated can be biased to the same direction asthat in the surveyed area, and the bias can be amplified in the total population
estimate. We feel that two extreme estimates of the total truei-type populationin Table 8 (29,372 for cruise no. 5 and 138,669 for cruise no. 6) have higher
probability of being far from the true figure than other figures. Additionally
two figures in Table 8 using the cruise no. 6, i.e. 138,669 and 69,779, havelower reliability due to the poor goodness of fit of the model (Table 7). Only
remaining estimate is 57 ,831 based on the cruise no. 4 in May 1986. As theconclusion, we consider that the population of the truei-type will be about
58,000 individuals. The confidence interval can not be estimated, but the c.v.
has to be over 0.25 the figure calculated for surveyed area.
DISCUSSION

We made two assumptions in the present population estimate. They are (1)all the Dall's porpoises on the trackline are counted, and (2) Dall's porpoiseschools do not respond to vessels. If Dall's porpoise schools respond to an
approaching research vessel by moving toward or away from the vessel before
the schools are detected by researchers the population estimate of the present
study will be seriously under or over biased, respectively (Hammond, 1986).
The response of the species to the vessel was investigated using helicopters(Bouchet, Braham and Tsunoda, 1983), and there was an attempt to calculate
the correction factor (0.22-0.41) for the attraction of porpoises to the vessel(Turnock, 1987). However, the species could be either attracted to the vessel,
neutral, or avoid the vessel depending on the area, season, growth stage, sex,
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

146

MIYASHITA AND KASUYATABLE 9. GEOGRAPHICAL COMPARISON OF THE
DALL'S PORPOISE DENSITY BASED ON DATA IN FIG. 8
School density

Area

Northern
offshore*
Northerninshore**Southerninshore***Porpoise densityno.
schoolsightedtransectlengthmn.m.

density/100 n.m.

no.
individuals

transectlengthin n.m.

density/100 n.m.

30

815

3.7

116

755

15.4

84

1,111

7.6

364

976

36.9

135

1,777

7.6

389

1,435

27.1

*: 40°-45°N, 14 7°-l 55°E. **: Pacific area north of 40°N and west of I 47°E. ***: Pacific area between 38°
and 40°N, and west of 155°E.

and reproductive status (Kasuya and Jones, 1984). Therefore we felt it risky
to use the above correction factor without further observation of the porpoise
behavior. If we missed some individuals on the trackline, which we believe
very possible especially for individuals that avoid vessels, it could have caused
an underestimate. Additionally, present estimate of the Dall's porpoise
population will also include possible underbias due to rounding of the sighting
angle and radial distance (Buckland and Anganuzzi, 1987), which have notbeen considered in the present study.
Using sighting data obtained from the salmon research vessels cruisingfrom Hokkaido to northern North Pacific in April to August (mainly June
and July), Kato (1986) estimated the Dall's porpoise population of both color
types in his truei-type area (40°-44°N, east of 155°E, which is slightly smaller
than corresponding area of the present study), as about 64,000 individuals.
Although Kato ( 1987) added 1986 data to the previous data set, expanded thesouthern range to 38°N (where some sighting efforts existed as well as the
distribution of Dall's porpoises), and obtained the estimate of 125,000, thiswill be an overestimate due to the extrapolation of northern high density tosouthern low desnity area (Table 9). Our estimate of the Dall's porpoise in thesimilar area, 72,410 individuals (57,831 truei-types plus 14,579 dalli-types) is
close to Kato (1986).
.
Our sighting survey confirmed results of previous studies on the general
pattern of distribution of two color types of Dall's porpoises in the Japanese
coastal waters, i.e. Sea of Japan and southern Okhotsk Sea inhabited bydalli-types, and the Pacific coast of northern Ja pan and southern Kuril Islands
by both dalli- and truei-types.
Although the previous studies (Kasuya, 1978, 1982) have assumed
without firm data that the majority of Dall's porpoises that summer off the
Pacific coast of northern Japan would be truei-types, the present study showedthat the assumption was not always correct. Dall's porpoises which winter off
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN147

the Pacific coast of northern Japan south of 40°N are composed mainly oftruei-types (Kasuya, 1978, and also see below). They migrate in late summer
and autumn to waters between 40° and 45°N and east of l 45°E, and almost
disappear from the Japanese coastal waters for some short period in
September/October. We cosidered that their southbound migration probably
start in October.
The Pacific coastal waters off Sanriku (38° -41°N) and southern Hokkaido(41°-43°N) are occupied mostly by dalli-types while truei-types are summeringin an offshore northern area. This agrees with the fact that the Dall's porpoisecatches of hand harpoon fishery which was landed in October and November
at Otsuchi (39°20'N) and Yamada (39°30'N) Fish Markets on the Sanriku
coast and reportedly caught off the Pacific coast of Hokkaido were mainly(87%) dalli-types (Anon., 1985b; N. Miyazaki, per. commn in 1986), but thosetaken off the Sanriku coast in January to March and landed at the same fish
markets were mostly (96%) truei-types (Anon., 1985b; Kasuya, 1978). Suchhigh dalli-type proportion was also confirmed in early November 1986 by oneof the authors (T.M.) on the Kamaishi Fish Market (39°15'N) on the Sanriku
coast.
Hand harpoon fishery for the Dall's porpoise had been operated only in
winter season and off the Sanriku coast (Kasuya, 1978; 1982), and the annual
catch during the 1960s and 1970s fluctuated between 5,000 and 9,000
individuals with the annual mean of 6,000 individuals (Kasuya, 1982). Kasuya(I 978) considered on the truei-type stock that the population of 125 to 400
thousands will be required to sustain the mean annual take. The corresponding
net annual recruitment rates were 0.048 to 0.015. The maximum net recruitment rate (Rmax) of the offshore stock of dalli-type Dall's porpoise has been
estimated to be 0.09 (Hester, 1986), 0.08 (Ohsumi, I 986), or 0.06 (Jones,
Breiwick, Bouchet and Turnock, 1986). Although these estimates will needfurther improvement with improved biological parameters or refined model,
it will be too optimistic to consider that the truei-type stock can sustain theannual take of over 10% of the population. If the present population of
60,000 individuals is not large enough to sustain the past level of the annual
catch, then it means that the population has declined by the past catch.
Although our data are unable to prove the past decline of the stock, we
believe that such change could have occurred in the population.
Some fishermen from Iwate Prefecture (part of the Sanriku area) started
in recent years the operation during other seasons and in other areas such as
Sea of Japan off Akita Prefecture (4l 0 N), off the Pacific coast of Southern
Hokkaido, and in the southern Okhotsk Sea (Anon., 1985b; Kawamura et al.,
I 983; Kasuya, unpublished), while operating the fishery off the Sanriku coastin winter as before. This expasion of fishery was due to the increased demandof porpoise meat. The total annual catch increased to around between 10,000
and 13,000 individuals, and there has been expressed a great concern on theeffect of the catch on the Dall's porpoise populatin (IWC, 1984).
Sci. Rep. Whales Res. Inst.,
No. 39, 1988

148

MIY AS HIT A AND KASUY A

The results of the present study indicate that the recent hand harpoon
fishery in northern Japan for the Dall's porpoise hunts truei-type population
off the Pacific coast of Japan during winter and dalli-types in the Sea ofJapan-Okhotsk Sea stock in summer operation. Available statistics of thefishery do not give the catch by color type or by month. With the absence ofcatch statistics by stock or any other alternative way to estimate it, we find it
impossible to assess the effect of the current fishery on the Dall's porpoisestocks. However, it should be stressed that the current catch of Dall's porpoises
by the Japanese harpoon fishery is still over 10% of the total number of Dall's
porpoises known to migrate annually to the fishing grounds, i.e. 104, 199
individuals (46,368 dalli-types plus 57 ,831 truei-types), and that there is agreat risk of further depletion of one or more stocks of the species by thefishery.

ACKNOWLEDGEMENTS
We wish to express our thanks to Dr L. L. Jones, National Morine FisheriesService (USA), for her reviewing the manuscript and correcting English. We
also owe to Dr N. Miyazaki, National Science Museum Qapan), for his criticalreview on the earlier version of the draft, and to two anonymous reviewers
who made valuable comments on the manuscript. Mrs Y. Yamamoto and Mrs
M. Ikeya helped us in data analysis and drawings.

REFERENCES
ANON., I 985a. C. V. estimates for sighting assessments. Appendix 7.2 of the Report of the Sub-Committee
on Southern Hemisphere Minke Whale. Rep. int. Whal. Commn, 34: 92.
ANON., 1985b (ms). [Report of investigation on the dolphin stocks exploited by dolphin fishery]. Whales
Research Institute, Tokyo. 128pp. (in Japanese).
BEST, P.B. and D.C. BUTTERWORTH, 1980. Report of the southern hemisphere minke whale assessment
cruise, 1978179. Rep. int. Whal. Commn, 30: 257-283.
BoucHET, G.C., H.W. BRAHAM and L.M. TSUNODA, 1983. Investigation of Dall's porpoise (Phocoenoides
dalli) responses to a survey vessel: Preliminary assessment. IWC/SC/35/SM13. 15pp.
BucKLAND, S.T. and A.A. ANGANUZZI, 1987. Comparison of smearing methods in the analysis of minkesightings data from IWC/IDCR Antarctic cruises. IWC/SC/39/Mi2. 26pp.
BURNHAM, K. P., D.R. ANDERSON and J. L. LAAKE, 1980. Estimation of density from line transect sampling of
biological populations. Wild. Monogr., 72: 1-202.
HAMMOND, P.S., 1986. Line transect sampling of dolphin populations. pp.251-279. In: M.M. Bryden and
R. Harrison (eds), Research on Dolphins. Clarendon Press, Oxford. 478pp.
HESTER, F.J., 1986. Estimates of reproductive rates of Dall's porpoise in the North Pacific. Statement for
the Public Hearings. MMPAH-1986-01, 27pp.
HoucK, W.J., 1976. The taxonomic status of the porpoise genus Phocoenoides. ACMRR/MM/SC/114(Document presented to the FAO Scientific Consultation on Marine Mammals, Bergen). 12pp.
JONES, L.L., J.M. BREIWICK, G.C. BoucHET and B.J. TuRNOCK, 1986. Report of the incidental take, biology
and status of Dall's porpoise. National Marine Fisheries Service, NOAA. 92pp.
IWC, 1984. Report of the sub-committee on small cetaceans. Rep. int. Whal. Commn, 34: 144-159.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

DALL'S PORPOISES OFF JAPAN149

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., 1982. Preliminary report of the biology, catch and populations of Phocoenoides in the western
North Pacific. pp.3-19. In: ].G. Clark,]. Goodman and G.A. Soave (eds) Mammals in the Seas. FAO
Fisheries Series No. 5, Vo. IV, FAO, Rome. 534pp.
KASUYA, T., 1986. Distribution and behavior of Baird's beaked whales off the Pacific coast of Japan. 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. Ocr, 1987. Distribution of mother-calf Dall's porpoise pairs as indication of calving
grounds and stock identity. Rep. Whales Res. Inst., 38: 125-140.
KATO, M., 1986. Outline of sighting survey for marine mammals Japanese salmon research vessels in 1985
and estimation of Dall's porpoise abundance in the Pacific Ocean. Document submitted to theInternational North Pacific Fisheries Commission. 7pp.
KATO, M., 1987. Outline of sighting survey for marine mammals by Japanese salmon research vessels in1986 and estimation of Dall's porpoise abundance in the North Pacific Ocean. Document submitted
to the International North Pacific Fisheries Commission. 8 pp.
KAWAMURA, A., H. NAKANO, H. TANAKA, N. SATO, Y. FUJISE and K. NISHIDA, 1983. [Sighting results ofdolphins from the Aomori-Hakodate ferry boat in the Tsugaru Strait]. Geiken Tsusin 351 and 352:
29-51. (in Japanese).
KrRISHIMA, K. 1986. [Analysis of sighting results]. pp.55-77. In: T. Tamura, S. Ohsumi and S. Arai (eds)
Report of the Investigation in Search of Solution of Dolphinjishery Conflict in Iki Island Area. Japan Fisheries
Agency. 285pp. (in Japanese with English summary.)
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.
MIYAZAKI, N., Y. FUJISE, T. KoMuTo and H. TAKETOMI, 1984. [Outline of Dall's porpoise research cruiseby the Hoyomaru No. 53 in 1984]. Published by Far Seas Fisheries Research Laboratory. 47pp. (inJapanese).
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, March 11-15, 1985. 25pp.
NrsHIWAKI, M., 1972. General biology. pp. 3-204. In: S. H. Ridgway (ed.) Mammals of the Sea. Charles C.
Thomas Publisher, Illinois. 812pp.
Nocucm, E., 1946. [Dolphin and its utilization]. In: E. Noguchi and A. Nakamura, Utilization of Dolphins
and Scomber Fishery. Kasumigaseki Shobo, Tokyo. 36pp. (in Japanese).
0GI, 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 meetng of the Scientific Subcommittee,
Ad Hoe Committee on Marine Mammals, International North Pacific Fisheries Commission, Tokyo,
March 5-9, 1984. 14pp.
0GI, H., H. TANAKA, T. KuROMACHI and Y. YAMAMOTO, 1986. Outline of the research on the 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,
March 10-14, 1986. 20pp.
0HSUMI, S., 1975. Incidental catch of cetaceans with salmon gillnet.J. Fish. Res. Board. Can, 32(7): 12291235.
0HSUMI, S., 1986. Estimation of biological parameters of Dall's porpoise related to reproduction. Statement
for the Public Hearings. MMPAH-1986-01, 23pp.
SUBRAMANIAN, A., S. TANABE, Y. FUJISE and R. TATSUKAwA; 1986. Organochlorine residues in Dall's
porpoises collected from northeastern Pacific and adjacent waters. Mem. Natl Inst. Polar Res., Spee.
Issue, 44: 167-73.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

150

MIYAS HITA AND KASUY A

TURNOCK, B.J., 1987. Analysis of experiments to assess movement of Dall's porpoise in relation to survey
vessels and population estimates corrected for movement and visibility bias for the North Pacific
Ocean. Document submitted to the Scientific Subcommittee, Ad Hoe Committee on Marine
Mammals, International North Pacific Fisheries Commission, March 10-14, 1987, Tokyo. 33pp.
WALKER, W.A., 1987. Geographical variation of the parasites Crassicauda (nemotoda) 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. l 7pp.
WINANS, G. A. and L. L. JONES, (in press). Electrophoretic variability in the Dall's porpoise, Phocoenoides dalli,in the North Pacific Ocean and Bering Sea.]. Mamm.
YosmoKA, M., M. 0GURA and C. SHIKANO, 1987. Results of the transpacific Dall's porpoise research cruises
by the Hoyomaru No. 12 in 1986. Document submitted to the Scientific Committee, Ad Hoe Committee
on Marine Mammals, International North Pacific Fisheries Commission, Tokyo, Japan, March
10-14, 1987, 25pp.
Zttou, K., 1986. An outline of marine mammalogical researches in China. Acta Theriot. Sinica, 6(3): 219-32.
(in Chinese with English summary).

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

SEALS IN LOCH NESSGORDON R. WILLIAMSON*ABSTRACTA Common or Harbour Seal Phoca vitulina L. lived in Loch Ness,
Scotland, for seven months from November 1984-June 1985. Photographsof the seal are presented. This is the first time a seal has been proven in
Loch Ness. Fishermen's reports indicate that Loch Ness is visited by a seal
approximately once every two years.
INTRODUCTION
Loch Ness is one of Britain's largest and deepest freshwater lakes. It is long,narrow, deep and straight 38 km long, 1.7 km wide and 230 m deep, is 16 m
above sea level and is connected to the sea by the 12-km-long River Ness. It
lies in the valley of a former glacier. Many salmon Salmo salar L. migrate
through Loch Ness. The temperature of Loch Ness surface water ranges
4-12°C (Wedderburn, 1907). The ecology of Loch Ness is described byMaitland (1981).
Common or Harbour Seals Phoca vitulina L. have a well-known habit of
exploring up rivers and in northern Canada permanent populations ofCommon Seals live in freshwater lakes 300 km inland from the sea (Mansfield,
1967; Hewer, 1974; King, 1983). About 100 seals, both Common Seals andGrey Seals Halichoerus grypus Fabricius, live in the sea near Inverness. Individual seals of both species can regularly be seen I km up the River Ness inthe middle of Inverness town, especially at high tides. There have been several
reports of a seal in Loch Ness (Anon, 1933; 1934; 1934) and beyond Loch
Ness in the River Oich (Harvie-Brown and Buckley, 1895, pl83), but thesereports were not supported by photographs and were not believed.
OBSERVATIONS AND DISCUSSION
Between November 16, 1984 and June 11, 1985, a seal was seen in Loch Nessby myself and other people. Photographs were taken (Figs I and 2). The seal
was identified as a Common or Harbour Seal Phoca vitulina by its head profile,with turned-up nose by its grey colour with black spots and by its estimatedlength of I .Sm. The other species of seal found around Scotland, the Grey
Seal, has a long straight nose, like an Alsatian dog.
* Heather Cottage, Kessock, Inverness, Scotland, U.K.
Sci. Rep. Whales Res. Inst.,
No. 39, 1988, 151-157

52
1

WILLIAMSON

.
5
8
9
,1
7
ry2
a
u
r
b
e
e.F
l
tCast
hUrquhartihNessw
c
nLo
li
a
e
.S
.I
g
i
F

.
5
98
,1
7
y2
r
a
.Febru
s
s
e
chN
nLo
onSeali. Com m
.2
g
Fi
n.
o
i
t
i
s
o
wimmingp
als
r
u
t
a
nn
li
a
e
:s
e
Abov
esoundmade
l
t
s
i
h
oww
etoal
ns
espo
nr
di
e
s
i
a
dr
hhea
t
i
alw
e
eandbelow:s
r
t
Cen
byme.

h
eofLoc
d
i
hs
t
u
o
hes
gont
n
i
v
i
hsl
t
enmon
v
e
ss
t
fi
pentmosto
als
e
Thes
y
n
a
m
n
i
n
e
e
s
s
a
alw
e
es
h
,t
.However
)
.3
g
Fi
e(
l
t
s
a
tC
r
eUrquhatsopposi
Nes
lwas
a
e
.Thes
a
e
es
h
om t
r
s48kmfuttAugus
r
o
gF
n
i
d
u
l
nc
,i
s
s
e
sofLochN
t
r
a
p
s
n
o
i
s
a
c
c
eo
t
a
r
a
p
e
rs
u
o
hendon fctLo
fLochNessatoverexi
i
er
h
nt
ni
e
e
s
.
a
e
es
h
ot
rt
e
v
i
er
h
tdescendt
o
dn
i
td
ti
e
)y
.8
b
e
,F
3
.1
Jan
1,
.2
c
e
,D
.I
c
e
D
(
,
.
t
s
n
.I
s
sRe
.Whale
p
.Re
i
c
S
988
,1
9
.3
o
N

153

SEALS IN LOCH NESS

about 100 seals hereNt

16 Km from sea

25 Km from sea

40 Km from sea•

Places whereseat was seen

0

Fig. 3. Loch Ness showing places where the seal was seen.

This suggests that the seal "knew" where it was, was not "lost", and that itdeliberately remained in Loch Ness. The seal appeared to be in vigorous good
health throughout its stay in Loch Ness. The seal was shot on June 11, 1985.
About 30 people reported about 60 separate sightings of the seal to me.
Of these 30 observers, twenty-eight were local. people who had close contact
with the surface of Loch Ness - either fishermen in salmon-trolling boats or
people who lived beside Loch Ness. Of the hundreds of thousands of people,
locals and visitors, who drove along the roads beside Loch Ness during the
7-month period, only two (that I know of) - a pair of Australian tourists at
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

1
54

WILLIAMSON

d心、フP竺、こフ ~~
Fi
g
.4
.S
e
a
lma
k
ings
u
c
c
e
s
s
i
v
ejumps
.a
ss
e
e
nbyf
i
s
h
e
r
m
a
nMrGe1T
yB
r
e
a
u
.

Fi
g.5
. A Comm
onSeal
jump
i
ngi
ns
e
ane
a
rOrkneyIslands.Phot
og
1
aphb
yP
a
u
l
Thomp
s
o
n
.

Urquhar
tC
a
s
t
l
e‑no
t
i
c
e
dt
hes
e
a.
lCom monSeal
sspendonl
yabout20% oft
het
imeatt
hes
urf
a
c
e
,andmakedive
sof3‑8minut
e
sd
u
r
a
ti
on(
P
.Thompson,pers.commn).Con
c
l
u
s
i
o
n
:i
nLochNe
s
si
ti
sv
e
r
yhardt
onoti
c
es
u
chas
mal
animala
sas
e
alu
n
le
s
syouspendmanyhour
sc
lo
s
et
ot
hew
a
t
e
r
.Whi
l
ea
tt
h
e
s
u
rf
a
c
e
,t
hes
e
albr
e
a
t
hedi
nandoutabout24t
imesperminute(measuredby
obs
er
vi
ngt
her
i
s
eandf
alofi
t
sbackwhenthesealwas日oatinghori
z
o
n
t
a
l
l
y
)
.
Thes
e
alo
f
t
enf
o
l
lowedtheboatsofs
almon fi
shermenwhotrolalong
t
hes
i
de
soft
heLoch,
of
t
enf
olowi
ngab
o
a
tf
orhal
fanhour,totheannoyance
oft
hef
is
hermen.OnedayfishermanMrGerr
yBr
eaua
c
c
el
er
a
t
e
dh
i
sb
o
a
t【O
t
ryt
ogetawayf
r
om t
hes
e
al
,andt
hes
e
alcha
s
e
da
f
t
e
rt
heb
o
a
ta
tt
o
ps
p
e
e
d
,
l
eapi
ngoutofandint
ot
hewatert
ens
u
c
c
e
s
si
vejumpsl
i
k
eap
o
r
p
o
i
s
e(
Fi
g.
4
)
.
However,thisbeha
vi
o
u
rwa
son
lys
e
enononeo
c
c
a
s
i
on
.
F
is
hermenandr
i
v
e
rbai
l
if
f
si
nf
o
rmedmeoft
hef
olowi
ngs
i
ghti
ng
sof
s
e
al
si
nLoch Nessduringr
e
c
en
tyear
s
:
1
972‑8
0
: About4s
e
al
ss
e
eni
nv
ar
iouspar
t
soft
h
eLo
c
h
,i
n
c
lu
d
ing2
t
o
g
e
the
ra
tmouthofR
iverMor
i
s
t
o
n
.
1
981April‑Augus
t
:Is
e
als
e
enatmout
hofR
iv
e
rMori
s
t
o
n
.
1
984November‑]une1
985:Isealse
en in many par
t
sofLo
ch (
t
hi
s
r
epor
t
).
Sc
.
iRe
p
.Whal
e
sRe
s.I
n
s
t
.
,
No.39
,19
88

SEALSI
N LO
CH NESS

155
LO
YAL

事
−

河初得

・・

−
z 主− eagEg22 8
h
g
t
−
Ez
−z

..
.
脚帆

，
。
0・·~・＂＇，。伺”・＇＂＂・1

"
°
"

F
i
g
.6.Dist• i
b
u
t
i
o
nofs
e
al
si
nS
c
o
u
i
s
hl
o
chs
,p
r
o
b
a
b
l
yPhocav
i
t
u
l
i
n
α

1
985October: Anadul
tanda4・month‑oldyoungCommonSeals
e
en
t
o
g
e
t
h
e
ra
tDochfourWeirandnearF
o
y
e
r
s(
i
den
t
i
f
i
e
d
fromphotographstakenbyMrJohnBal
ie
y
)
.
Thist
o
t
al
sabout8s
e
al
si
n1
5year
s(
1
9
7
2‑
8
6
)
:anaverageofones
e
ale
n
t
er
i
ng
Lo
ch Nesse
v
er
ytw
oy
e
a
r
s
.Twos
e
al
st
o
g
et
herweresee
nontwoo
c
c
as
i
o
n
s
.
The numbe
rofs
e
a
l
sr
e
p
o
r
t
e
dbyi
n
d
ivi
d
ualf
is
hermenv
a
ri
edgr
e
at
ly:onemanhads
e
ens
i
xs
e
al
sdur
i
ngt
heper
io
d
,s
omemenhavenevers
e
e
nas
e
al
y
e
t
.
S
e
a
l
si
nLochNessl
i
ve
di
ngoo
dheal
t
handt
hep
l
a
c
eatwh
ichs
e
al
swere
mo
s
tcommonl
ys
e
e
nwast
h
emout
hoft
heR
iv
e
rMori
s
t
on(
Fi
g
.3
)
,a
l
t
hough
t
hep
r
e
s
e
n
ts
e
alwasnots
e
e
nt
h
e
r
e
.S
e
a
l
si
lvedi
nLochNe
s
sf
o
rupt
os
e
v
e
n
months.Whatfinalyhappenst
os
e
al
st
h
a
ten
t
e
rLoc
hNess?L
o
c
a
lment
ol
d
met
h
a
ts
e
v
e凶 s
e
al
shavebeens
hotbys
almonfishermen.Onerai
nyJan凶 r
y
da
ys
omey
e
a
r
sagowhent
heR
iverNesswasi
ns
pa
t
e
,ab
i
gs
e
alwasseenswimmingdowntheRiverNessatDochgarrochnearDo
chf
ou
r
.I
tseemst
h
a
t
mosts
e
al
st
h
a
ten
t
erLochNessg
e
ts
ho
t
,b
u
.
tafewr
e
turnt
ot
hes
e
a
.
As
e
almakings
uc
c
e
s
si
vejumps
,e
s
p
e
c
i
a
l
l
yi
fs
e
ens
il
houe
t
t
e
da
g
a
i
n
s
tt
h
e
s
e
t
t
i
n
gs
un,e
t
c
.coul
dwell
o
o
kl
i
k
eamany‑humpeds
erp
entormonst
e
r(
F
i
g
s
4‑5
)
. Perhapsa proportionofs
i
g
h
t
i
n
g
soft
h
e Loch Ne
ss Monster"andother s
e
a
‑
s
e
r
p
e
n
t
s maybes
i
g
h
t
i
n
g
sofjumpings
e
al
s
.A s
uc
c
e
s
si
v
e
て
jumpi
ng
S
c
i
.Rep
.Whal
e
sRe
s
.I
山 t
.
,
No.3
9
,1988

156

WILLIAMSON

seal looks more like a "sea-serpent" than a dolphin: a seal jumps equal-length
jumps in fast close-spaced rhythm; whereas a dolphin jumps regularly andthe jumps are spaced further apart.
The distribution of seals in the larger Scottish lochs is shown in Fig. 6
and was discovered by interviewing fishermen and river bailiffs etc. In nearto-the-coast Loch Shiel, Hope and Maree, seals are seen as follows:
L. Shiel : one or two seals seen most years, may stay several months, once
five seals seen together.
L. Hope : one seal six weeks in loch June-July 1983, one definite Grey Seal
one month in loch August 1984.
L. Maree: one seal seen 1981, five seals seen Sept-Oct 1983.
In lochs which have hydroelectric dams blocking their outlet river, suchas Lochs Morar, Lochy and Awe, seals are not seen. In former times in Loch
Awe, however, when the outlet river flowed freely to the sea, seals were seen:"The seal comes up from the ocean, through a very rapid river, into Loch
Awe in quest for salmon, and retires to the sea at the approach of winter".
(Anon, 1793, p260). "For ten years, up to 1883, we saw one or more seals in
Loch Awe almost every year, most frequently in the Autumn, but also in Aprilin some years". (Harvie-Brown, 1891). In Loch Lomond, which is near the sea
and whose river is unobstructed, seals have not been reported (P.S. Maitland
pers. commn): perhaps the industrial pollution in the Firth of Clyde during
the past century is the cause.
The former occurrance of seals in Loch Awe is interesting for it provesthat seals can ascend rivers at least four times steeper than the R. Ness (slopeof R. Awe 5. lm/km, R. Ness l.3m/km). (Fig. 6).
In rivers on the east coast, the furthest upstream places and distances
above tidewater at which individual seals have been seen are:R. Spey
Aberlour 27 km
R. Deveron : Bridge of Marnoch 30 km
R. YthanFyvie 37 km (A young Common Seal was photographed Nov.
30, 1984).
R. DonGrandholme Works 2 km (Industrial pollution and weirs inriver).
Park Inn Pool, Drumoak 19 km
R. DeeCaputh 24 km.
R. TayCONCLUSION

The data presented prove that a Common or Harbour Seal lived in Loch Nessduring seven months of 1984-85, indicate that Loch Ness is entered by a seal
about once every two years, and prove that a seal can live for many months
in Loch Ness. The route of entry of a seal must be from the sea up the River
Ness. These data suggest that past reports of seals in Loch Ness were true andthat seals have probably been visiting Loch Ness for thousands of years.
Sci. Rep. Whales Res. Inst.,

No. 39, 1988

SEALS IN LOCH NESS

157

ACKNOWLEDGEMENTS

I thank following persons, R. Niall Campbell, Peter S. Maitland, Paul
Thompson, Sidney G. Brown, Sheila Anderson, John Horwood, Mike Fedak,
Julian Hunter, Tony Harmsworth, Adrian Shine, Dick Raynor, Gerry Breau,
John Bailey, Tony Chapman, Willie Paterson, D.G. Smith, Samantha Paske,
Sandy Steel, George Reid, Peter Grant, John Cathcart, Brian Allely, Andy
Brady, Alec Slaney, James Macdonell, Peter Wilkinson and Angus Kennedy.
REFERENCES
ANON., I 793. Statistical Account of Scotland. Edinburgh. 6.
ANON., 1933. Strange spectacle on Loch Ness. What was it? Inverness Courier newspaper, May 2.
ANON., 1934. Loch Ness Mystery: Seal said to be seen at Fort Augustus. Inverness Courier newspaper,Jan. 16.
ANON., 1934. A Grey Seal: London scientists and Monster's identity. Inverness Courier newspaper, Oct 5.
HARVIE-BROWN, J.A., 1891. The Common Seal in freshwater streams and lochs of Scotland. Scottish Naturalist, Jan 1891: 1-5.
HARVIE-BROWN, J.A. and T.E. Buckley, 1895. A fauna of the Moray Basin. Edinburgh, David Douglas.
HEWER, H.R., 1974. British Seals. London, Collins.
KING, J.E., 1983. Seals of the World. London, British Mus. Nat. Hist./Oxford Univ. Press, 2nd edition.
MAITLAND P.S. (ed), 1981. The ecology of Scotland's largest Lochs. Lomond, Awe, Ness, Morar and Sheil. The
Hague, Junk. 283pp.
MANSFIELD, A. W., 1967. Distribution of the Harbour Seal Phoca vitulina Linnaeus in Canadian arctic waters.
]. Mamm., 48: 249-257.
WEDDERBURN, E. M., I 907. The temperature of the freshwater Lochs of Scotland, with special reference toLoch Ness. Trans. Roy. Soc. Edin., 45 (2): 407-489.

Sci. Rep. Whales Res. Inst.,
No. 39, 1988

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 borealis
L.).

8-10

Akiya, S., S. Tejima, and Y. Ishikawa. Studies on the utilization of whale meat by the use of pancreatic
tryptase of whales. 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 B, 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--06

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. I). 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 whalr. 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 of Japan. 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 tl:ie 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 ofhistidine from whale blood using 3,4-dichlorobenzene sulfonic acid.
41-47
Tawara, T. and R. Fukazawa. Studies on kitol. IV. Purification of kitol 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(Balaenopteraphysalus) 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 haleen plates as the sign of annual growth. 133-152
Nishiwaki, M. and T. Hibiya. On the sexual maturity of the sperm whales (Ph_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. Experimental 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 sei-, 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 (Prodelphinus caeruleo-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 I955
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 ,Z,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 I I, JUNE I 956
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 I2, JUNE I957
Omura, H. Osteological study of the little 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 of linear 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. Banda. 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. lchihara 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
lchihara, 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 of Japan. 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 131 1 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 of cetacea. 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. Ichihara 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. Calaprire. 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 of Ca/anus cristatus and C. plumchrus in the Bering and its neigh·bouring 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 withleadsal t 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, M. 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 (Stenella attenuata) from Arari,Japan. 53-64
Nishiwaki, M., T. Kasuya, T. Tobayama, T. Kamiya and M. Nakajima. Feresa altenuata captured at the
Pacific Coast of Ja pan 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 (Stenella 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
Ichihara, 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
Ichihara, 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.

213-221

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. lchihara 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 of sei 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. Itoh. 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-H7

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 Mesoplodon 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. Po.;sible migration route of the gray whale on the coast of Japan. 1-14
Sa take, Y. and H. Omura. A txonomic study of the minke whale in the Antarctic by means of hyoid 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 Stenella 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 Stenella 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. Tht> hyoid bones of two kinds of harbour seals in the adjacent waters of Hokkaido. 313-3~0

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 ofGlobicephala melaena in the western North Pacific. 95--108
McCann, C. A study of the genus Berardius Duverney. 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 Stenella 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 Qvamus 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 oflipid 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 w1'aling 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. l-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 lzu
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 ol Dugong dugo11.
301-310
Kagei, N., K. Asano and M. Kihata.
superba. 311-313

On the examination against the parasites of Antarctic krill,

Euphausia

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 11ovaeangliae, 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 macrorhy11chus 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 ]. Bou. On a massive stranding of short-finned pilot whale, Globicephala macrorhynchus
Gray, 1846, on Margarita Island (Venezuela). 145-148
Mermoz, ]. 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. l19-124
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 of bowhead 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 of Dall'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,]. 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, J. 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 appraisal. 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. lvashin. 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.

NUMBER 39, MARCH 1988
Omura, H. Distribution and migration of the western Pacific stock of the Gray whale. 1-9.
Kato, H. Ossification pattern of the vertebral epiphyses in the southern minke whale. 11-19.
Paterson, R. A. and S. Van Dyck. Bryde's whale in the coastal waters of eastern Australia. 21-29.
Kasuya, T. and T. Miyashita. Distribution of sperm whale stocks in the North Pacific. 31-75.
Kasuya, T., T. Miyashita and F. Kasamatsu. Segregation of two forms of short-finned pilot whales off the
Pacific coast of Japan. 77-90.
Wada, S. Genetic differentiation between two forms of short-finned pilot whales off the Pacific coast ofJapan. 91-101.
Kasuya, T., D. E. Sergeant and K. Tanaka. Re-examination of life history parameters of long-finned pilot
whales in the Newfoundland waters. 103-119.
Miyashita, T. and T. Kasuya. Distribution and abundance of Dall's porpoises off Japan. 121-150.
Williamson, G. R. Seals in Loch Ness. 151-157.

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
Balaenoptera musculus 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, 39: 21-29
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, 39: 11-19
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
Ziphiussp. 37: 109-127
Ziphius cavirostris 24: 1-34
Berardius 27: 111-137
B. bairdii 10: 89-132
Hyperoodon planifrons 28: 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, 39: 91-102, 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
Eschrichtiusrobustus

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
Isoenzyme 38: 141-163, 39: 91-101

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: 4 7-56
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 I: 41-4 7
Sensory tubercle, lip 3: 1-16
Lingual margin 28: 137-140
Taste buds, Stenella 30: 285-290
Tongue, Sirenia 32: 127-144
Head section, Stene/la 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, lnia 36: 89-95
Stomach 23: 91-101, Inia 33: 69-81

11

Renculi 13: 253-267
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: 269-301
Epidermal cyst 31: 93-94
Small cetaceans; Tierra de! Fuego 30: 197-230
Mirounga leonina 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
Isoenzme 38: 141-163, 39: 91-102

Body and organ weight
Eubalaenaglacialis 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
Stenella attenuata 26: 157-226
S. coruleoalba 33: 27-67
Platanista gangetica 24: 87-108, 26: 265-270
Pontoporia 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

Ear plug 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 spp. 35: 57-91, 39: 103-119
Tursiops truncatus 32: 39-66
Stene/la caeruleoalba 8: 133-146, 24: 57-79, 28:
73-106, 29: 21-48
S. attenuata 26: 157-226, 28: 73-106
Platanistagangetica 24: 87-108
Pontoporia 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
Eubalaenaglacialis 13: 1-52, 21: 1-78
Eschrichtius robustus 5: 71-79, 13: 201-205, 22:

29-37, 22: 39-43, 26: 1-14, 39: 1-9
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, 39: 11-19
Megaptera novaeangliae 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:
39-4~ 37: 167-172, 39: 31-75
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
Balaenoptera musculus

iii
Odontoceti 34: 1-4 7
Oreinus orca 13 : 85-96
Globicephala spp. 27: 95-110, 35: 57-91, 36:

Balaena mysticetus 35 : 1-16
Balaenoptera borealis 22: 127-152, 22: 153-158,

97-106, 39: 77-90, 39: 103-119
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, 39:
121-150
Neophocaena phocaenoides 31: 1-44
Cephalorhynchus commersonii 32: 149-154, 36:
153-164
Platanistagangetica 24: 87-108, 24: 109-115, 27:
81-94,29: 87-94
Pontoporia blainvillei 31 : 45-67
School, baleen whales 18: 89-110
Corpora albicantia 18: 123-148
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: 175-185, 39: 151157
Distribution, Phoca 31 : 105-119
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

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: 153-

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

25: 219-236, 25-144

161, 18: 111-122, 28: 145-151, 32: 199-218
Kogia simus 38: 171-186
Orcinus area 29: 107-111
Stenella 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
27-36
Energy budge 27: 61-79

23:

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, 39: 1-9, 39: 77-90
Statistical review 25: 105-203
Pack-ice limit 29: 137-141
Sighting
By boat 25: 205-217, 26: 289-302, 30: 117178, 30: 179-195, 39: 121-150
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 1 : 3-7
pancreas I: 8-10, I: 11-14, 2: 55-60,
3: 71-78
Whale meat, peptone I : 15-16
freshness I: 17-26, I: 28-30, 2: 3134, 3: 63-70, 5: 1-4, 6: 167-176,
7: 23-3~7: 31-36,9: 1-10
tryptophane 2: 51-54
digestion 2: 61-66

iv
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
Krill 28: 167-174
Metal, Dugong 31: 125~128

Organochlorine compounds,Dugong
Mesoplodon 38: 91-105

31: 125-126

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, I: 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.]. 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
del Campo, S. B. 30: 117-177
Delhon, G. A. 38: 107-115
Dixon,]. 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: 16~ 13: 269-301, 19: 105-133, 21: 95-123, 23:v

vi
91-101

I
Ichihara, 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: 127, 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: 105-12~
32: 127-144, 33: 69-81, 33: 127-129
Kaneko,A. 2:46-50
Kanno, H. 2: 42-45
Kasamatsu, F. 39: 77-90
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: 1-103, 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: 125-140,39:31-

75, 39: 77-90, 39: 103-119, 39: 121-150
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: 39-4~ 38: 47-73, 39: 11-19
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
Kita, K. 35: 165-172, 36: 89-95
Klima, M. 30: 253-269
Koba, 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. l 7: 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,]. 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
Miyashita, T. 39: 31-75, 39: 77-90, 39: 121-150
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
Mol, T. 21-125-129

viiMori, 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
Nakai,]. I: 41-47
Nakai, T. I: 17-26, I: 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, II: 132, II:
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: 1-16, 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: 139-14~ 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: 6169, 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, l l: 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: 183-193,39: 1-9
Ono, H. 6: 177-185
Osawa, M. 13: 303-307
Oya, M. 29: 121-128pPagnoni, G.

38: 107-115

Panizza,]. 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,]. 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

viii
167-174

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, 39: 103-119
Shida, T. 1: 41-47, 3: 1-16
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

Wada, K. 29: 129-135
Wada, S. 30: 179-195, 30: 233-246, 33: 1-26,
39: 91-101
Watar, T. 10: 151-167
Watkins, W. A. 33: 83-117
Williamson, G. R. 25: 279-292, 27: 37-59, 39:
151-157

TyTakahashi, 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
Tanaka, K. / 39: 103-119
Tanza~. 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:

Yabu, 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: 49-52

uUchida, 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: 125-129w

zZhao, 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

Editorial Board
HmEo OMURA; Editorial Director
SEIJI OHSUMITAKAHISA NEMOTO
Tosmo KASUYA
TosmRo KAMIYAy ASUHIKO NAITO
General Secretary
HrnEHIRO KATO
TosmE SHIRAI

11B fo 63 ±f. 3 A Is 13
11B fo 63 ±f. 3 A 30 13

Mffil*Af.Wlt

m~p .IPIJ~rr

13 ::<$: tJft Afj( ~ ~1iJf ~m

JltJll::mi'.I:Jlt 1253: ~ 3 T ~ 32 ift: 11 -%*1iJf ~ f± FP ,lj!Ij ;f* ~ ~ f±j\lj- ::i;:

* *'f

~ $

Printed by
Kenkyusha Printing Co.
Niiza-shi, Saitama 352!l!f )<. li:: 7-14-8~{illi

Obtainable from Japan Publication Trading Co. Ltd.,
Sarugakucho, Chiyoda-ku, 1-2-1, Tokyo 101

4,000 FI