ISSN 0083-9086

THE

SCIENTIFIC REPORTS
OF
THE WHALES RESEARCH INSTITUTE
No. 34

THE WHALES RESEARCH INSTITUTETOKYO·JAPANl

Sci. Rep. Whalesl~

DECEMBER 1982

THE
SCIENTIFIC REPORTS
OF
THE WHALES RESEARCH INSTITUTE

No. 34

THE WHALES RESEARCH INSTITUTETOKYO, JAPANDECEMBER, 1982

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

THE SCIENTIFIC REPORTS OF THE WHALESRESEARCH INSTITUTE
CONTENTS OF NUMBER 34Page

SERGEANT, D. E.
Mass strandings of toothed whales (Odontoceti) as a population phenomenon ..................................................... .
NrsHIWAKI, M.
The mandible of bowhead in Kathmandu . . . . . . . . . . . . . . . . . . . . . . . . . .

49

KAWAMURA, A.
Food habits and prey distributions of three rorqual species in the North
Pacific Ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
ZHOU, K.
Classification and phylogeny of the superfamily Platanistoidea, with noteson evidence of the monophyly of the cetacea. . . . . . . . . . . . . . . . . . . . . . . . 93
NrsHIWAKI, M. and T. Tobayama
Morphological study of the hybrid between tursiops and pseudorca. . . . 109
KATO, H.
Food habits of largha seal pups in the pack ice area ................ 123
NrsHIWAKI, M., M. YAMAGUCHI, S. SHOKITA, S. UCHIDA and T. KATAOKA
Recent survey on the distribution of the African manatee ............ 137

日 次
S
e
r
g
e
a
n
t
,D.E
.
歯鯨類の集団乗り上げについての考察．．．．．
西脇昌治
カトマンズに保存されている鯨の大下顎骨について．．．．．．．．．．．．．．．．．．．．．．．．．．．．

49

河村章人
北太平洋産ヒグクジラ 3種の餌生物．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．．

59

Zhou,K.
カワイルカ上科の系統，附鯨類の単一先祖説について．．．．．．．．．．．．．．．．．．．．．．．．．．

93

商脇昌治・鳥羽山照夫
09
パンドウイルカとオキゴンドウの交雑種について.............................. 1加藤秀弘
流氷域におけるゴマフアザラシ （Phocalargha）の食性，特に当才獣について........ 1
2
3
西脇昌治・山口正士・諸喜田茂充・内田詮三・片岡照男
3
7
アフリカ・マナティーの現状................................................ 1

MASS STRANDINGS OF TOOTHED WHALES (ODONTOCETI)
AS A POPULATION PHENOMENON
D. E. SERGEANT
Fisheries and Oceans Canada, Arctic Biological Station, 555 Blvd. St.
Pierre, Ste. Anne de Bellevue, Quebec, H9X 3R4, Canada

CONTENTS

Abstract
Introduction
Three case histories
a. North Atlantic pilot whale Globicephala melaena in the northwest
Atlanticb. White-sided dolphin, Lagenorhynchus acutus in the northwest Atlanticc. Sperm whale Physeter catodon at New Zealandd. Conclusions
Distribution of mass strandings among the Odontoceti
a. Definitionb. Offshore and onshore mortalityc. Reporting bias
d. British strandings(i) Frequency of mass strandings(ii) Consistency of mass strandings through timee. Strandings in the southern hemispheref. Strandings in Florida
g. United States Eastern Seaboard
h. Geographical variation in mass stranding rate within a species
i. Individual species considered
Social structures compareda. Orcininae
b. Delphininaec. Phocaenidae
d. Sperm whale
Herd size
Age-specific mortality in Cetacea
a. Generalb. Mysticetes
c. Odontocetes
Reproductive cycles of Mysticetes and Odontocetes
Density-dependence
a. Time series within one populationb. Comparisons of two populations of the same species(1) by the same author(2) by different authors
Sci. Rep. Whales Res. Inst.,
No. 34, 1982, 1-47

2

SERGEANT

Proximate causes of strandings
Mass strandings as emigrations
Practical applications
Summary
Acknowledgments
References
ABSTRACT

From a study of Globicephala melaena and Lagenorhynchus acutus in thenorthwest Atlantic, and Physeter catodon at North Island, New Zealand, it isshown that mass strandings of Odontoceti occur at high population densities.
Moreover, within the range of a single species, mass strandings occur withinthe " core " of the range but not at its periphery. They occur at high frequency among species of the subfamily Orcininae. In Globicephala spp. andPseudorca crassidens the stranded herds include all sizes of animals of both
sexes, and these species are therefore highly social. Amongst most Delphininae, mass strandings occur at lower frequency. Herds consist of reproductively mature animals and calves, or of immatures, or solitary immatures
may strand. These species are therefore less social and, in captivity, an adultmale Tursiops truncatus is aggressive towards immature animals. The social
Orcininae nevertheless show greater sexual dimorphism than the Delphininae,
a more delayed sexual maturity and a lower frequency of males, features
usually associated with polygyny. The sperm whale Physeter catodon shows
frequent mass strandings of harem herds and occasional mass strandings ofadolescent males in warm seas, singleton strandings of solitary males in coolseas.
Age-specific mortality rates of Odontoceti and Mysticeti were studied
from length-frequencies of stranded as compared with randomly-captured
animals. Two Mysticetes (minke, humpback) showed a high mortality of
newly-weaned animals, and minke-a high mortality at greatest lengths,
among strandings. A weakly social Odontocete (Phocoena phocoena) showed
the first feature. Three Delphinid species showed evidence of more evenmortality through all ages. This feature is related to their sociality, including
long parental care. Nevertheless there is evidence for enhanced mortality ofimmatures of both sexes in species showing aggression by adults. There isalso evidence for density-dependent reproduction in several species of Odontoceti, though not so far in the most highly social Orcininae. Since most
mortality in these latter species is mass mortality, mass mortality must regulate their populations. Psychological mechanisms leading to mass strandings remain to be investigated, but could include stress. The animals about
to strand are regarded as being in a passive, moribund state, drifted to thecoastline by currents.
INTRODUCTION

The Cetacea are divided into two suborders which differ in many ways, not least
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

3

in size. The baleen whales or Mysticeti are all large (6 to 30 m adult body length)and feed by engulfing organisms much smaller than themselves which they trap
and strain with their baleen plates. The toothed whales or Odontoceti are smaller(2 to 15 m) and feed on fish or squids not so much smaller than themselves. Veryoften, active cooperation aids capture of their prey, a habit which may have resulted
in their commonly found and highly-developed social behaviour. Only among
the Odontocetes, especially in the most highly social families, do we find the very
curious tendency to come ashore and die in groups; the phenomenon of mass strandings. Mysticetes are found stranded en masse in only one circumstance, whenpressed by pack ice on to the shore, a phenomenon found also in Odontocetes thatlive in cold seas (Taylor 1957; Sergeant, Mansfield and Beck 1970). This seems
to be an accidental phenomenon, which does not necessarily imply social behaviour,
other than that individual whales may be feeding or travelling together.
Mass-stranded animals are not obviously diseased or in an abnormal bodystate, and the phenomenon has so far defied explanation (Geraci 1978). Observers
who have sought the cause at the level of the specific site and set of circumstances
have so far produced no convincing explanations. \Vhile the stranding animals
must be exhibiting abnormal behaviour, since it is almost always lethal, I havefound it useful to look first at the phenomenon at the level of the population.
Opportunity to do this came from the lucky chance that 30 years' data existed,from 1950 to date of writing (1981), on the abundant north Atlantic pilot whale
Globicephala melaena at Newfoundland. I also found some less complete data on
another delphinid, the white-sided dolphin Lagenorhynchus acutus in the northwest
Atlantic, and on the sperm whale Physeter catodon at New Zealand. I have also been
fortunate in that networks of published strandings have increasingly developed inrecent years, notably in France and the United States.
THREE CASE HISTORIESNorth Atlantic pilot whale Globicephala melaena in the northwest Atlantic.
Northern pilot whales have long been known to mass-strand in cool watersof the North Atlantic, from Cape Cod to Newfoundland, in Greenland, and from
France to Iceland (Figure 1). In several regions of their abundance, especiallyat the Faeroes and at Newfoundland, inshore fishermen have taken advantage ofthis tendency to drive the animals ashore (Mitchell 1975a).
Catching in Newfoundland was intensive, with an organised industry, from1947 to 1971 (Fig. 2). In the later years of this drive-fishery, annual catches became very low. It appeared that a population, of ill-defined extent, but probably
inhabiting the area east of Newfoundland, had been decimated; the total catchhad been approximately 54,000 animals (Mercer 1975). Figure 2 shows that highcatches at the outset, peaking in 1956, were steadily reduced, lesser fluctuations
being associated with variable abundance of the main food, the squid Illex illecebrosus, from year to year. There was, however, no overall decline of squid overthe period of decline of pilot whales.
a.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

4

SERGEANTFig. 1. P
a
r
to
fa he
r
d of58 pi
l
o
tw
h
a
l
e
sG
l
o
b
i
c
e
p
h
a
l
am
e
l
a
e
n
as
t
r
anded a
tP
o
r
t
Mait
l
a
nd,NovaS
c
o
t
i
a(
4
4
°
0
1N,66
°1
0叫 ＇
）August 1
‑2
,1
9
6
0
. Photo byKen
Ox
ne
r
,Ya
r
mout
h,N
.
S
.

Thear
eai
nhab
it
e
db
yG.m
e
l
a
e
n
at
hroughoutt
hey
e
a
ri
so
v
e
rdee
pw
a
t
e
r
,ex
・
t
en
d
i
ngi
nt
ot
h
eCont
i
ne
nt
a
lS
l
o
p
e
,whe
r
et
h
es
pe
c
i
e
si
sg
e
n
e
r
a
l
l
yabundant(
F
i
r
3
)
. Inl
at
es
umme
rwate
rt
emp
e
r
a
t
ur
e
sbe
c
omewarm enought
oa
l
l
owt
hes
qu
i
d
andpu
r
s
u
i
ngp
i
l
o
twha
l
e
st
oc
onc
ent
r
a
t
eo
v
e
rt
hecont
i
n
e
nt
a
ls
h
e
lfandi
ns
h
o
r
e
.
Du
r
ingt
heper
i
odoft
h
ed
ri
vef
i
she
r
y
,t
he
r
ewerenon
a
t
u
r
a
ls
t
r
a
n
di
n
g
si
n
e
a
s
t
er
口N
ewfoundl
and. Th
i
si
ss
c
a
r
c
e
l
ys
u
r
pr
i
s
i
ngs
i
ncef
i
s
hermenactivel
ydrove
pi
l
otwha
l
e
sa
s
ho
r
℃ i
nmuchofthearea(Conce
pt
i
on,Tr
i
ni
t
y
,Bona
v
i
s
t
aandNotreパ：herewasones
t
r
a
n
di
n
gi
n1
9
57i
nw
e
s
t
巴r
nNewfoun
d
la
nd
Dameb
a
y
s
)
. However
(
S
er
gean
t
,Mans
f
ie
l
dandBeck1
970)wherenodr
i
v
ingt
o
o
kp
l
a
c
e(Tabl
e1
)
.
Wh
i
lep
i
l
o
twha
l
e
sap
pe
a
r
e
dt
obes
c
a
r
c
ee
a
s
tofNewfoundl
andi
nt
h
el
a
t
e
S
c
i
.Rψ
.Whale
sRe
s.I
n
s
t.
,

N
o
.3
4
,1
9
8
2

MASS STRANDINGS OF TOOTHED WHALES

5

Globicephala melaena
Newfoundland

10

...,
I

....><
C>

Vl

(j)

iii
..r::.

;:
0

=a
....

cumulative

catch-54,348

5

end of0..r::.

whaling,

I.I

mass
strandings

I

j"~+

I'll

u

1960

1950
Fig. 2.

Globicephala melaena.

1970

1980

Catches and strandings at Newfoundland, 1948 to 1980.

1950's to early 1970's, they were still common off Nova Scotia (Fig. 3), and natural
mass strandings took place both on the mainland and at offshore Sable Island(Table 1). This adjacent popula,tion must have contributed to the rather rapid
recovery that took place when hunting stopped at Newfoundland, where by 1980
pilot whales were again abundant off the eastern coast (K. Hay, unpublished MS
1981 ).
In 1972 all whale hunting in Canada, with the exception of aboriginal hunting
in the arctic, was prohibited. In 1975, natural strandings of pilot whales began
to occur at Newfoundland (Mitchell 1977, Geraci and St. Aubin MS 1975; Table
1). Such had been the change in the world climate of opinion about Cetacea thatfishermen were employed to save the animals by towing them to sea. In 1978 twomass strandings occurred at Miquelon Island off Newfoundland's south coast, andone in Notre Dame Bay on the east coast. In 1979 one large stranding occurred on
the Burin Peninsula on the south coast. In 1980 strandings occurred on the south
and northeast coasts of Newfoundland, and one at Prince Edward Island (Table 1).
In 1981 there were two mass strandings in Newfoundland, one at the Magdalen
Islands, Quebec, four in Nova Scotia and Cape Breton Island, and one at Cape
Cod, Massachusetts. In 1980 K. Hay (unpublished MS 1981) estimated fromaerial survey at least 14,000 pilot whales in Newfoundland's eastern waters up to
150 km offshore, and animals were seen to enter inshore waters in large numbers
Sci. Rep. Whales Res. Inst.,

No. 34, 1982

SERGEANT

6

Globicephala melaena
o May-Oct.
• Nov.-April
100 fathoms

•
00
0

o·

;o
5'11s0o

o

•
o

•o

0

•
0

..
35

0

.-0 ..
J

70°

I
65°

60°

55°

50°

45°

Fig. 3. Sightings and strandings (s) of G. melaena in the northwest Atlantic, 1957 to1972 (from Sergeant 1979).

in early September (M. Moore, pers. comm.). In 1981 large numbers agam
entered inshore waters in late summer.
Mass strandings had therefore begun, coming from a population which had
increased again and resumed its habit of moving inshore in late summer. A roughassessment of mortality due to mass strandings of G. melaena at Newfoundland in1975 to 1980 can be made from the mean number stranded (Table 1), which is
not less than 150 out of the population estimate of at least 14,000, or about 1%;
this assumes that all animals were vulnerable to this kind of death, and excludes
animals further than 150 km offshore. This is not a large proportion, but fromthe 1980 and 1981 data, mass strandings seem to be increasing in frequency andin area affected, if not in total number of animals dying.

b.

White sided dolphin Lagenorhynchus acutus in the northwest Atlantic.
Lagenorhynchus acutus was observed at Newfoundland (Sergeant and Fisher
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

7

MASS STRANDINGS OF TOOTHED WHALESTABLE 1. MASS STRANDINGS OF PILOT WHALES IN EASTERN CANADA, 1957-1980
Sources: Sergeant, Mansfield and Beck (1970); Geraci and St. Aubin (1975, 1977),
Mitchell (1977, 1980, 1981, MS 1981).
Date

Lat.

Long.

Locality

Province/State

Number

VIII 1957
x 1959VIII 1960
XII 1967
24
IX 1975
28
XII 197626
IX 1978
19
3
x 1978VII 1979
16
x 198018
x 198025
9-18 XI 1980

49°51'
43°58'
44°
46°13'
48°35'
43°58'
47°
49°28'
46°54'
49°09'
47°15'
46°23'

57°48'
59°48'
66°10'
59°57'
53°30'
59°48'
56°15'
53°56'
55°33'
55°20'
55°30'
63°48'Cow Head
Sable I.
Yarmouth
Glace Bay, Cape Breton I.
Charleston, Bonavista Bay
Sable I.
Miquelon-LanglandeMusgrave Hbr., Notre Dame Bay
Pt. au Gaul, Burin Peninsula
Pt. Leamington, Notre Dame Bay
Grand Beach, Burin Peninsula
Bedeque Bay

Newfoundland
Nova Scotia
Nova Scotia
Nova Scotia
Newfoundland
Nova Scotia(France; S. ofNfld.)
Newfoundland
Newfoundland
Newfoundland
Newfoundland
Prince Edward Island

12 or more
18
58
15
300
130 or more
93+63
70
135
75
18
52

4
2

1957) and at New England (Schevill 1956) in the early 1950's and its noteworthiness, as well as the infrequency of previous reports, suggests that it was nota particularly abundant species in the northwest Atlantic at this time. The
same was true in the 1960's when Mercer (1973) recorded it in southern Newfoundland and far to the east of the island over deep water, and Sergeant, Mansfieldand Beck (1970) recorded it stranded on Sable Island. During the 1970's, however, it has very often been reported in the waters off New England and Nova
Scotia, and in summer in the Gulf of St. Lawrence (Katona, Testaverde and Barr
1978; Sergeant, St. Aubin and Geraci 1980; Testaverde and Mead 1980). Whilesome of this increase must be due to an increase in observers, it seems certain thata real increase of population has occurred. The aerial surveys carried out by the
University of Rhode Island's Cetacean and Turtle Assessment Program (CETAP;
see Hain, Edel, Hays, Katona and Roanowicz 1981) found Lagenorlrynchus acutus in1979 to be the most numerous cetacean along the northeastern seaboard of the
U.S.A., exceeding 10,000 individuals observed. The species occurred throughout
the Gulf of Maine, especially in the vicinity of Cape Cod and over Georges Bank,and south to waters off Chesapeake Bay.
During the 1970's there were two mass strandings of L. acutus: at Cape Cod
in May 1973 and in the northern Gulf of Maine in September 1974. There wasa third multiple stranding at almost the same site in the Gulf of Maine in September
1981 and also a small multiple stranding at Prince Edward Island in the Gulf of
St. Lawrence in November 1979 (Mitchell 1981). There have been numerous
single strandings in New England, Nova Scotia and the Gulf of St. Lawrence
throughout the 1970's. In September and October 1981, the species several
times entered the waters of Bedford Basin, Halifax Harbour, Nova Scotia. Thus
irregular mass strandings, and frequent single strandings, have been a feature of
the biology of L. acutus during the period of its population abundance in the northwest Atlantic.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

8

SERGEANT

1. Singleton strandings, Britain

North Atlantic Pilot Whale
G lobicephala melaena

N=65

10

5

10

•.

~......
200

300

400

,. •.·...

..

··-...........

500

600

700

800

Body length in cm.
Fig. 4.

Length frequencies of G. melaena, stranded naturally and driven shore.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

9c.

Sperm whale Physeter catodon at New Zealand
At North Island, New Zealand, multiple strandings of harem herds of sperm
whales have repeatedly occurred up to at least 1972 (Gaskin 1968; Robson and
Van Bree 1971; Stephenson 1975). Best (1974, Figs.-1 and 11-2) shows that thesurrounding area of sea has one of the highest known densities of sperm whales,
and the highest known density of female sperm whales, in the southern hemisphere.
Conclusions
From the preceding review of three commonly-stranding species one may
conclude that mass strandings come from a dense population and not from a reduced one. In ecological parlance, they are either density- or resource-dependent(DeMaster 1981 ). As to the condition of naturally-stranded G. melaena, I am
indebted to K. A. Hay (in litt. 1979) and ]. Lien and staff (in litt. 1981) for
measurements and sexings of animals in three herds stranded at Newfoundland in1979 and 1980. The distribution of lengths (Fig. 4) differs little from length
frequencies which were obtained from large samples of driven animals in the 1950's(Sergeant 1962). The sex ratio is more variable, being low for males in the two
1980 samples, and high for a stranding at Sable Island in 1976 described by Geraci
and St. Aubin (1977), but with little difference if the samples are summed (Table2). The length-specific blubber thickness is comparable (Table 3). There is
therefore no obvious difference between the state of animals driven ashore by man
and those naturally stranded. Both sets of beachings result from the dense herds
which form up in the coastal waters when the population is abundant.
d.

TABLE 2.

SEX RATIOS OF NORTHWEST ATLANTIC PILOT WHALES,DRIVEN AND STRANDED. Date from Sergeant (1962)
Geraci and St. Aubin (1977), Hay (pers. comm.), and Lien (pers. comm.).

Sample

Date

Males

Females

Male ratio

DrivenStranded

1952-1957
1977-1980

1,825
141

2,778
173

.395
.450

TABLE 3. MID-LATERAL BLUBBER THICKNESS OF FEMALE PILOT
WHALES AT NEWFOUNDLAND, DRIVEN AND STRANDED
Data from Sergeant (1962, Table IV) and Hay (pers. comm.).
Date

SampleDrivenStrandedAugust
July

1952
1979

N

Range of bodylengths (cm)4074

185-470
206-470

Blubber thickness (cm)
Range

Mean

2.1-3.2
2.3-4.0

2.7
3.3

DISTRIBUTION OF MASS STRANDINGS AMONG THE ODONTOCETI

Definition
I define a mass- or multiple-stranding as one consisting of two or more animals,
other than the simultaneous stranding of a female and her calf.
a.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

10

SERGEANT

Offshore and onshore mortaliry
Although I have assumed up to now that all dead cetaceans arrive on the
coastline, this cannot be true. Skulls of pilot whales G. melaena are dredged bytrawlers from Georges Bank off New England (Lord and Chandler 1969). Thisbank is separated by channels from the land, showing that animals which die at
sea may sink there. Mass strandings, by definition, occur on the coast and it isdifficult to imagine mass, almost simultaneous deaths occurring at sea among aherd of Cetacea. If they do occur, no concentrations of carcasses have been reported at sea, to my knowledge, nor of a sequence of carcasses drifting ashore.
Mass strandings are of live animals, though singleton animals can arrive on thebeach dead or alive. That some dead singletons do not reach the shore could
bias upward the percent of animals recorded dead en masse. Other sources ofbias work in the same direction.
b.

Reporting bias
For most past reporting, it is likely that multiple strandings are over-reported
as compared with single animals because they are the more conspicuous phenomenon.
It is extremely hard to quantify this statement, but it seems likely that themore intensive the stranding network, the more this bias is removed. I have identified three relatively intensive stranding networks: that of Great Britain from 1913
to 1966, of France from 1971 to the present, and of the United States from 1976 to
the present. Since none of these is complete or perfect, not all bias has been removed. For France I compared reports of strandings of pilot whales in the period
1961-1960 (Duguy and Baudouin-Bodin 1965, Budker 1968 and Le Tallec 1968)
to those in 1971-1980 (Duguy and Budker 1972, Duguy 1973, 1974, 1975, 1976,
1977, 1978, 1979, 1980, 1981). In the earlier decade, there were reports of 310
individual G. mqlaena of which 303 (97. 7%) were mass-stranded. In the later
decade there were only 5 out 80 (6.25%) G. melaena mass-stranded. Clearly thechange cannot be due solely to a change in sighting intensity since the absolute
frequency of mass strandings of pilot whales decreased. This could be due, inpart, to chance: mass-strandings are rare events and more than a decade may benecessary to obtain an index of their frequency. Unfortunately, the density ofthe population involved may change during a decade (see section 4 d (ii), so thatsolution of the problem seems impossible There seems little left to do except touse the most complete data available, and to use the much more evenly distributed
singleton strandings, together with the mass strandings, as an index of natural
mortality rate, and therefore of abundance.
The classification of the Odontoceti as usually divided (Rice 1977, Fraser and
Purves 1960) is shown in Table 4.
c.

British strandings
Systematic observations of stranded Cetacea around the British coasts were
begun in 1913 and I have drawn freely on this long-continued record (Harmerd.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

II

MASS STRANDINGS OF TOOTHED WHALESTABLE 4.

SYSTEMATIC ORDER OF ODONTOCETI ACCORDING TO RICE (1977)
Genera including species known to mass-strand shown with an asterisk.

Ziphiidae

Tasmacetus* Mesoplodon* -?,iphius* Hyperoodon
Berardius
Physeteridae* Physeter
Kogia

Platanistidae
Stenidae

Phocaenidae
Delphinidae
Delphininae

Sotalia
Sousa* Steno* Phocoena
Phocaenoides* Delphinus* Grampus* Lagenorhynchus
Lagenodelphis* Stenella* Tursiops
Cephalorhynchinae
Lissodelphinae
Orcininae

Cephalorhynchus* Lissodelphis? Feresa* Globicephala
Orcaella* Orcinus* Peponocephala* Pseudorca

1929; Fraser 1934, 1946, 1953, 1974.) While it is impossible to define its completeness, the existence of a reporting network, together with a responsible central
museum over a long period of time, makes it a good starting point.
(i) Frequency of mass strandings:
As stated at the outset, there are no mass strandings of Mysticeti. The British
records give the number of individual Odontoceti in each mass stranding and also
the number of singleton strandings of each species. Table 5 summarises these data.
There are rare species, such as the arctic white whale Delphinapterus leucas andnarwhal Monodon monoceros, and the more southerly blue-white or euphrosyne
dolphin Stenella coeruleoalba, that give few records. The others can be divided intoa group of mainly mass-stranders, comprising pilot whale G. melaena, false killer
whale Pseudorca crassidens and white-sided dolphin Lagenorhynchus acutus and a groupof species stranding mainly as individuals, comprising killer whale Orcinus area,
several other dolphin species (Lagenorhynchus albirostris, Grampus griseus, Delphinusdelphis, Tursiops truncatus), bottlenose whale Hyperoodon ampullatus and common porpoise Phocoena phocoena. All sperm whales Physeter catodon stranded singly, althoughSci. Rep. Whales Res. Inst.,
No. 34, 1982

12

SERGEANTTABLE 5.

FREQUENCY OF MASS-STRANDED TO TOTAL STRANDED INDIVIDUALODONTOCETI BY SPECIES IN BRITAIN, 1913 TO 1966
Data from Harmer (1927) and Fraser (1934 to 1974).
Number of animals
Species

Delphinapterus leucas
Delphinus delphis
Globicephala melaena
Grampus griseus
Hyperoodon ampullatus
Lagenorhynchus acutus
Lagenorhynchus albirostris
Monodon monoceros
Orcinus orca
Phocoena phocoena
Physeter catodon
Pseudorca crassidens
Stenella caeruleoalba
Tursiops truncatussinglemultiple

total

121
66
63
61
24
78
2
36
596
13
5
3
175

14
429
4
11
67
9

135
495
67
72
91
87
2
42
631
13
232
3
189

Percent
multiple
(-)

6
35
227
14

10.4
86.7
5.9
15.3
78.2
10.3
(-)
14.2
5.5
0.0
97.8
(-)
7.4

the species is known to mass-strand elsewhere and has done so in western Europe(Boschma 1938). However, mainly solitary males reach northern seas, and singleton strandings are the rule also in Norway (Haug and Gulliksen 1981) and in
Newfoundland CJ. Lien MSS 1980, 1981).
(ii) Consistency of mass strandings through time:
Because of the uniquely long (53 year) period of the British strandings, it isinstructive to examine the consistency through time of mass-strandings of a species.
In Table 6 I have done this for 6 species, retaining the unequal time periods into
which Harmer and Fraser divided their reports. [To use decades, as S. G. Brown(1975) did, would not materially alter results.] The analysis shows that one species,
Pseudorca crassidens, stranded at high frequency during its short occurrence in seasaround Britain. Three species, Grampus griseus, Lagenorhynchus albirostris, andTursiops truncatus, mass-stranded at low frequency throughout the 5 episodes of time.
Two species remain. Lagenorhynchus acutus decreased markedly after 1932, whereas
Globicephala melaena increased markedly after 1937. Not unexpectedly, both species
TABLE 6. MULTIPLE STRANDINGS PER TIME PERIOD IN BRITAIN
Number of individuals stranded in multiple strandings and in total.
Years
Species

1913-1926(14)

1927-1932(6)

1933-1937(5)

1938-1947(10)

1948-1966(19)

G. melaena
G. griseus
L. acutus
L. albirostris

2/10
2/10
32/40
2/30

405/447
0/19
0/6
5/28

4/27

2/6
0/10
0/3
2/14
77/82
4/23

20/26
2/19
0/3
0/7

P. crassidens
T. truncatus

0/6
0/9
35/39
0/8
150/150
2/27

2/35

2/77

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

;->·

l;<
;:i.

~

~

""""'

.._
~~

"° ~
v~~

~

~~

-

25

-

24
-

19
24
81
152
6
10
19

19
4
16
4
6
8
19

0
20
65
148
0
2
0

-

51.0

-

49

-

6

-

0
83.3
80.2
97.4
0
(20.0)
0.0

-

(0)
4.5
15.0
(100)
0

-

0.0
0
0
99.7

%M

17
16
15
859
1
2
22
20
3
6

T

0
0
0
856
0
0
1
3
3

M

-~-----

17
16
15
3
1
2
21
17

s

--- - - - - - - - - - - " -New Zealand
S. Australia

6
8

1
1
3
1
3
1
13
6

1

-

15

129
243

-

-

-

-

-

-

-

21
8

1
1
3
1
3
1
142
249

1

120
917

114
908

6
9

71.4
0.0

0
0
0
0
0
0
90.8
97.5

0

95.0
99.0

0

-

%M

T

-

M

1

s

12
1

1
3
(a few)

0

1
10

-

7

1

s

( )
12
1

-

3

1
10

250

-

0

%M

-

0.0

0
32
(high)

0

0
0.0

7
0
5 (high)

1
3

5

-

T

-

-

-

-

-

-

M

----------·-------- ------------------

Tasmania

7
1
30
1
22
6
32
10
6
26
28

-

19
16
28
12
1
3
32
17

s

-

1
3
3

17

-

20
194
391

-

-

25

-

-

-

-

0
0
114
1,769

M

%M

--~---

0.0
19
0
16
80.2
142
1,781
99.3
1 (0)
3
(0)
33
3.0
15.0
20
(100)
3
0.0
7
1
(0)
55 45.5
(0)
1
0.0
22
76.9
27
226 85.8
97.5
401
(0)
6
43
39.5
0.0
28

T

Overall

FREQUENCY OF SINGLE (S), MULTIPLE (M) AND TOTAL (T) STRANDED INDIVIDUAL ODONTOCETIIN NEW ZEALAND (Gaskin 1968, Fraser 1955), Tasmania (Guiler 1978) and South Australia (Aitken 1971)

Berardius arnouxi
Cephalorhynchus commersoni
Delphinus delphis
Globicephala melaena
Grampus griseus
Hyperoodon planifrons
Kogia breviceps
Lagenorhynchus obscurus
Lissodelphis peroni
Mesoplodon bowdoini
M. densirostris
M. grayi
M. hectori
M. layardi
Orcinus orca
Physeter catodon
Pseudorca crassidens
Tasmacetus
Tursiops truncatus
Ziphius cavirostris

Species

TABLE 7.

~

-""

rri

l:.'j

::r:
>
t""

~

t:I

::r:
l:.'j

>-1

>-1

0
0

>rj

0

rri

z>t:I
......
zCl

:;o

>-1

rri

rri

>
rri

SERGEANT

14

show high mass stranding rates with high overall stranding rates. None of thesedata support the idea that mass-stranding rates vary with time, in contrast to the
French data discussed earlier (section 4-c). The data do, however, support theconcept that populations of Odontocetes may change in abundance with time.

Strandings in the southern hemisphere
In amplification of the British stranding records, there is an excellent set of
tabulated data on strandings on New Zealand coasts, chiefly due to Gaskin (1968).
To these I have appended details given for Tasmania by Guiler (1978) and forsouth Australia by Aitken (1971), since all are cool-water coasts with much thesame fauna (Table 7).
In these seas Globicephala melaena and Pseudorca crassidens retain a very highpercentage of individuals mass-stranded (97.5-99.3%). Nearly as high are Physetercatodon with 85.8% of individuals mass-stranded, Delphinus delphis with 80.2% andOrcinus orca with 76.9%. High values are also found for lvlesoplodon grayi (45.5%),
Tursiops truncatus (39.5%) and Lagenorhynchus obscurus (15.0%). Other Ziphiidae(Berardius arnouxi, :(,iphius cavirostris and other Mesoplodon spp.) had no multiple
strandings, nor did the pigmy sperm whale Kogia breviceps.
e.

Strandings in Florida
Table 8 shows strandings from a well-documented sub-tropical region, thatof Florida with its extensive sandy coasts.
High multiple stranding frequencies are again shown by pilot whales, thistime the tropical short-finned species Globicephala macrorlryncha, and by false killer
whales Pseudorca crassidens, which are here within their normal range of distribution
at sea in the sub-tropical North Atlantic (Morzer-Bruyns 1969), Gulf of Mexico(Bullis and Moore 1956; Brown, Caldwell and Caldwell 1966) and Caribbean Sea(Caldwell, Caldwell, Rathjen and Sullivan 1971 ). Stenella longirostris shows a highmass-stranding rate (92. 7%) with two mass strandings, and Steno bredanesis with
but a single one. Both Tursiops truncatus and Kogia breviceps show singleton strandf.

TABLE 8. STRANDINGS IN FLORIDA
Sources: 1Moore, 1953; 2 Layne, 1965; 3 Caldwell, Caldwell and Walker, 1970; 4 Mead,
Odell, Wells and Scott, 1980; 1 0dell, Asper, Baucom and Cornell, 1980.
SingleGlobicephala macrorhynchal
Globicephala macrorhyncha2
Kogia brevicepsi,2Mesoplodon europaeus 1
Physeter catodon1,2
Pseudorca crassidenst,s,oStenella longirostris 4
Steno bredanensis2
Tursiops truncatus1, 2:(iphius cavirostris 1

6
12
5
3
5
13
3

Multiple

Total

%M

323
212

324
218
12

99.7
97.2
0.0

5
242
69
16
13

0.0
99.6
92.7
(100.0)
0.0
(0)

241
64
16

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

15

ings only; for other species data are scarce.

United States Eastern Seaboard
Six years' intensive observations, from 1976 to 1981, were available to me
for this region from the monthly reports of strandings given in SEAN (Smithsonian
Scientific Event Network).
The resulting summary of data (Table 9) refers to 32 species, such a large
fauna being the result of the wide geographical extent of the coast from a cold toa warm sea. Some cold-water species, e.g. Hyperoodon ampullatus, were absent,
others, e.g. Orcinus orca, were rare.
g.

TABLE 9.

UNITED STATES EASTERN SEABOARD. STRANDINGS, 1976-1981(Source-SEAN monthly reports).
1977-1981
Species
Total

Balaenoptera acutorostrata
B. borealis
B. edeni
B. musculus
B.physalus
Delphinapterus leucas
Delphinus delphis
Eubalaena glacialis
Feresa intermedia
Globicephala macrorhyncha
G. melaena
Grampus griseus
Hyperoodon ampullatus
Kogia breviceps
K. simusLagenorkvnchus acutus
L. albirostris
Megaptera novaeangliae
Mesoplodon bidens
M. densirostrisM. europaeus
M. mirus
Orcinus orca
Phocoena phocoena
Physeter catodon
Pseudorca crassidens
Stenella caeruleoalba
S. longirostris
S. plagiodon/attenuata
Steno rostratus
T ursiops truncatus
Ziphius cavirostrisMultiple

Multiple
Frequency

27

3
22
1

29
3

4

.138

42
21

28
18
5

.651
.429
.238

105
30
78

2

.066

19

.245

(12)
30
6
29

(.062)
.366
1.000
.133
.906

21
(7)*

(.913)(.013)

4

43

10

3
14

3
3
. 177
30
30

45
32

11

32
23

543
6

* Strandings of several animals close in space and time were reported but it could not be determined if
these were in fact multiple strandings.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

16

SERGEANTThe data allowed comparison with older data (Table 8) from parts of thesame seaboard. Thus, multiple strandings of Globicephala macrorhyncha fell from99.7-97.2% for earlier data from Florida to 65.1 % for the whole coast. At first,
I thought this was the result of more thorough examination of beaches for singletons. However, examination of SEAN records by state showed a geographicaltrend. A high multiple stranding rate was still recorded for Florida but northward this decreased to zero. I therefore analysed data for G. macrorhyncha and G.
melaena by latitude in order to quantify such geographical changes (section h).
The strandings from the east coast of the United States show a similar sequence of frequency of mass-strandings to that found in other regions. Ten species
show multiple stranding frequencies exceeding 10%, in order of descending rank:
Number ofSpecies

Pseudorca crassidens
Sterw rostratus
Stenella longirostris
Globicephala macrorhyncha
G. melaena
Physeter catodon
Lagerwrhynchus acutus
Grampus griseus
Delphinus delphis
Stene/la caeruleoalba

Frequency

I.OOO
.913
.906
.651
.429
.366
.245
.236
.138
.133

--~-----·-

animals

mass events

30
23
32
43
42
30
78
21
29
45

1
2
4

4
2
1
2

The three commonest species to strand: Tursiops truncatus, Phocoena phocoena
and Kogia breviceps, all showed extremely low rates of multiple strandings, as noted
earlier by Mead (1979). Indeed, for P. phocoena and T. truncatus, there was doubt
whether animals that stranded at the same time and place were, in fact, from thesame group. These data agree with those from Britain (Table 5), although mass
strandings of Tursiops truncatus were noted from the southern hemisphere (Table 7),
where perhaps a different species or stock with different social behavior is involved.

Geographical variation in mass stranding rate within a species.
This problem is sufficiently common to require resolution. In order to study
it I selected the east coast of North America where the excellent data from the
U.S.A. (from SEAN and from earlier fauna! studies) could be supplemented byless complete data from Canada. I selected the two pilot whale species G. melaena
and G. macrorhyncha because of their high mass stranding frequency, and listed all
strandings known to me by geographical position, and whether single or multiple,
then analysed these by half-degrees of latitude (Table 10).
·
The table shows that the cold-water species G. melaena mass-strands mainlyin the northern part of its range north of 46°N. Sable Island, located at 44°N,
accounts for most mass strandings south of this latitude. There are in modern
times few mass strandings at Cape Cod, at ea 41°30'N Lat., although the species wash.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

17

MASS STRANDINGS OF TOOTHED WHALESTABLE 10. STRANDINGS OF THE PILOT WHALES GLOBICEPHALA MELAENAAND G. MACRORH'YNCHA ALONG THE EASTERN SEABOARD OF
CANADA AND THE UNITED STATESThe records are summed by half degrees of latitude, and separated into single
and multiple strandings. Sources: Various, from varied starting
dates up to end 1981 in SEAN.

G. melaena
Latitude Zone

51°31'-52°
-5W
-51°
-50!0
-50°
-49!0
-49°
-48!0
-48°
-47! 0-47°-46! 0-46°-45! 0-45°-44! 0
_440
-43!
-430
-42!0
-42°
-4W
-41°
-40!0
-40°
-39! 0-39°-38! 0
-38°
-37!°
-37°
-36!0
35°31'-36°(I)

G. macrorhyncha

(2)

12
129
125
3
4
3

1
3
2

5
4
3

18
291
15

203

18

3
(I)*
1

Latitude Zone
39°00'-39!0(1)

35°31'-36°
-35!°
-35°
-34! 0-34°-33! 0-33°-32! 0
-32°
-31!°
-31°
-30! 0
-30°
-29!°
-29°
-28!0
-28°
-27!0
-27°
-26! 0-26°-25! 0-25°
24°00' -24!0

4
3

(2)

3

5
19
13+
26
3
30

2

150
72
57+
63
64

1
2

2

51

70+
12
50

(I) Number of animals stranded singly.
(2) Number of animals in multiple strandings.
* Species uncertain.

driven here in the past and herds are sometimes seen (e.g. by Starrett and Starrett
1955 ). Singleton strandings occur further south as far as about 36°N.
The warm-water G. macrorhyncha has its highest frequency of mass-strandingsin the southern part of its range. Mass strandings occur along the U.S. east coast
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

18

SERGEANTfrom the Florida Keys at 24°30'N to about 34°'30'N. Northward only singleton
strandings occur, as far as 39°N. Thus, both species show a " core " area where
mass-strandings occur, and a peripheral area where they do not. I would deducefrom this that mass-strandings occur where the population of the species is high.
Mass strandings of G. macrorhyncha continue through the West Indies southward toat least Isla Margarita, Venezuela, at 12°N Lat. (Casinos and Bou, 1980). Thusin G. melaena there seems to be no northern limit to the mass strandings (in relation
to the population as a whole), in G. macror!ryncha no southern limit, suggesting that
it is inter-specific competition between the species that determines density of both.
I know no other pair of contiguous species where such an analysis is possible,
but note other cold-water species that show mass strandings towards the north oftheir range, e.g. Orcinus orca in Norway but not in Britain, see footnote this p.; otherwarm-water species that show mass strandings mainly in the south of their range, e.g.
Delphinus delphis in west Africa but not in Europe, see pp. 37 and 11 respectively.

Individual species considered.
The false killer whale Pseudorca crassidens is unusual in that virtually all of its
mortality on the coasts of Britain, New Zealand, Tasmania, South Australia, South
Africa (Smithers 1938) and Florida, occurs as mass strandings. It is a warm-water
species (Bullis and Moore 1956, Morzer-Bruyns 1969), that does not normally occur
round the British coasts; thus the mass strandings that occurred there in 1927, 1935
and 1936 were in the nature of immigrations followed by mass mortality. However,its mass strandings in Florida occur within the species' normal range. As its dietconsists of large fish and squids, including tuna which it frequently takes offlongline hooks (Moore 1953, Brown, Caldwell and Caldwell 1966, Mitchell 1975), we
have the impression of a top carnivore exerting pressure on its food supply.
In tropical seas, the short-headed electra dolphin Peponocephala electra has massstranded in eastern Australia (Dawbin, Noble and Fraser 1970), the New Hebrides(Rancurel 1974) and Japan (T. Kasuya, pers. comm.). Analysis of some of theserecords by Perrin (1975) gives a very high frequency (about 95%) of individuals
mass-stranded. The genus is placed within the Orcininae as is another tropicalgenus Feresa, of which we know little. We now have three genera from among
this subfamily: Globicephala, Pseudorca and Peponocephala, which show high frequencies of multiple strandings. The killer whale Orcinus orca has shown a low
incidence of mass strandings in Britain\ but a high incidence in New Zealand.
Killer whales mass-stranded in British Columbia before live captures for aquaria
started in 1964 (Ford and Ford 1981). Carl (1946) and Pike and MacAskie (1969)
together record 39 animals stranded in the period 1941-1967, of which 36 or 92.3%
represented multiple strandings.
Among the typical dolphins (Delphininae) many species have been recordedI.

1

None were recorded by Harmer or by Fraser from 1913 to 1966, but Turner (1871) described a drive-huntof 18 Orcinus orca at Bressay Sound, Shetland in February 1871, which makes it seem likely that mass
strandings might occur to the north of Britain. A pod of 14 animals indeed stranded at Lofoten, Norway
in June 1981 (Haug and Sandnes, 1982).

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

19

with a high frequency of strandings, yet there is considerable variability in thisfeature; e.g. Delphinus delphis and Tursiops truncatus may show a low incidence in
one region and a high incidence in another. There is also a high incidence of
strandings in the pelagic long-snouted dolphin Stenella longirostris in Florida. The
species Stenella coeruleoalba and S. attenuata are driven ashore in large groups byfishermen in Japan, which makes one believe that they would mass-strand there
naturally, if not being hunted.
Among the porpoises Phocoenidae, the harbour porpoise Phocoena p!wcoena
normally strands singly or in groups of 2-4 animals. It is known to be weakly
gregarious, with schools of 9 animals or less observed by Gaskin, Arnold and Blair(1974).
There are about 20 known mass strandings of Physeter catodon in the world in
the last 300 years and more than half of these have come from New Zealand (Anon
1979). I have also heard of two unpublished mass strandings (in the Seychelles
and Falkland Is.) since beginning this study. Most mass strandings are of harem
herds (Robson and van Bree 1971, Stephenson 1975). Considering that the main
mass of harem herds of sperm whales live in the tropical oceans, which are grossly
under-reported for Cetacea (consider the late discovery of tropical genera such as
Feresa, Peponocephala and Lagenodelphis), the scarcity of reported mass strandings ofPhyseter is not surprising. At high latitudes most strandings of sperm whales areof single adult or subadult males. The pigmy sperm whale Kogia breviceps seems
always to strand singly or in numbers not exceeding three, suggesting a group size
no larger than a family.
Mass strandings are also known among several genera of the Ziphiiidae: e.g.
a herd of 25 Mesoplodon grayi at the Chatham Is., New Zealand (Gaskin 1968);
a herd of 4 :(iphius cavirostris at the Netherlands Antilles; and records of Hyperoodon
ampullatus in Britain (van Bree and Kristensen, 1974). There are no known mass
strandings from among the freshwater Platanistidae, nor from among the small
group Cephalorhynchinae, but we have noted one of three animals from among
the Lissodelphinae (Lissodelphis peroni at New Zealand, Fraser 1955).
Considering the high incidence of mass strandings among members of theOrcininae it is worth looking at the biological characteristics of the subfamily, as
compared with those of members of the typical dolphin subfamily Delphininae.
There are now sufficient studies oflife histories of a number of genera to make sucha comparison possible. The social structure of the sperm whale Physeter is also
well known.
SOCIAL STRUCTURES COMPARED

Orcininae
As Norris and Dohl (1980) have previously observed, mass strandings occur
especially in the group Orcininae of the Delphinidae, which contains the genera
Pseudorca, Orcinus, Orcaella, Globicephala, Feresa, and Peponocephala. Of these only
Globicephala is well known bionomically, Orcinus is beginning to be so (Bigg 1981),
a.

Sci. Rep. Whales Res. Inst.,
No. 31:, 1982

SERGEANT

20

and knowledge on Pseudorca must be assembled from the few data of various authors.
I studied the social structure of G. melaena from a drive fishery in Newfoundland in the 1950's (Sergeant 1962), having a large number of animals available toexamine. Main features relevant were: (I) a marked sexual dimorphism, males
reaching 20 ft (6 m) in length compared with 16 ft (5 m) for females; (2) an extremely delayed sexual maturity for males-16 ft (5 m) length and 12 years of age
compared with 12 ft (4 m) and 6 years of age for females; (3) a higher male mortality rate throughout life. The last two features resulted in a low ratio of adultmales to adult females. Most importantly (4), the composition of 91/92 schools
was homogeneous, consisting of all sizes of both sexes of animals. The only atypical
herd was a group of adult males with a few very large females. I deduced thatthe species was exceptionally social, with no signs of aggressiveness, there being nosegregation of size groups associated with aggression.
McCann (1974) found tooth scars or scratches on the body of almost all
Odontocete genera studied which he attributed to various behaviour patterns,
including play between younger animals and aggression by adult males. In driven
G. melaena I found fresh scratches on all animals, which I attributed to the panicof the drive, since I could find no old scars. Norris and Prescott (1961) found
tooth scratches on young male G. scammoni and not on adult males, leading Norris
Pseudorca crassidens

clcl

10

N=126

5

...

20

!i!!i!

QI .

N=152

.Q

E
::s

z 15

10

5

3 0

350

400

450

500

Length in cm.
Fig. 5. Length frequencies of naturally stranded male and female Pseudorca
crassidens.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

21(1967) to deduce that these were produced by schoolmates in play. Thus I supposethat tooth scratches are not necessarily an index of aggression. McCann notedthat Ziphiids have deeper scars than most Delphinidae and he believed that suchless social species show more aggression.
Information on Pseudorca crassidens comes from samples examined by Hinton(1928), Fraser (1936), Peacock, Comrie and Greenshields (1936), and Yamada(19S6) from animals stranded in Britain; by Smithers (1938) from strandings inSouth Africa; by Scott and Green (197S) from strandings in Tasmania; and by
Odell, Asper, Baucom and Cornell (1980) from strandings in Florida. Comrie
and Adam (1938) examined reproductive tracts collected by Peacock et al. (1936).
Figure S shows length frequencies which indicate clearly that the species is sexuallydimorphic. Extreme recorded lengths in all these strandings are males S89 cm
and females 489 cm, or a ratio of about 1.2: I, which compares with 1.3: 1 inextreme and peak lengths for large samples of G. melaena (Sergeant 1962). If one
omits the length frequencies of Scott and Green (197S), who examined part of thesame set of females twice, the sex ratio is about S3.S% females for a sample size of
198. Lengths at first maturity of female Pseudorca were well-studied by several
authors, as follows:
Body length (cm)Hinton 1928
Fraser 1936
Comrie and Adam 1938
Harrison, Brownell and Boice 1972
Scott and Green 1975
Odell et al. 1980
Highest/lowest

largestimmature

smallest mature

418
284
293
337
358
418

427 (pregnant)429 (several corpora albicantia)
425 (9 corpor~ albicantia)
414 (large corpus luteum plus corpora albicantia)
360 (pregnant)
440 (8 corpora albicantia)
360

This analysis gives a range of 360 to 420 cm for length at first pregnancy,
a wide spread. One wonders if all workers measured length in the same way, or
whether the populations differed in size. For males, we know only that a large
male S20 cm in length was mature, with testis in active spermatogenesis weighing
8.2 kg (Odell et al. 1980), and that a male 366 cm was immature, while males
SI I, S30 and S34 cm in length were mature with testis volumes SOX 16X8 cm orlarger (Fraser 1936). Thus, we can only say that male Pseudorca crassidens mature
at body lengths of S 11 cm or less. Since the animal measured by Fraser as S 11 cm
in length had a testis significantly smaller in volume (SOX 16x8 cm) than those of
S30 and S44 cm in length (60 X 20 X 16 cm and 62 X 22 X 11 cm) it is possible that
it was just mature; this compares with a S20 cm male P. crassidens measured by
Odell et al. (1980), the testis of which weighed 8.2 kg (see also Sergeant 1962,
Fig. 19 for a curve relating testis length to body weight in G. melaena). If P.
crassidens males mature at about SOO cm body length, as compared with about
400 cm for females, then the ratio of numbers of mature females to mature males
from the data of Fig. S is about 90/34 or 2.6S: 1, a ratio comparable with that
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

SERGEANT

22
TABLE 11.
Species
Delphininae
Delphinus delphis
Stenella attenuata

Tursiops truncatus

RATIO OF ADULT LENGTHS OF ODONTOCETES (cm)Region of Study

Peak

Extreme

M

F

M

F

Ratio
M/F

170

170

205
200

200
190

1.02
1.05

46

270

250

1.08

120
16

250
254
260

250
252
245

1.00
1.01
1.06

944 822

1.15

610
590

1.15
1.21
1.20
1.44

Sample
size

4,217
3,504

Black Sea
E. Tropical
Pacific
FloridaN. W. Atlantic
Tursiops truncatus
Tursiops aduncus
S. Africa
Lagerwrhynchus acutus N. W. Atlantic
Orcininae
Orcinus orca

567

Globicephala melaena
Pseudorca crassidens
Physeter catodon

TABLE 12.

655

609

890

780

15.8

Length (cm)Age (yr)

M

F

M

F

170
195
245
230

158
181
235
210

12
13
(10)
12
12
19

579
488
487
366
12m 8.5m

TABLE 13.

Delphininae
Delphinus delphis
Stenella attenuata
Orcininae
Orcinus orca

Globicephala melaena
Pseudorca crassidens

Nishiwaki & Handa
1950
Bigg 1981
Sergeant 1962
(seep.21)
Lockyer 1976

Ratio
lengths

Authors

9
12
(9)

1.08
1.08
1.05
(1.11)

Sleptsov 1941
Perrin, Coe & Zweifel 1976
Sergeant, Caldwell & Caldwell 1973
Sergeant, St. Aubin & Geraci 1980

8
6-8
9

1.18
1.33
2.1

Bigg 1981 and in litt.
Sergeant 1962
Best 1974

SEX RATIO OF ODONTOCETESOverallSpecies

Sleptsov 1941
Perrin, Coe & Zweifel
1976
Sergeant, Caldwell &Caldwell 1973
Hohn 1980
Ross 1977
Sergeant, St. Aubin &Geraci 1920ATTAINMENT OF SEXUAL MATURITY OF ODONTOCETES

Species
Delphininae
Delphinus delphis
Stenella attenuata
Tursiops truncatus
Lagenorhynchus acutus
Orcininae
Orcinus orca
Globicephala melaena
Physeter catodon

503
490

Authors

MatureNo. of No. ofmales females

Male
ratio

No. of No. ofmales females

Male
ratio

Authors

2,079

2,138

0.493
0.449

890

1,179

0.435
0.43

Sleptsov 1941
Perrin, Coe & Zweifel 1976

247

320

0.436

60*

72*

0.455

92

106

0.396
0.465

418
90

1,364
34

0.234
0.265

Nishiwaki & Handa 1958;
Bigg 1981
Sergeant 1962
(See discussion)* excluding juveniles and calves.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

23

found in G. melaena. Unfortunately the variance of estimate of this ratio is high as
between samples: using Scott and Green's (1965) mean female maturity length of348 cm it would be 128/34 or 3.8: 1, using Fraser's (1936) value of 423 cm it would
be 68/34 or 2: 1 (Fig. 5 ).
For Orcinus orca, Nishiwaki and Banda (1958) and Bigg (1981 and in litt.)
provide good data on body lengths of adult males and females, allowing calculation
.45
.40
0

~... Ul .35.... iii
Cl):s E .30

"O

<t

.25

0

~... UlCl).50=~ iiiE .45
Cl)

>

.40

0

.s

1.3

.... Cl):!:o E""'.!2 ~ 1! 1.2
ia)( c,a:: Cl)] 1.1

0

i 1.3

0

..c 1.2

I

~

~...

•)

Ul-

....Cl
c:

1.1

2

3

Delphininae

4

5

6

7

Orcininae

Fig. 6. Summary of information on sexual dimorphism within the Delphinidae.
I. Delphinus delphis, 2. Tursiops truncatus, 3. Stenella attenuata, 4. Lagenorhynchus acutus,
5. Orcinus orca, 6. Globicephala melaena, 7. Pseudorca crassidens. (The ordering ofspecies within each subfamily was random.)Sci. Rep. Whales Res. Inst.,
No. 34, 1982

24

-SERGEANTof the degree of sexual dimorphism, which seems to be somewhat less than in
Globicephala and Pseudorca. There is less good information on lengths and ages at
sexual maturity. Data are summarised in Tables 11 to 13 and Figure 6. One
gains the impression that Orcinus in some ways is an intermediate between thestrongly sexually dimorphic Orcininae and the weakly dimorphic Delphininae (seebelow).
For Peponocephala electra, data are as yet too few to assess the degree of sexual
dimorphism in length and at sexual maturity with any accuracy (see Bryden,
Harrison and Lear 1977).

Delphininae
Good information on the bionomics exists for several genera. Sleptsov (1941)
studied large numbers of Delphinus delphis in the Black Sea, this species proving toshow very little sexual dimorphism in either body size or length at sexual maturity.
Perrin, Coe and Zweifel (1976) studied equally large numbers of Stenella attenuata
in the eastern tropical Pacific with rather similar results. There is some information
for the species Tursiops truncatus (Sergeant, Caldwell and Caldwell 1973, Hohn
(1980); and T. aduncus (Ross, 1977), summarised in Tables 11 and 12.
In Lagenorlrynchus acutus (Sergeant, St. Aubin and Geraci, 1980) mass stranded
herds were found to be composed of adults, mostly females, together with young
calves. Singly-stranded animals by contrast were found to be made up chiefly ofadolescents. This kind of heterogeneity could account for much of the variability
which we have found in the frequency of mass strandings in various members of
the Delphininae, as discussed in section 4 above.
In both Stenella attenuata and S. coeruleoalba driven ashore in Japan, abundantdata show the existence of juvenile schools and adult schools, with the juveniles
rejoining the adult, mating schools at puberty (Kasuya, Miyazaki and Dawbin
1974; Miyazaki and Nishiwaki 1978).
A valuable study on living animals, which indicates the behaviour that may
be involved in such segregation, comes from the work of Tavolga and Essapian(1957) and Tavolga (1966) on the former captive colony of Tursiops truncatus at
Marineland, St. Augustine, Florida. This colony in the 1950's was not subjected
to heavy pressure to perform in public; it was large (13 animals) and composed ofvariably sized animals. Its behaviour was thus probably close to that of a wild herd.
In this colony a dominant male drove off three immature males and maintained
a harem structure of females and calves. There was also a dominance hierarchyof adult females, although other pubertal and older females took much care of
the calves. Another study, from the USSR, gave similar findings. Shurepova(1973) states that a large male in a group of 11 captive animals "had the dominating position in the school: it grabbed fish from the others during feeding, chased
young females which shied away from its mating advances, chased young males,
bit them, beat them vigorously with its tail and snout and so on."Aggressiveness and dominance hierarchies could give rise to the segregation of
immature animals seen among the Delphininae, and we have seen, at least inb.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

25

Lagenorhynchus acutus, that it is often these immature animals which strand singly.
Indeed such animals may attach themselves to a group of one of the social species,
such as Globicephala melaena (Sergeant and Fisher 1957) or Orcinus area (Sergeant,St. Aubin and Geraci 1980 fide R. D. Elliot). Hence, probably, arises the lower
frequency of mass strandings among the Delphininae. But of course in all species
sick and injured animals can strand singly.
In summary the Orcininae are more sexually dimorphic than the Delphininae,
males having a greater excess of asymptotic body length over females. There isalso a greater delay in attainment of male sexual maturity, and with this delay
comes a greater male mortality, resulting in a lower overall male sex ratio than in
the Delphininae.
All these features are usually associated with polygyny and male aggression insea mammals (e.g. in elephant seals, fur seals and the sperm whale). Yet, paradoxically, the polygynous Orcininae are the more highly social of the Delphinidae,
with a more homogeneous herd composition and with a higher mass stranding rate.
Thus polygyny is not necessarily associated with male aggression.
Phocaenidae:
Phocoena phocoena shows a larger size of females than males (Mohl-Hansen
1954 ). It seems likely that this is due to the need to produce a neonate which islarge enough to be viable in cold water (Kanwisher and Sundnes 1965). In
support of this, a larger member of the family Phocoenidae, Phocoenoides dalli, hasa male asymptotic length about 1.05 times that of the female (207 and 198 cm,
Kasuya 1978), as typical for Delphininae. I have noted previously (Sergeant 1969)
that Phocoena phocoena has a high metabolic rate throughout life, as determined fromits food consumption and heart weight/body weight ratio, and that the same istrue for Phocoenoides dalli. The high activity appears to be an adaptation to life
in cold water with a thin blubber layer.
c.

Sperm whale
The sperm whale Physeter catodon is a well-researched species because of its
commercial importance. Because of the migrations of males to high latitudes wealready know that its sociality is not total. A number of mass-strandings havebeen well-documented (e.g. by Robson and van Bree (1971) and by Stephenson(1975) in New Zealand), and these are usually harem herds. It seems likely fromthe records of Gilmore (1957, 1959) and Bryant (1979) in the Gulf of California
that herds of adolescent males may also strand. This distribution of strandings
would accord with the types of sperm whale schools classified by Gaskin (1970)
and Best (1979), which include bachelor schools of young males. As the males
mature, they become less and less social and some become the harem bulls, loosely
attached to the schools of females and calves, others the northern wanderers. Sexual
maturity in male Physeter is much delayed as compared with the female (Best 1969,1974), sexual dimorphism is marked and harem-masters are intolerant of other
adult males. The social structure of the sperm whale therefore comes closer to thatd.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

26

SERGEANTof the Delphininae than of the highly social Orcininae, which fits the sperm whale's
lower frequency of mass-strandings to total strandings.
HERD SIZE
Herd size is extremely difficult to define. As Norris and Dahl (1979) and others
have shown, there is a whole range of groupings within a species (pod, herd, school)from the family up to large schools with varying cohesion and varying stability.
The basic subgroup does not vary very much and is thus not a useful measure ofsociality. Thus for Pseudorca crassidens, which we would judge from its stranding
behaviour to be a species travelling in large aggregations, Morzer-Bruyns (1969)
has this to say from observations of animals feeding at sea:
" The normal school of Pseudorca crassidens contains 20 to 30 animals divided
into "family" groups of four to six animals, covering an area of about 0.5 mile indiameter."
About the only generalisation possible is that inshore species e.g. Sousa plumbea
have only small school sizes, while in offshore species, e.g. Delphinus delphis, Stenella
coeruleoalba, large aggregations can occur (Saayman, Bower and Tayler 1972,
Saayman and Tayler, 1979); but the basic unit remains small, a family of females
and calves with loosely attached males of all ages older than calves in Stenella
longirostris (Pryor and Kang 1980 ), much as in Tursiops truncatus (Tavolga 1966 ).
In both these species in the wild groupings may have a very temporary, changing
existence (Norris and Dahl 1979, Wursig and Wursig 1979).
There seem to be two features which must be separated in considering therelation of mass strandings to school size: 1. Species such as Phocoena phocoena,
Kogia breviceps and perhaps also some of the Ziphiidae (Morzer-Bruyns 1968) havesmall herd size; that is, one scarcely or never finds large aggregations. These show
mass strandings rarely because they are rarely in groups; 2. Social species may
have aggressive adult males, which split the herd into harem (or reproducing)herds and the rest, chiefly immature (occasionally adult) males, and immature
females. Harem herds tend to mass-strand, presumably because females andcalves are closely associated and females are rarely aggressive (Tavolga 1966 for
Tursipos truncatus). The rest tend to strand singly because they are weakly associated, so mass stranding frequency is reduced.
For Globicephala melaena I noted (Sergeant 1962) that the mean number ofanimals in groups driven ashore was about 85, the same as in natural massstrandings reported around the world; however the mean number for animals
observed far to sea was about 20. This could be due to aggregation of herds as
they increase in density in inshore waters. For Orcinus orca stranded herd sizes
recorded are: in British Columbia 20, 11 and 5 (Carl 1946); 10 for an ice-stranded
herd in Newfoundland (Dearden 1958); 19 for a herd stranded in Norway (Haugand Sandnes 1982), for an overall mean of 14. This compares with means of
10.5 and 11.4 for observed pod sizes in the southern and northern components of
the killer whale population observed in the sounds of British Columbia andSci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

27

Washington by Bigg, MacAskie and Ellis (MS, 1976).
AGE-SPECIFIC MORTALITY IN CETACEAa.

GeneralIt is rather generally assumed that age-specific patterns of mortality in Cetacea
are similar; that Odontocetes can be lumped together with Mysticetes, in spite of
their very different social structure. I shall here show that this is not the case,and the evidence I shall use is again from strandings.

b.

Mysticetes

British strandings again prove useful and the source is a compilation by Fraser(1953) of strandings of the minke whale Balaenoptera acutorostrata on British coasts,
reproduced here as Figure 7. Fraser showed a peak stranding length of 16 ft (5 m)and one again at the greatest lengths attained. The latter peak, one must assume,contains a good many estimated lengths. However the peak at 16 ft must be
measured or estimated accurately and I believe it is significant that this is thelength at which weaning occurs (Jonsgaard 1951). In other words, minke whales
strand (die) especially at the length of first independence, and again in old age.
These peaks do not represent the normal occurrence of these length-classes in
the North Sea, as can be seen from data (1951) on length-frequencies of catchesfrom different areas around Norway given by Jonsgaard (1951). For areas suchas Lofoten, immature whales were commonly hunted, but in Jonsgaard's area 1(Skagerrak and the eastern North Sea), catches consisted mainly of adults (Fig. 7).
Thus the evidence suggests that newly weaned animals strand selectively.
For a long time I was unable to obtain information on mortality patterns ofother Mysticetes owing to the paucity of stranding information. However, recently
there became available information on the length frequency of humpback whales
Megaptera novaeangliae caught in nets at Newfoundland (Perkins and Beamish 1979,
Lien MS 1981), and further information on some natural deaths and several accidental deaths from gill-netting and a ship collision on the U.S. east coast (Mead
12

I 10

Minke B. acutorostrata
20

"O

~

8

,.

6

!'!

4

~

g

!

·.......

...
w n

u

m m w

~

M

~

u

w

Length in feetFig. 7. Solid line: mortality by length for minke whales B. acutoroslrata stranded on
British coasts. Dotted line: catches by length in the North Sea.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

SERGEANT

28(a) Netted and stranded, 1978-1980
16

D Nfld.

12~ E'n U.S.A.

8

N=80

4
6

7

8

9

10

11

12

13

14

15

(b) Caught with minimum length limit, Nfld., 1969-1971

N=41

12
8
4

6

7

8

9

10 11 12 1.3
Length in m.

14

15

Fig. 8. Lengths of humpback whales M. novaeangliae caught in nets (a) and harpooned at sea with a lower length limit (b).

1980). Both sets of data come from the same population, which migrates between
the Caribbean in winter and the Gulf of Maine and eastern Newfoundland insummer (Kellogg 1929).
Analysis of these data (Fig. 8) shows that the dead humpbacks, many of whichwere imperfectly measured because of their entrapment in floating nets, werelargely immature animals, 6 to 12 m in length. Weaned immatures, about 9-10
m in length, greatly exceeded younger calves and older animals, though sometimes
an adult female entrapped itself with its calf. The lower frequency distribution
in the Figure essentially shows the length of adults, upwards of 12 m, from thispopulation; it is derived from a selective and specially licensed catch taken in
1969-1971 off eastern Newfoundland (Mitchell 1973). Thus, mainly immature
humpbacks die in nets, owing to their inexperience. I infer that immature humpbacks probably have a higher death rate than adults to other forms of hazard whichmight be considered more "natural" than nets. Putting minke whales and humpbacks together, I would expect that Mysticetes as a whole show similar patterns ofmortality. Allen (1980) can throw little light on the subject, doubtless becauseof the imposition of a lower size limit on whaling for all species except the minke
whale.

Odontocetes
Natural mortality rates of Odontocetes are profitably examined from strandings, owing to the large numbers of animals involved and to some precision of size
estimation. For several genera (Phcooena, Delphinus, Tursiops, Globicephala) somecomparison is possible between length frequencies of stranded animals and nonselective length-frequencies coming from fisheries made by mass-netting or driving.
c.

Sci. Rep. Whales Res. Inst.,

No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

29

Phocoena phocoena
100

50

I
,,

40

!j.

i

]

c

~
i;j

30

0

~.,

~
~ 20

l"

"

C"

....2!

10------------100

80

120

140

160

180

length in cm

Fig. 9. Common porpoise P. phocoena. Length frequencies of animals stranded in
Britain (solid line) and taken by driving in Denmark (dotted line).

Phocoena phocoena (Fig. 9). Size frequency of strandings in the U.K. (fromFraser 1934 to 1974) is compared with a revived drive-fishery in Denmark during
the second world war (from Mohl-Hansen 1954). The size range of the animals
is the same, as might be expected from the nearness of the two samples. The maindifference is a peak of stranded animals at 4 ft (120 cm) which seems to be real,in spite of rounding of estimates of size in strandings. This size corresponds toanimals aged about 1 year, which is also the age at weaning (Fisher and Harrison1970). Thus it is possible that Phocoena phocoena endures a somewhat higher mortality rate at weaning than at younger or older ages, just as do minke whales.
The distribution of older deaths seems to be proportional to the abundance ofanimals.
Delphinus delphis (Fig. 10). The distribution of stranded animals comes from
British strandings (Fraser, op. cit.); that of unselected hunted animals from Soviet
fihseries in the Black Sea (Sleptsov 1941 ). Black Sea D. delphis constitute a dwarf
race (Kleinenberg 1956), although exceedingly abundant. Thus, the peak of adultlengths is very different. However there is no sign of a peak of juvenile deaths ineither graph.
Tursiops truncatus (Fig. 11 ). The sample of stranded animals again comesfrom Britain. The very small sample of driven animals comes from Cape Hatteras,
North Carolina, as described by True (1890). From what is known about relative
sizes of T. truncatus from Europe and North America (Hohn 1980), adults from thesecond area should be considerably smaller. There seems to be no difference inthe distribution of deaths.
Globicephala melaena. If one compares driven and naturally-stranded animals
from Newfoundland, there are no differences in the size frequencies (Fig. 4).
Owing to the high percentage of multiple strandings there are only small numbers
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

SERGEANT

3030Delphinus delphis

N=128

25
20
15
10

120

100

140

180

160

200

220

240

260

N =2079 d'cf
=2138 'i?'i?

600

r:!cl'

./

f

!

E 500

:I

z

'i?'i? ..........

\

160

180

400

300

200
............•······
100............
IOO

120

140

200

220

Length in cm
Fig. 10. Length frequencies of saddleback dolphin D. de/phis stranded in Britain(above) and taken in net fisheries in the Black Sea (below).

of measured, singly-stranded animals from Britain. Thus, although there may bea tendency for neonates and old animals to die selectively in these strandings, thenumber of animals involved must be small.
In summary, the porpoise Phocoena phocoena may show raised juvenile mortality,
Sci. Rep. Whales Res. Inst.,.No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

31

Tursiops truncatus: Strandings in Britain

20

N=175

10

.c

E

Drive-in catch, Cape Hatteras, 1886

N=25

z
5

400
Length group (cm)Fig. 11. Length frequencies of bottlenosed dolphin T. truncatus stranded in Britain(above) and taken in a drive fishery at Cape Hatteras (below).

but the three Delphinid genera examined show no sign of this phenomenon. Theirnatural mortality, as measured by their strandings, appears to occur in proportion
to the abundance of animals of different sizes in the population. If this is so,then the Delphinidae (at least) must have evolved adaptations to reduce juvenile
mortality. What these adaptations might be involve a comparison of Mysticete
and Odontocete reproductive cycles (see next section).
However, many weaned, immature dolphins remain independent of the reproductive herds: in Lagenorhynchus acutus they may travel as singletons or in loose
immature herds (Sergeant, St. Aubin and Geraci 1980); in S. coeruleoalba they may
keep together in semi-permanent herds (Miyazaki and Nishiwaki 1978), and perhaps in Stenella attenuata also when not aggregated by purse-seining (Pryor andKang 1980). Perrin and Powers (1980) found a higher incidence of skull lesions
caused by the nematode Crassicauda sp. in juvenile than in older Stenella attenuata;highest rates were at 2-8 years, which are just those animals expected to be inseparate schools. A higher mortality is implied because of the permanent scars
left by the parasite on the skulls. Therefore in this species, there is evidence froma unique source for higher immature than adult mortality; there are not sufficientSci. Rep. Whales Res. Inst.,
No. 34, 1982

32

SERGEANT

strandings of the same species to make a comparison by the method we have used
for the more inshore species.
REPRODUCTIVE CYCLES IN MYSTICETES AND ODONTOCETESAs Laws (1959) made clear, the length of gestation in most Balaenopterid whales is
one year. This feature involves an accelerated foetal growth rate in late pregnancy.
Coupled with it is a short lactation period of 6-11 months (Gambell 1973). Since
pairing occurs in winter, and a migration to high latitudes in summer, the two
features appear to ensure that birth will occur in the winter, and independence inthe following summer, so that the lactating female and young animal are loosed
upon a rich food supply. The whole process of gestation and lactation is extremely
rapid for such large animals.
The Odontocetes by contrast have gestation lengths which increase with thesize of the animals, from 10-11 months in Phocoena phocoena (Fisher and Harrison1970), 11-12 months in genera such as Stenella (Perrin, Coe and Zweifel 1976;
Kasuya 1976) and Delphinus (Sleptsov 1941), to 16 months in large Delphinidae
such as Globicephala (Sergeant 1962) and 14-15 months in the Monodontid genus
Delphinapterus (Sergeant 1973). The sperm whale Physeter catodon also has a gestation of 16 months (Best 1968).
The lactation period also increases with body size, being 8 months (as short
as in a Mysticete) in Phocoena phocoena (Fisher and Harrison 1970), ranging up to
two years in Tursiops, Globicephala, etc. From Tursiops truncatus in captivity it is
known that, though solid food may be taken at 6 months, lactation may continueintermittently to 2 years (Tavolga and Essapian 1957).
Care of juveniles continues during this period or beyond (Tavolga 1966),
and adult females ("aunties") other than the mother may share this task. Caregiving or succorant behaviour is well-known in many Delphinids, in sperm whales
and in Ziphiids (Caldwell and Caldwell 1966; Best 1979; Benjaminsen andChristensen 1979). It is little wonder, then, that juvenile mortality is reduced
among Odontocetes.
We may suppose, therefore, that one major direction of evolution in Odontocetes has been towards increasing the length of the reproductive cycle coupledwith an increase in size. The resulting lowered reproductive rate is offset bya decrease in juvenile mortality. One may ask, therefore, if density-dependent
control of reproductive rate still occurs in the Odontoceti.
Mysticeti (Balaenoptera sp.) exhibit a shorter period between pregnancies, andage at sexual maturity falls, when populations are reduced (Gambell 1973 ).
Attempts to find the same phenomenon in Odontoceti have been more recent andhave shown less clear-cut results. Let us start with the examination of a time series
within one population which has been reduced by hunting-or the reverse, apopulation which has been allowed to increase by relaxation of hunting-and pass
to comparisons of adjacent populations of the same species believed to exist at
higher and lower population densities.
Sci. Rep. Whales Res, Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

33

Density-dependence:a. Time series within one population
In 1952 to 1954 and again in 1957 I measured the reproductive rate in unselected samples of Globicephala melaena in search of a change of reproductive rate
(Sergeant 1962, Table XIX). I failed to find such a change (Table 14), there
being a decrease rather than an increase of pregnancy rate and no change in lactation length. Yet we now know (Fig. 2) that 15% of the population had been removed at the mid-point of the first sample, 50% at the beginning of the second.
At the time, I put the failure to find a change in reproductive rate to the short time
period between samples and to a possible lag in the system, since female pilot whales
take 6 years to reach sexual maturity. This still seems a reasonable explanation.
However, had I returned to resample, it might not have been possible to obtainadequate further data owing to depletion of the population (Fig. 2).
Perrin, Coe and Zweifel (1976) studied the reproductive rate of a populationof the spotted dolphin Stenella attenuata in the eastern tropical Pacific from 1968 to
1973. Perrin, Miller and Sloan (1977) continued these studies up to 1975.
Reproductive rate was best calculated as the proportion of females in the population, times the proportion of females reproducing, times the annual pregnancy rate;
this was 0.146 in 1968-73, 0.14+0.008 in 1973, 0.135+0.008 in 1974, 0.140+0.007
in 1975 and 0.140+0.004 in 1973-75, thus showing no significant change in 7 years.
In 1974 this population was at or near its maximum productivity, with a kill of
about 80,000 to 100,000 occurring annually in a purse-seine fishery for tuna (Perrin,
Smith and Sakagawa 1975). Kills had been higher in 1971 to 1973 and the population was believed to have declined, though the amount was unknown.
Length oflactation period was 11.2 months in 1968-1973.
Henderson, Perrin and Miller (1980) calculated a reproductive rate of about
0.12 for northern S. attenuata from the eastern Pacific in 1974-1978. Length oflactation increased steadily from 8 to 36 months between 1973 and 1978. They
noted a "dramatically decreased (porpoise) kill over the same period" in tunapurse-seines. These data would tend to suggest that length of lactation can be very
sensitive to exploitation rate in Stenella spp., given a long enough time for study.
Here it increased, making the reproductive rate fall, as the rate of exploitation
slackened.
TABLE 14.

REPRODUCTIVE RATES OF PILOT WHALES THROUGH TIME
Data from Sergeant (1962, Table XIX).
1952-1954

1957

FemalesMaturein active reproduction in oestrus
or ovulated
pregnant
lactating
Percent animals removed from population
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

No.

%

No.

%

415
395
35
140
220

100
95.2
8.4
33.7
53.0

114
105
16
29
60

100
92.l
14.0
25.4
52.6

15

50

SERGEANT

34

TABLE 15.

INCIDENCE OF FEMALE SPERM WHALES IN EARLY AND LATEPREGNANCY FOR TWO TIME PERIODS
from Best (1980).

No females examined
Percent in early pregnancy
Percent in late pregnancy
Percent with large corpus luteum but no foetus
Total

1962-1967

1973-1975

1,029
17.1
4.5
2.2
23.8

1,127
20.7
3.1
6.2
30.0

Kasuya (1976) studied Stenella coeruleoalba off eastern Japan. The population
was depleted to about half its initial size between about 1945 and 1972-73. The
mean calving interval beeame shorter, changing from 3.2 years in 1952 to 2.4 years
in 1972-73, with a decrease in lactation period of from two years to less than one
year. This is the same process in reverse as seen by Henderson et al. (1980) in
S. attenuata.
Best (1980) studied female sperm whales off Natal, South Africa (Table 15).
Sampling was done twice with an interval of 10 years, during which period thefemale population was believed to have been halved. The results are a little hardto interpret, because a category "females with large corpus luteum but no foetus "might have been either females with large foetuses lost in towing, or recently calved
females. The total number of pregnant females, if this category is included, increased from 23.8% to 30.0%, if excluded, from 21.6% to 23.5%. Even thougheach sample exceeded 1000 animals, Best regarded them as barely adequate. It
cannot be said that this example is clear-cut, but the conditions of sampling were
not ideal.
Judging from the studies reported above, about a decade of studies is neededon a population subject to a changing exploitation pattern, probably because of
the long time required to attain sexual maturity in the genera studied.
b. Comparisons of two populations of the same species(1) by the same author
Perrin and Henderson (1979) compared reproductive rates in two populationsof spinner dolphins Stenella longirostris which had been exploited at markedly different rates. There was no difference in gross reproductive rates (proportion of
females times proportion mature times pregnancy rate) although there were differences in these individual components of reproduction.
(2) by different authors
These comparisons are listed separately since methodology cannot always beclosely compared.
Perrin, Coe and Zweifel (1976) and Perrin, Miller and Sloan (1977) examined
the reproductive rate of Stenella attenuata in the eastern tropical Pacific Ocean, apopulation which had sustained a heavy fishery. Kasuya, Miyazaki and Dawbin(1974) examined the reproductive rate of the same species off Japan, from a popuSci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALESTABLE 16.

35

WHITE WHALES: A COMPARISON OF LIFE HISTORYPARAMETERS IN TWO POPULATIONS
from Brodie 1971, Sergeant 1973.

Character
Sample size:
HuntedNettedTotal
Maximum no. tooth layers
Maximum no. corpora albicantia
Mean age at sexual maturity (tooth layers):
malefemaleGestation
Lactation
Frequency of calving

Western Hudson Bay
257
293
550
50
15
16-18
8-13 (10)14 months
20 months
1 in 3 years

Cumberland Sound
17
107
124
40
9
16
9-11 (10)14.5 months
2 years
1 in 3 years

lation which had only been exploited for about 10 years at a low rate (6000 caught
in 1963-1973), both fisheries exploiting populations of unknown size. Reproductive
rate was calculated in a different way from Perrin et al., but the data allow recalculation by Perrin et al.'s (1976) method: thus percent females (193/323)=0.60;
percent reproductive females (124/193)=0.64; and annual pregnancy rate=0.256,
including simultaneously pregnant and lactating females assigned half to eachcategory. This gives a reproductive rate close to 0.100 as compared with Perrin
et al.'s rate of 0.140 to 0.145. The difference appears to be due to a lower rate ofovuiation prolonging lactation in the population from the Japanese seas.
Brodie (1971) examined the reproductive rate of a population of white whales
Delphinapterus leucas as Cumberland Sound, Baffin I. This population has undoubtedly been under heavy exploitation for a long time (Brodie, Parsons and Sergeant1981) and should show the maximum reproductive rate of which the species iscapable. Sergeant (1973) examined a population of white whales in western
Hudson Bay which he later believed (Sergeant 1981) to be in a balanced though
not low state of exploitation. No differences are apparent (Table 16) in mean age
at female sexual maturity, nor in frequency of calving. It is unfortunate that thewestern Hudson Bay population was not sampled for these features around 1950
at the outset of the industrial fishery at Churchill, Manitoba.
Thus the majority of the comparative population studies show a difference inreproductive rates between lightly and intensively exploited populations. Sergeantand Brodie's populations of white whales may have been exploited at similar rates,or the parameters may not have been measured sufficiently accurately. No change
in mean age at first reproduction has yet been demonstrated in any of the withinpopulation or between-population studies; the changes are all changes in length oflactation. Probably the mechanism is between a lactation anoestrus in females
within a denser population, and ovulation during lactation in better-fed females
within a heavily exploited population. There is therefore a density-dependent
reproductive rate within an Odontocete population. It remains to be shown
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

36

SERGEANT

whether or not a calf suckled for only 8 months by its mother has a higher mortality
rate than a calf suckled for 24 months. Probably, the length of lactation has
little significance, since later lactation is intermittent (Tavolga and Essapian 1957;
Tavolga 1966) in Tursiops truncatus; and the existence of" aunties" from among
younger or anoestrous females safeguards an older calf when the mother has a newone. Therefore, a higher reproductive rate is probably not necessarily associatedin Odontoceti with a higher calf mortality rate. It is only when the adolescents
form herds on their own account that their mortality rate may rise, as demonstrated
by the high singleton death rate of adolescent Lagenorhynchus acutus, and by Perrin
and Powers (1980) in Stenella attenuata from infections with Crassicauda (p. 31).
These mortalities might be density-dependent. However the existence of social
mechanisms maintaining calves within the herds will continue to keep calf mortality
low.
Thus in Odontocetes survival of juveniles is maximixed by a high degree ofparental care and sociality. Old animals too may benefit from care-giving behaviour. The only mechanism remaining to increase mortality among adolescentsis aggressiveness of older animals, and this mechanism disappears within the mostsocial species.
A population however must expand slowly if it is to maintain itself. Eventually it will come up against an environmental barrier which will limit its continued growth. Such barriers must in some way involve either food or space.
Mass strandings represent a high proportion of the total mortality of the social
species and must therefore constitute the main mechanism by which populations ofthese species are limited.
.
It is just possible that the true Delphinidae can be divided into two groups:
the Delphininae with about a year's gestation, and a normally long lactation
period which can be shortened in the way described; and the Orcininae with a long
pregnancy, and a long lactation not susceptible to being shortened. This dichotomy, if real, would fit with the subdivision into frequent mass-stranders and others.
Unfortunately there are not yet enough data on pregnancy length or on densitydependence in lactation length to know if the suggested division is real. For instance, the lengths of pregnancy and of lactation of Orcinus orea seem to be unknown.
The same is true for Pseudorca crassidens and Peponocephala electra though it should be
only a matter of time before a sufficient number of animals are examined in mass
strandings of these species.
PROXIMATE CAUSES OF STRANDINGS

Examination of mass-stranded Cetacea has shown no obvious bacteriological,
helminthological or other pathological findings including those of neuropathology(Hall, Gilmartin and Mattson 1971, Hall and Schimpff 1979). Yet single-stranded
animals are frequently highly infected either with trematodes in the liver and brain(Ridgway and Dailey 1972), or with nematodes in lung alveoli or head air sinuses(Delyamure 1955, Dailey and Perrin 1973, Dailey and Stroud 1978). Since
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

37

many delphinds are known to have heavy infections of nematodes in air-sinuses orlungs, it is important to obtain quantitative information on numbers of parasites
in normal and stranded animals. The only such data known to me are due toDelyamure (1955), who examined D. delphis from the Black Sea. Seven naturallystranded animals had heavy infections of the nematode Skjrabinalius cryptocephalus in
their tracheae and bronchi with pus blocking the small respiratory passages, together with hyperemia, and destruction of the bronchial mucosa. Examination of
the lungs of 604 D. delphis caught in the fishery showed that 175 (28.9%) had S.
cryptocephalus infections with from 3 to 227 nematodes present. Infections increased
with age, though a few adults were self-cured with healed lesions. Evidence for
acute bacterial infections tends to come more from captive animals where the watermust have high concentration, e.g. of Staphylococcus aureus (Colgrove and Migaki1976). In summary, nearly all singly-stranded animals are diseased or highly
parasitised, but mass-stranded animals are not. Geraci and St. Aubin (1979)
found that the adrenal cortex of mass-stranded adult female Lagenorhynchus acutus
showed cysts characteristic of prolonged stress. This interesting observation needs
to be followed up, and it is particularly important to examine the cortex fromfree-living controls to compare with those of the stranded animals.
Most authors (e.g. Dudok van Heel 1962) have placed emphasis on the immediate circumstances of mass-strandings, such as the configuration of the coastline,
but I do not believe these features to be important. Certainly, many strandings
occur on shoaling coasts. Thus Maigret (1979) notes a concentration of mass
strandings of Globicephala macrorhyncha, Delphinus delphis, Tursiops truncatus and Steno
bredanensis on the north side of the Cap-Vert peninsula, Senegal. Six of sevenstrandings occurred in May and June when there are trade winds from the northwest and a surface current setting from the northeast on to the shore. Anothersuch region may be the neighbourhood of Wellfleet, Cape Cod, where, according
to SEAN reports, Lagenorhynchus acutus strand repeatedly as well as other species
such as Globicephala melaena occasionally. I believe that the animals can best be
regarded as " drift bottles" which will inevitably tend to arrive on such sites.
Passivity of the animals is stressed in many observations, e.g. the pilot whales
G. macrorhyncha which stranded repeatedly along the west coast of Florida in August
1971 (Fehring and Wells, 1976); and the 30 Pseudorca crassidens which were filmed
coming ashore at the Dry Tortugas, Florida in June 1976 (Porter, 1977). Moreover,as is well known, a herd once so stranded is likely, if taken out to sea, to strand
again (Fehring and Wells, 1976). I therefore judge it more important to examine
the internal causes of the observed passivity.
MASS STRANDINGS AS EMIGRATIONSConsidering the extralimital occurrences of mass-stranding Pseudorca crassidens at
Britain and probably also in south temperate seas one would expect mass-strandings
within an increasing population to be accompanied by some range expansion.
This does not seem to have occurred as yet with Lagenorhynchus acutus which has
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

38

SERGEANT

merely increased within its known range in the northwest Atlantic, there being noevidence of a concomitant increase of the same species within the northeast Atlantic(Evans, 1980, 1981 ). Thus for this species, the scope of a population increase so
far been has quite restricted. It will be worthwhile to continue to monitor it.
PRACTICAL APPLICATIONSSergeant (1977) used the frequency of singleton strandings of fin whales on the
coasts of Britain over time, expressed as an order of rank within all Cetacean
strandings, in order to determine changes of the population as a result of commercial
whaling.
If frequency of mass and singleton strandings varies directly with the abundance of an Odontocete species, prone to mass strand, then occurrence of mass
strandings could give additional evidence on the state of such a stock. This could beof practical value for a species such as the sperm whale.
In the eastern North Atlantic, Fairlie (1981) notes that there has been no decline in recent years in the (singleton) stranding rate of sperm whales in Ireland,though all Mysticetes have declined in their stranding rate at Britain, this correlating well with the reduction of their populations by hunting (Sergeant 1977,1979). From the evidence given I would deduce that sperm whales have not declined in the eastern North Atlantic. Mitchell (1975b) demonstrated a cross-overfrom Nova Scotia to Spain from tagging, showing that eastern and western North
atlantic sperm whales are not isolated from one another. Allen, Compton-Bishop
and Gordon (1979) demonstrated a reduction in catch and increase in catch perunit effort of sperm whales at the Azores between the 1950's and 1970's, due tomassive human emigration and reduction in number of whaling stations. Catches
there in the 1950's were about 400 per annum; in the 1970's about 200 and falling.
The main catch of sperm whales is now at Iceland (about 200 per annum) where
only adult males are available. I conclude that the North Atlantic population of
sperm whales is probably not reduced nor are present catches excessive. The mainconcern appears to be whether the falling mean size of males due to selective
catching of them(Martin 1981) could affect reproductive success.
In the eastern North Pacific there have been 4 recent mass strandings: in the
Gulf of California in 1953 and 1954 (Gilmore 1957, 1959) and in 1979 (Byrant
1979; SEAN Bull.,January 1979), and on the coast of Oregon in June, 1979 (Anon,
1979, SEAN Bull. June 1979). The Mexican strandings were all or mainly of
males; the Oregon stranding was of a harem herd. Pike and MacAskie (1979)
show that harem herds normally extend as far north as off the coast of British
Columbia between spring and autumn. Knowledge of stock identity of sperm
whales in the North Pacific Ocean is still incomplete, but Bannister and Mitchell(1980), basing themselves partly on unpublished tagging recoveries due to D. W.
Rice, and partly on discontinuous distributions of sperm whales at sea, accept theexistence of an eastern North Pacific or American stock. Horwood and Garrod(1980), examining the state of this stock from catch per unit of eftort and cornSci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

39

parisons of pregancy rate over time, conclude it is in a healthy state.
At New ,Zealand, there were mass strandings of sperm whales in 1970 (Robson
and Van Bree 1970), 1972 (Robson 1978) and 1974 (Stephenson 1975)with apparently none subsequently (fide SEAN Bulls. to December 1981). Best (1976),
table 2) shows that stock reductions of sperm whales in the southern hemispheregenerally and the New Zealand area in particular (Best's division VII) were severe
for exploitable males, reducing them to about half initial stock size by 1972.
However it had been computed that the stock of mature females was reduced only
to ea 90% of initial sock. Clearly, the females are the main animals which appear
in strandings of harem herds.
I conclude that analysis of mass and single strandings of sperm whales may
throw light on the status of stocks additional to that which may be obtained byother methods, and that this finding makes important the widespread dcoumentation of their strandings.
SUMMARY

1. In eastern Newfoundland from 1950 to 1971 an abundant oceanic populationof pilot whales Globicephala melaena was hunted down to low catch levels. Its cumulative catch gave an initital population estimate of 54,000. It was protected in1972. The population was estimated in 1980 to number at least 14,000 animals.
Recovery of the population was presumably accelerated by immigration fromareas where the species had remained common. From 1975, mass-strandings
began at Newfoundland and neighbouring areas and continue at the rate of between
100 and 200 animals a year.
In the area of the northwest Atlantic extending from the Gulf of Maine to
the Gulf of St. Lawrence, white-sided dolphins Lagenorhynchus acutus have become
very common since about 1970 with at least 10,000 individuals present in the U.S.
sector of this range. During the 1970's there were two mass strandings and many
singleton strandings of this species.
At North Island, New Zealand, harem herds of sperm whales have massstranded on many occasions, and this area contains one of the highest densities ofsperm whales and especially females in the southern hemisphere.
From these examples, mass strandings can be associated with dense populations of Odontocetes.
2. From an examination of the literature, mass strandings are the main sourceof coastal mortality (perhaps exceeding 90% of deaths) in a group of species (Globicephala spp., Pseudorca crassidens, Peponocephala electra) belonging to the subfamily
Orcininae of the family Delphinidae. Mass strandings represent a lower percentage
of deaths in typical dolphins of the subfamily Delphininae.
3. The frequency of mass strandings can vary geographically, whatever the rateof overall incidence. A study of the incidence of mass strandings by latitude in
the allopatric species Globicephala melaena and G. macrorhyncha along the eastern
North American seaboard showed that each species has a wide" core" area where
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

40

SERGEANT

both mass and singleton strandings occur, located to the northward in G. melaenaand southward in G. macrorhyncha. At the edges of the respective ranges, where
the two species are in contact, only singleton strandings occur in both species.
This evidence is taken to mean that mass strandings occur in that part of the range
where the species is abundant.
4. A comparison of life histories shows that Globicephala melaena among theOrcininae exhibits greater sociality, expressed by greater homogeneity of herds,
than do Tursiops truncatus and Lagenorhynchus acutus among the Delphininae. Pilot
whales also show absence of aggression by adult to immature a~imals. This
greater sociality occurs among member species of the Orcininae in spite of a greater
sexual dimorphism, delayed sexual maturity and higher male mortality rate,features typical of territorial marine mammals of other groups.
Physeter catodon exhibits mass mortality among harem herds, but solitarystranding mortality of subadult and adult males at high latitudes, consistent withthe known aggressive behaviour of harem bulls.
5. No evidence exists for emigration among mass-stranding populations of Odontoceti, except for the examples of Pseudorca crassidens stranding in cool seas.
6. In Mysticetes, high mortality occurs among young animals just after weaning,
and at extreme old ages. This pattern remains among Odontoceti in the weaklysocial Phocoena phocoena, but is not observed from length frequencies of stranded
Delphinus, Tursiops and Globicephala. However high adolescent mortality remains
due to aggression in Lagenorfrynchus acutus and Stenella attenuata at least. It is argued
that sociality reduces the mortality of juveniles of the social Odontoceti, probably
through such features as the long lactation and other features of parental caresuch as succorant behaviour. Since length of lactation has been demonstrated to
be density-dependent among members of the Delphininae and among sperm whales,social behaviour must be important in reducing calf mortality. When other sourcesof mortality are reduced, social mortality expressed in mass strandings becomesthe major source.
7. The main purpose of the study has been to emphasise internal factors andespecially population density as responsible for mass strandings and to discount
immediate external factors such as coastal configuration. What the internal factors
might be leading to morbidity of herds is unknown but it is suggested that studies
of stress might be valuable, with the need to study controls from among normal
animals at sea.
ACKNOWLEDGMENTS
I am greatly indebted to Jon Lien, Memorial University of Newfoundland, and to
Keith Hay, Department of Fisheries and Oceans of Canada in St. Jonh's for unpublished information on mass strandings and on net catches of humpback whales.
Michael Moore and Paul Brodie also provided useful observations. Especially I
wish to thank the compilers of the Scientific Event Alert Network (SEAN) of theSmithsonian Institution, Washington, D. C. and many observers on the United
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

41

States east coast for the opportunity to analyse their carefully documented observations of Cetacea.
M. Didier Marchessaux, Aix-en-Provence, France, recently a visitor to Ste.
Anne de Bellevue, Hr. Chr. Hysing-Dahl, Bergen, Norway and especially Dr.
Margaret Klinowska, Department of Anatomy, Cambridge University, provided
me with many valuable references. Robin Allen and Michael Scott of the Intertropical Tuna Commission, William F. Perrin and Douglas DeMaster of Southwest
Fisheries Center, La Jolla, and James Mead and Aleta Hohn of the National
Museum of Natural History, Washington, criticised earlier versions of the paper;
Dr. A. W. Mansfield-a later draft. They are not responsible for its imperfections.
REFERENCES
AITKEN, P. F., 1971. Whales from the coast of South Australia. Trans. Roy. Soc. S. Australia, 95: 95-103.
ALLEN, K. R., 1980. Conservation and management of whales. Univ. of Washington Press, Seattle; Butterworths,
London. 107 pp.
ALLEN, P., Q. COMPTON-BISHOP, and J. GORDON., 1979. Report of the Cambridge Azores Expedition 1979.
Dupl., 46 pp.
ANON., 1979. Teeth of stranded sperm whales studied to determined age. U.S. Dept. of Commerce, Nat. Mar.
Fisheries Serv., Northwest and Alaska Fisheries Center Monthly Rept., July 1979. U.S. Nat. Mar.
Mammal Lab., Seattle, Washington.
BANNISTER, J., and E. D. MITCHELL., 1980. North Pacific sperm whale stock identity: Distributional
evidence from Maury and Townsend charts. Rep. int. Whal. Commn (Special Issue 2): 219-230.
BENJAMINSEN, T., and I. CHRISTENSEN., 1979. The natural history of the bottlenose whale Hyperoodon ampullatus (Forster). pp. 143-164. In: H. E. Winn, and B. L. Olla (eds.) Behavior of marine animals,
3 Cetaceans. Plenum Press, 438 pp.
BEST, P. B., 1968. The sperm whale Physeter catodon of the west coast of South Africa. 2. Reproduction in
the female. Invest[. Rep. Div. Sea Fish. S. Africa, 66: 1-32.
BEST, P. B., 1969. The sperm whale Physeter catodon of the west coast of South Africa. 3. Reproductionin the male. Investl. Rep. Div. Sea Fish. S. Africa, 72: 1-20.
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, Mass.,
419 pp.
BEST, P. B., 1976. Review of sperm whale stocks. Food and Agr. Org. Un. Nations, Advis. Ctee. on Mar.
Res. Research, Marine Mamm. Symp. EC 8, 35 p., Mimeo.
BEST, P. B., 1979. Social organization in sperm whales. pp. 227-289. In H. E. Winn and B. L. Olla(eds.) Behavior of marine animals, 3. Cetaceans. Plenum Press, 438 pp.
BEsT, P. B., 1980. Pregnancy rates in sperm whales off Durban. Rep. int. Whal. Commn (Special Issue 2):
93-97.
Bmo, M. A., 1981. An assessment of killer whale ( Orcinus orca) stocks off Vancouver Island, British Columbia.
Int. Whal. Commn, Workshop on killer whales, Cambridge, U.K. 23-25 June 1981. Working Paper
SCJJN81/KW4, 31 pp.
Bmo, M.A., I. B. MAaAsKIE and G. ELLIS., 1976. Abundance and movements of killer whales off easternand southern Vancouver Island, with comments on management. Unpubl. MS, Arctic Biological
Station, Ste. Anne de Bellevue, Que., 20 pp.
BosaHMA, H., 1938. On the teeth and some other particulars of the sperm whale (Physeter macrocephalus L.).
Temminckia, Leyden III: 151-278, XIII plates.
BREE, P.J.H. VAN, and I. CRISTENSEN., 1974. On the intriguing stranding of four Cuvier's beaked whales,<:,iphius cavirostris, G. Cuvier 1823, on the Lesser Antillean Island of Bonaire. BiJdr. Dierkd., 44: 235238.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

42

SERGEANTBRODIE, P. F. 1971. A reconsideration of aspects of growth, reproduction and behavior of the white whale(Delphinapterus leucas), with reference to the Cumberland Sound, Baffin Island, population. J. Fish.
Res. Board Can., 28: 1309-1318.
BRODIE, P. F., J. L. PARSONS, and D. E. SERGEANT., r981. Present status of the white whale (Delphinapterus
leucas) in Cumberland Sound, Baffin Island. Rep. int. Whal Commn, 31: 579-582.
BROWN, D. H., D. K. CALDWELL, and M. C. CALDWELL., 1966. Observations on the behavior of wild andcaptive false killer whales, with notes on associated behavior of other genera of captive Delphinids.
Contr. Sci. Mus. Los Angeles County, 95: 32.
BROWN, S. G., 1975. Relation between stranding mortality and population abundance of smaller Cetacea
in the Northeast Atlantic Ocean. J. Fish. Res. Board Can., 32: 1095-1099.
BRYANT, P., 1979. The Baja sperm whale mass-stranding. Whalewatcher. J. Amer. Cetacean Soc., 13(2):10.
BRYDEN, M. M., T.J. HARRISON, and R.J. LEAR., 1977. Some aspects of the biology of Peponocephala electra(Cetacea, Delphinidae). Part I. General and reproductive biology. Aust. J. Mar. Freshwater Res., 28:
703-716.
BuDKER, P., 1968. Stranding of pilot whales (Globicephala melaena (Traill)) on the coast of Normandy, France.
Norwegian Whaling Gazette 1968 ( 1): 17-19.
BULLIS, H. R., and J. C. Moore., 1956. Two occurrences of false killer whales, and a summary of American
records. Amer. Mus. Novitates 1756: 5.
CALDWELL, M. C., and D. K. CALDWELL., 1966. Epimeletic (care-giving) behavior in Cetacea. pp.
755-789. In: K. S. Norris (ed.) Whales, dolphins and porpoises. University of California Press, Berkeley
and Los Angeles, 789 pp.
CALDWELL, D. K., M. C. CALDWELL, W. F. RATHJEN, and J. R. SULLIVAN., 1971. Cetaceans from theLesser Antillean Island of St. Vincent. Fishery Bull., 69: 303-312.
CALDWELL, D. K., M. C. CALDWELL, and C. M. WALKER. 1970. Mass and individual strandings of false
killer whales, Pseudorca crassidens, in Florida. J. Mamm. 51: 634--636.
CARL, G. C., 1946. A school of killer whales stranded at Estevan Point, Vancouver Island. British Columbia,
Prov. Mus. Nat. Hist. and Anthrop., Rep. 1915: 321-328.
CASINOS, A., andJ. Bou., 1980. On a massive stranding of short-finned pilot whale, Globicephala macrorhynchus
Gray, 1846, on Margarita Island (Venezuela). Sci. Rep. Whales Res. Inst., 32: 145-148.
COLGROVE, G. S., and G. MIGAKI., 1976. Cerebral abscess associated with stranding in a dolphin. J. Wild.
Dis., 12: 271-274.
COMRIE, L. C., and ANN B. ADAM., 1938. The female reproductive system and corpora lutea of the false
killer whale Pseudorca crassidens Owen. Trans. Roy. Soc. Edin., 59(2): 521-531.
DAILEY, M. D., and W. F. PERRIN., 1973. Helminth parasites of porpoises of the genus Stenella in theeastern tropical Pacific. Fish. Bull., 71 : 455-471.
DAILEY, H., and R. STROUD., 1978. Parasites and associated pathology observed in cetaceans stranded
along the Oregon U.S.A.coast. J. Wild. Dis., 14: 503-512.
DAWBIN, W. A., B. A. NoBLE, and F. C. FRASER., 1970. Observations on the electra dolphin, Peponocephalaelectra. Bull. Brit. Mus. Nat. Hist., 20: 173-201.
DEARDEN, J.C., 1958. A stranding of killer whales in Newfoundland. Can. Field-Nat., 72: 166-167.
DELYAMURE S. L., 1955 [1968). Helminthofauna of marine mammals (Ecology and Phylogeny). Trans!.
from Russian. U.S. Dept. of the Interior, and Nat. Sci. Foundation, Washinton, D.C., 522 pp.
DE MASTER, D., 1981. Editorial. pp. 1-2. In: Marine Mammal Information June 1981. Oregon State
Univ., Sea Grant College Program, Corvallis, Oregon. 23 pp.
DuDOK VAN HEEL, W. H., 1962. Sound and Cetacea. Netherlands J. Sea Res., l: 407-507.
DuGUY, R., 1973. Rapport annuel sur les Cetaces et les Pinnipedes trouves sur les cotes de France. II
Annee 1972. Mammalia, 37: 669-677.
DuGuY, R., 1974. Ibid. III Annee 1973. Mammalia, 38: 545-555.
DuGuY, R., 1975. Ibid. IV Annee 1974. Mammalia, 39: 689-701.
DuGuY, R., 1976. Ibid. V Annee 1975. Mammalia, 40: 671-681.
DuGuY, R., 1977. Ibid. VI Annee 1976. Ann. Soc. Sci. Nat. Charente-Maritime, VI(4): 308-317.
Sci. Rep. Whales Res. Inst.,
No. 31, 1982

MASS STRANDINGS OF TOOTHED WHALES

43

Duauv, R., 1978. Ibid. VII Annee 1977. Ann. Soc. Sci. Nat. Charente-Maritime, VI(5): 333-344.
Duauv, R., 1979. Ibid. VIII Annee 1978. Ann. Soc. Sci. Nat. Charente-Maritime, 6(6): 463-474.
Duauv, R., 1980. Ibid. IX Annee 1979. Ann. Soc. Sci. Nat. Charente-Maritime, 6(7): 615-632.
Duauv, R., 1981. Ibid. X Annee 1980. Ann. Soc. Sci. Nat. Charente-Maritime, 6(8): 803-818.
Duauv, R. and J. BAUDOUIN-BODIN., 1965. Rapport sur l'echouage d'une troupe de Globicephales Globicephala melaena (Traill, 1809) a l'Ile d'Yeu. Mammalia, 29: 61-64+ Tables, Fig.
Duauv, R., and P. BuDKER., 1972. Rapport annuel sur les Cetaces et Pinnipedes trouves sur les Cotes deFrance. I. Annee 1971. Mammalia, 36: 517-520.
EVANS, P.G.H., 1980. Cetaceans in British waters. Mammal Review, 10: 1-52.
EVANS, P.G.H., 1981. Cetacean expedition around western Britain] uly 15-0ct. 17, 1980. Marine Mammal
Information, June 1981: 4-5.
FAIRLIE, J., 1981. Irish whales and whaling. Blackstaff Press, Belfast, 234 p.
FEHRING, W. K., and R. S. WELLS., 1976. A series of strandings by a single herd of pilot whales on the west
coast of Florida. J. Mamm., 57: 191-194.
FISHER, H. D., and R. J. HARRISON., 1970. Reproduction in the common porpoise (Phocoena phocoena) of
the North Atlantic. J. Zoo/. Land., 161: 471-486.
FoRD, J., and D. FORD., 1981. The killer whales of B.C. Waters, J. Vancouver Public Aquarium, 5: 3-32,
ill us.
FRASER, F. C., 1934. Report on Cetacea stranded on the British coasts from 1927 to 1932. No. 11. Brit. Mus.
(Nat. Hist.) 1-41, 6 maps.
FRASER, F. C., 1936. Recent strandings of the false killer whale, Pseudorca crassidens, with special reference
to those found at Donna Nook, Lincolnshire. Scottish Nat.,Jul_y-Aug., '36: 105-114.
FRASER, F. C., 1946. Report on Cetacea stranded on the British coasts from 1933 to 1937. No. 12. Brit. Mus.
(Nat. Hist.), 1-56, 7 maps.
FRASER, F. C., 1953. Report on Cetacea stranded on the British coasts from 1938 to 1947. No. 13. Brit. Mus.
Hist.), 1-48, 9 maps.
FRASER, F. C., 1955. The southern right whale dolphin, Lissodelphis peroni (Lacepede). External charactersand distribution. Bull. Brit. Mus. (Nat. Hist.) Zool., 2: 341-346, l pl.
FRASER, F. C., 1974. Report on Cetacea stranded on the British coasts from 1948 to 1966. No. 14. Brit. Mus.
(Nat. Hist.) 1-65, 9 maps.
FRASER, F. C. and P. E. PURVES., 1960. Hearing in cetaceans. Bull. Brit. Mus. (Nat. Hist.) Zoo!., 7: 1-140,
53 pls.
GAMBELL, R., 1973. Some effects of exploitation on reproduction in whales. J. Reprod. Fert., Supple., 19:533-553.
GASKIN, D. E., 1968. The New Zealand Cetacea. Fish. Res. Bull. No. l (N.S.), Fisheries Research Division,
N.Z. Marine Dept. 92 pp.
GASKIN, D. E., 1970. Composition of schools of sperm whales Physeter catodon Linn. east of New Zealand.
N.Z. J. Mar. Freshw. Res., 4: 456-471.
GASKIN, D. E., P. W. ARNOLD, and. B. A. BLAIR., 1974. Phocoena phocoena. Mammalian Species, 42: 1-8.
GERACI, J. R., 1978. The enigma of marine mammal strandings. Oceanus, 21: 38-47.
GERAm,J. R., and D.J. ST. AUBIN., MS 1975. A mass stranding qfpilot whales in BonavistaBay, Newfoundland.
U.S. Mar. Mammal Comm. Rep. Contract MMC-47.
GERAm,J. R., and D. J. ST. AuBIN., 1977. Mass stranding of the long finned pilot whale, Globicephalamelaena,
on Sable Island, Nova Scotia. J. Fish. Res. Board Can., 34: 2196-2199.
GERACI,]. R., and D.J. ST. AUBIN., 1979. Stress and disease in the marine environment: Insights throughstrandings. pp. 223-233. In: J. R. Geraci, and D.J. St. Aubin (eds.) Biology ef Marine Mammals:
Insights through strandings. U.S. Dept. of Commerce, Nat. Tech. Info. Service, PB-293 890, 343 pp.
GILMORE, R. M., 1957. Whales aground in Cortes' Sea: Tragic strandings in the Gulf of California.
Pacific Discovery, 10: 22-27.
GILMORE, R. M., 1959. On the mass strandings of sperm whales. Pacific Naturalist, l: 9-16.
GurLER, E. R., 1978. Whale strandings in Tasmania since 1945 with notes on some seal reports. Pap.
Proc. Roy. Soc. Tasmania, 112: 189-213.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

44

SERGEANTHAIN, J.H.W., R. K. EDEL, H. E. HAYS, S. K. KATONA, andJ. D. RoANowrcz., 1981. General distributionof cetaceans in the Continental Shelf waters of the Northeastern United States. Section II, 277 pages.
In A characterization ef marine mammals and turtles in the Mid and North Atlantic areas ef the U.S. outer Continental
Shelf. Ann. Rept. for 1979 for the Cetacean and Turtle Assessment Program (CETAP). Univ. of
Rhode Island, Kingston, R.I.
HALL, J. D., W. G. GILMARTIN, and J. L. MATTSSON., 1971. Investigation of a Pacific pilot whale stranding
in San Clemente Island. J. Wild. Dis., 7: 324--327.
HALL, N. R., and R. D. SCHIMPFF., 1979. Neuropathology in relation to strandings: rnass stranded whales.
pp. 236-214. In: J. R. Geraci, and D. J. St. Aubin (eds.) Biology ef Marine Mammals: Insights throughstrandings. U.S. Dept. of Commerce, Nat. Tech. Info. Service PB-293 890, 343 pp.
HARMER, S. F., 1927. Report on Cetacea stranded on the British coasts from 1913 to 1926. No. 10. Brit. Mus.
(Nat. Hist.) 1-91 7 rnaps.
HARRISON, R.J., R. L. BROWNELL, and R. C. BorcE, 1972. Reproduction and gonadal appearances insome Odontocetes. pp. 362-429. In: R.J. Harrison (ed.). Functional Anatomy of Marine Mammals,Vol. I. Academic Press, London and New York.
HAUG, T. and B. GULLIKSEN., 1981. Remarks concerning a sperm whale stranding in North Norway inDecember 1980. Fauna, 34: 68-76.
HAUG. T., and 0. K. SANDNES., 1982. Mass stranding and successful rescue of killer whales Orcinus orca(L.) in Lofoten, North-Norway. Fauna, 35: 1-7.
HENDERSON, J. R., W. F. PERRIN, and R. B. MILLER., 1980. Rate of gross annual production in dolphin populations(Stenella spp. and Delphinus delphis) in the eastern tropical Pacific, 1973-1978. U.S. Dept. of Commerce,Nat. Mar. Fish. Serv., Southwest Fisheries Center Admin. Rept.JL-80-02. La Jolla, CA. 51 pp.
HINTON, M.A.C., 1928. Stranded whales at Dornoch Firth. Nat. Hist. Mag. 1: 131-000 (cited and quoted
by Purves and Pilleri 1978) Irwest. on Cetac:ea IX: 67-227, Berne.
HOHN, A. A., 1980. Age determination and age related factors in teeth of western North Atlantic bottlenose
dolphins. Sci. Rep. Whales Res. Inst., 32: 39-66.
HoRWOOD,j. W. and D.J. GARROD., 1980. The status of the North Pacific Sperm Whale. Rep. int. Whal.
Commn, 30: 187-192.
J ONSGAARD, A., 1951. Studies on the little piked whale or minke whale. Norwegian Whaling Gazette, 1951 (5):55.
KANWISHER, J ., and G. SuNDNES, 1965. Physiology of a small cetacean. Hvalraadets Skrifter, 48: 45-53.
KASUYA, T., 1976. Reconsideration of life history parameters of spotted and striped dolphins based on
cementa! layers. Sci. Rep. Whales Res. Inst., 28: 73-106, 4 pls.
KASUY A, 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., N. MIYAZAKI, and W. H. DAWBIN., 1974. Growth and reproduction of Stenella attenuata on
the Pacific coast of Japan. Sci. Rep. Whales Res. Inst., 26: 157-226.
KATONA, S. K., S. A. TESTAVERDE, and B. BARR., 1978. Observations on a white-sided dolphin, Lagenorhynchus acutus, probably killed in gill nets in the Gulf of Maine. Fishery Bull. U.S.A., 76: 475-476.
KELLOGG, R., 1929. What is known of the migrations of some of the whalebone whales. Ann. Rept. Smithsonian Inst., 1928: 467-494.
KLEINENBERG, S. E., 1956. Mlekopitayuschie Chernogo i Azovskogo morei (Mammals of the Black and Azov Seas).
U.S.S.R. Academy of Sciences Press, Moscow, 287 pp. (Trans!. 1978 by Dept. of Secretary of State ofCanada, for Arctic Biological Station, Ste. Anne de Bellevue, Que.)
LAws, R. M., 1959. The foetal growth rates of whales, with special reference to the fin whale, Balaenoptera
physalus Linn. Discovery Rep., 29: 281-308.
LAYNE, J. N., 1965. Observations on marine mammals in Florida waters. Bull. Flo. State Mus., Biol.
Sci., 9: 131-181.
LE TALLEC, J., 1969. Quelques notes sur les echouages en masse de Globicephales, Globicephala melaena(Traill, 1809) en Bretagne le 29 aout 1968. Mammalia, 33: 735-737.
LIEN, J. Ms, 1980. Baleen whale collisions with inshore fishing gear in Newfoundland. MS, Memorial
Univ. of Newfoundland, 26 p.+tables.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

MASS STRANDINGS OF TOOTHED WHALES

45

LIEN, J. Ms, 1981. Humpback whale collisions with inshore fishing gear in Newfoundland. MS, Memorial
Univ. of Newfoundland, 64p.+figs., tables.
LORD, E. I., and R. A. CHANDLER., 1969. \Vhale skulls on Georges Bank. Fisheries of Canada, 11 (!): 17-18.
MAIGRET, J., 1979. Les echouages massifs de cetaces clans la region du Cap-Vert (Senegal). Univ. de
Daker-Inst. Fondamental d'Afrique Noire. Puhl. Trimestrielle,Jan. 1979: (161) 23-28.
MARTIN, A. R., 1981. Further analysis of the post-war Icelandic sperm whale catch. Rep. int. Whal. Commn,
31: 765-768.
McCANN, C., 1974. Body scarring on Cetacea-Odontocetes. Sci. Rep. Whales Res. Inst., 26: 145-155, 8 pls.
Mead, J. G., 1979. An analysis of Cetacean strandings along the eastern coast of the United States. pp.
54-68. In: .J. R. Geraci and D . .J. St. Aubin (eds.). Biology of marine mammals: insights through strandings. Mar. Mamm. Commn, Washington, D.C. N.T.I.S. PB-293890, 343 pp.
MEAD, J. G., 1980. Strandings (of humpback whales) along the Atlantic coast of the U.S. from 1970Novermber 1980. Abstr. Proc. Workshop "Humpback whales of the western North Atlantic," 17-21
Nov. 1980, New England Aquarium, Boston, pages 13-14. In Mate, B. (ed.) Marine Mammal Information,
Dec. 1980 (Oregon State Univ., Corvallis, Oregon).
MEAD, .J. G., D. K. ODELL, R. S. WELLS, and M. D. ScoTT., 1980. Observations on a mass stranding of
spinner dolphin, Stenella longirostris, from the west coast of Florida. Fish. Bull., 78(2): 353-360.
MERCER, M. C., 1973. Observations on distribution and intraspecific variation in pigmentation patternsof Odontocete Cetacea in the western North Atlantic. J. Fish. Res. Board Can., 30: 1111-1130.
MERCER, M. C., 1975. Modified Leslie-DeLury population models of the long finned pilot whale (Globicephalamelaena) and annual production of the short finned squid (Illex illecebrosus) based upon their interaction
at Newfoundland. J. Fish. Res. Board Can., 32: 1145-1154.
Mitchell, E. D., 1973. Draft report on humpback whales taken under special scientific permit by eastern
Canadian land stations 1969-1971. Rep. int. Whal. Commn, 23 (App. B): 138-154.
MITCHELL, E. D., 1975a. Porpoise, dolphin and small whale fisheries of the world. Status and problems.
Int. Union Cons. Nat. Natural Res., Monograph No. 3, 129 pp.
MITCHELL, E. D., 1975b. Preliminary report on Nova Scotia fishery for sperm whales (Physeter catodon).
Rep. int. Whal. Commn, 25: 226-235.
MITCHELL, E. D., 1977. Canadian progress report on whale research-June 1975 to May 1976. Rep. int.
Whal. Commn, 27: 73-85.
M1TCHELL, E. D., 1980. Canada Progress Report on Cetacean Research, June 1978 to May 1979. Rep.
int. Whal. Commn, 30: 145-151.
MITCHELL, E. D. 1981. Ibid., June 1979 to May 1980. Ibid. 31: 174-175.
MITCHELL, E. D. 1981. Ibid., .June 1980 to May 1981. Rep. Int. Whaling Commn, Doc. SC/33/Prog.
Rep. Canada, 19 p.
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.
MOHL-HANSEN, U. 1954. Investigations on reproduction and growth of the porpoise (Phocoena phocoena(L.)) from the Baltic. Vidensk. Medd. Dansk. naturh. Foren., 116: 368-396, 3 pls.
MooRE, J. C., 1953. Distribution of marine mammals to Florida waters. Amer. Midi. Nat., 49: 117-158.
MoRZER-BRUYNs, W.F ..J., 1968. Sight records of Cetacea belonging to the genus Mesoplodon Gervais 1950.
Z· Saugetierk., 33: 106-107.
MoRZER-BRUYNs, \V.F ..J., 1969. Sight reords and notes on the false killer whale, Pseudorca crassidens (Owen
1846). Saugetierk. Mitteil., 17: 351-356.
NISHIWAKI, M., and C. RANDA., 1958. Killer whales caught in the coastal waters off .Japan for recent 10
years. Sci. Rep. Whales Res. Inst., 13: 85-96.
NORRIS, K. S., 1967. Aggressive behavior in Cetacea. pp. 225-241. In: C. D. Clemente and D. B. Lindsley(eds.) Aggression and defence. Neural mechanisms and social patterns. Berkeley, Univ. Calif. Press.
NORRIS, K. S. and T. P. DoHI., 1979. Behavior of the Hawaiian spinner dolphin Stenella longirostris. Fishery
Bull., 77 (4): 821-849.
NORRIS, K. S., and T. P. Doh!., 1980. The structure and functions of cetacean schools. pp. 211-261.
In: L. M. Herman, (ed.) Cetacean behavior: mechanisms and functions. Wiley-lnterscience, 463 pp.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

46

SERGEANTNoRRis, K. S., and J. H. PRESCOTT., 1961. Observations on Pacific cetaceans of Californian and Mexican
waters. Univ. Calif. Publ. <:,ool., 63: 291-462.
ODELL, D. K., E. D. AsPER, J. BAUCOM, and L. H. CORNELL., 1980. A recurrent mass stranding of the false
killer whale Pseudorca crassidens, in Florida. Fish. Bull. U.S.A., 78(1): 171-176.
PEACOCK, A.D.L., L. COMRIE, and F. GREENSHIELDS., 1936. The false killer whales stranded in the Tay
estuary. Scot. Nat., July-Aug. 1936: 93-104.
PERKINS, J. S., and P. C. BEAMISH., 1979. Net entanglements of baleen whales in the inshore fishery of
Newfoundland. ]. Fish. Res. Board Can., 36: 512-528.
PERRIN, W. F., 1976. First record of the melon headed whale Peponocephala electra in the eastern North Pacific,
with a summary of world distribution. Fishery Bull. U.S.A., 74: 457-458.
PERRIN, W. F., J.M. CoE, and J. R. ZwEIFEk., 1976. Growth and reproduction of the ~potted porpoise,
Stenella attenuata, in the offshore eastern tropical Pacific. Fishery Bull. U.S.A., 74: 229-268.
PERRIN, vV. F., and J. R. HENDERSON., 1979. Growth and reproductive rates in two populations qf spinner dolphins,
Stenella longirostris, with different histories of exploitation. U.S. Dept. of Commerce, Nat. Mar. Fish. Serv.
Southwest Fish. Center, La Jolla. Admin. Rept. LJ-79-29, Aug. 1979, 13 pp.
PERRIN, vV. F., R. B. MILLER, and P.A. SLOAN., 1977. Reproductive parameters of the offshore spotted
dolphin, a geographical form of Stenella attenuata, in the eastern tropical Pacific, 1973-75. Fishery Bull.
U.S.A., 75: 629-633.
PERRIN, vV. F., anrl J.E. PowERs., 1980. Role of a nematode in natural mortality of spotted dolphins.
]. Wild!. Mgmt., 44: 959-963.
PERRIN, W. F., T. D. SMITH, and G. T. SAKAGAWA., 1975. Status of populations of spotted dolphin, Stene/laattenuata, and spinner dolphin, Stenella longirostris, in the eastern tropical Pacific. Working document
for meeting of ad hoe consultants on small cetaceans and sirenians. Food Agric. Org. United Nations,
Advis. Ctee. Mar. Resources Res., Wkg. Party on Marine Mammals, Dec. 1974, 22 pp.
PIKE, G. C., and I. B. MAcAsKm., 1969. Marine mammals of British Columbia. Bull. Fish. Res. Board Can.,
171: 1-54.
PoRTER, J. W., 1977. Pseudorca stranding. Oceans, 10(4): 8-15.
PRYOR, K. and I. KANG., 1980. Social behavior and school structure in pelagic porpoises (Stenella attenuata and S.
longirostirs) during purse seining for tuna. U.S. Dept. of Commerce, Nat. Mar. Fish. Serv., Southwest
Fisheries Center. Admin. Rept. LJ-80-1 lC, 80 pp+Apps.
RANCUREL, P., 1974. Echouage en masse du Cetace Peponocephala electra aux Nouvelles-Hebrides. Biol.
Cons., 6: 232-234.
RICE, E.W., 1977. A list of the marine mammals of the world. U.S. Dept. efCommerce, Nat. Mar. Fish. Serv.,
Spee. Sci. Rept. Fish. 711: 1-15.
RIDGWAY, S. H., and M. D. DAILEY., 1972. Cerebral and cerebellar involvement of trematode parasites indolphins and their possible role in stranding. J. Wildl. Dis., 8: 33-43.
RoBSON, F. D., 1978. The way of the whales: Why they strand. Whalewatcher. ]. Am. Cdacean Soc.,
12(4): 4--11.
ROBSON, F., and P.J.H. VAN BREE., 1971. Some remarks on a mass stranding of sperm whales (Physeter
macrocephalus L. 1758) near Gisborne, New Zealand on March 18, 1970. <:,.f Saugetierk., 36: 55-60.
Ross, G.J.B. 1977. The taxonomy of bottlenosed dolphins Tursiops species in South African waters, with
notes on their biology. Ann. Cape Prov. klus. (Nat. Hist.), 11: 194 p.
SAAYMAN, G. S., D. BowER, and C. K. TAYLER., 1972. Observations on inshore and pelagic dolphins on
the south-eastern Cape coast of South Africa. Koedoe, 15: 1-24.
SAAYMAN, G. S., and C. K. TAYLER., 1979. The socioecology of humpback dolphins (Sousa so.). pp. 165226. In: H. E. Winn and B. L. Olla (eds.) Behavior ef marine animals. 3. Cetaceans. Plenum Press, N.Y.
and London, 438 pp.
ScHEVILL, W. E., 1956. Lagenorhynchus acutus off Cape Cod. J. klamm. 37: 128-129.
ScoTT, E.O.G., and R.H. GREEN., 1975. Recent whale strandings in northern Tasmania. Pap. Proc. R.
Soc. Tasmania, 109 : 91-96.
SERGEANT, D. E., 1962. The biology of the pilot or pothead whale Globicephala melaena (Traill) in Newfoundand waters. Bull. Fish. Res. Board Can., 132: 84.
Sci. Rep. Whales Res. Inst.,
No. 34 1982

MASS STRANDINGS OF TOOTHED WHALES

47

SERGEANT, D. E., 1969. Feeding rates of Cetacea. Fisk. Dir. Skr. Ser. HavUnders., 15: 246-258.
SERGEANT, D. E., 1973. Biology of white whales (Deplhinapterus leucas) in western Hudson Bay. J. Fish. Res.
Board Can., 30: 1065-1090.
SERGEANT, D. E., 1977. Stocks of fin whales Balaenoptera physalus L. in the North Atlantic Ocean. Rep. int.
Whal. Commn, 27: 460-473.
SERGEANT, D. E., 1979. Ecological aspects of cetacean strandings. pp. 94-113. In: J. R. Geraci and
D.J. St. Aubin (eds.) Biology of marine mammals: Insights through strandings. Mar. Manmm. Comm,
Washington, D.C. N.T.I.S. PB-293 890, 343 pp.
SERGEANT, D. E., 1981. On permissible exploitation rates of Monodontidae. Rep. int. Whal. Comm, 31:
583-588.
SERGEANT, D. E., D. K. CALDWELL, and M. C. CALDWELL., 1973. Age, growth and sexual maturity ofbottlenosed dolphin (Tursiops truncatus) from Northeast Florida. J. Fish. Res. Board Can., 30: 1009-1011.
SERGEANT, D. E., and H. D. Fisher., 1957. The smaller Cetacea of eastern Canadian waters. ]. Fish.
Res. Board Can., 14: 83-115.
SERGEANT, D. E., A. VV. l\1ANSFIELD, and B. BECK., 1970. Inshore records of Cetacea for eastern Canada,
1949-1968. J. Fish. Res. Board Can., 27: 1903-1915.
SERGEANT, D. E., D.J. ST. AumN, and J. R. GERACI., 1980. Life history and northwest Atlantic status of
the Atlantic white-sided dolphin, Lagenor~ynchus acutus. Cetology, 37: 1-12.
SHUREPOVA, G. A., 1973. Aggressive behaviour of captive Tursiops truncatus Barabasch. pp. 130-153.
In: K. K. Chapskii and V. E. Sokolov (eds.) lllforphology and ecologyqf marine mammals: Seals, dolphins andporpoises. Israeli Program for Scientific Translations. John Wiley and Sons, 232 pp.
SLEPTsov, M. M., 1941. 0 Biologii Rasmnozheniya Chermonorskaya Del'fina (On the biology of reproduction of the Black Sea dolphin Delphinus delphis). :(ool. :(h., 20: 632-653. (Russian with English
summary).
SMITHERS, R.H.N., 1938. Notes on the stranding of a school of Pseudorca crassidens at the Berg River mouth,
December 27, 1936. Trans. Roy. Soc. S. Africa, 25: 403-411.
STARRETT, A., and P. STARRETT., 1955. Observations on young blackfish, Globicephala. ]. Mamm., 36:
424-429.
STEPHENSON, A. B., 1975. Sperm whales stranded at Muriwai Beach, New Zealand. N.:(.J. Mar. Freshw.
Res., 9: 299-304.
TAVOLGA, M. C. 1966. Behavior of the bottlenose dolphin (Tursiops trucnatus). Social interactions in a
captive colony. pp. 718-730. In: K. Norris, (ed.) Whales, dolphins and porpoises. Univ. of Calif. Press.
TAVOLGA, M. C., and F. S. EssAPIAN., 1957. The behavior of the bottle-nosed dolphin (Tursiops truncatus);
Mating, pregnancy, parturition and mother-infant behavior. :(oologica, N.Y., 42: 11-31, 3 pls.
TAYLOR, R.J.F., 1957. An unusual record of three species of whales being restricted to pools in Antarctic
sea-ice. Proc. Z,ool. Soc. London., 129: 325-331.
TESTAVERDE, S. A., and J. G. MEAD., 1980. Southern distribution of the Atlantic whitesided dolphin
Lagenorhynchus acutus in the western North Atlantic. Fish. Bull. U.S.A., 78(1): 167-169.
TRUE, F. W., 1890. Observations on the life history of the bottlenose porpoise. Proc. U.S. Nat. lvlus., 13:
197-203.
TURNER, W., 1871. On the gravid uterus and on the arrangement of the foetal membranes in the Cetacea.
Trans. Roy. Soc. Edinb., 26: 467-504.
WuRsIG, B., and M. WuRsIG., 1979. Behavior and ecology of the bottlenose dolphin, Tursiops truncatus, in
the South Atlantic. Fishery Bull., 77(2): 399-412.
YAMADA, M., 1956. An analysis in mass osteology of the false killer whale, Pseudorca crassidens (Owen).
Okajimas Folia Anat. Jap., 28: 451-463.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

THE MANDIBLE OF BOWHEAD IN KATHMANDUMASAHAR U NISHIWAKI
National Science Museum, Tokyo

ABSTRACTThe huge mandibular bones which I unexpectedly found at National
Museum of Nepal, Kathmandu, was compared with a mandibular specimenof the bow head whale in Taiji Whale Museum and those of the Pacific rightwhales in Tokyo University of Fisheries and National Science Museum, Tokyo.
It was cleared that the owner of the huge bones was a Balaena mysticetus, andfrom their size, the whale must have been about 16 m in body length. It is
still a matter of investigation that when and how they came up to Kathmandu.
INTRODUCTION

It was quite unexpeced encounter of myself with huge mandibular bones of whale
at a dark corridor of the National Museum of Nepal, Kathmandu, in my second
visit to the city in July 1974 on the wayback from USSR. As I had been to
Kathmandu in the investigation on the Ganges river dolphin in Pakistan (nowBangradesh) in times between 1970 and 1974, trying to know if distribution of
the dolphin was extended to the upper Ganges in Himalayan out-skirts, but had
least imagined that such a thing was in the museum.
Instantly after I saw the bones, I tried to inquire about them and asked totake photographs, but there was only an attendant of the museum who did not
speak English, and he only shook his head. Unfortunately it was Sunday and I
had no time to stay for another inquiry.
Since then, I tried to make contact with the museum to get permission forinvestigation and photograph on them. My asking had been in vain for a few
years, but through introduction of many kind people, permission came from Dr.
R. J. Thapa, Director General of the Department of Archaeology, Kathmandu,
Nepal, in 1979. With great expectation, I visited Kathmandu again on my way
to west Africa in Jan. 1980. As shown in Fig. 1, photographs of the bones weretaken by having them taken out to the hall from the dark corridor. Measurements
were also taken.
INVESTIGATION AND DISCUSSION

The mandible was a pair of bulky bones of about five meter in length. Speciesof whales who have such a big mandible, are the blue whale (Balaenoptera musculus),
the fin whale (Balaenoptera physalus), the right whale (Eubalaena glacialis) and thebowhead whale (Balaena mysticetus). As I saw the indistinct coronid processes ofSci. Rep. Whales Res. Inst.,
No. 34, 1982, 49-57

50~ I S Hl \V八 Kr

1
1
eround 1ibl
dgewhale man. A hu
.I
ig
F

,
e
a
d
i
n
e
a
l
sofBa
ie
c
e
p
thavebeenas
s
tmu
rofi
heowneeofKathmandu,tlbhemandi
t
‑
i
l
c
, man
e
sofwhal
e
i
pec
hes
rt
a
e
l
oc
ing t
y
). Tr
.2
ig
F
,(
e
a
d
i
r
e
t
p
o
n
e
a
l
faBa
ero
v
ne
.
ae
d
i
n
e
a
l
a
nsofB
e
im
c
pe
rs
e
h
t
ho
t
ompared wi
fKathmandu were csor bone
a
l
u
b
i
j
i
a
nT
onsofbowheadi
t
e
l
e
k
hes
hemandibleoft
dfromt
e
t
c
ole
ec
uewer
aval
Dat
‑
i
nTokyoUn
twhalesi
igh
cr
i
f
i
c
a
etwoP
h
eoft
s
ho
VA1)andt
1eum(Tf
us
I
V
cl
l
ha
V
'
〜
a‑
nme
enceMuseum(NSM),Tokyo. I
onalScii
TUF)andNat
es(
i
r
he
s
yofFi
t
・i
.
；
e1
v
he
ft
th)o
p
de
ght(
i
e
h and htr)gie1n,(Tablcime
peurement ofKathma吋 u s
s
al
s
r
o
ed
h
ongt
pal
i
tt
n
o
r
ef
h
rfromt
e
t
oneme
ntl(
d atPoi
e
ur
s
a
e me
s wer
e
n
o
b
s
r
e
t
eeme
r
h
t
t3(
n
i
o
,P
p)
i
het
sfromtretwomet
t2 (
n
,Poi
)
ne
i
ed l
v
r
u
eo「c
c
a
f
r
u
s
d
onoi
r
o
hec
,t
r
e
v
e
. How
s
s
e
c
o
r
dp
onoi
r
o
hec
ft
ero
ent
ec
h
tt
, anda
p)
i
het
rom t
f
le
b
i
pt
e
e
us
tas
ta
n
i
o
stp
ighe
heh
cht
a
e
or
tImanagedt
ha
tt
nc
i
t
is
d
n
oi
swass
s
e
c
o
pr
h・
nKat
ei
os
h
ot
tt
i
sf
t
n
i
o
eep
r
h
tt
da
e
k
r
o ma
s
swerealncimeep. Others
r
te
en
e
h
ngt
e
. Thel
h
t
g
n
e
rl
a
l
u
b
i
d
heman
tt
ns
eagai
g
a
t
cen
r
e
nequalp
imeni
pec
manduserheettandard,becaus
o beasdetn wasmaimepethmandus
ightboneofKa
ofr
d
n
a
,
s
u
o
i
r
e
s
s
a
ew
dyl
tcon
f
e
hel
日 t
gei
pecimen and dama
hes
nt
si
e
t
i
tb
a
er
wer
n
ime
c
e
p
edKathmandu s
d. Compar
e
i
r
a
amev
c
tbonesbe
f
e
tandl
gh
i
fr
ho
t
ng
e
L
al
r
e
at
rl
i
he
erwitht
h
t
e
g
o
,t
sofTUFinTable 1
i
l
a
i
c
a
l
leofE.g
b
i
d
heman
ht
t
wi
c
・
sm01
hapei
,s
r
a
l
i
m
i
es
hetwoar
hoft
ngt
e
tl
a
h
dt
oo
t
s
r
sunde
ti
,i
g.3
i
nF
viewi
s
ti
r
orpa
i
er
t
epos
h
巴n t
pecim
n TUFs
,buti
n
ime
c
pe
nIく~athmandu s
si
onu
t
o
mon
ghtof
i
th and he
r
,gi
y
l
al
r
. Natu
t
tofi
rpar
o
i
r
e
e ant
h
han t
rt
e
k
c
i
h
yt
l
nt
e
appar
,
.
t
nr
s.l
sRe
t
l
a
i
1
I
I
.Rφ.
i
c
S
982
,1
4
λo.3

＇

￡
1

(
o，
（
司0
ム 山n
:
l
s
n内 :
J
:
>
U
:
l
!
:
J
S)
l
?
U
O
!
I
C
N） ・
:
i
1
u
1
1
"
'uリ u
:
i
s山！ '
l
:
J 1 su：~
勺J
U河川 :
i
n
1
qコリ口ld l
)
l
.
1
0
)
(

686{'
r
￡"
ON
.
./
S
i
t
("
S3
l
fS3
/V
杭1
1・
＜
f
3
l
f・
！
＇
S

:
1
u
:
i
u
:l
U
U
l
S
!
P
・
i・
f
i
!,
J

： 日I
G
!
P
u
u
u
1J
Os
s
i
;Jo
.
1
dP
!OuoI
O
Jf
i
u
1川 O
l
J
S

円

puc山 t
pe
予I'
1
e
dJNJ
O山 l
l
:
:
J
S
l
l
J
ぺ）
3
1l
l
0
!
1
E
NO
t
p

flONVJ
¥
!H.
l
.
V)
l1
'1 av~1 H人＼ OU .
:J
O ~nHICINVJ 可 3.H.l.

2
5

VAKT
lV
S卜l
Nl

. Fromns
imecep
r knowns
e
h
t
ho
t
d wi
e
r
a
mp
thmandu con Kapecimen i
es
bl
di
. Man
.3
g
Fi
.
)
s
i
l
a
i
c
a
l
.g
￡
)andTUFspecimen(
s
i
l
a
i
c
a
l
.g
gE
oun
y
(

.,
t
s
n
I
s.
sRe
e
l
.Wha
.Rψ
i
Sc
982
,1
4
.3
o
N

f;~

ON
Z86fe世E・
S
'
J
u'
a
f
t
1M ・
t
1
ljE勾0
S3
日ザ ・
1
・
a

ddn
o
̲ ： 品 川I01J
I
)
l
ll
f
山l
i
i
u
p
sn
i
e
l
.:
＞
！＇
山
:
ul
) u:lu• ! ”ds Will.L '
(
,
uno
J
f:
[
1'
1
i
l
s
n
n
1
1
1
s
dsJNSN （
>
:
:
>
w!:
l
u:

L
よ
H
I
.
'
!:
¥
J
NV
仁I
10 31Hl
λ ＼OH.
1
‑
31
/
¥
l
I NIC
)
/
¥
L
可H.
J
V
!
.
>
:
Cl

""~

'- ~
<.c "'°"~..~ ~:_,, ~

"'
~~

~

~

~

~

23
22
30
39
45
28
30+
67
81
87
97

23
21
31
39
40+
53
68
81
86
96
88

514

509+

87

right
491

left
480+

17.1

33

9.8
19.6
25.4
18
22.5
25
27
31
36

9.5

4.3
5.8
7.6
8.7
5.5
10.3(L)
13.0
15.8
16.9
18.9

9.4

189

640
right
184

17.5

58

37
68
57
50
55
77
96
108
145

34

5.0

526

1710
right
510

32

5.2
10.4
13.4
9.5
11.9
13.2
14.3
16.4
19.0

--·-

34

19
39
39
28
38
41
50
62
78

7.0
12.9
10.8
9.5
10.5
14.6
18.3
20.5
27.6
11.0

16

15

318

1165
right
296

10.7

6.0
12.3
12.3
8.8
11.9
12.9
15.7
19.5
24.5

5.0

4.7

%
100.0

Eubalaena glacialis------·-----

National Science
Museum, Tokyo

6.5

6.1

%
100.0

Eubalaena glacialis-----

Tokyo Universityof Fisheries

5.0

%
100.0

Balaena mysticetus

Taiji Whale
Museum

4.5

%
100.0

Natiomal Museumof Nepal, Kathmandu

MANDIBLE MEASUREMENT OF THE KATHMANDU SPECIMEN COMPAREDWITH OTHER KNOWN SPECIMENS. (in cm)

Body length of whale
Straight length of mandible
between tip and condyle
Curved length of mandible
along mid-dorsal surface
Height of mandibleat point! 1(19.5% of curved
length from the tip)
at point 2 (39.0% of curved
length from the tip)
at point 3 (58.5% of curved
length from the tip)
at coronoid process (highest)at condyle (biggest)
Length of condyle
Breadth of condyle
Girth at point 1
at point 2
at point 3
at coronoid process
Length between coronoid process
and rear end of condyle

Name of specimen
Species of whale

TABLE 1.

...

rJJ

i"i
......

~:i::......

z......

Ul

TH E M
八NDIBLEOFBO W
HEAD T
N KATHM A
ND U

F
i
g
.4
. Sha
pe of ant
e
r
i
o
r
pa
r
t of the mandibl
e
s
,
!
!
!
'
I
I
Kathmanduspeci
men ~·
(
t
op)
, T
W
i
¥
I
Is
pe
cimen,
β l
a
e
n
am
y
s
l
i
c
e
l
u
s(middle)and TUFs
pe
c
imen
,E
u
‑
b
a
l
a
e
n
ag
l
a
c
i
a
l
i
s(
bot
t
o
m
)
.

。

S
c
i
.Rψ.Wh
a
l
e
sRe
s.I
n
s
t.
,

λ匂.34,1982

5
5

56

NISHIWAKI

anterior and posterior parts show less differences in Kathmandu specimen, butsome variety in TUF specimen. In Kathmandu specimen there is a little unusual
value, height at Point 2 is lesser than that in Point 1, which can be seen in Fig. 3
in shape. In all the four specimens, the coronoid process is indistinctly developed.
In TWM specimen, the whale is presumed as the youngest of the four, (1+1/3
years old), the process is recognized, but in Kathmandu speimen (presumably very old), the process is hardly recognized. The coronoid process in the
Kathmandu specimen must be relatively under-developed in accordance withgrowth. The coronoid processes in both Eubalaena specimen of TUF and .NSM
are, however, located 6% more posterior against the length than in Kathmandu
and TWM specimens. In the photograph of Fig. 3, both TUF and .NSM specimens have a swell at the ventral side just under the coronoid process. The feature
can not be perceived in the Table 1. While, the swell is less distinct in Kathmandu
and TWM specimens. The shapes of the anterior-most of the three specimens arecompared in Fig. 4. The anterior tip of Kathmandu specimen might have worna little, but the shape resembles well TWM specimen. After those comparisonin shape and mesaurement values, it may be safe to say that the Kathmandu specimen is a pair of mandibles of a bowhead whale (Balaena mysticetus ).
Estimation of body length from a mandible is not so difficult. The young
individual of TWM specimen was 640 cm in body length, and the mandibular
bones are 184 cm (right) and 185 cm (left) respectively, and the head portion ofthis species of whale becomes bigger proportionally and reach l /3 of the bodylength in adult animals. This is not a presumption at this moment, but thisphenomenal tendency is generally known among whalers and scientists. Then, if
30-33% is the adult head length rate against the total length, the whale, ownerof Kathmandu mandible (419 cm), must have been more or less 16 m in bodylength. Although Eskimo people might have some huge specimens, this Kathmandu mandibular bones is one of the biggest specimens of B. mysticetus known
among museums at present.
PROCESS TO KATHMANDUAs I have studied and discussed the huge mandibular bones in the National
Museum of Nepal, Kathmandu, and presumed the species of it as the bowhead whale(Balaena mysticetus) and the body length as about 16 m, though sex can not be
identified. It may be natural to wonder, from where and how the bulky heavybones were transported to such a long distant and high place of Kathmandu.
If it was in an old time, transportation might have been without machinary.
Inquiry was made to many people in the museum and those who kindly opened aroad to this investigation, but nobody knew the process of delivery or history of
the specimen. Only Dr. Badri Prasad Shrestha, Ambassador of Napel to Japan,
presumed that the mandible bones were thought to be there since about 100 years
before. Many royal people of Nepal Kingdom have studied in England since oldtimes. Presumably, one of those royal people might have seen the bones at theSci. Rep. Whales Res. Inst.,
No. 34, 1982

THE MANDIBLE OF BOWHEAD IN KATHMANDU

57

British Museum (Natural History) or somewhere else, and wanted to have it andwas transported to Kathmandu as a present. His story is one of the presumptions,and I asked the National Museum of Nepal to investigate the process.
ACKNOWLEDGMENT

I should like to extend my sincere gratitude to Mrs. Sushuma Omata, Nepal
princess in Japan, and Dr. Badri Prasad Shrestha, Ambassador of Nepal to Japan,
who helped me in contact to the National Museum of Nepal, and Dr. R.J. Thapa,
Director General of the Department of Archaeology who gave me permission to
study on the mandibular bones through Mr. J. L. Sharma of the same Department,
and Mr. J. K. Shrestha of National Msueum of Nepal who helped my investigationin the museum. My gratitudes are also to Mr. M. Kumazawa of the Museum ofTokyo University of Fisheries, Mr. Masami Shoji of Taiji Whale Museum andMrs. Haruka Ito, postgraduate student of the Department of Fisheries, Universityof Tokyo, for their good assistance in taking measurements and photographs ofthe comparable specimens at home. At the end, I cannot omit Dr. Hiroo Kanaiof the National Science Museum, Tokyo, who made effort to have me contact
with the National Museum of Nepal.
REFERENCESOMURA, H., 1958. North Pacific right whale. Sci. Rep. Whales Res. Inst., 13: 1-52.
OMURA, H., S. 01-ISUMI, T. NEMOTO, K. NAsu and T. KASUYA., 1969. Black right whales in the North
Pacific. Sci. RejJ. l'l'hales Res. Inst., 21: 1-78.
OMURA, H., M. NISHIWAKI and T. KAsUYA., 1971. Further studies on the two skeletons of the black rightwhale in the North Pacific. Sci. Rep. Whales Res. Inst., 23: 71-81.
N1smwAKI, M. and T. KASUYA., 1970. A Greenland right whale caught at Osaka Bay. Sci. Rep. Whales

Res. Inst., 22: 45-62.

Sci. Rep. Whales Res. Inst.,
No. 34. 1982

FOOD HABITS AND PREY DISTRIBUTIONS OF THREERORQUAL SPECIES IN THE NORTH PACIFIC OCEANAKITO KAWAMURA
Faculty of Fisheries, Hokkaido University, Hakodate, Hokkaido

ABSTRACT

Stomach conditions and a total of 1675 stomach samples of fin, sei and
Bryde's whales caught in the North Pacific during the seasons of 1969-1979
were examined. The percent of filled stomach to all animals examined wasabout 60% with varying fullness; and this figure was considered to be very highnotwithstanding the fact that large number of whales were caught in the subartic to subtropical waters where the zooplankton distribution is poorer than
the northern North Pacific region. Due to southerly shifted whaling groundthere found many warm water prey species in the stomach samples. Of morethan 40 prey species occurred, however, very few number of the species actuallycomprised principal prey items, i.e., Calanus cristatus, C. plumchrus, C. pacificus,
Euphausia pacifica, E. similis, Thysanoessa longipes, T. spinifera, T. inermis, Nematoscelis dijficilis, Sergestes similis, Vinciguerria nimbaria, Scomber japonicus, Cololabis
saira and Pseudopentaceros richardsoni. The composition of stomach contents bywhale species revealed that the fin, sei and Bryde's whales eat mainly euphausiid, copepods, and small gregarious fish species in this order. From thecharacteristics of geographical distributions of the major prey items by eachwhale species, it was suggested that the North Pacific rorqual whales share apossible food species among them by selecting different prey items. Therealso suggested that the feeding conditions in the pelagic waters of the North
Pacific region differ from those in the marginal sea regions such as the Kurile
Islands and/or the Bering Sea in the composition of prey fish species.
INTRODUCTION

Since the establishment of the Whales Research Institute in 194 7, one of main
study areas was to know the food habits of baleen whales of both northern andsouthern species. In the North Pacific region including Japanese coastal waters,
Mizue (1951) was the first who dealt with the food habits oflarger whales caught
by the land-based whaling around Japanese waters during 1946-1948, and pointed
out an extreme importance of krill for fin whales, whilst squid and/or Japanesesardine may contribute as main food items in sei whales. In accordance withthe development of the North Pacific pelagic whaling since 1952, the whaling
ground geographically expanded year after year towards more northern latitudesof the Bering Sea (Omura, 1955; Nasu, 1957; Nemoto, 1957), which caused theshift of main study area from the coastal regions to the pelagic catches of whales.
Studies of the food habits of baleen whales by Nemoto (1957, 1959, 1963) conSci. Rep. Whales Res. Inst.,

No. 34, 1982, 59-91.

60

KAWAMURA

tributed to clarify the feeding conditions of baleen whales over the North Pacificand Bering Sea, and the prey items of baleen whales by whale species bacame
clear in detail, although some more earlier Russian works in this field have beenreported (e.g. Zenkovitch, 1937). Nemoto (1959) finally compiled large amountof data that came from a total of 9,270 animals caught in the North Pacific, Bering
Sea, and Okhotsk Sea during 1952-1958. Later, Nemoto (1963) discussed distribution characteristics and importance of two major Calanus species as the preyof whales using additional materials obtained up to the 1961 season.
After a pause of effort to collect the stomach contents of the North Pacificbaleen whales during the 1962-1968 seasons, activity of material collection by the
Whales Research Institute was restored again in 1969, and the effort was continued
until 1979 except 1978 season, while the geographical occupation of whaling groundalong with the composition of exploitable whale species changed considerably during
these periods. However, stomach samples of whales covering last 10 years havenot been examined nor reported todate except several short articles of limited subjects (Omori et al., 1972; Kawamura, 1973; Nemoto & Kawamura, 1977; Kawamura, 1978; Kawamura & Hamaoka, 1981; Kawaguchi & Kawamura, 1981).
Among these reports, Omori et al. ( 1972) reported the mass occurrence of the sergestiid shrimp, Sergestes similis Hansen, and pointed out its importance as whales foodparticularly in the eastern half of the northern North Pacific, while Kawamura (1973)
focussed his discussion on the food conditions of whales in the southern part ofthe subarctic North Pacific region, and he (Kawamura, 1973) pointed out apossible significant ecological role of several commercially important fish species
as food of sei whales.
The long-lasted Japanese activity in the North Pacific pelagic whaling ceased
its 18-year operations in 1979 as it was the final expedition. This report aims toprovide a knowledge about the food habits of the North Pacific baleen whales, fin, sei,and Bryde's that were caught largely in the southern waters from subarctic to subtropical regions. In this point of view, this report can be regarded as a supplement of our earlier knowledge that was obtained in the boreal to arctic regions.
MATERIALS AND METHODS

The stomach contents of whales were collected randomly from the cut opened
first stomach that was found to be containing fresh enough food for the identificationof each prey item. Usually, several hundred grams (wet weight) of stomach contents were collected, and they were preserved in plastic bottles with 10% formalinsolution. The number of samples should be collected by each season and by the
fleet was basically guide lined to take one stomach sample per every ten animals
processed, but actually it varied considerably by situations in the field and by
the fleet participated. However, being independent of the sampling scheme
above mentioned, the materials were collected to meet with the necessity of data
analysis, i.e., to collect the materials so as to totally represent the geographicalexpansion of whaling ground and the month (=season) occupied. Sampling wasSci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

61

TABLE I. NUMBER OF STOMACH SAMPLES COLLECTED IN THE NORTH PACIFIC
AND BERING SEA WHALING DURING THE SEASONS OF 1969-1979.*( ): Number of whales caught
Season

Fin

Sei

1969

56
(576)
32
(518)
62
(542)
14
(426)
24
(256)
46
(216)
31
(118)

316
(3,591)258(3,235)181(2,431)70(2,041)98**(1,710)100(1,190)
52
(454)

1970
1971
1972
1973
1974
1975
1976
1977

No sampling

1978
1979
Total

265
(2,652)

1,075(14,641)

Bryde's

I
(98)

(5)
(2)
46
(522)
51
(688)
56
(578)
97
(424)
(200)
94
(175)
345
(2,694)* A catch of ten minke whales in 1970 was excluded** One unknown stomach sample probably belongs to sei whale stomach was included

also conducted whenever the species of prey items seemed to have changed by avisual observations. Several number of stomach samples were damaged by aleakage and evaporation of preserving solution under an unfavourable conditionsof storage during the past 13 years.
During the summer period of 1969-1979 a total of 19,992 baleen whales
were harvested by the Japanese pelagic whaling in the North Pacific and Bering
Sea regions. The number of materials actually examined in this study was 1,685
stomachs in all as given in Table 1. The whale species treated were fin, sei and
Bryde's. During the study period there were several number of pelagic catchesof minke whales but they were excluded in this study due to small number in theavailable amount of materials.
The traditional catch records (Geirui Hokaku Daicho) on each animal processed along with some results of biological observations in situ by fleet and whaling
season that were compiled by the Far Seas Fisheries Research Laboratory of theFisheries Agency were available, and these statistical data were referred or quoted
whenever it was felt necessary. To construct an approximate expansion of thewhaling ground occupied in the past seasons, I consulted a report series (TheSci. Rep. Whales Res. Inst.,
No. 34, 1982

62

KAWAMURA

reports on the biological investigations of the North Pacific whale stocks) publishedby the Japan Whaling Association or the Whales Research Institute, Tokyo.
Since the general methods and items of observations in recording the stomach
conditions of whales in the field have been reported elsewhere (e.g. N emoto, 195 7;
Kawamura, 1974), no details were mentioned in this report.
RESULT

1.

Whaling ground
Geographical occupation
As it was reported earlier (e.g. Nemoto, 1957, 1959), the fin whales occur
more larger numbers in the Bering Sea and higher latitudes of the northern North
Pacific regions from May to August. Due to reduced catch quotas for fin whales
year after year the catches of this whale species during study period were confinedin small local areas closer to the Pribilof Islands, whereas in the North Pacific the
majority of fin whales were caught in the southeast region off Kamchatka and in
the Gulf of Alaska. However, the trends of their catches on the whole were somewhat sporadic during the l 960's. In contrast to fin, the sei whales, a major exploitable species during the study period, were found to be distributed over a wide
range of the subarctic North Pacific region of north of 40°N. With the change in
exploitable whale species from sei to Bryde's along with the opening of warmer
temperate/subtropical region down to 20°N as a possible whaling ground in thewestern North Pacific, the Bryde's became a major species of pelagic whaling since1971 (Kawamura, 1973).
In order to show approximate trend of the changes in geographical occupations of whaling ground, Fig. I was constructed by selecting several representative
whaling seasons. During the 1950's the expansion of whaling ground was confinedin geographically smaller area of higher latitudes of the North Pacific. The major
whaling ground was established both in the eastern/southeastern waters off Kamchatka Penninsula and in the eastern North Pacific/Bering Sea regions. With
the developments of whaling activity along with the change in exploitable whale
species from fin to sei the whaling ground during the first half of the 1970's became wide ranged occupation where the southern most whaling ground extended
to 40°N such the case as shown in 1971. The trend of more southerly shift ofwhaling ground in 1972 indicates that the movements of whaling fleet were intense
in pursuit of more profitable whaling ground in accordance with lifting of thebanned area, and this along with covering the catch quotas for fin and sei resulted
a largest occupation of whaling ground during the first half of the 1970's throughout the whole North Pacific whaling.
Since the close of hunting fin and sei whales in 1976, there left the Bryde's
alone, a warm water species that inhabits widely the temperate to subtropicalwaters in the North Pacific (Omura & Nemoto, 1955; Kawamura & Satake, 1976).
In order to catch the Bryde's whales there found a new whaling ground in far
southern waters down to 20°N particularly in the western North Pacific. The
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

63

40" .......~~-'-~~-'-~~~'--~~...J_~~l-.....I
N40°.._~~_,_~~~-'--~~---'-~~~-'-~~-'--'

N

50°

50•

160°

180°

160°

140°

120°w

Fig. 1. Geographical occupations of the North Pacific whaling grounds in the pastnine seasons.

geographical changes in the occupation of whaling ground can be comparable withthe changes in the composition of exploited whale species; the fin and blue were themain species during 1952-1962 when they were hunted in somewhat geographicallySci. Rep. Whales Res. Inst.,
No. 34, 1982

64

KAWAMURA(Fig. 1 continued)

N

60°

40°
30°'-------'----'----~---~~--

N

60°
50°

30°1------+-200.L-----'----'----'-----'----~

Nso•

2oo,___ ___.____.._____._____,__ ____
N

1979

60°
50°

30• 1-~~-1---.••--r--1
20°.___ ___.:_____,,,'----''------'------1---~140°E 160°
1eo 0
160°
140°
120° w
Sci. Rep. Whales Res. Inst.,
No. 31:, 1982

FOOD OF NORTH PACIFIC RORQUAL

65

smaller local regions. With larger increase in the number of sei whale catch fromthe 1962-1963 seasons onwards (e.g. 4-945 animals in 1955 vs 1398-3819 animals in
1963-1975, IWS, 1967-1972), the whaling ground began to occupy more larger
sea area into all horizontal directions until 1975. The very small geographicaloccupation of whaling ground in the southern North Pacific came from hunting
a relatively smaller number of Bryde's whales since 1976, and similar situation
continued until 1979, the final whaling season of the long-lasted pelagic whaling in
the North Pacific Ocean.

Monthly changes in geographical occupation
Since pelagic whaling in the North Pacific is usually operated for four months
or more, the main whaling ground changes in its geographical occupation inaccordance with the proceeding of seasons and catch conditions by whale species.
Fig. 2 demonstrates such example of changes as shown by monthly occupation
through the whaling years of 1969-1973. To see the figures, there observed different monthly occupations from one year to another. In some years such thecase as in August of 1970, there were two or more geographically separated whaling
grounds occupied within the same month due to difference in accomplished catch
conditions by each whaling fleet.
2.

Stomach conditions of whales in generalMonthly changes in prey item
Examination of stomach conditions of whales that were processed on thefactory ship is one of the items of biological observations in the field. Due to visualobservations on the ship each prey item was recorded by the larger taxonomicalgroups such as the Euphausiacea, Copepoda, Amphipoda, Pisces, and Cephalopoda.
One of these available data is found in the catch records of whales by the Fisheries
Agency, and a related part of the records were modified to show a monthly changesof prey items in Figs. 3-4, and in appended table, where all data obtained during
the 1969-1979 seasons were combined altogether.
It is observed in Figs. 3-4 that there were no significant monthly changes in
the percent figure of animals with filled stomach to the total catches, where about
60% of stomachs were found to be filled with variable amount of food over thethree whale species and whaling seasons. In the prey items, however, there observed a considerable difference between each whale species. More than 65% of
fin whales feed on the Euphausiacea from May through August without notablemonthly changes in percent figures. The Euphausiacea along with the Copepoda
comprise major food items of the North Pacific fin whales. Towards mid summer,
however, the Cephalopoda (=squid) become to share a similar percent to the
Copepoda. Sei whales, on the other hand, feed almost exclusively on the Copepoda,
and this prey alone accounts for about 75.8% of the animals with filled stomach.
Different from the case found in fin whales, relative importance of the Pisces andEuphausiacea is a characteristic food habits of sei whales. In both fin and sei
whales the major prey item showed a quite high and less varibale percent fugures
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

KAWAMURA

66

N
60°
50°
40°
30°
60°

1973
140°E

rn
MAY

Fig. 2.

160°
100°
160°
140°
~
llilIIIlIIllil t=========dJUNE JULY AUG SEP

120°w

rn

Monthly occupation of the whaling grounds.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

370 442

100N:

624

67

225

>u

zw

::::>
G

w
fE50

-

'..c::
.8
0
u

0

z

..c
u
0

u

I-

zw

0

z

u
0::
w
0...

0

FIN
1463 3213 2957 1010

100N:

24

>-

zu

w

::::>

..c.
u

@
0::: 50

lJ...

I-

-8
0

z

z

~w

D...

0
151

~uJ

::::>
G

w

[E 50
z
w

1-

~
w

0...

305

76

~1
'

lfil-2
D. -3

ra - 4lillLJJ·-5§-6

Fig. 3. Composition of stomach contents by the larger prey taxa in fin, sei and
Bryde's whales caught during the seasons of 1969-1979.
1-Euphausiacea 2-Copepoda 3-Amphipoda 4-Pisces 5-Cephalopoda(decapoda)
6-Cephalopoda(octopoda)
N: Number of filled stomach

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

68

KAWAMURA

537 697 1085 343

100N:
>-

~
w

:J
G

w

..c
u

I-

u

0:: 50
LL

zw

-

..c
u

0

z

8

Cl

0

z

ii
w

a..
0
100N:

FIN
2303 5375 5232 1688

39

SEI
543 1180 337 452

96

>u

z

uJ
:J
G

w

0::
LL 50
I-

z

..c
u

0

u
0

z

w
~
w

a..

0

>~
w

:J

Q-2

0::
LL

~-3

1-

·-4

@
z

w

ii
w
a..

Fig. 4.

Stomach fullness in fin, sei and Bryde's whales caught during the seasons of

1969-1979.
0-Empty I-Few 2-Moderate 3-Rich 4-Full
N: Number of whales

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

69

throughout the whaling season. In contrast to this, there observed considerable
seasonal changes in the major. prey items in Bryde's whales, where both the
Euphausiacea and Pisces comprised most important prey items. The Copepoda
occurred only in 0.12% of animals with filled stomach, and this prey item alongwith the Amphipoda and Cephalopoda was unlikely to keep any importance inthe food habits of the Bryde's whales. During April the Bryde's feed exclusively
on the Pisces, but the Euphausiacea becomes very important food towards mid
summer, then fish shares 50% again in September. Although there found the occurrence of ' Octopus ' as one of prey items in the catch records of whales, its occurrence seems to be doubtful since none of this prey was collected as the stomach
samples. The overall figures in Fig. 3 clearly show that the major prey items offin, sei and Bryde's whales in the North Pacific region including a part of the Bering Sea are quite different by each whale species. Dominancy of the Euphausiacea
in fin, and the Copepoda in sei whales was seasonally unchanged while that of
the Euphausiacea and Pisces in Bryde's whales showed distinct seasonal changes.
These characteristics of possible selection in prey items by the whale species havebeen pointed out elsewhere (e.g. Nemoto, 1959; Nemoto & Kawamura, 1977,
Kawamura, 1981).

Monthly changes in stomachfullness
The stomach fullness of killed animal was also available in the catch recordsof whales. Usually, it is recorded in the field by classifying the fullness of stomach into five different categories, being based on approximate volume of stomach
contents against a whole stomach volume, i.e., few (less than 25%), moderate(25-50%), rich (50-75%) and full (more than 75%). To see Fig. 4 and appended
table the fullness of stomach by each volume category does not seem to change
seasonally over the three whale species concerned, but there was slightly higher
percent of empty stomach in July. The percentages of empty stomach throughout the whaling months in the order of fin, sei and Bryde's were 31.1-42.5%,
38.5-43.5%, and 20.8-55.2% respectively. Both fin and sei whales showed nearly
constant fullness during the whole whaling season whereas the Bryde's alone showedseasonally variable figures. This is probably due to the difference in major prey
items of Bryde's whales from fin and sei whales, that is, the Bryde's whales feed
mainly on both the Euphausiacea and Pisces, while the latter two feed almost exclusively on one of the Euphausiacea and Copepoda.
The categories of both ' rich ' and ' full ' among filled stomachs were relatively
fewer than that of' few' and/or 'moderate'. It can be observed over the threewhale species that both 'rich' and 'full' stomach generally increase in theirpercentage figures when the ' empty ' stomach decreases, but no clear relationshipwas observed between the principal prey items and the stomach fullness (Figs. 3-4).
An unusual high percentage of filled stomach of Bryde's whales in September camelargely from the catches in both the 1974 and 1975 seasons when a vast amountof the gonostomatid fish, Vinciguerria nimbaria and euphausiids, Nematoscelis difficilis
comprised major prey items.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

70

KAWAMURA

3.

Species of prey item
Prey item in general
Because of wider geographical and longer seasonal occupation of whaling
ground, there occurred a considerable large number of prey species throughout
this study. However, some zooplankton and fish species as whales food known fromthe animals caught during past seasons in the waters of higher latitudes did notoccur completely throughout the present study due to very little effort to catch whales
in such regions as reported by Nemoto (1957, 1959). They were: Metridia lucens,
Gnathophausia gigas, cod (Gadus macrocephalus), walleye pollock (Theragra chalcogramma), Atka mackerel (Pleurogrammus monopterygius) Pacific sandlance (Ammodytes
hexapterus hexapterus), capelin (Mallotus villosus), rockfish (Sebastes polyspinis), Pacificherring (Clupea harengus pallasi) and sea lamprey (Entosphenus tridentatus) (Nemoto,1957).
Instead of these northern fish species there found the occurrence of more variable prey items of warm temperate species in the southern whaling ground. Some ofthem composed major prey item but some others were considered to be occasionalor even accidental cn::currence. Table 2 shows all prey items found in the stomach
samples taken from fin, sei and Bryde's whales during the 1969-1979 seasons.
One of characteristics in the composition of prey items is an occurrence of so variablefish species as whales food, among which a mass occurrence of the gonostomatid
fish, Vinciguerria nimbaria (see Kawamura & Hamaoka, 1981) and relative importance of the clupeid, scombrid, pentacerotid, scomberesocid, and engraulid fish
species are noteworthy. Some of these characteristics found in southerly shifted
whaling ground were reported earlier by Kawamura (1973), and he pointed out theecological significance of the juvenile forms of commercially important fish species
for sei whales. The mass occurrence of pelagic armorhead as prey item of sei
whales was another interesting evidence that was firstly reported by Chikuni (1970).
Although relatively large number of fish species were found in the present study,nine species out of 18 occurred with small number of individuals, and were considered to be an occasional or accidental occurrence.
In crustaceans there occurred four species of calanid copepods, Calanus plumchrus, C. cristatus, C. marshallae and C. pacijicus, and natantia shrimp, Sergestes
similis (see Omori et al., 1972). All these five crustacean species were consideredvery important prey items except C. marshallae that was found in one stomach collected in the Alaskan shelf waters in the Bering Sea. In the Euphausiacea, however, the 14 species of euphausiids, which cover such northern temperate species as
Tlrysanoessa group to the southern temperate or even subtropical species as Euphausia
similis and Nematoscelis dijficilis were found to be another important prey items for fin
and Bryde's whales. The luxuarious species composition in euphausiids can be regarded as one of another characteristics that came from the southerly shift of whaling
ground during the last decade. It was noticed that there were no other taxonomicalgroups to be noted as whales food, but locally limited occurrence of the larvae ofa squid, Berryteuthis anonychus.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUALTABLE 2.

71

PREY ITEMS OCCURRED IN THE STOMACHS OF
FIN, SEI AND BRYDE'S WHALESCOPEPODA
Calanus plumchrus MARUKAWA
Calanus cristatus KROYER
Calanus pacijicus BRODSKY*
Calanus marshallae FROSTEUPHAUSIACEA
Euphausia pacijica HANSEN
Euphausia similis G. 0. SARS
Euphausia recurva HANSEN
Euphausia tenera HANSEN
Euphausia gibboides ORTMANN
Euphausia diomedeae ORTMANN
Thysanoessa inermis (KROYER)
Thysanoessa raschii (M. SARS)
Thysanoessa longipes BRANDT
Thysanoessa gregaria G. 0. SARS
Thysanoessa spinifera HOLMES
Nematoscelis difficilis HANSEN
Nematoscelis gracilis HANSEN
Th;ysanopoda monacantha ORTMANN
DECAPODA
Sergestes similis HANSENAMPHIPODA
Themisto sp.
MOLLUSCA
Berryteuthis anonychus (PEARCY & VOSS)**
Gonatus sp. **Limacina helicina helicina (PHIPPS)
COELENTHELATA
Velella sp.
PISCES
Scomber japonicus HOUTTUYN
Maurolicus muelleri (GMERIN)
Tarletonbeania taylori MEAD
Sardinops melanosticta (TEMMINCK & SCHLEGEL)
Engraulis japonica HOUTTUYNCololabis saira (BREVOORT)
Pseudopentaceros richardsoni (SMITH)
Exocoetus volitans LINNAEUS***
Decapterus lajang BLEEKER
Argyropelecus aculeatus CUVIER ET VALENCINNES****
Myctophum asperum (RICHARDSON)****
Diaphus bertelseni NAFPAKTITIS*****
Pof,ypnus matsubarai SCHLUTZ****
Ranzania laevis makua JENKINS
Pleurogrammus azonus JORDAN & METZ
Gasterosteus aculeatus LINNAEUS
Sebastes sp.
Vinciguerria nimbaria (JORDAN & WILLIAMS)* During discussions about this result with Dr A. Fleminger of the Scripps Institute of Oceanography,
it was suggested that there must be some occurrence of Calanus orientalis among C. pacijicus occurredin the northern waters.
** Identified by T. Kubodera***,, K. Amaoka,, H. Nakaya****",, K. Kawaguchi*****
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

72

KAWAMURA

Some biological notes of the major prey species
Copepoda
C. cristatus: Occurrence of copepodid stage V (CV) alone. The body length
was recorded up to 7. 7 mm.
C. plumchrus: Occurrence of CV with occasional occurrence of CIV. The
former was 41-50 mm with major body size of 41-43 mm, and the latter was about
30mm.
C. pacificus: CIII-CV, and both adult male and female. Usually CV of
33-36 mm was predominated among all. The prey composition by the developmental stages was usually CV alone, but there were also the case of adult male andfemale with a dominancy of male, CV +male+female, CV +female, CV +male+
female, and CIII+CIV+CV+female. CIII was about 25 mm.
Euphausiacea
E. pacijicus: Both adult male and female of 21-22 mm with occasional occurrence of juveniles of 12-17 mm and 6.8-9.3 mm size classes. There was no clear
trend in the dominancy of one of two sexes. Some male and female carried asingle spermatophore.
E. similis: Adult female alone or juveniles of 17-21 mm.
T. longipes: Both male and female of ordinal and spine forms (12-13 mm)
were found. Most example of prey comprised female alone, but sometimes
mixture of very few number of adolescent males, or juveniles of furcilia stages. No
spermatophore was observed.
T. inermis: Both male and female of ordinal and 2-spined forms. Verystrongly biassed in sex composition. Usually, male or female predominates fromanother.
T. spinifera: Female alone, but occassional mixture with very few number ofmales. Body size was 23-30 mm. Two spermatophores were found in both sexes.
T. raschii: Male alone or both sexes with considerable predominancy infemales.
T. gregaria: Male and female of about equal number. Sometimes juvenilesof 9-10 mm were found among adult forms, but lesser extent in quantity. Some
adults of both sexes carried one spermatophore.
N. difficilis: Both male and female with variable predominancy of one oftwo sexes.
T'poda monacantha: Recorded in one sample collected in the northern watersof Hawaii Islands in April 9, 1979.
Decapoda
S. similis: Usually matured adult forms (49-50 mm) and juveniles composed the prey. Occasionally, adolescent forms of 27-35 mm formed the principal prey composition. (see also Omori et al., 1972 ).
Amphipoda
Only unidentifiable small hyperiids including Themisto sp. (4-5 mm). There
was no occurrence of adult forms of any amphipod species.
PiscesSci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

73

V. nimbaria: Most individual was 46-60 mm (T.L.). Details of this fish andits food habits were reported by Kawamura and Hamaoka (1981).
T. taylori: Recorded body length (T.L.) was 46-75 mm. The prey item
found in 6 individuals (49-60 mm) was very small hyperiids, Ostracoda, young
euphausiids and Copepoda including Euchirella sp.
M. muelleri: Recorded body length was 34-58 mm (T.L.) with dominancy
of 42-48 mm individuals. Prey items found in 42-58 mm individuals were hyperiids, Conchoecia sp., Pareuchaeta sp., Candacia sp. and micro-calanoida.
G. aculeatus: 36-48 mm (T.L.)
P. azonus: 83-115 mm (T.L.).
E. japonica: 60-125 mm (T.L.), but 60-70 mm was the main body length.
Prey item of this fish in June were CV and adult female of C. pacificus, furciliaof eupahusiids, Oikopleura sp. and micro-calanoida.
S. japonicus: 99-188 mm (T.L.). Very variable prey items were found; C.
pacificus (CV), Candacia bipinnata, Candacia sp. Pseudocalanus sp., Oncaea sp., unidentifiable micro-calanoida, Phronima pacifica, Salpa sp., Muggiaea sp. and fish scale.
S. melanosticta: 75-106 mm (T.L.). Prey item was furcilia of euphausiids,
Clausocalanus arcuicornis, Corycaeus sp. and other micro-calanoida.
C. saira: 98-133 mm (T.L.). Prey item was simply composed of CV of
C. plumchrus.
R. laevis makua*: 89-147 mm (T.L.)
E. monicirrhus*: 98 mm (T.L.)
D. lajang*: 118 mm (T.L.)
A. aculeatus*: 56 mm (T.L.)
D. bertelseni*: 100.5 mm (S.L.) Very rare occurrence as reported by Kawaguchi and Kawamura (1981).
Cephalopoda
B. ano11:Jchus: 10-52 mm
4. Geographical distribution of prey organisms
Copepoda
Figure 5 demonstrates the distribution of three copepod species that werepreyed upon by fin, sei and Bryde's whales during the summer seasons of
1969-1977 and 1979. Since the stomach samples collected were combined together
all through the fishing season and month, the geographical distribution of preyorganisms by species showed somewhat complicated features. For example,
northern boundaries of Calanus pacificus distributions in the eastern half of the North
Pacific showed local irregularity, that is, there were several tongue like intrusionsof distribution range and/or even an isolated patches in the region occupied byanother prey species. The southern boundaries of C. plumchrus was the case ofsimilar pattern to C. pacificus. As it was mentioned in Table 2, copepods were

* The number of specimens was single or very few, and their occurrence in whale stomachs was considered
to be accidental.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

~

~?

~~

'"l{:i..

;_,_, ~

" "'

~~

~

~

::i:i

?:

35°

40°

45°

500

55°

N

I

~

,.,

'

'<·
·~·'
•~
•/>

'

I

~

160°

I •

lj

'
•1
I ; ' ,•

I' J
lb I

,.

'I
> ,

.... '\! ~·, $~,'·,

170°,.

, ... >

...

,,

,.

I

,

6

:-...\.._..

...

••'

,(

.....

••
',~ u , ' I•

6

170°

~

... ... ...

,.

160°

I

~

Qo, ·r.~
''"

~·
~·~'6

'"'

' ._' '
I

" '

~·

~t

, &,.

i•

~

\I>

,0.. ... ..~ ~ ~

' '

u

..

'

'

c. cristaus~ ...

:.."~ '~

•

~··

~*~

~~~

.. ~I '"' I~..., ' ' ''b• ' ,'.!t,•. '. ~ ·,~. . . . •"'
~t.

'

6 '

~

.

.

I

••

''.

150°

FIN

0

140°

©•
BRYDE'S SE!

130°w

}~

,y.,' , ...

c. pacificus ~c. plurnchrus

'"

I>

._

'
1

6 t\~

,. ,,,. .. \~•
'

Q.

•••

1
6 10

Cm: Calanus marshallae.

'. ,. ,,~\: ... '\' ~ ;· "''\ ,,, ':::' \.\~~u •'

,...

I>

6 b

...,
... ""'~.......

,, ,

'~·"
.. t ' '6' '~Distributions of prey copepods.

160°

j, A.

Fig. 5.

,. ,.,. > I ,,,.,. ,.>,I',. ')"
,,,,
I'
,.
,

,.

::~' ...'''~ " ,. . " . ~'n6~4 r ,,. i ~'' :. 4-,..' ~"'" bf ,. ' p" l~h\~;~r:~;· ,•, ' ~" .....,...... t..

1'1

I

j' I

I

•

I

66 ... ,,"O.QO., "• •·6·'l "•~•6,•1i• •'-'iet\-;M~.~ '" ,1' •' •I,·'!~dt'i't' .....
~~t'}'·,•,j' ' I> 0 t 6 >,.o>

:

1,

4

~

6

0

Cm

~

~

c

~

~

FOOD OF NORTH PACIFIC RORQUAL

75

largely preyed upon by the sei whales, and this resulted to show an absence ofany copepod food in the Bering Sea, because the sei usually does not enter thisregion (Nemoto, 1959). One of copepod samples collected at the slope region of
the Alaskan Continental Shelf consisted of Calanus marshallae. This evidence isperhaps the first record of the species as whales food from this region. To see
the general distribution pattern over the whole North Pacific, it is clearly observedthat the major occurrence region of Calanus pacificus is concentrated in the western
half of the subarctic North Pacific with two eastern most occurrences in 155°W. C.
cristatus, one of another major prey item was found to be the most important food
copepods both for fin and sei whales in the western half region. C. cristatus,
however, may possibly become important prey item in the northern latitudes in
the Gulf of Alaska.
C. plumchrus, on the other hand, began to occur frequently towards the eastern
half region with most prominent occurrence in the pelagic region of the mid latitudes in the east of 150°W. In the central region of the North Pacific the distributions of C. plumchrus became very scarce or almost absent between 180° andl 70°W, but this species occurred at 37°N as the southern most record throughout
this study. Due to somewhat sporadic whaling effort in the Gulf of Alaska, information of this region is very limited but suggesting a possible importance of C. cristatus
both for fin and sei whales.
In general the characteristics of copepod prey in its distributions are summerized as that C. cristatus+C. pacificus dominate in the western half but they change
to C. cristatus alone or C. cristatus+C. plumchrus community in the middle. Towards
more east, C. cristatus occurs again but it finally changes to C. plumchrus.
Euphausiacea
In contrast to copepod, the prey species of the Euphausiacea comprised atleast 14 species (Fig. 6). Due to smaller number in the catch of fin whales thatfeed mainly on euphausiids, spots of distributions in Fig. 6 showed more dispersed occurrence than the copepod food. In the northern waters north of 50°N
there occurred only fin whales except a very few sei whales, but the fin also occurredconsiderably in the southern waters down to 35°N in the western half region.
In the shelf region of the Bering Sea there were five collections from fin whales,
and Thysanoessa rashii was the major prey item. In the higher latitudes of theNorth Pacific, T. spinifera, T. inermis and T. longipes were found to be the mostimportant prey items, of which T. spinifera showed its importance in the offshore
region of British Columbia, while the latter two species frequented in the pelagic
regions. In the middle latitudes between 40°-50°N, Euphausia pacifica was exceptionally occurred both in fin and sei whales along with two Thysanoessa species.
Towards southern waters, however, the composition of prey became to show more
complexity by the local and sporadic occurrence of many rare species such as
Thysanopoda monacantha, Nematoscelis dijficilis, Euphausia gibboides, E. tenera, E. recurva
and E. diomedeae. Apart from fin and sei whales, the catch of Bryde's whales wasclearly confined in the southwestern region down to 25°N, where E. similis, N.
dijficilis and T. gregaria were found to be most important as the prey items.
Sci. Rep. Whales Res. Inst.,
No. 31, 1982

""~

""'~

~~

--~ ~

~~

~~
c "'

~

~

~

~

E

o-

160°

"'

•

0'9 0-.... •'.

~. . ·ii··

...
6.

II

.

~

<;/

Pl'fi>

<I

'
p

·170°

<;/

0

0

~'l

•:.

n'J

" ::I<

ll

6
6

. '·~

9

~

··~··...0 ·"~!i~' '~.. .....°'1-tg. .,.Jl : ~.II9"-t .,.

.,.
'I'... ~~

2

3 °4

'e 'e

180°

0

Midway

p

b

't

..,.,

13..,
G'Q

9"

"

,. b
••

~\99'

; ~.,..,..,

~J 0

~

"

0

.. ..

~

'G-e:s:>e6.... 1

~

b'o-

~(I

...

qol>

<\'

~~

"'

...

11,

b

5

"

•11

0

II

b

0

0 Hawaii
006

0

0

b

"

9

"J

..,

</_;,

u

a

w

g

·;:;

4-

•

b

~ '9 ...

"c>

"--r.

'11

•••

• O'.·/}'q.,,-Oji~\o;p.,0... .&... ,.,.

.()

~v
d,>

•

<y•

0

0

~

...

..,

'\'

g;_

U)

SE!

•

/

"'~1,,..

~ .....9

BRYDE'S

,_::

0

·-g

0 ®
FIN

""()

o,<:i'
0,"«;spinifera~T. inermis

••

..,

T.

q ••

•t

• 9'1

~

0 0

140°
130°
160°
150°
170°
Fig. 6. Distributions of prey euphausiids.
I-Euphausia recurva 2-Euphausia similis 3-Euphausia gibboides 4-Nematoscelis gracilis 5-Thysanopoda monacantha 6-Euphausia diomedeae

2o·L__J_ _ _~~--;:w----,:~--16o-""~

25°

30°

35°

40•

45°

N

0

w

s;

i

~

~-

<.,

S<

:-~

<.,

~~
"o;-

v

.......~~ :::i:i

~ ?:

:11
' ..

'o.."'· 11'tJ,.•":

.. ;

JtfiJ

a.

fiJ

4>

....
.,3

..

";.

"' '
•

"a.

.

&.

a.

"

b

8

a_'\.

MidWOY

'"o

3

.. '

"

0

o~o 'i?~o<>.
. . . ..

..

..........

d'··~

~

~

' "''t.•' ~ .....
H ' <!>
~ '

6•

'

o'. 8

10

08

/o t- ~a-• "~10 • 10"s"s 5

4

7.,

6 .,

'

~"

lo

al>

~-

e""'
\.G

·"=>

"*-"'()
<i!>G

0

vo

-

·~

g

c

u

E

u

5l

2
·-

170°
180°

./

&,...

:.-'.!'.

&v

;fr
.<?;,

Fig. 7. Distributions of prey fish. The encircled areas show approximate range of the occurrences of pelagic armorhead andPacific saury that found in the catch records of whales compiled by the Fisheries Agency.
1-Pseudopentaceros richardsoni 2-Exocoetus volitans 3-Decapterus lajang 4-Argyropelecus aculeatus 5-Myctophum asperum 6-Diaphus
bertelseni 7-Polypnus matsubarai 8-Pleurogrammus azonus 9-Sebastes sp. 10-Myctophids(unidentified) 11-Trigger fish(unidentifed)

160°

-\.

~>

:-,c:i._<:}>

10

.

•:

9 ••

~ s. melonosticto

"'v.s

&o

v.t'.

Oc

E. joponico

•

6'

:::J

(/)

..

20·._~...........~~~~.....~~~~~......~~~~~..._~~~~--''--~-'---~-..L~~~~

25°

30°

35°

40°

45°

N

.

-.J
-.J

;J>
!:""'

ig

:;::I

~

0
......
:::1
0

;;;:

~

"".!

"".!

0
0
tl
0

KAWAMURA

78

PiscesThere were very few stomach samples of fin that preyed upon fish, but both sei
and Bryde's whales fed largely on such various kind of fish species as pointed out by
Nemoto & Kawamura (1977). To see Fig. 7 there observed very clear differencein major prey items between western and eastern halves of the North Pacific.
The fin and sei occurring in the western half region of the mid latitudes ate preN

40° .--~~-.-~~~~~~-.-~~~~~~-r~~~~~~-..~~~~~~-....~

May

..

Sep_yl(_Apr
AugYJune.

.'t 0 6 6

4 .i.·

July

q

0-

.

.,.

.., q

qq

-0
0-

0

d

.d

MidwayHawaiio•0oO

BRYDE'S SEI

20°._~~......~~~~~~--"~~~~~~--"~~~~~~--'"--~~~~~......1---1
E
180°
160°
160°W
170°
170°
Fig. 8. Monthly distribution of Vinciguerria nimbaria eaten by the sei and Bryde's
whales.

N55°

s. similis
L. helicina-Q-'.. Ba..

Batt'' ' Ba0FIN BRYDE'
©S e
SEI

oP'

Themisto sp,

Squid

50°

45.0

o•

91
9
0-

..

'l

Ba

.. . '
9'' '....._.Ba

b

''

"'

't ..'I

' io'

Ve

.

bi

'

b

b

'

0

.. ~

~,,' '-t, b~ ' 46
' Ve
•o

•
40° E~---1~6~0-_ _ _ _ _ _ _ _ _ _17~0~------~--1~8-0_000 _ _.....__ _ _ _ _ _1~7-00 ------~
Fig. 9.

Distribution of shrimp, Sergestes
Ba: Berryteuthis
Sci. Rep. Whales Res. Inst.,

No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

79

dominantly on mackerel (S. japonicus) among all and both anchovy (E. japonica)
and Japanese sardine (S. melanosticta) came to the next. Towards more northernwaters, however, the major prey item changed to a myctophid fish (T. taylori) andthree spine stickleback (G. aculeatus) while gonostomatid fish (V. nimbaria), M.
muelleri, R. laevis makua and myctophids (M. asperum and Diaphus bertelseni) may
become important prey for the Bryde's whales (see also Fig. 8, and Kawamura &Hamaoka, 1981 ). Among various species of fish prey V. nimbaria is considered mostimportant item for the Bryde's whales occurring in the subtropical regions of theNorth Pacific during April through September (Fig. 8).
In the eastern North Pacific the collection of stomach samples was fewer than
the western region due to difficulty in collecting and preserving such large-sizedfish prey as the pelagic armorhead (P. richardsoni). Being based on the catch recordsof whales by the Fisheries Agency, it was proved that the sei eat mainly Pacificsaury (C. saira) during July to August in the pelagic waters of the eastern halfregion.
One of another important fish species was pelagic armorhead in the Gulf of Alaska
region. Because of its large-sized body length and easiness in identification in thefield, no P. richardsoni was collected as stomach samples, but their occurrence inthe catch records of whales was indicated by the encircles in Fig. 7. Closer towaters off Vancouver Island, there were another possible important prey item, thelarval forms of rock fish (Sebastes sp. ).
OthersAmong several other prey items the sergestid shrimp, S. similis was mostimportant prey both for fin and sei whales in the midst towards eastern region of
the northern latitudes between 40°-50°N as it was reported previously (Omori etal., 1972). To see Fig. 9 along with Figs 5-7 it can be observed that S. similis was0Ba

o'o ,o6 '

' '

0

0

'
',, t'
0'' 't 6f .

9

9

'

'

... 6.

o.&,,.
•'•~•'• l• ~

ci.o

'

6o

'

0

160°

'

150°

similis and other prey species.
anonychus, Ve: Vellela

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

140°

130°

w

80

KAWAMURA

one of very few prey items that was available in the midst of the northern North
Pacific. Towards west, however, larval forms of squid (B. anonychus and Gonatussp.) and hyperiid amphipods were considered to be moderately important.
However, amphipods represented largely by Themisto sp. never showed such importance of appreciable extent as the case known in the southern counter part,
Parathemisto gaudichaudii (Kawamura, 1970, 1974).
5. Species composition of stomach contents
Fin whales
It was indicated in Table 3 that the euphausiids were relatively more important than the copepods as food of fin whales. However, the detailed compositionof prey species being based on the collected material shows that very limited
number of euphausiid species actually comprise a major food of fin whales. The
matrix of prey composition clearly shows a predominant occurrence of three euphausiid species, i.e., E. pacifica, T. longipes, T. spinifera, and T. inermis (Table 3).
Although there were several examples of mixture with other prey species in boththe case of E. pacifica and T. inermis, most stomach contents were found to be monospecific in the composition.
In copepods, C. cristatus was a major prey item, and this species along withsergestid shrimp, S. similis formed additional important prey items. The veryclear monospecific composition in T. spinifera was noteworthy, while there weremany examples of mixed composition in T. inermis. The major prey species thatcomposed a stomach contents was usually monospecific.
In three examples,
however, there found mixed compositon of food with three species such as C.
cristatus+ T. longipes+ T. spinifera, T. inermis+N. difficilis+C. pacificus and T.
inermis+ T. longipes+C. cristatus. There were only four stomachs that were filledwith fish. Although there occurred a considerable number of prey species on
the whole, it can be said that the fin whales in the North Pacific region mainly live
on by eating six species of crustaceans where euphausiids account for a largest partof the prey composition.
Sei whales
In contrast to somewhat simple or poor composition of prey species in fin
whales, a total of 27 prey items were found to be important in sei whales. As
mentioned before, copepod food was found in quite large part of the sei whale
stomachs, and C. cristatus, C. plumchrus and C. pacificus accounted for more than 79%
among all stomachs examined (Table 4 ). One of the characteristics in the copepod food was a frequent occurrence of mixed composition with different prey
items such as with euphausiids particularly the case in C. plumchrus. To see thefrequency in the number of stomachs, relative importance of euphausiid food
reduced largely in sei whales except the case in E. pacifica, but sergestid shrimp,
S. similis that was a very important prey item in fin whales also showed considerable
importance again in sei whales. One of characteristic compositions was the relative importance of commercially important fish species as a major prey cornSci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

viaf!uJ<fs ·J,+sJULtaUJ •J,
wafiuJ<fs ·J,+ sa<fJiluo1 ·J,sa<fJiluo1 ·J,+ sn1v1>'JJJ ·a
JJ1fOSVJ •J,+ sn1v1sJ11 •:J
sm11Jfip .N+ sn1!ft1v<f ·a
P!nbs

c<')

JlOjl(V/ •J,
snuozv ",JN

v.1afiu.zqs ·J,
sa<fJiluOj ·J,l!')

VJ!f!JVq ·g c<')sn1!ft1vq •:J
aVllV1fSJIJW •:J
sn.1111wn1<f ·ar-co ('

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

CO

81

82

KAWAMURA
TABLE 4.

COMPOSITION OF THE STOMACH
Minor

]
tj

o~
t)

C,j

C. cristatus
C. plumchrus
C. pacificus
E. pacifica
E. diomedeae
E. recurva
E. tenera
T. longipes
T. spinifera
T. inermis
T. gregaria
N. difficilis
N. glacilis
S. similis
G. aculeatus
P. azonus
C. saira
S. japonicus
S. melanosticta
E.japonica
Sebastes sp.
M. muelleri
T. taylori
myctophido
P. richardsoni ( ?)SquidL. helicina~ ~ o~

~ w~

-~
·~ ~
.~ ~ .§-.§ ~ ~ .~ f5 ~ ~C,j ki ki

ki kiv)C!i~C,jv)v)ki~~$~E~~;;i ~ ~]

V)

-Q..-Q.,.~~~--

C,j

398
3
9
10 270 3 5
3 89 255 4 37;;;~tj~ ·~ ~ ·~

1

1

3

11

2

4

3

4

3
7

2
2
4

48

2
5

1 2

33 2
5
3

5
5

* Since the occurrence of the pelagic armorhead, P. richardsoni was based on the catch records of whales
excluded from this table.

ponent. They were, Japanese mackerel, Sebastes sp., Pacific saury, Japanesesardine, Japanese anchovy, and lanternfish, M. muelleri. These greater variety
of prey composition in sei whales is the refiexion of larger geographical occupationof whaling ground along with longer duration in sei whale catches. There wereseveral records of mixed stomachs composed of more than three prey items; theywere, E. pacifica+C. cristatus+ T. taylori, E. pacifica+S. similis+ Vellela sp., T.
longipes+C. plumchrus+ T. inermis, T. longipes+ T. inermis+ T. spinifera, E. pacifica+
C. pacificus+C. cristatus, C. plumchrus+C. pacijicus+C. cristatus, and S. similis+C.
plumchrus+C. cristatus. Although prey composition showed greater variety in sei
whales, but it can be said that the sei in general feeds largely on three species ofcopepods, one species of euphausiids, sergestid shrimp, and scombrid fish.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

83

CONTENTS IN SEI WHALES* (NUMBER OF STOMACHS)
components

5

5

427
318
103
60

2

12

1.1

7
1

0.6
0.09
0.18
0.18
0.09
4.9
0.18
0.09
0.47
3.6
0.47
0.28
0.56
0.56
0.09
0.09
0.09
1.11
0.09

2
3

1

2
2
53
2
5
39
5
3
6
6

1

3

8

12

39.8
29.7
9.6
5.6
0.09
0.09
0.09

alone, the actual composition of stomach contents was unknown, and consequently this fish species was

Bryde' s whales
Due to different geographical occupation of whaling ground in the case of
the Bryde's whales, the composition of major prey item for this whale species was
far different from that in fin and sei whales (Table 5 ). Most important prey
item was a gonostomatid fish, V. nimbaria which accounted for more than 55%
among all instance, and E. similis came to the next (25.2%). N. dijjicilis was
also important member of the prey composition (10.8%). Except a single record of multispecific prey composition (V. nimbaria+E. gibboides+N. gracilis), thefood of Bryde's whales can be considered quite monospecific with stronger trendsof eating small and gregarious fish species in the pelagic waters.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

84

KAWAMURA
TABLE 5.

COMPOSITION OF THE STOMACH CONTENTS IN BRYDE'S WHALES(NUMBER OF STOMACHS)
Minor components~.::i ] ..
·~

...
"'

...,

cj ~ ~

C. cristatus
E. pacifica
E. similis
E. recurva
T. gregaria
T. inermis
Thysanoessa sp.
"E"'<I) N. difficilis.::0 T' da monacantha
S. similis0
u V. nimbaria.... M. muelleri
0S. japonicus
S. melanosticta
T. taylori
L. laevis makua
E. volitans
D. lajang

+...,

...,~

.Et

•s

~

.::i

h h ~~~c,)

.~

•s

.

•s

~

::.: ~ c,) c,) h

~ ~

2

2

5

35

8'

i

3

1 1

175
3
4

4

Fish bones

"@

0

E-<

.::

<I)

....<I)(.)
P-c~ t:i.; ...: ~ ~ ~

1
80

.....

·,;

f(J
~
~ ~
" ...,... ... 03 -~...,
c·- .~.,.,. " 2l -~ ~ ~... .::i " 2f ~" -!:l i'! ~" .::""... "... ~ ~::; ~~0"" t::" .0'E}i~ ·~ ~""' " "~
~ .5 ~~]] .~ ~ ·~ ~ ~ ~"" " .....
"'~ """'"'" "~ A"" """"'::; "
"
.~

0.03
0.03
84 25.2
0.03
5 1.5
1 0.030.03
36 10.8
0.03
0.03
184 55.1
4 1.2
4 1.2
0.03
0.03
5 1.5
1 0.03
1 0.03
0.03
334

DISCUSSION

The whaling ground during the seasons of 1969-1979 was occupied in the more
southern sea regions than that occupied during the I 950's to early I 960's. This
geographical difference along with somewhat seasonally longer whaling operation
resulted to show a wide ranged variety in the taxon of prey items, particularly
in species composition of the Euphausiacea and Pisces. The conditions of surface
sea temperature in general over the whaling ground is considered to be somewhere
between about 26°C and I0°C in August (Sverdrup et al. 1942), and from thezoogeographical point of view in zooplankton communities, the whaling ground ofunder consideration includes the region of boreal complex, zone of mixing andeven tropical complex (Zenkevitch, 1963).
The stomach condition of whales in general revealed that about 60% ormore stomachs of fin, sei and Bryde's were filled with variable amount of food without showing any notable seasonal changes in the percent figures of filled stomach.
According to Nemoto (1957), 52% of fin and 44% of sei caught in the northern
North Pacific during the 1952-1956 seasons were found to be filled stomachs. These
percentages seem to be considerably lower than the above mentioned figures (ea.
Sci. Rep. Whales Res. Inst.,

No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

8560%) found in this study. During the years of 1952-1971 when the whaling
ground began to expand southwards, the corresponding percentages for fin and sei
were 60% and 55.5% respectively (Nemoto & Kawamura, 1977), while it was
94% and 81 % respectively in the Kurile region (after Sleptsov, 1955). Thesefigures seem to be high enough when it is compared with that found in the present
study and also in the Antarctic feeding grounds (Kawamura, 1978). Usually the
distribution of zooplankton biomass in the boreal region of the northwestern North
Pacific decreases to about l / 5 or 20% towards the tropical region (Zenkevitch, 1963 ).
According to Odate (1966), the wet zooplankton biomass in the south of 40°N of
the western North Pacific was 20-30 gr/1000 m 3 while it was 200-400 gr/1000 m 3
in the boreal regions of the North Pacific and Bering Sea. Notwithstanding thesefacts the comparisons mentioned above strongly suggest that the boreal or subarctic
North Pacific to the subtropical or even tropical regions may provide very important feeding ground for the baleen whales as well as the northern North Pacificregion. One of possible, but important explanations for this is the local and extremely biassed patchy distributions of prey species (e.g. Brodie et al. 1978;
Kawamura, 1979). The occurrence of fish prey in the southwestern North Pacificmay come from the scarceness of patch-forming zooplankton species in this region since those fish species can eat and survive on such variable zoo plankton
species as studied in Vinciguerria nimbaria (Kawamura & Hamaoka, 1981).
As it was shown in Fig. 4 the stomach fullness by the quantity of contents did
not change seasonally in its general pattern over the three whale species. However,stomachs combined both ' full ' and ' rich ' showed relatively higher figures in fin
and Bryde's than sei whales. This evidence seems to be related to the differenceof major prey items between whale species as shown in Fig. 3, where it was suggested that the larger the size of prey organisms, the larger percent of well filled
stomachs were expected (Nemoto, 1963). Similarly, the smaller percent figures of' full ' and ' rich ' stomach in sei whales that feeds mainly on copepods are resulted
from more smaller size of prey, since the biomass of prey organisms may become
smaller in accordance with the reduction of their body size (Nemoto & Kawamura,1977). The prey items which occurred in boreal regions of the North Pacific wereagreed on the whole to those known previously in the pelagic waters (e.g. Nemoto,1959), and distributions of Thysanoessa species and copepods were agreed well tothat found in the Olyutorsky and Commandorsky regions (Ponomareva, 1949).
However, when each prey item is compared with the case found in marginal seassuch as the Kuril or Bering Sea regions, there were considerable difference in thecomposition of prey fish species. As mentioned before, there occurred no common
fish species between the results from the Bering Sea and the present study (seeKawamura, 1980, Table 17), while only two species, Pacific saury and anchovy
were common with the Kurile region (Betesheva, 1954, 1955). In the Far Eastern
Seas, of 14 prey fish species only Pacific sardine and Pacific saury were common
with the present study (Sleptsov, 1955; Tomilin, 1967). These characteristics inthe prey composition suggest that the feeding conditions of whales in the North
Pacific may differ considerably from place to place especially in the marginal sea
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

86

KAWAMURA

regions, but they also differ in several prey taxa even in the pelagic waters.
Distributions of each prey species showed very interesting results (Figs. 5-9).
Since stomach samples obtained during 1969-1977 and 1979 seasons were plotted
altogether simply by separating each major prey species, the number of plots do
not agree with the number of stomachs sampled because there were many examplesof mixed stomach composition of two or more species. Figures 5-9 however, demonstrate a zoogeographical pattern of ditribution of each prey item during April to
September, where variable density of plot distribution suggests relative abundanceof whale distribution by sea regions. To see through Figs. 5-9 the overall distribution pattern of each prey species agrees well with the generally known zoogeography of planktonic animals such as the distribution boundary of Calanus species(e.g. Minoda, 1958; Omori, 1965 Frost, 1974), euphausiids (e.g. Boden et al., 1955;
Mauchline and Fisher, 1969) and lanternfishes (e.g. Wisner, 1974; Gjosaeter and
Kawaguchi, 1980). However, important evidence is that the plotted region indicates more possible area of frequent occurrence of plankton aggregations that are
preferable food condition for baleen whales, and a vacancy of the plots never means
negative distribution of each corresponding prey species. In this connection, thelack of amphipods as whales food in the North Pacific must be noteworthy, while
Parathemisto gaudichaudii constitutes important prey item in the southern sei whales(Kawamura, 1974). Actually several number of Themisto species are known toform dense swarms, but they were not eaten by the whales.
The characteristic of the stomach contents as shown in Tables 3-5 is such an
extremely predominant occurrence of monospecific composition over the stomachs ofthree whale species as it was reported by Kawamura (1974, 1980) for the southernsei and Bryde's whales. Although data on the freshness of stomach contents by eachprey species were not shown in this study, it was observed that the freshness of preyspecies which occurred together in a stomach such as the case of C. plumchrus andC. pacijicus, was different from one to another. Similarly the different freshness canbe observed in many stomachs when their contents were composed of more than
two prey species. As it was discussed on the mixed prey with C. cristatus and C.
plumchrus (Nemoto, 1963), these phenomenon was perhaps caused by the time-lag
in picking up each prey species due to horizontal and vertical differences in the
distribution of prey organisms. Occurrence of the Siphonophora, Velella sp.,
however, indicates that the whales often feed in the very surface waters. The plot
in Figs. 5-9 consequently, suggests that how frequently each prey organism occurs
patchily in the region by forming dense monospecific swarms, aggregations, and/or
schools. After analysing a small scale of distributions of whales and their stomach contents observed within a short enough period, Kawamura (1978) estimateda spacial scale of patchiness of prey species as less than 5-6 km as an estimateddiameter of patches in C. cristatus, C. plumchrus and C. pacijicus complex whereas it wasslightly larger in E. pacifica, T. inermis, T. raschii, T. longipes, T. spinijera and possibly in N. dijficilis.
To conclude the geographical distributions of prey species that form dense
swarms or aggregations, it can be summerized that the North Pacific fin, sei andSci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

87

N
60°----...,...,...r-"'T~~..--~~~M"'-,"72'~--.~....,----,

50°
40°
30°
E 160°

180°

160°

140°

120°W

Fig. 10. Approximate geographical occupations of the principal prey species.
1-Calanus marshallae
2-Thysanoessa inermis / T. longipes
3-Calanus cristatus
4Tarletonbeania tqylori 5-Calanus plumchrus 6-Cololabis saira 7-Sergestes similis 8Pseudopentaceros richardsoni
9-Thysanoessa spinifera
10-Euphausia pacijica
llCalanus pacijicus
12-Nematoscelis difficilis
13-Vinciguerria nimbaria 14-Euphausia
similisBryde's whales share a possible prey species each other by selecting euphausiids, copepods and fish communities respectively. Among so many variable prey
items, the distribution ranges of major prey species over the whole North Pacific
can be demonstrated in schema (Fig. 10). Although C. cristatus, C. plumchrus andC. pacificus are known to distribute widely over the whole North Pacific, the mainoccurrence of their patchy swarms show different geographical distributions, i.e.,
both C. cristatus and C. pacificus predominantly form their patches more frequently or
intensively in the northwestern to western North Pacific whereas C. plumchrus doesin the eastern North Pacific. Although physical and chemical conditions of thesea surface in the northern North Pacific shows very homogeneous features fromthe west to the east in general, the distributions of many prey species on the wholesuggest that there seems to exist geographically discontinuous region somewehere
between 160°-l 70°W where the variety of prey species is very poor.
ACKNOWLEDGMENTS

I am very grateful to Dr. H. Omura and his staff of the Whales Research Institutefor their support and encouragement throughout my 10-year sampling scheme.
Thanks are also due to Dr. S. Ohsumi and his colleagues of the Far Seas
Fisheries Research Laboratory for their welltimed supervision and advice throughwhich the collection of stomach samples was implemented. Data in the CatchRecords of Whales by the Fisheries Agency become also available by their
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

88

KAWAMURA

courtesy, and all these support that facilitated the present study is greatly
acknowledged. I am grateful, as well, to all personnel who belonged to whaling division of the Nippon Suisan K.K., Taiyo Gyogyo K.K., K.K. Kyokuyo
and Nippon Kyodo Hogei K.K. for their long-term cooperation in collecting alarge part of the stomach materials during the seasons of 1969-1979.
REFERENCES
BETESHEVA, E. I., 1954. Data on the feeding of baleen whales in the Kurile region. Trans. Inst. Oceanogr.
Acad. Sci. USSR, 11: 238-245 (in Russian)
BETESHEVA, E. I., 1955. Food of whalebone whales in the Kurile Island region. Trans. Inst. Oceanogr.
Acad. Sci. USSR, 18: 78-85 (in Russian)
BoDEN, B. P., M. W. JOHNSON, and E. BRINTON, 1955. The Euphausiacea (Crustacea) of the North Pacific.
Bull. Scripps Inst. Oceanogr., 6: 287-400.
BRODIE, P. F., D. D. SAMEOTO, and R. W. SHELDON, 1978. Population densities of euphausiids off Nova
Scotia as indicated by net samples, whale stomach contents, and sonar. Limnol. Oceanogr., 23: 12641267.
CHIKUNI, S., 1970. On the occurrence of a phantasmal fish, pelagic armorhead. Enyo, 3: 1-4 (in Japanese)
GJOSAETER, J. and K. KAWAGUCHI, 1980. A review of the world resources of mesopelagic fish. FAO Fisheries Tech. Pap., 193: 1-151.
IWS, 1967-1972. International Whaling Statistics. Sandefjord.
KAWAMURA, A., 1970. Food of sei whale taken by Japanese whaling expeditions in the Antarctic season
1967/68. Sci. Rep. Whales Res. Inst., 22: 127-152.
KAWAMURA, A., 1973. Food and feeding of sei whale caught in the waters south of 40°N in the North Pacific.
Sci. Rep. Whales Res. Inst., 25: 219-236.
KAWAMURA, A., 1974. Food and feeding ecology in the southern sei whale. Sci. Rep. Whales Res. Inst., 26:
25-144.
KAWAMURA, A., 1978. An interim consideration on a possible interspecific relation in southern baleen
whales from the viewpoint of their food habits. Rep. int. Whal. Commn, 28: 411-419.
KAWAMURA, A., 1979. An extremely biassed distribution of marine zooplankton. An estimation of their
spacial scale of patchiness. Marine Science Monthly, 10: 877-888 (in Japanese).
KAWAMURA, A., 1980. A review of food of balaenopterid whales. Sci. Rep. Whales Res. Inst., 32: 155-197.
KAWAMURA, A. and Y. SATAKE, 1976. Preliminary report on the geographical distribution of the Bryde's
whale in the North Pacific with special reference to the structure of filtering apparatus. Sci. Rep.
Whales Res. Inst., 28:1-35.
KAWAMURA, A. and S. HAMAOKA, 1981. Feeding habits of the gonostomatid fish, Vinciguerria nimbaria
collected from the stomach of Bryde's whales in the southwestern North Pacific. Bull. Plankton Soc.
Japan, 28: 141-151.
KAWAGUCHI, K. and A. KAWAMURA, 1981. A rare myctophid fish, Diaphus bertelseni from the stomach of
Bryde's whale captured in the subtropical western North Pacific. Jap. ]our. Ichthyol., 28: 169-170.
MAuCHLINE, J. and L. R. FrsHER, 1969. The biology of euphausiids. Advances Mar. Biol., 7: 1-454.
MrnoDA, T., 1958. Report from the Oshoro Maru on oceanographic and biological investigations in the
Bering Sea and northern North Pacific in the summer of 1955. V. Observations on copepod community. Bull. Fae. Fish. Hokkaido Univ., 8: 253-263.
MrNODA, T., 1971. Pelagic copepoda in the Bering Sea and the western North Pacific with special reference
to their vertical distribution. Mem. Fae. Fish. Hokkaido Univ., 18: 1-74.
MrzuE, K., 1951. Food of whales (In the adjacent waters of Japan). Sci. Rep. Whales Res. Inst., .5: 81-90.
NASu, K., 1957. Oceanographic conditions of the whaling grounds in the waters adjacent to Aleutian Islands
and the Bering Sea in summer of 1955. Sci. Rep. Whales Res. Inst., 12: 91-101.
NEMOTO, T., 1957. Food of baleen whales in the northern Pacific. Sci. Rep. Whales Res. Inst., 12: 33-89.
NEMOTO, T., 1959. Food of baleen whales with reference to whale movements. Sci. Rep. Whales Res. Inst.,
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

89

14: 149-290.
NEMOTO, T., 1963. Some aspects of the distribution of Calanus cristatus and C. plumchrus in the Beringand its neighbouring waters, with reference to the feeding of baleen whales. Sci. Rep. Whales Res.
Inst., 17: 157-170.
NEMOTo, T. and A. KAWAMURA, 1977. Characteristics of food habits and distribution of baleen whales
with special reference to the abundance of North Pacific sei and Bryde's whales. Rep. int. Whal. Commn(Special Issue I): 80-87.
0DATE, K., 1966. On the comparative study of volumes of zooplankton distributions in the Oyashio area
and in the seas adjacent to that area. Bull. Tohoku Reg. Fish. Res. Lab., 26: 45-53.
0MORI, M., A. KAWAMURA, and Y. ArzAwA, 1972. Sergestes similis Hansen, its distribution and importanceas food of fin and sei whales in the North Pacific Ocean. In: A. Y. Takenouti, M. Anraku, K. Banse,
T. Kawamura, S. Nishizawa, T. R. Parsons, T. Tsujita, (ed.), Biological Oceanography ef the Northern
North Pacific Ocean, Idemitsu Shoten, Tokyo, 626 pp.
0MORI, M., 1965. The distribution of zooplankton in the Bering Sea and northern North Pacific, as observed by high-speed sampling of the surface waters, with special reference to the copepoda. ]our.
Oceanogr. Soc. Japan, 21: 18-27.
OMURA, H. and T. NEMOTo, 1955. Sei whales in the adjacent waters of Japan. III. Relation between
movement and water temperature of the sea. Sci. Rep. Whales Res. Inst., 10: 79-87.
PoNOMAREVA, L. A., 1949. On the food plankton of baleen whales in the Bering Sea. Doklady Acad. Nauk,
USSR, 68: 401-403 (in Russian).
SVERDRUP, H. U., M. W. JOHNSON, and R.H. FLEMING, 1942. The Oceans. Their physics, chemistry and general
biology. Prentice Hall, Inc., N.Y., 1042 pp.
SLEPTsov, M. M., 1955. Biology and.fishing of whales in the Far Eastern Seas. (Translated from the Russianby H. Sakiura, 1955), Whales Res. Inst., Tokyo, 51 pp . .(in Japanese).
ToMILIN, A. G., 1967. Cetacea. Vol. 9. Mammals of the U.S.S.R. and adjacent countries. Heptner, V. G. (ed.)
Israel Prog. Sci. Transl.,Jersalem, 717 p.
WISNER, R. L., 1974. The taxonomy and distribution of lanternfishes (Family Myctophidae) of the eastern
Pacific Ocean. NORDA Rep. 3. Navy Ocean Res. Develop. Activity, Bay St. Louis, 229 p.
ZENKEVITCH, L., 1963. Biology of the seas of the U.S.S.R. Trans!. S. Botcharskaya, George Allen & Unwin,
London, 955 p.
ZENKOVITCH, B. A., 1937. The food of the Far-Eastern whales. Doklady Acad. Sci. S.S.S.R., 16: 231-234(in Russian).

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

KAWAMURA90
APPENDIX I.

STOMACH CONDITIONS OF FIN, SEI AND BRYDE'S WHALESCATCH RECORDS OF WHALES COMPILED BY THE FAR SEAS
Food item

Catch
Euphausiacea

Copepoda Amphipoda

PiscesSquidl (0.3)l (0.2)
92 (14.7)
61 (27.1)
154
9.32

May
June
July
AugustTotal% to total

537
697
1,085
343
2,662

268 (72.4)
281 (63.6)
410 (65.7)
128 (56.9)
1,080
65.4

101 (27.3)
139 (31.4)
115 (18.4)
35 (15.6)388
23.5

6 (1.4)5 (0.8)l (0.4)
12
0.7

May
June
July
AugustSeptember
Total% to total

2,303
5,375
5,232
1,688
39
14,637293 (20.0)
169 (5.3)
278 (9.4)
123 (12.2)
l (4.2)864
9.97

1,092 (74.6)
2,574 (80.1)
2,080 (70.3)
800 (79.2)
22 (91.7)
6,568
75.8

69 (4.7)456 (14.2)
523 (17.7)
48 (4.8)l (4.2)
1,097
12.66

Bryde's April
May
June
July
AugustSeptember
Total% to total

93
543
1,180
337
452
96
2,703*

1 (2.1)191 (53.4)
274 (37.6)
22 (14.6)274 (89.8)
38 (50.0)
800
47.99

Fin

Sei

(0.3)

2 (0.07)

I (0.3)I (0.3)

(0.7)

2
0.12

2
0.12

9 (0.6)8 (0.3)65 (2.2)
38 (3.8)120
1.38

47 (97.9)
165 (46.l)
454 (62.3)
128 (84.8)
31 (10.2)
38 (50.0)
863
51.76

* Two Bryde's whales that were unknown their catch month were excluded

Sci. Rep. Whales Res. Inst.,.No. 34, 1982

FOOD OF NORTH PACIFIC RORQUAL

91

CAUGHT DURING THE SEASONS OF 1969-1979. (CONSTRUCTED USINGFISHERIES RESEARCH LABORATORY OF THE FISHERIES AGENCY)
Total
of filled
Octopus stomach
15 (3.4)
2 (0.3)17
1.02
6 (0.2)9 (0.3)1 (0.1)
16
0.18

% of

Stomach fullness

filledstomachto total

Few

Moderate

Rich

Full

Empty

370
442
624
225
1,661
62.39

68.90
63.41
57.51
65.60
62.39

167 (31.1)
188 (27.0)
265 (24.4)
83 (24.2)
703 (26.4)

115 (21.4)
146 (20.9). 190 (17.5)
64 (18.7)515 (19.3)

39 (7.3)
55 (7.9)
84 (7.7)35(10.2)
213 (8.0)

49 (9.1)
53 (7.6)
85 (7.8)43(12.5)230 (8.6)

167 (31.l)
255 (36.6)
461 (42.5)
118 (34.4)
1,001 (37.6)

1,463
3,213
2,957
1,010
24
8,667
59.21

63.53
59.78
56.52
59.83
61.54
59.21

824 (35.8)
1,731 (32.2)
1,625 (31.l)
587 (34.8)
8 (20.5)
4,775 (32.6)

393 (17.1)
974 (18.1)
834 (15.9)297 (17.6)
3 (7.7)2,501 (17.1)

128 (5.6)
265 (4.9)
254 (4.9)
72 (4.3)
7(17.9)726 (4.9)

118 (5.1)
243 (4.5)
244 (4.7)
54 (3.2)
6(15.4)665 (4.5)

840 (36.5)
2,162 (40.2)
2,275 (43.5)
678 (40.2)
15 (38.5)
5,970 (40.8)

48
358
729
151
305
76
1,667

51.61
65.93
61.78
44.81
67.48
79.17
61.67

34 (36.6)
141 (26.0)
361 (30.6)
88 (26.1)
80 (17.7)
39 (40.6)743 (27.5)

10 (10.8)66 (12.2)
181 (15.3)
43 ( 12.8)
99 (21.9)
17 (17.7)
416 (15.4)

4 (4.3)66(12.2)
68 (5.8)
7 (2.1)57(12.6)
10(10.4)
212 (7.8)

85 (15.7)
119 (10.1)
13 (3.9)69 (15.3)
10 (10.4)296 (11.0)

45 (48.4)
185 (34.1)
451 (38.2)
186 (55.2)
147 (32.5)
20 (20.8)
1,034 (38.3)

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF THE SUPERFAMILY
PLATANISTOIDEA, WITH NOTES ON EVIDENCE OF THE
MONOPHYLY OF THE CETACEAZHOU KAIYA
Department of Biology, Nanjing Normal College, Nanjing

ABSTRACT

Important basis provided by the morphological studies on the skeleton,
digestive and respiratory organs of the Platanistoidea have further provedthat this group can be divided into four families. Considering the characteristics of the skeleton and other morphological features, the phylogenetic
relationships among the four families are discussed. The systematic sequenceof the families should be Iniidae, Lipotidae, Pontoporiidae and Platanistidae.
Some characters noticed in the investigations are evidence in favour of themonophyly of the cetacea.
INTRODUCTION

The superfamily Platanistoidea possesses a number of primitive characters similar
to the Oligocene-Miocene Squalodontoidea, some characters similar to the primitive forms of the higher cetacean families and some specialized structures. Two
different opinions advocating divide or combination concerning the classificationof the Platanistoidea have been held over a long period of time.
In the middle of the 19th century, Gray (1863, 1866) first divided the Platanistoid dolphins into groups. In his catalogue, Platanista constitutes the fourthfamily of Cetacea-Platanistidae; Inia constitutes the fifth family-Iniidae; Pontoporia was placed into the sixth family-Delphinidae. Flower (1869) gave another
opinion before long, put together the above mentioned three genera into thePlatanistidae. He made Platanista and Inia belong to the subfamily Platanistinae
and Iniinae respectively and placed Pontoporia into the subfamily Iniinae provisionally.
At the beginning of the 20th century, Miller (1918) named Lipotes, the fourth
genus of the modern Platanistoids, and referred it to the Iniidae. In anotherpaper published in 1923, he followed Gray in recognizing Platanistidae and Iniidae
and still considering Pontoporia a member of the Delphinidae. Nevertheless, hehas placed Pontoporia into the subfamily Stenodelphininae to differ from othergroups of the Delphinidae. Kellogg (1928) held the same opinion as Miller did,whereas Winge (1918) maintained to put Platanista, Inia, Pontoporia and the newly
discovered Lipotes together into the Platanistidae. In this period, argument concerning divide or combination of the Platanistoids was continued and different
opinion was set in whether Pontoporia belongs to Platanistoids.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982, 93-108

94

ZHOU

In 1936 Slijper adopted the concept in favour of combination and placed all
the living genera of Platanistoids into the family Platanistidae. Following Slijper's
opinion, Simpson (1945) recognized Platanistidae but retained three subfamilies
and, moreover, established superfamily Platanistoidea in the higher category.
This taxonomical system has been accepted by most cetologists ever since. Slijper's
system has been adopted by Norman and Fraser (1948), Slijper (1962), Nishiwaki(1965, 1972), Tomilin (1974), Matthews (1978), Lockley (1979), and others.
Simpson's system has been followed by Fraser and Purves (1960), Carvalho (1961),
Marcuzzi and Pilleri (1971), Brownell and Herald (1972), Mead (1975), Rice (1977),
and others. The single family system was also adopted by Hershkovitz (1966), but
a new name Susuidae which he proposed has not been accepted by other cetologists. Authors studying fossil Platanistoids such as Kellogg (1944, 1955 ), Rensberger(1969) have continued to recognize the iniid as a distinct family. Gaskin (1976)
who is studying modern cetaceans has followed their opinion.
The investigations of Platanistoid dolphins have gained great attention again
since 1960s. Kasuya (1973) recognized the Platanistidae, lniidae and Pontoporiidae of the Platanistoidea on the basis of the study of the tympano-periotic bone.
In a paper on the study of Lipotes, van Bree and Purves (1975) put it in the lniidae.
Pilleri et al. (1976) proposed to separate Inia, Lipotes and Pontoporia from the
Platanistidae and put them in the lniidae. The coexistence of the one familysystem (Slijper, 1936; Simpson, 1945) with the two and three family systems(Pilleri et al., 1976; Kasuya, 1973) occured. In 1978, Zhou et al. proved that
Lipotes is not closely related to Inia and the differences between the two genera
exceed those between the Delphinidae and Phocoenidae, and placed Lipotes into
a separate family-Lipotidae. After this, Pilleri and Gihr (1980) have turned
to use a four family system, but no argument has been given.
The present paper summarizes the important basis provided by the morphological studies of the skeleton, digestive and respiratory organs of Inia (Flower,
1869; Mead, 1975; Lonnberg, 1928; Pilleri and Gihr, 1976c, 1977; Yamasaki andKamiya, 1981; Zhou, Li and Pilleri, 1982), Lipotes (Miller, 1918; Chen and Chen,
1975; Zhou et al., 1978, 1979a, b; Chen et al., 1980; Liu and Lin, 1980; Zhou andLi, 1981), Pontoporia (Burmeister, 1867; Flower, 1869; Carvalho, 1961;"Schenkkan,
1972; Yamasaki et al., 1974, 1975, 1977; Mead, 1975; Pilleri and Gihr, 1976b;
Yamasaki and Satomi, 1976) and Platanista (Eschricht, 1852; Anderson, 1879;
Arvy and Pilleri, 1970; Yamasaki and Takahashi, 1971 ; Takahashi and Yamasaki,
1972; Yamasaki et al., 1972; Purves and Pilleri, 1973; Pilleri and Gihr, 1976a;
Yamasaki, Komatsu and Kamiya, 1977) and further proves that the Platanistoids
can be divided into four families. The phylogenetic relationships among the fourfamilies and the evidence in favour of the monophyly of the cetacea are also discussed.
BASIS OF THE CLASSIFICATION OF THE SUPERFAMILY

An uniform understanding of the genera of Platanistoids has been acquired earlySci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEATABLE I.

IniidaeLipotidae
Pontoporiidae
Platanistidae
Ziphiidae
Physeteridae
Monodontidae
Delphinidae
Phocoenidae
Balaenopteridae

95

COMPARISON OF THE COMPARTMENTS OF
THE STOMACH OF CETACEA
Fore-stomach

Main stomach

Connecting
channel

0
0

3

0

0

Pyloric stomach

1
2
0
0

many compartments

1

0

in the third decade of the twentieth century. However, no identical result on
the classification in family rank has been obtained so far. The materials studied
which were mostly confined to skulls have something to do with the matter. When
studying the affinity between Lipotes and Inia, Zhou et al. (1978, 1979a) comparedattentively the vertebrae, sternums, flipper skeletons and other available materials
of external and internal structures in addition to the careful comparison of thestructure of the skulls. As a result of these studies, the close relationship between
Lipotes and Inia was refuted. In recent decade, the studies of the skeleton anddigestive tract of Platanistoids by Yamasaki et al., Pilleri et al. and Zhou et al.
have provided important basis for the classification of the modern Platanistoids.
Table 1 indicates that the stomachs of other modern cetaceans consist offore-stomach, main stomach and pyloric stomach except those of the Ziphiidae
in which the fore-stomach is absent. They differ from each other only in thepresent (Delphinidae, Monodontidae, Phocoenidae) or absent (Physeteridae,
Balaenopteridae) of the connecting channel. The stomachs of different groupsof Platanistoids differ from each other not only in the above mentioned characters,
but also in the subdividing of the main stomach or not (Fig. 1). Both Inia andPlatanista possess fore-stomach, but the main stomach is single chambered in theformer and divides into two compartmei:its in the latter. In Lipotes and Pontoporia
the fore-stomach is lacking. The main stomach divides into three compartments
and the connecting channel is absent in the former, while the latter possesses single
chambered main stomach and the connecting channel. The differences between
the stomach of any two groups of Platanistoids go beyond the mutual differences
between the stomach of most of the odontocetes. Refer to the Artiodactyla, thenumber of compartments of the stomach goes so far as to be the main character indistinguishing Infraorder Tragulina (3 compartments) and Infraorder Pecora (4compartments). Thus the structure of the stomach is one of the key charactersin weighing the degree of separation among different groups of Platanistoids.
The structure of the skeleton is still important basis in classifying the Platanistoids. Attention should be paid first of all to four note-worthy differences between
Inia and three other groups of Platanistoids. 1. The palatal portion of the two
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

96

ZHOU

c

Fig. 1. Diagram of the stomach of (A) Inia geo.ffrensis, (B) Lipotes vexillifer, (C)Pontoporia blainvillei, (D) Platanista gangetica.
CC. connecting channel; DA. duodenal ampulla; DP. duodenum proper;E. esophagus; FS. fore-stomach; MS. main stomach; MSI. first compartment of
main stomach; 2. second compartment of main stomach; 3. third compartmentof main stomach; PS. pyloric stomach; HPO. opening ofhepato-pancreatic duct.

->Fig. 2. Ventral aspect of skull of (A) Inia geoffrensis, (B) Lipotes vexillifer, (C) Pontoporia blainvillei, (D) Platanista gangetica.
Bo. basioccipital; Fr. frontal; Mc. maxillary crest; Mx. maxilla; Pl. palatine;
Pt. pterygoid; Pth. pterygoid hamulus; Ptp. lateral plate of pterygoid; Sq. squamosal; Vo. vomer; Zy. zygomatic process ofsquamosal.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEA

Sci. Rep. Whales Res. Inst.,.No. 34, 1982

97

ZHOU

98

ertob>-~· IniaDgeojfrenszs,. (B)f: L ;hotes. . (C) Ponvexillifer,ts (bold !me .

toporza
. vD)
of "
(A)
blaUwil••'( PMtam<ta
F"ig. 3. . Thorac1:" ' ". ' "howffig =<'1

•~

i,,

•

)

11,,.
"'·
&i. R.p. ff(Im/""34' Im<..
1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEA

99

maxillas and palatines of lnia is separated by the vomer. In three other groups of
Platanistoid, the palatal portion of maxilla contacts that of the opposite side
(Fig. 2). 2. Only irregular tubercles are found on the ventral aspect of the pterygoid hamuli of lnia, whereas the pterygoid hamuli of Lipotes possess a thin plate
which recurves dorsally. This portion enlarges to form the lateral plate of pterygoid in Pontoporia and Platanista. 3. In lnia, the costal facets are located at the

A

c

B

D

Fig. 4. Flipper skeleton (not including phalanges) of (A) Inia geoffrensis, (B) Lipotes
vexillifer, (C) Pontoporia blainvillei, (D) Platanista gangetica. Ulnare hatched;pisiform stippled.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

ZHOU

100

anterior and posterior edges on each centrum of the first two thoracic vertebrae
and occured at the anterior edge only in the hinder thoracic vertebrae. In Lipotes,
they are located both at the anterior and posterior edges of the centrum of the firstvertebra and occured at the posterior edge only on the centrum of the 2nd-5th
thoracic vertebrae. In the 7th thoracic vertebra, the facet occurs on the anterior edge only. The costal facets are located at the hind edge on the centrum of
the thoracic vertebrae in most individuals of Pontoporia. In few individuals, thoseof 5th or 4th-5th thoracic vertebrae are situated at the front edge of the centrum.
All costal facets of the thoracic vertebrae of Platanista are situated at the hind edgeof the centrum (Fig. 3 ). 4. According to the radiograph published by Pilleri andGihr (1976a, b, c), the ulnare and pisiform are free in Inia; the ulnare is free but
the pisiform is missing in Pontoporia; both bones are missing in Platanista. According
to our specimens, although the ulnare and pisiform of Lipotes are fused to the ulna
and 5th metacarpal respectively, they are still distinguishable (Fig. 4).
The tympano-periotic of the cetacea has moved ventrally and lost the direct

A

c

B

D

Fig. 5. Connection between tympano-periotic and skull in (A) lnia geoffrensis,(B) Lipotes vexillifer, (C) Pontoporia blainvillei, (D) P!atanista gangetica, Waved edge
indicates suture of bones and dotted are the laminated structure. (A) and (C):
fixed with ligament; (B) and (D): direct joining. (Modified from Kasuya, 1973,)
Sci. Rep. Whales Res. Inst.,

No. 34, 1982

:"'·

~[

""'

~

1;;"

""""'

~~

......

""~
u""'~

~

~~

Costal facet ofthoracic vertebrae
Carpals

Palatal portion of
two maxillas
Bony plate of pterygoid hamulus
Connection between
tympano-periotic
and skull
Teeth
thin bony plate recurves
dorsally
posterior process of tympanic
bulla loosely sutured tosquamosalcrown with reticulate enamelrugositysmall tubercles on ventral
aspect of pterygoid hamulus
fixed with ligament

located mostly at anterior
located mostly at posterioredge of centrum
edge of centrum
7, ulnare and pisiform present 4--5, ulnare fused to ulna
and pisiform fused mostly to
5th metacarpal

crown with nodular enamelrugosityin contact

separated by vomer

absentnot reaching supraorbital
process of frontal

absentnot reaching supraorbital
process of frontal

located at posterior edge ofcentrum in most individuals
6, ulnare present, pisiform
missingcrown simple

enlarges to form lateralplate of pterygoid
fixed with ligamentin contact

absentreaching supraorbital processof frontal

enlarges to form lateralplate of pterygoid
posterior process of tyropanic bulla loosely sutured
to squamosalcrown simple, upper toothrows merged together andalmost in contact
located at posterior edge ofcentrum
5-6, ulnare and pisiform
missingvery well developed
reaching orbital plate offrontal from which a supraorbital process is usuallydeveloped
in contact

present
3.6-4.9

absent24.0-37.3

absent12.5-14.9

absent19-20

located at duodenum proper

Opening of hepatopancreatic duct
CaecumRatio of intestinal
length to body length
Maxillary crest
Zygomatic process
of squamosal

Platanistidae

fore-stomach absent, threefore-stomach absent, single
compartments of main stomach main stomach, connecting
and pyloric stomach present
channel and pyloric stomach
present
located at duodenal ampulla
located at duodenum proper

absenttransverse, crescentic
arising from trachea justabove bifurcation of rightand left bronchi

Pontoporiidae

fore-stomach, single main
stomach, connecting channel
and pyloric stomach present

Stomachabsentlongitudinal, elliptic
arising from trachea markedly
higher than bifurcation ofright and left bronchi

Lipotidae

absentlongitudinal, slitlike
arising from trachea
markedly higher than bifurcation of right and left
bronchifore-stomach, two compartments of main stomach, connecting channel and pyloric
stomach present
located at duodenum proper

sparsely on snout
transverse, crescentic
arising from trachea slightly
higher than bifurcation ofright and left bronchi

Iniidae

COMPARISON OF THE MAIN CHARACTERS OF THE FAMILIES OF THE SUPERFAMILY PLATANISTOIDEA

Hairs
Blow hole
Apical bronchus

Characters

TABLE 2.

0

--

;i:..

l:'l

tJ

0.....

i-,lC/J.

z.....~

r

"'C

><:
0>zj

~

Q

r

::c:
><:
0

"'C

tJ

~

z

~
.....
0

0

.....
>zj
.....

C/J.
C/J.

;i:..

r

0

ZHOU

102

joining to the skull in various degrees in the course of the adaptations to the aquatic
life. In Lipotes and Platanista the posterior process of tympanic bulla is still loosely
sutured to the skull (Kasuya, 1973; Zhou et al., 1979a). The tympano-perioticof Inia and Pontoporia is fixed with ligament to the skull (Fig. 5 ). Besides, Inia and
Lipotes differ from Pontoporia and Platanista in having the zygomatic process ofsquamosal not reaching the supraorbital process of frontal. The distinction between the teeth of different Platanistoids is as follows: The crown of the teeth ofInia and Lipotes is covered with nodular and reticulate enamel rugosity respectively
and that of Pontoporia and Platanista is simple. The upper tooth rows of Platanista
merge together and are almost in contact with each other. Platanista also differsfrom three other Platanistoids and all other living odontocetes in having the curious maxillary crest.
The morphological distinctions between different Platanistoids showing in
Table 2 are far more than those between different families of most mammals.
This fact proves that each of the four Platanistoid dolphins represents a separate
lineage derived from the primitive ancestor at an early stage of the evolutionary
process. Their taxonomic categories should be referred to family rank.
PHYLOGENY

The traditional view concerning the relationship of different Platanistoid dolphinsis that Lipotes is closely related to Inia and that Pontoporia is close to them. The
systematic sequence of these groups has been arranged as A and B by most authors(Simpson, 1945; Carvalho, 1961; Marcuzzi and Pilleri, 1971; Kasuya, 1973;
Tomilin, 1974; Mead, 1975; Matthews, 1978 other). It has been arranged as C
by Slijper (1936, 1962) and some authors (Norman and Fraser, 1948; Nishiwaki,
1965, 1972) according to the sequence of naming. There are still few othersequences (Fraser and Purves, 1960; Hershkovitz, 1966; Rice, 1977). According to
the informations now understood, these arrangements can not express the natural
relationships of Platanistoids.
Asubfamily Platanistinae(or family Platanistidae)
genus Platanista
subfamily Iniinae(or family lniidae)
genus Inia
genus Lipotes
subfamily Pontoporiinae(or family Pontoporiidae)
genus PontoporiaBcfamily Platanistidae
genus Platanista
genus Inia
genus Lipotes
genus Pontoporia

family Platanistidae
genus Platanista
genus Inia
genus Pontoporia
genus Lipotes

By inference from the analysis of the characters, the phylogenetic relationships
among the families of Platanistoids may be expressed as Fig. 6. The Iniidae is
a side branch diverged from primitive Platanistoids. This family is characterized
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEA
Pontoporiidae
IniidaeLipotidae

Platanistidae

Hairs on snout
Palatal portion of maxillas
Bony plate of pterygoid
Costa! facet of thoracic
vertebrae
Ulnare and pisiform
Zygomatic process of squamosal
Crown of teeth
Opening of hepato-pancreatic duct
CaecumCo1,1n~ction between tympanopenot1c and skull·

Maxillary crest
Upper tooth rows
Apical bronchus

0

Plesiomorphous character•

Apomorphous character
Symplesiomorphous character
Synapomorphous character

Fig. 6.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

Diagram of the phylogeny of the superfamily Platanistoidea,

103

104

ZHOU

by apomorphous characters, i.e. the separation of the palatines by the vomer andthe location of most of the costal facets at the anterior edge of the centrum of thethoracic vertebrae, which differentiate lniidae from other Platanistoids. The position of the head of the ribs articulating to the centrum of the thoracic vertebrae
indicated by the costal facets is features differentiated during the early stage of adaptation to the aquatic life. In view of the fact that the costal facets of the thoracic
vertebrae of Delphinoidea and Physeteroidea locates on the posterior edge of thecentrum, the position of that of lniidae probably situates opposite that of all otherliving odontocetes. The synapomorphous characters of Lipotidae, Pontoporiidae
and Platanistidae are the development of the bony plate of pterygoid hamuli andthe reduction of the carpals. Through the development of the recurved thin platefrom the irregular small tubercles of pterygoid hamulus and the formation of theformer to the well-developed lateral plate of pterygoid, the evolutionary sequencesof this feature can be seen. The evolutionary trend of the carpals is the fusion of
the ulnare and pisiform to adjacent bones or missing of both bones.
The Lipotidae is the second branch descended from the primitive Platanistoids. A series of features of the Lipotidae such as the bony plate of pterygoid
hamuli, costal facet of thoracic vertebrae, carpals, zygomatic process of squamosaland crown of teeth is relatively more primitive than those of Pontoporiidae andPlatanistidae. The Lipotidae also differs from these two families by the apomorphous character in having the hepato-pancreatic duct opens into the duodenal
ampulla.
The Pontoporiidae and Platanistidae have diverged from the primitive Platanistoids slightly later than the Lipotidae. The maxillary crest, upper toothrows, carpals and apical bronchus of Platanistidae are characters more specialized
than those of the Pontoporiidae, whereas the caecum and the direct joining of the
tympano-periotic to the skull in the same family are primitive characters as compared with those of the Pontoporiidae. The mosaic distribution of the Plesiomorphous characters and apomorphous characters between Pontoporiidae and Platanistidae also has been formed.
The structure of the digestive tract of lniidae remains relatively close to theancestor. In Lipotidae and Pontoporiidae the fore-stomach is absent, the stomach of the former is most specialized in the losing of the fore-stomach and thedividing of the main stomach into three compartments. The digestive tract ofPlatanistidae is characterized by the differentiation of the main stomach and notable shortening of the intestine on the one hand, and is unique among odontocetes
in retaining the caecum on the other hand. The transverse crescent shaped blowhole of lniidae and Pontoporiidae is similar to that of most of the recent odontocetes,
whereas the shape of the blow hole ofLipotidae and Platanistidae has been changed
separately. The process of moving of the apical bronchus from the right bronchus
to trachea hasoccured in the course of phylogenetical development. The degreeof forward shift of the apical bronchus varies in different group of Platanistoids.
The reduction of the visual apparatus has taken place in relation to the increaseof the turbidity of the water and the weakening of the light. The eyes of theSci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEA

105

Pontoporiidae are comparatively well-developed and those of the fresh water
Platanistoid species exhibit a marked regression. The eyes of the Platanistidae
are almost completely blind. The degree of reduction of the eyes is in order ofPontoporiidae, Lipotidae, Iniidae, then Platanistidae (Zhou, Pilleri and Li, 1980).
The orbit of Platanistoids is reduced in correspondence with the regression of theeye. In the case of Iniidae and Lipotidae, the zygomatic process of the squamosalis not lengthened in correspondence with the reduction of the orbit and is not in
contact with the supra orbital process of the frontal. The unique maxillary crest of
the Platanistidae functions together with the air sinuses in the reflection of the soundsignals. It was probably developed parallel with regression of the eye to compensate for the loss of vision (Pilleri, 1979). The development of the brain of the
Platanistoid families is comparatively low as compared with that of other living
odontocetes. In totality, the lniidae is the family keeping relatively more primitive characters and the Platanistidae is the most specialized one. The systematicsequence of the families in accordance with their evolution should be Iniidae,
Lipotidae, Pontoporiidae and Platanistidae.
According to the fossils of the primitive Platanistoids discovered, these four
·families probably diverged during the Miocene from the marine ancestor originated from the Squalodontoidea. Three of the recent families of Platanistoids
have entered fresh-water rivers secondarily, whereas Pontoporiidae has remainedin coastal waters. Although the structures of Platanistoids have been differentiatedduring the long period of evolution, their development level is still lower thanthat of other recent odontocetes. Further studies on fossil groups of the Platanistoids
are needed.
EVIDENCE OF THE MONOPHYLY OF THE CETACEA

Whether the cetacea originated from a common ancestor or two or several ancestors is a disputed problem. Slijper (1962) and some Soviet investigators havereached a conclusion in favour of polyphyly that the three suborders of the cetacea
probably originated separatly from respective terrestrial ancestors. On the contray, Gaskin (1976) and van Valen consider that the cetacea as a whole are probably monophyletic. The basis of their argument is a series of morphological characters which are common to mysticetes and odontocetes such as the loss of thepelage, the lacking of the true vocal cord, the similarity in the structure of the
tympanic bulla and the shape of the lung, the oblique position of the diaphragmand the moving of the blow hole to the dorsal aspect of the head, etc. The cytogenetic studies of Amason (1969, 1972, 1974) and Kulu (1972) are also quoted bythem to indicate the close agreement of mysticetes and odontocetes in the number
and shape of the chromosomes as well as the distribution of C-heterochromatin in
the chromosomes. No reasonable explanation would be obtained if the cetaceans
were not of common ancestry.
A character common to mysticetes and odontocetes, which has not beenbrought to great attention yet, has been noticed during the studies on the phylogeny
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

106

ZHOU

of the Platanistoids. That is, the stomach of most cetaceans is composed of threecompartments, the fore-stomach, main stomach and pyloric stomach. The forestomach covered with esophageal epithelium is not subdivided further and theglandular stomach is divided into two or more compartments. The cetacean
stomach composed of single chambered fore-stomach and subdivided glandular
stomach is different from that of any other mammals. This fact makes me tocome over to the side of the monophyly.
The mysticetes are grazers and the odontocetes are predators. Since theydiffer not only in feeding methods but also in food, the similarity of the stomach
could not be explained by parallel adaptations. If the cetaceans were not ofcommon origin, it would be impossible for majority of them to possess the forestomach formed by the esophagus and the subdivided glandular stomach. It isreasonable to infer that such basic structure was developed before the differentiation of the mysticetes and odontocetes. It is the symplesiomorphous characterof the two groups and another evidence of the monophyly of the cetacea.
Certain characters which were thought to be found in mysticetes only still
remain in some Platanistoids, such as the hair on the snout of Iniidae and the caecum of Platanistidae. These features add evidence to support the monophyly of
the cetacea. It should be stated that the unique musculus palpebrales of the cetaceans (Hosokawa, 1951) is also a proof which has not been cited by previous authors.
ACKNOWLEDGEMENTS

The present paper was completed after I had examined the Platanistoid skeletons deposited in the Ocean Research Institute of the University of Tokyo. I am greatly
indebted to Dr. M. Nishiwaki, Professor Emeritus of the University of Ryukyus,
for his kind invitation made my studies in Japan possible, and to Dr. T. Kasuyaof the Ocean Research Institute of the University of Tokyo who provided theabove mentioned specimens in his collection. Thanks are also due to Xu Xinrong
for drawing.
REFERENCES
ANDERSON, J., 1879. Anatomical and zoological researches: comprising an account of the zoological resultsof the two expedition to western Yunnan in 1868 and 1875; and a monograph of the two cetacean
genera, Platanista and Orcella. 2 Vols. B. Quaritch, London.
ARNASON, U., 1969. The karyotypes of the fin whale. Hereditas, 62: 273-84.
ARNASON, U., 1972. The role of chromosomal rearrangement in mammalian speciation with special reference to Cetacea and Pinnipedia. Hereditas, 70: 113-18.
ARNASON, U., 1974. Comparative chromosome studies in Cetacea. Hereditas, 77: 1-36.
ARVY, L. and G. PILLER!, 1970. The tongue of Platanista gangetica and remarks on the cetacean tongue.
Invest. Cetacea, 2: 75-77.
BREE, P.J.H. van and P. E. PuRVEs, 1975. On the dimensions of three skulls of the species of dolphin
Lipotes vexillifer Miller, 1918 (Cetacea, Platanistoidea, Iniidae). Beaufortia, 24(308): 1-5.
BROWNELL, R. L. Jr. and E. S. HERALD, 1972. Lipotes vexillifer. Mamm. sp., 10: 1-4.
BURMEISTER, H., 1867. Preliminary observations on the anatomy of Pontoporia blainvillii. Proc. Zoo!. Soc.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

CLASSIFICATION AND PHYLOGENY OF PLATANISTOIDEA

107

London, pp. 484-489.
CARVALHO, C. T., 1961. "Stenodelphis blainvillei" na costa meridional do Brasil, corn notas osteologicas(Cetacea, Platanistidae). Rev. Brasil Biol., 21: 443-454.
CHEN PErxuN, LIN KEJIE and Lru RENJUN, 1980. Study on the anatomy and histology of upper respiratory
tract of Lipotes vexillifer Miller. Acta Hydrob. Sinica, 7: 131-137. (in Chinese with English summary).
CHEN YrYu and CHEN WEI, 1975. Notes on some morphological and anatomical features of the white-flag
dolphin, Lipotes vexillifer Miller. Acta Hydrob. Sinica, 5: 360-370. (in Chinese with English summary).
EscHRICHT, D. F., 1852. On the Gangetic dolphin. Ann. Mag. nat. Hist., 9: 161-188, 279-293.
FLOWER, W. H., 1869. Description of the skeleton of Inia geoffrensis and the skull of Pontoporia blainvillei,
with remarks on the systematic position of these animals in the order Cetacea. Trans. Z,ool. Soc. London,
6: 87-116.
FRASER, F. C. and P. E. PURVES, 1960. Hearing in cetaceans, evolution of the accessory air sacs and thestructure and function of the outer and middle ear in recent cetaceans. Bull. Brit. Mus. Nat. Hist., 7:1-141.
GASKIN, D. E., 1976. The evolution, zoogeography and ecology of cetacea. Oceanogr. Mar. Biol. Ann. Rev.,
14: 247-346.
GRAY, J.E., 1863. On the arrangement of the cetaceans. Proc. Z,ool. Soc. London, pp. 197-202.
GRAY, J.E., 1866. Catalogue ef seals and whales in the British Museum. 2nd ed. Brit. Mus. Nat. Hist., London,
pp. 220-231.
HERSHKOVITz, PH., 1966. Catalog ofliving whales. Bull. U.S. Natn. Mus., 246: 1-259.
HosOKAWA, H., 1951. On the extrinsic eye muscles of the whale, with special remarks upon the innervation and function of the musculus retractor bulbi. Sci. Rep. Whales Res. Inst., 6: l-'-33.
KASUYA, T., 1973. Systematic consideration of recent toothed whales based on the morphology oftympanoperiotic bone. Sci. Rep. Whales Res. Inst., 25: 1-103.
KELLOGG, R., 1928. The history of whales-Their adaptation to the life in the water. Quart. Rev. Biol.,
3: 29-76, 174-208.
KELLOGG, R., 1944. Fossil cetaceans from the Florida Tertiary. Bull. Mus. Comp. Z,ool., 94: 433-471.
KELLOGG, R., 1955. Three Miocene porpoises from the Calvert Cliffs, Maryland. Proc. U.S. Natn. Mus.,105: 101-154.
Lru RENJUN and LIN KEJIE, 1960. Study on tht< anatomy and histology of trachea and lung of Lipotes vexillifer Miller. Acta Hydrob. Sinica, 7: 141-148. (in Chinese with English summary).
LooKLEY, R. M. 1979. Whales, dolphins and porpoises. London, 192 pp.
LoNNBERG, E., 1929. Some remarks on a skeleton of Inia geojfrensis Blainv. Ark. Z,ool., 20A(l 1): 1-3.
MARcuzzr, G. and G. PrLLERI, 1971. On the zoogeography of cetacea. Invest. Cetacea, 3: 101-170.
MATTHEWS, L. H., 1978. The natural history of the whale. Weidenfeld and Nicolson, London, 219 pp.
MEAD, J. G., 1975. Anatomy of the external nasal passages and facial complex in the Delphinidae (Mammalia, Cetacea). Smiths. Contri. Z,ool., 207: 1-72.
MILLER, G. S.JR., 1918. A new river-dolphin from China. Smiths. Misc. Coll., 68(9): 1-12.
MILLER, G. S.JR., 1923. The telescoping of the cetacean skull. Smiths. Misc. Coll., 76(2720): 1-70.
NrsmwAKI, M., 1965. Whales and Pinnipeds. University of Tokyo Press, Tokyo. 439 pp.
NrsHIWAKI, M., 1972. General biology. pp. 3-204. In: S. H. Ridgway (ed.) Mammals of the sea, biolog.Y andmedicine. Charles C Thomas Publisher, Springfield, 812 pp.
NORMAN, J. R. and F. C. FRASER, 1948. Giant.fishes, whales and dolphins. Putnam, London, 376 pp.
PILLER!, G., M. GrnR, P. E. PuRVES, K. ZBINDEN and C. KRAus, 1976. On the behaviour, bioacoustics andfunctional morphology of the Indus River dolphin (Platanista indi Blyth, 1859). Invest. Cetacea, 6: 13141.
PILLER!, G. and M. GrnR, 1976a. The function and osteology of the manus of Platanista gangetica and Platanista indi. Invest. Cetacea, 7: 109-118.
PILLER., G. and M. GrnR, 1976b. On the manus of the La Plata dolphin, Pontoporia blainvillei. Invest.
Cetacea, 7: 119-128.
PILLER!, G. and M. GrnR, 1976c. The manus of the Amazon dolphin, Inia geoffrensis (de Blainville, 1817),
and remarks concerning socalled 'polydactyly '. Invest. Cetacea, 7: 129-137.
Sci. Rep, Whales Res. Inst.,
No. 34 ,1982

108

ZHOU

PILLERI, G. and M. GIHR, 1977. Observations on the Bolivian (Inia boliviensis d'Orbigny, 1834) and the
Amazonian Bufeo (Inia geojfrensis de Blainville, 1117) with description of a new subspecies (Inia geoffrensis
humboldtiana). Invest. Cetacea, 8: 11-76.
PrLLERI, G., 1979. The blind lndus dolphin, Platanista indi. Endeavour, 3: 48-56.
PILLERI, G. and M. GrnR, 1980. Checklist of the cetacean genera Platanista, Inia, Lipotes, Pontoporia, Sousa
and Neophocoena. Invest. Cetacea, 11 : 33-36.
PuRVES, P. E. and G. PILLERI, 1973. Observations on the ear, nose, throat and eye of Platanista indi. Invest.
Cetacea, 5: 13-57.
RENSBERGER, J.M., 1969. A new iniid cetacean from the Miocene of California. Univ. Calif. Puhl. Geol.
Sci., 82: 1-43.
RrcE, D. W., 1977. A list ef the marine mammals of the world. NOAA Techn. Rep. NMFS, SSRF 711,
Seattle, 16 pp.
ScHENKKAN, E.J., 1972. On the nasal tract complex of Pontoporia blainvillei Gervais and d'Orbigny, 1844
(Cetacea, Platanistidae). Invest. Cetacea, 4: 83-90.
SIMPSON, G. G., 1945. The principles of classification and a classification of mammals. Bull. Amer. Mus.
Nat. Hist., 85: 1-350.
SLIJPER, E. J., 1936. Die Cetacean, vergleichend-anatomisch und systematisch. Capita Z,oologica, 7: 1-590.
SLIJPER, E.J., 1962. Whales. Hutchinson Publishing Group, London, 475 pp.
TAKAHASHI, K. and F. YAMASAKI, 1972. Digestive tract of Ganges dolphin, Platanista gangetica. II. Smalland large intestines. Okajimas Fol. anat.jap., 48: 427-452.
ToMILIN, A. G., 1974. In the world of whales and dolphins. lzdatel'stvo "Znanie ",Moscow. 206 pp.
WINGE, H., 1918. Udsigt over hvalernes indbyrdes slaegtskab. Vidensk. Medd. fra Dansk. naturh. Foren.,70: 59-142.
YAMASAKI, F. and K. TAKAHASHI, 1971. Digestive tract of Ganges dolphin, Platanista gangetica. I. Oesophagus and stomach. Okajimas Fol. anat.jap., 48: 271-293.
YAMASAKI, F., K. TAKAHASHI and T. KAMIYA, 1972. Liver and bile-passage of Ganges dolphin, Platanista
gangetica. Okajimas Fol. anat.jap., 49: 365-390.
YAMASAKI, F., K. TAKAHASHI and T. KAMIYA, 1974. Digestive tract of La Plata dolphin, Pontoporia blainvillei.
I. Oesophagus and stomach. Okajimas Fol. anat.jap., 51: 29-52.
YAMASAKI, F., K. TAKAHASHI and T. KAMIYA, 1975. Digestive tract of La Platata dolphin, Pontoporia blainvillei. II. Small and large intestines. Okajimas Fol. anat. jap., 52: 1-26.
YAMASAKI, F. and H. SATOMI, 1976. The tongue of Franciscana (La Plata dolphin), Pontoporia blainvillei.
Okajimas Fol. anal.jab., 53: 77-92.
YAMASAKI, F., S. KOMATSU and T. KAMIYA, 1977. A comparative morphology of anal tonsils in Platanistidae.
Sci. Rep. Whales Res. Inst., 29: 95-100.
YAMASAKI, F., K. TAKAHASHI and T. KAMIYA, 1977. Lungs of Franciscana (Pontoporia blainvillei), withspecial references to their external aspects, weights and bronchial ramifications. Okajimas Fol. anat.
jap. 53: 337-357.
YAMASAKI, F. and T. KAMIYA, 1981. The stomach of the Boutu, Inia geoffrensis: comparison with those ofother Platanistids. Sci. Rep. Whales Res. Inst., 33: 69-81.
ZHOU KAIYA, QIAN WEIJUAN and Lr YuEMIN, 1978. Recent advances in the study of the Baiji, Lipotes vexillifer Miller. J. Nanjing Normal Coll. (nat. Sci.), (1): 8-13. (in Chinese with English summary).
ZHOU KAIYA, QIAN WEJUANI and Lr YuEMIN, 1979a. The osteology and the systematic position of the Baiji,
Lipotes vexillifer. Acta :(ool. Sinica, 25: 58-74. (in Chinese with English summary).
ZHOU KArYA, Lr YuEMIN and QIAN WEIJUAN, 1979b. The stomach of the Baiji, Lipotes vexillifer. Acta :(ool.
Sinica, 25: 95-100. (in Chinese with English summary).
ZHOU KAIYA, G. PILLER! and L1 YuEMIN, 1980. Observations on Baiji (Lipotes vexillifer) and Finless Porpoise (Neophocaena asiaeorientalis) in the lower reaches of the Changjiang-With remarks on physiological
adaptations of Baiji to the environments. Scientia Sinica, 23: 785-794.
ZHou KAIYA and Lr YuEMIN, 1981. The intestine of the Baiji, Lipotes vexillifer. Acta Z,ool. Sinica, 27: 248253. (in Chinese with English summary).
ZHOU KAIYA, Lr YuEMIN and G. PrLLERI, 1982. The digestive tract of Inia boliviensis. Invest. Cetacea, 13:
123-137.
Sic. Rep. Whales Res. Inst.,
No. 34, 1982

MORPHOLOGICAL STUDY ON THE HYBRID BETWEENTURSIOPS AND PSEUDORCA
MASAHAR U NISHIWAKI
National Science Museum, TokyoANDTERUO TOBAYAMA
Kamogawa Sea World, Chiba

ABSTRACT

A hybrid calf born in Kamogawa Sea World, Chiba, on May 3, 1981
was supposedly between mother Tursiops truncatus gilli and a male Pseudorca
crassidens. It lived 277 days. In the past record of Kamogawa Sea World,
there were three abortively born fetuses of hybrid in different degree of growth.
External observation and comparison of osteological examinations on the calf,
the fetuses and parents species cleared that the calf was an offspring of theabove two species. Situation of the pool and relation between the motherdolphin and males of variety of species, and the process of growing and deathof the particular individual were studied.
INTRODUCTION
The first report on the interspecies hybrid of cetaceans is the three anomalous
dolphins stranded at the Blacksod Bay, Ireland. The specimens were presumed
as hybrids between Tursiops truncatus and Grampus griseus (Fraser, 1940). It is
well known that a hybrid individual was born in Sea Life Park, Hawaii in Oct.
1971 between male Tursiops truncatus and Steno bredanensis (Shallenberger andKing, 1977; Nishiwaki, 1978). The present hybrid was born in Kamogawa Sea
World in 1981. From morphological aspects and also from the situation in thepool, in which the mother and males were living together, we presumed that it wasa hybrid between Tursiops truncatus gilli and Pseudorca crassidens. The senior author
spoke on the hybrid calf while it was living, at Symposium on Cetacean Reproduction, La Jolla, California at the end of 1981. Cromozome study was desired on
the hybrid in the symposium in case if the individual should have died, and wasto be carried out in cooperation with Dr. Deborah S. Duffield of the Portland
State University. The death of the individual was a big disappointment, but
the study became available, undesirablly soon. The senior author carried a fresh
blood sample from the dead calf to USA on his way to Silver Bank, a breeding area of humpback whales. A result of examination has not yet appeared,
morphological aspects of the hybrid calf in comparison with data of other hybrid
fetuses and those of parents species are in this report.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982, 109-121

11
0

NIS
HlWAKI AND TOBAYAMA

F
i
g
.I
. Thehybr
i
d cal
fw
i
th he
rp
a
r
e
n
t
s.

PROC
ESSOF GROWINGAND DEATHOF THE CALF
巴d a
t1
6:
45 on May3
,1
9
8
1
. The f
ir
s
ts
uc
k
ing oft
he
P
a
r
t
u
r
i
t
i
o
n wasobs
e
r
v
new
‑
born calfwas r
e
c
o
c
rn
iz
ed a
f
t
e
rf
iv
e hours. Themotherand t
hecal
fwere
。
s
w
immin
gc
los
el
yf
o
rt
he日r
s
tc
ou
p
l
eofw
e
e
k
s
,andt
h
ec
a
l
fwasgrowingi
nvery
good health,whi
ch had been known a
sf
ema
l
et
i
l
lt
h
e
n. I
nd
i
v
i
dualsw
immingapar
tf
rom mother was i
nc
r
e
as
i
n
gl
y f
r
e
que
n
t a
f
t
e
r 1
9 da
y
s or so. Shes
howedherat
t
r
act
e
dt
of
ood af
t
e
r7
4
・da
y
sands
heb
i
ta hand ofc
a
r
e
t
ake
ra
f
t
er
8
5 da
y
s
,s
o hegavehe
ra smel
t(
N
l
a
l
l
o
t
u
sv
i
l
l
o
s
u
s)
. Shet
o山 he
e
lt
hef
i
s
h byh
e
r
s
nou
tt
i
p,b
iti
tand swalowed i
t
. Th
i
sf
i
r
s
tf
o
o
dt
a
ki
ng was about a mont
h
ea
r
l
iert
h
an t
ha
toft
h
ec
al
v
e
so
fgeneralT
u
r
s
i
o
p
s
. Shehadf
oure
r
r
u
pt
e
dt
e
e
t
h
i
nt
h
ee
ent
r
alpa
r
to
fe
a
c
h up
pe
rt
oothrowatthatt
ime. S
i
n
c
et
he
n,t
h
eca
l
f
co
n
t
i
n
ue
dt
ot
a
kebone
l
e
s
ss
melt
sa吋 mac
ke
r
e
l(
S
c
o
m
b
e
r
j
α
i
j
l
o
n
i
c
u
s
)a
swe
l
la
ss
u
c
k
i
n
mi
lk
,wh
il
es
hewasof
t
e
ns
e
e
nwi
t
hhe
r
・t
o
ngue
‑
t
i
ps
howingoutofmout
h. Number
off
i
s
hi
n
di
c
li
vualt
ak
enbyt
hec
al
fi
neachmonthinaveragepe
rdaywas0
.
1
9kg
i
nAu
g・
，0.
5kgi
nS
e
p
t
.
,1
.3kgi
nDe
c.and1
.
4kgi
nJa
n
,1
9
8
2
.

S
c
i
.Rψ.W
h
a
l
e
sRe
s.
I
n
s
l
.
,
λt
o
.3
4
,1
982

HYBRID BETWEEN TURSIOPS AND PSEUDORCA

111·-· .. - ·-- - ·-·-®

B mm

BB

vz/ /? //7//7771

B B~E?~z-7zz~z7-/~z~z~//~?~/~?~/~/?~/~/~/?~a t z / / ///Z/Z/?/77777 /????/ //Z//72??2zzzzzzzzzzz721

D

Sep.

:\ug.

Oct.

Dec.

,\!Ol\TH E\ 1979

BB@)

z

B

--BB

B

B

B---------B@)

B

B

BB

B

t2Z?ZZVZ77777?7777ZZZ7?Z77 / ?7/ /Z?//ZIZ/ /077 !7077 !J?Z?ZZZVZ/7/?77?/Vll?ZZZ?ZZZJ. :7:.
Ca~e ol KS\\'.57--

BtZ/??Z/?ZZ////ZZ/77;1

D-----1111111 B

B

B

VZ/ZVZ/7/7////d V/VZZZ?Z?ZZ//////771@)

V//////ZZJ

c::::rCase ol KS\Y-58

B

B

•••
Case ol KS\\' ·56

Mar.

Jun.

Apr.

Jui.

MOl\TH I'\ 1980

Fig. 2. Situation of the mother dolphins live together with each male in the pool.
Periods of each males in the mothers' pool.
• Pseudorca crassidens [Z1 Lagenorhynchus obliquidens D Tursiops gilli (immature)
B Witnesses of chasing ® Witnesses of copulation

On the late afternoon of the 273rd days after birth, calf's appetite decreased,
and without serious disorder seen in appearence, she died three days later, Feb.
2, 1982. The sudden death of the calf was a shock to whole Kamogawa Sea Worldand related scientists. Examination after death made it clear that the cause
was acute-pneumonia. Body length was 190 cm and weight was 81.6 kg at its
death.
INCIDENTS OF HYBRID BETWEEN TURSIOPS AND PSEUDORCA

When the two abortive fetuses occurred, it was considered each time that a hybrid
from so divergent parents would never grow normally to reach parturition and was
not a matter of serious report. However, after one successful birth of KSW-57,
Sci. Rep. Whales Res. Inst.,

No. 34, 1982

112

NISHIWAKI AND TOBAYAMATABLE I.

LIST OF HYBRIDS BETWEEN TURSIOPS GILL! AND PSEUDORCACRASS/DENS AND THEIR MOTHER DOLPHINS
Hybrids

Specimen
No.

Sex

Body
lengthin cm

KSW-55
KSW-56
KSW-57
KSW-58

F
M
F
M

74.0
116.0
190.6*
121.5

Date of birthJan. 29 1980
Apr. 30 1981
May 03 1981
Jui. 07 1981

Mother dolphins

Dead born
Dead born
Live born
Dead born

SpeciesName

Body
lengthin cm

Period in
captivity

Tursiops gilli
Tursiops gilli
Tursiops gilli
T ursiops gill i

Slim
Suzii
Slim
Flip

289
284
289
278

10 years
5 years
10 years
10 years* measured at her death on Feb. 02 1982.
TABLE 2.
Species
Pseudorca crassidens
Lagenorhynchus obliquidens
Tursiops gilli

LIST OF MALE DOLPHINS KEPT IN THE POOL
WITH MOTHER DOLPHINS
NameBody length in cm

Period of captivity

Leo
Billy
Ace

409
185
250

10 years
6 years
4 years

another abortive delivery occurred, and the fetus was nearly parturient.
In the pool of Kamogawa Sea World, in which all those incidents of hybrid
occurred, there happened to be no mature male Tursiops, but one Pseudorca, one
Lagenorhynchus and one immature male Tursiops, less than four years old.
Observation on mating behavior in the pool is shown in Fig. 2, in which mark
" B " is chasing behaviors and " M " is copulations. From Fig. 2, we can tellthat mating between the female Tursiops (by the name of Slim) and a male,
Pseudorca (Leo) in August or that in October 1979 delivered abortive fetus KSW-55
74 cmin length, which may have been in mother's womb for about 4 months.
Similarly, mating between female Tursiops (Flip) and Leo in July 1980 delivered
the abortive KSW-58. Again, mating between the third female Tursiops Suzii and
Leo in April 1980 delivered abortive KSW-56. The present specimen KSW-57
was an offspring of mother Slim, her mating with Leo had been seen from April toJune 1980. Other male Lagenorhynchus in the pool was also chasing females, but
his lesser sized body may not have been strong enough, no mating mark of him
is recorded. The only male Tursiops in the pool was a young son of Slim anda male Tursiops, his father died before those incidents. The young Tursiops wasfour years old (fifth year from birth) reaching an age of sexual maturity, heonly showed some chasings.
MORPHOLOGICAL FEATURE OF THE FOUR HYBRID SPECIMENS

To compare the body proportion of the three hybrid fetuses and that of general
T. t. gilli in similar stage of growth, external measurement in the certain parts ofthe body is shown in Table 3, in which values are indicated in parcentage against
the total length. As a reference, measurements from parents species in respecSci. Rep. Whales Res. Inst.,
No. 34, 1982

:--·

?

!;;'<

~

°'~

~

"""'

~~

._

~
v~~

"'°

?

~~

* calf

116.0
1.9
14.6
16.3
16.7
21.0
4.5
62.9
72.4
52.7
21.6
18.7
13.3
6.9
12.5
7.8
15.5
8.2
15.7

73.0
3.4
13.0
16.4
17.1
4.7
58.9
73.9
52.0
28.7
16.4
10.9
6.8
14.3
10.9
21.9
8.9
16.4

-

-

KSW-56M
16.8

T. gilli
M
KSW-57*
F
81.6
190.6
1.4
11.0
13.l
15.0
20.0
3.5
63.4
70.1
46.5
24.1
17.1
12.5
6.3
16.4
8.5
23.6
7.3
15.8

T. gilli
F
15.6
113.0
4.0
13.4
14.2
16.1
26.0
3.5
63.9
70.3
49.5
21.0
18.9
13.4
6.7
15.0
7.7
20.7
8.7
18.0

KSW-58
M
17.2
121.5
1.8
12.7
13.9
15.0
23.8
4.5
61.3
71.3
50.1
19.1
17.4
12.5
5.9
15.2
9.6
17.0
7.9
16.5

T. gille*
M
68.8

188.0
4.3
13.6
20.2
16.5
22.9
3.5
61.7
71.8
48.7
27.4
18.4
13.3
6.4
17.0
8.5
21.0
8.5
15.4

COMPARISON OF FOETAL AND CALF BODY PROPORTION BETWEENTURSIOPS-PSEUDORCA HYBRIDS AND NORMAL T. GILL!.

Specimen No.
KSW-55Sex
F
Body weight in kg.
4.4
Point of measurement
74.0
I. Total body length in cm.
1.8
2. Tip of upper jaw to apex melon
3. Tip of upper jaw to angle of gape
11.5
4. Tip of upper jaw to blowhole
12.9
14.2
5. Tip of upper jaw to center of eye
23.7
6. Tip of upper jaw to anterior insertion of flipper
3.6
7. Center of eye to external auditory meatus
62.2
8. Tip of upper jaw to tip of dorsal fin
9. Tip of upper jaw to center of anus
72.7
51.4
10. Tip of upper jaw to midpoint of umbilicus
18.6
11. Maximum height of body
12. Length of flipper, anterior insertion to tip
17.3
11.9
13. Length of flipper, axilla to tip
6.1
14. Width of flipper, maximum
13.5
15. Length of dorsal fin (base)
9.7
16. Height of dorsal fin
17. Width of flukes, tip to tip
21.6
18. Anterior insertion of tail flukes to notch
10.2
18.9
19. Anterior insertion of tail flukes to tip

TABLE 3.

127.0
3.7
13.7
15.1
17.3
24.8
3.9
68.0
71.4
49.7
23.2
15.2
12.9
6.4
16.6
9.4
19.0
8.0
17.6

T. gilli
F
22.8

bi

--""

Q

~

0

§

t>i

~

lj

>z

~

0

~

§

z
...,

i:zj
i:zj

~

>--3

i:zj

ttl

1--<

~
lj

::r:

"" ~

<.o'"'
co
~

._ ~

~~ ~

"'~ ::i:i
'"'

~~

;;::

~

~

::i:i

~

24.0
13.7
10.l
5.3
10.7
7.0
21.0
5.5
12.9

6.6%
JO.I
9.2
13.9
1.9
49.2
65.5
39.1

-

465

Pseudorca
crassidens
M

272
3.7%
10.7
11.4
12.9
18.9
2.7
57.7
67.3
48.7
46.3
54.8
32.3
16.9
12. I
6.2
15.8
10.1
27.5
8.7
18.0

Tursiops
gilli
F

292.5
3.4%
12.1
11.4
11.6
19.5
4.0
61.9
72.0
45.6
35.9
47.9
32.8
16.1
10.6
5.9
17.4
10.2
21.0
6.8
lG.7

Tursiops
gilli
F

15.2
10.9
5.1
18.3
8.8
20.1
7.4
IG.2

-

283.5
3.0%
10.4
I I.I
12.2
20.3
3.0
60.8
70.4
44.3
39.1
48.0

Tursiops
gilli
F

290
3.8%
10.7
13.8
12.4
19.6
2.7
57.2
70.9
45.2
34.5
43.l
21.0
14.1
10.l
5.2
14.8
8.3
18.3
6.5
14.8

Tursiops
gilli
F

ADULT BODY PROPORTION ON EXTERNAL MEASUREMENT OF A MALE
PSEUDORCA CRASS/DENS AND FIVE FEMALES TURSIOPS GILL!.

Sex
Pint of measurement
I. Total length in cm
2. Tip of upper jaw to apex melon
3. Tip of upper jaw to angle of gape
4. Tip of upper jaw to blow hole
5. Tip of upper jaw to center of eye
6. Tip of upper jaw to anterior insertion of flipper
7. Center of eye to extermal auditory meatus
8. Tip of upper jaw to tip of dorsal fin
9. Central notch of tail flukes to center of anus
10. Central notch of tail flukes to midpoint of umblicus
11. Girth on anterior insertion of flipper
12. Girth on anterior insertion of dorsal fin (maximum)
16. Maximum height of body
17. Length of flipper, anterior insertion to tip (curved)
18. Length of flipper, anterior insertion to tip (straight)
19. Width of flipper, maximum
20. Length of dorsal fin (base)
21. Height of dorsal fin
22. Total spread of tail flukes
23. Anterior insertion of tail flukes to notch
24. Anterior insertion of tail flukes to tip

Species

TABLE 4.

316
3.7%
JO.I
J0.6
11.9
20.9
3.0
59.5
65.2
44.9
38.3
40.8
23.7
17.0
15.7
5.7
19.0
9.2
25.9
8.5
18.2

Tursiops
gilli
F

>

~~

td

0

>--J

zl>j

>-<

>
;;:::

::;:;

t.n
21

z

-::;:

S八 N D PSEUDORCA
N TURS!OPTWEE！ YBRTD BE
下

5
1
1

s
n
e
d
i
s
s
a
r
.c
tmalePlueonead,specimensar
her
et
g
o
hown tcsso[body ar
t
c par
v
i
t
nTable4.
,i
i
l
l
i
.g
.t
so[T
emale
iveadultf
andf
eapex
h
ot
awt
po[upperj
i
et
h
y什omt
,namele3
lnPoint2ofTab
】 i
er
e
Ass
t of
ha
han t
rt
e
t
r
ho
ys
l
ent
sappar
id specimensi
he hybre beak ort
h
n,t
o
l
o[me
i.
l
l
i
.g
.t
normalT‑leapeeimensar
lborns
l
i
t
es
e
hr
fand other t
id ealr
he hyb
ro[t
u
o
ol
ly c
>c
B:
r
a
l
i
m
i
sofs
e
v
al
ngc
vi
i
sandl
e
s
etu
if
l
l
i
.g
.t
hatofnormalT
han t
rt
ke
ogetherdar
t
f
l
a
e
e
h
t
n
a
h
t
r
e
k
r
a
d
l
l
i
t
s
e
r
a
8
5
d
n
a
6
5
,
5
5
‑
W
. Speeimen KShn growtage its
KSW‑57.

3

5
.
s
r
e
p
p
i
l
ff
eo
p
ha
. S
.3
g
i
F
.
i
l
/
Sgi
J
/
o
tT1川 idul
I; A).
KSW‑55
s(
u
t
e
o
mf
0c
.
4
: 7
3
.
)
7
KSW・5
f(
l
a
ngc
i
iv
;L
5
,
t.
s
n
I
s.
sRe
e
l
a
h
/
I
.J
J
j
.Re
i
Sc
982
.3ι1
o
λr

.
s
1
e
d
i
s
s
a
r
ac
c
r
o
d
u
e
tPs
l
; Adu
2
.
)
6
5
.‑
KSV
s(
u
et
o
mf
0c
.
6
1
4: 1
)
.
8
5
KSW‑
s(
u
t
e
o
.5cmf
21
6: 1

.._ ~\c "'~-=...~ ;>;.,, ~

"
~~

~

~

!:I:)

?:

*

Upper
Lower

c

I

v
I

I

7
5
2

I

7
5
2

L

17
17

10
24
52
16
16
66
R

II

74.0
7

I
II
III
IV

D
L
Ca
Sum
Left Right
Left Right
Sum

Number is equal in left and right side.

Phalangeal formula

Dental formula

Body length
Vertebral formula

KSW-55

I

I

116.0
7
II
11
25
54
15 16
15 16
62
L
R
2
2
8
8
6
6
3
3

KSW-56
190.6
7
12
13
25
57
17 17
17 17
68
L
R
2
2
9
9
7
7
4
4
3
3

KSW-57

L
2
8
6
4
2

15
15

25
55
16
16
62
R
2
8
6
4
2

11

121.5
7
12

KSW-58

7
14
15
29
65
20-25*
20-25*
80-100*2
97
42

Tursiops
gilli

7
10
10
23
50
8-11 *
8-11*
32-44
*
2
8
6
4
2

Pseudorca
crassidens

VERTEBRAL, DENTAL AND PHALANGEAL FORMULAE OF THE HYBRIDS BETWEEN TURSIOPS AND PSEUDORCACOMPARED WITH THOSE OF STANDARD FORMULAE OF TURSIOPS GILL! AND PSEUDORCA CRASSIDENS.

Specimen

TABLE 5.

>-

~

;;;

>-

t:d

0

>-:l

z>-u

c>-

z

u.;
::r:
......
:-2

C"l

--

HYBRID BETWEEN TURSIOPS AND PSEUDORCA

117

Osteological X-ray survey was done on the hybrid fetuses. Naturally, there
are no big variation in the standard phalangeal formulae between adult Tursiops
and Pseudorca, however, there are considerable varieties in the number of pharanges
in KSW 55 and 56, but in 58. Varieties may because of preparturient stages.
Specimen KSW-58, 128 cm in length, has the same phalangeal formula as in thestandard Pseudorca. So, if KSW-55 and 56 had lived longer, they would growone more finger bone in II and III. Although the phalangeal formulae donot suggest a clear trace to Pseudorca, the external shape of flippers are showing
more visible characteristics of Pseudorca. Shape of flipper in Pseudorca has distinct
peculiarity among all cetacean species. As seen in Fig. 3, all the fetuses have
similar shape of flippers which is descended from father. On the other handthe calf specimen KSW-57 has same numbers as in T. t. gilli in pharange I, II,
III, and IV except V which shows one more finger bone than in general Tursiops.
But shape of the flippers is more similar to the flippers in the father species of
Pseudorca.
In X-ray examination, number of teeth is 15-17 in each fetus specimen.
The senior author spoke in the Symposium in La Jolla that the dental number inthe calf KSW-57 was 15 in counting on the clear photographs, and that the calf
would grow one or two more teeth according to its growth. Actual counting
at its death cleared that the dental number was 17. The dental formulae of thosehybrid specimens are just inbetween Tursiops and Pseudorca.
In the vertebral formulae, thoracic, lumber and caudal, of the all hybrid
specimens are altogether just inbetween the two species. Table 5 shows all
those number and formulae of bones and teeth with the standard of adult T. t. gilli
and Pseudorca. Tables may explain more clearly than words that there is little
doubt that all the four specimens are hybrid between the two species.
SKULL MEASUREMENT OF THE HYBRID CALF

The skull and other bones of the hybrid calf was made to be skeletal specimens
and preserved in Kamogawa Sea World. The measurement values on the skull
are in Table 6. Photographs of them are in Fig. 4 and 5. The tympanic bones
are in Fig. 6. Table 6. also indicates that the calf is inbetween T. t. gilli and
Pseudorca in values.
EXPECTATION IN FUTURE

Among land animals, the first interspecies hybrids, between the lion and the tiger
for an example, must have been born accidentally, however, it became somehow
intentional experiments in some zoos. "The liger" or "the tyon" by intentional
hybridization has been seen in many places. But those hybrid animals havenever had following generations. The fact is considered as a proof that each parent
species is independent.
All the four specimens in this report were born accidentally. In this rare
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

1
1
8

:
'
¥I
SHl
¥VAKI /¥ND TOBAYAJ¥［
八

F
i
g.4
. S
k
u
l
l of the Hybridbetween T
1
川 i
o
/
1
sandl
'
s
e
u
d
u
日向 T
1
1
r
s
i
o
p
sg
i
l
l
iandl
うe
1
1
‑
d
o
r
c
oc
r
a
s
s
i
d
e
u
s
.
Top t
obottom: Dorsaland l
a
t
e
r
a
lv
i
e
w
.
Le
f
t
,Hybrid(KSW・5
7)between ア1
1
r
s
i
o
p
sand Ps
e
u
d
o
r
c
o
.
Middle, T
1
1
r
s
i
o
/
1
sg
i
l
l
i(
1
3
.L
.2
70c
m
)
.
R
ight
,l
'
s
印 d
o
r
c
oc
r
a
s
s
i
d
e
n
s(
1
3
.I
. 41
5cm)
.

c
a
s
e
,e
x
am
i
n
a
t
ionontheirc
hromosomenumber,b
l
o
o
dt
y
p
e,e
l
e
c
t
r
o
ph
o
r
e
t
i
cpa
t
t
e
r
n
ofp
r
o
t
e
i
n(
an
a
l
y
si
so
fb
l
o
o
dcomponent)etc.weredesired,butonlyachromosome
s
tudyi
sgo
i
ngoni
nc
o
o
p
e
r
a
t
i
o
nbyD
r
.D
u
f
f
i
e
l
d
. Inf
u
tu
re
,b
a
s
e
dont
h
o
s
eg
e
n
e
‑
t
ics
tu
d
ie
s
, we mi
ghtr
e
a
ch t
oap
o
intt
h
a
ti
ft
he
r
ea
r
ep
o
s
s
i
b
i
l
i
t
i
e
sofa t
hi
r
d
S
c
i
.Rψ
.IVlwl
e
sRe
s
.I
n
s
t
.
,

N
o
.3
4
,1
982

！ D PSELDORCA＼：
ET¥¥'F.EN TCRSIOl'S八！YBRTDB
下

9
1
1

iand
l
l
sgi
1
/
o
川 i
, T1
a
c
r
o
d
u
e
s
'
戸sandfo、't'('t1 アJ川 i
db引
i
・
1
yb
l
eI
h
. Mandibleof t
.5
g
i
F
.
s
n
e
d
i
;
s
a
r
ac
c
r
o
d
u
e
Ps
l view.
aretal and lasobottom: Dor
Top c
.
a
c
r
o
d
u
c
sandPs
1
j
o
i
s
r
1
1
en T
e
tw
KSW‑57)be, Hybrid (
t
f
e
L
.
70cm)
..2
.I
3
1
i(
l
l
i
sg
p
o
i
s
,Tur
e
l
dd
Mi
5cm).
.41
.L
3
1
s(
u
e
d
i
s
a口百s
c
r
o
d
u
e
t,Ps
Righ

.
s
e
i
c
pe
ans
e
c
a
t
e
rc
e
l
l
ma
dofs
i
onhybr
i
t
a
r
gene
he
ot
nt
e
v
i
swereg
e
r
a
ec
l
b
a
l
i
lava
,al
d
l
r
o
w
fKamogawaSea・
eo
s
a
hec
In t
,
t
a
e
sgr
rgrowingwa
rhe
o
onf
ti
a
t
c
e
p
x
. As e
d
o
o
l
tb
n
e
g
r
e
v
i
od
hs
t
i
fborn w
cal
s
a
d
e
s
o
n
g
a
i
d
s
a
w
h
t
a
e
d
f
o
e
s
u
a
C
.
s
s
e
n
d
a
s
d
n
a
t
n
e
m
t
n
i
o
p
p
a
s
i
d
a
s
a
w
h
t
a
e
d
r
e
h
,
.
t
s
n
.I
s
sRe
e
l
a
i
/
'
1
.1
J
j
.Re
i
c
S
982
,1
4
.3
o
N

1
2
0

NISHIWAKlAND T Oi
lAYAMA. ShapeofTympano‑pcrioticbone
s
.
l
'i
g.G
I
. Hy
b
r
i
d c alf~ KSW・5
7
,l
e
f
ts
i
d
e.
i
川 i
o
/
J
sg
i
l
l
i
,I
l
.L
. 270cm, l
e
f
ts
i
d
e
.
2
. T
e
u
d
o
r
c
ac
r
a
s
s
‑
i
d
e
n
s
, B.
し. 41
5cm, l
e
f
ts
i
d
e
.
3
. Ps

a
c
u
t
e‑
pneumonia, butt
herer
emainedadoubtt
ha
twh
e
t
h
e
rdeathwasi
n
d
i
r
e
c
t
l
y
o
rdi
r
e
c
t
l
yc
a
u
s
e
d byherabnormalbloodfromparen
t
ss
pe
ci
e
ss
od
i
f
f
e
r
e
n
te
a
c
h
巴n
t
i
o
ni
nc
u
l
t
i
v
a
t
i
ngi
n
t
e
r
s
p
e
c
i
e
‑
hybr
i
da
n
i
m
a
l
s
. How
e
v
e
r
,
o
t
h
e
r
. ¥
1
Vehav
enoi
n
t
i
nl
im
i
t
e
dnumber ofpoolsinanoceanariumoraquarium,inwh
ichmale
sand
f
e
m
a
l
e
sofv
a
r
i
e
t
yo
fs
p
e
c
i
e
sa
r
ek
e
p
tt
o
g
e
t
he
r
,a
c
c
id
e
n
t
a
li
n
t
e
r
s
pec
i
e
shybr
i
db
i
r
t
h
fwe would haves
uch c
a
s
e
saga
i
n,wewi
l
lgi
ve
wi
l
lbe s
e
en a
g
a
i
ni
nf
u
r
u
r
e
. I
mor
ecar
e
st
os
a
v
eca
l
v
e
s.
ACKNOWLEDGMENT
Thiss
t
u
d
ys
t
a
r
t
e
d from unexpectedb
i
r
t
hoft
h
ehyb
r
i
dcal
f
. I
nKamogawaSea
World,generouscare wasg
i
v
en t
ot
hecal
fa
f
t
e
ri
t
sbi
1t
h byv
e
t
e
r
ina
r
i
a
nsand
car
e
t
a
ke
r
s
. Owingt
ot
h
ehel
pbyt
hos
enumbe
rofp
e
o
p
l
ea
t
t
endedtothedolphin
p
o
o
l
,i
nob
s
e
r
v
a
ti
o
n
,r
e
c
o
r
d
ingand ph
o
t
o
g
r
a
phst
ak
enands
oo
n
,t
hi
ss
t
udywas
po
s
s
i
b
le
. Wearedeepl
yi
n
d
e
b
t
e
dt
o al
lt
ho
s
epeople and pa
r
t
i
c
ul
ar
l
yt
o Mr.
Y
o
s
h
i
a
k
iMaedaofKamogawaSeavVorlcl,whohe
l
p
e
dusi
nc
ol
l
e
c
t
i
n
gdat
aand
t
a
k
i
n
gs
ku
l
lphotographs
.

Sc
i
.Re
/
J
.Whal
e
sRe
s
.I
n
s
t.
,

N
o
.34
,1982

HYBRID BETWEEN TURSIOPS AND PSEUDORCA

121

TABLE 6. SKULL MEASUREMENTS OF THE CALF HYBRID BETWEENTURSIOPS AND PSEUDORCA COMPARED WITH ADULTS TURSI OPSGILLI AND PSEUDORCA CRASSIDENS
Specimen
Sex
Body length in cm.
Point of measurement
Condylobasal length
Length of rostrum"Width of rostrum at base\'\lidth of rostrum at midlength
Length of premaxillae, L.

R.
Maximum width of premaxillae
1\1aximum breadth of superior nares
Tip rostrum to anterior marginof superior nares
Tip rostrum to center of eye
Preorbital width
Postorbital width
Parietal width
Length of temporal fossae, L.
Depth of temporal forssae, L.
Length of maxillary toothrow, L.

R.
Length of mandibular rami, L.
R.
Breadth across mandibular condyles
Length of symphsis
Coronoid height of ramus, L.
R.
Length of mandibular toothrow, L.

R.

KSW-57
F
190.6

T. gilliF
270.0

P. crassidens
M
415.0

422mm (100%)208(49.3)
117(27.7)
79(18. 7)297(70.4)
318(75.4)
85(20.1)
58(13. 7)258(61.1)

505mm (100%)(55.0)
278(28.1)
142(18.8)
95373(73.9)(78.0)
394(18.8)
95(11.3)
57
328(65.0)

624mm (100%)(47.1)
294(36.1)
225(29.2)
182(68.8)
429(71.8)
448(24.2)
151(13.8)
86(58.2)
363

259
190
214
191
105
79
180
182
351
353
203
59
82
84
184
189

345
246
273
202
112
86
236
233
432
432
268
67
89
88
238
238

(61.4)(45.0)(50. 7)(75.3)(24.9)(18.7)(42. 7)(43.1)(83.2)(83.6)(48.1)(14.0)(19.4)(19.9)(43.6)(44.8)(68.3)(48.7)(54.1)(40.0)(22.2)(17.0)(46.7)(46.1)(85.5)(85.5)(53.1)(13.3)(17.6)(17.4)(47.1)(47.1)

340
332
363
262
196
143
232
236
489
489
356
87
133
135
243
243

(54.5)(53.2)(58.2)(42.0)(31.4)(22.9)(37.2)(37.8)(78.4)(78.4)(57.1)(13.9)(21.3)(21.6)(38.9)(38.9)REFERENCES
FRASER, F. C., 1940. Three anomalous dolphins from Blacksod Bay, Ireland. Proc. Roy. Irish Acad., 45(Sect. B): 413-462.
HmosAKI, Y., M. HoNDA and T. KINuTA., 1981. On the three Hybrids between Tursiops truncatus andGrampus griseus. (1) Their parents and external measurements. ]. Jap. Ass. Z,ool. Gardens andAquariums, 23(2): 46-48. (in Japanese).
NISHIWAKI, M., 1978. Remarks on the Systematics of Cetacea. New Result of Cetacean and Pinniped Research.
Acad. See. USSR, Severtsov Memorial Inst., Evolutional Morpholo. and Ecolo. Animals, Nauka, 9-19
pp. (in Russian).
NuMACHI, K., 1970. Lactate and mulate dehydrogenase isozyme patterns in fish and marine mammals.
Bull. Jap. Soc. Sci. Fish., 36(10): 1067-1077.
SEZAKI, K., Y. HmosAKI, S. WATABE and K. HASHIMOTO, 1981. Determination of hybridity in a newborn
cetacean by analyzing blood components. ]. Jap. Ass. Z,ool. Gardens and Aquariums, 2(23): 29-31.
(in Japanese).
SHALLENBERGER, E.W. and I. KING, 1977. Dolphin birth at Sea Life Park, "Breeding dolphins. Present status,suggestions/or the Future". (ed., S. M. Ridgway and K. Benirschke). U.S. Marine Mammal Commission,
Washington, 77-84 pp.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD HABITS OF LARGHA SEAL PUPSIN THE PACK ICE AREA
HIDEHIRO KATO
Whales Research Institute, Tokyo
ABSTRACTThe stomach contents from largha seal (ice-breeding harbor seals) collectedin the pack ice areas off the eastern Hokkaido and the east coast of Sakhalin
were examined. Analyses revealed that fishes, cephalopods, euphausiids anddecapods were principal foods. Among them, fishes were primary foods as wellas Theragra chalcogramma, secondary cephalopods as well as squids and octopus.
The result of stomach contents analyses suggested that this seal used manyorganisms of wide range as foods in the pack ice areas.
Although there are no definite trends of changes in foods by age among
the older seals, specialized feeding on euphausiids was found in newly weaned
pups. Euphausiids appeare to be not only available but also indispensable
foods for pups after the weaning, this would be evolved feeding adapted tothe pack ice condition.
INTRODUCTION
Ice-breeding harbor seals (largha seal), Phoca largha, is relatively frequent species in
the pack ice areas off the Western Hokkaido and Southern Okhotsk Sea occurring inearly spring (Inukai, 1942; Wilke, 1954; Tikhomirov, 1968; Naito and Nishiwaki,
1972; Naito and Konno, 1980). In these days, the informations related to the reproduction and distribution have been reported (Naito and Nishiwaki, 1972; Naito
and Konno, 1980). However, no studies on food of this species have been madeexcept the fragmental informations.
Fay (1974) reviewed the relations between sea ice and marine mammals, andhe pointed out that one of the roles of sea ice for pagophilic seals was food supply.
In this connection, the investigations on food of largha seals would be meaningful
so as to consider the relations between sea ice and this seal.
In the present study, stomach contents of largha seals collected in the open
pack ice area of the east coast of Sakhalin and Nemuro Strait were examined.
The sampling was carried out in the early to mid spring of post-breeding season
for largha seals. Then, changes in food with age, especially for pups after the
weaninng, were examined.
MATERIALS AND METHODS

Sampling areas and seasons
During this study, some parts of stomachs were collected from the carcase
Sci. Rep. Whales Res. Inst.,
No. 34, 1982, 123-136

KATO

124

I

200m

(

.f

\/31
j,

•
6/1

5130
5129
5/27
5/28

~5/26

OKHOTSK
SEA

r

50°N

,~)

\
(~

0.

45°N

ro

NE MUROSTRAIT~·

145°E•;sealing

150°E
Location• : sealing Area
Fig. I.

(1975, 5/1-6/4)(1974. 3/25-5/12)

Catch locations of the largha seal.
Sci. Rep. Whales Res. Inst.,
No. 31:, 1982

FOOD OF LARGHA SEAL PUPS

125

accumulated in Kanazawa Fur Co., Nemuro, Hokkaido. Those seals were hunted
in the pack ice area ofNemuro Strait during 25 March and 12 May 1974. Others
were obtained in the pack ice area off the east of Sakhalin from the operation of
Dairin maru No. 5 (75.00 gross ton.), which is floating factory sealing type, in theearly spring during 4 March and 2 July 1975 with chasing to" front" of pack ice
area. Both of sampling areas are shown in Fig. 1.

Stomach contents and data collection
All seals used in the present study were killed by shot guns or rifles. Initially,
for the convenience of sampling stomach contents, all stomachs which were supposed
to contain foods were reserved, but empty stomachs were not sampled after checkingof contents. The stomachs were removed from the carcase bound at acrdiac orficeand pylorus with strings to avoid flowing out of contents. Sampled stomachs
were reserved in 20% of formalin solution. The details of samples are summarizedin Table 1. At the same time, body length and sex data follow on the all samples
in both areas.
For the ageing carnine teeth were taken from under jaws, the growth layers
were counted based on the same methods as reported in Naito and Nishiwaki(1972). Among the Sakhalion samples, 43 animals with stomach contents wereaged by above methods, however, no ageing materials were collected in Nemuro
Strait.
Identification offood species
Stomach contents were examined at the laboratory after the sampling works.
If the contents are found under the very fresh condition in the stomach, food species
was identified based on the outside characters, whereas in the case of contents
heavily digested identification was aided by several collections of fish skelton, otolithand beak of cephalopods obtained in the adjacent waters of Hokkaido, as well as
following publications; Hotta (1961), Matsubara (1955) and Watanabe (1958).
However, I was not able to succeed in satisfactorily identifying most of squids
and octopus which consisted of only beak.

TABLE 1.

SAMPLING SAMMARY ON STOMACHS OF LARGHA SEALSIN THE PRESENT STUDY

Sampling Area & periods
Nemuro Strait
25 March-9 May 1974
15 March-15 May 1970
Sakhalin
I May-4 July 1975

No. stomach
with age andlength data

No. stomach
with length data

47
26*

26*

47
26*

43

43

18

No. stomach
examined* Samples collected by Mr T. Itoh in 1970, these were used in only examination of changes in food withage.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

126

KATO

Index of food composition
Several problems have been devoted in index of stomach contents analysis,
therefore following two methods similar to the indices used in Spalding (1964)
were considered for the present study.
Weight index: The stomach contents were weighed in each 5 g scale under
the wet condition separately by food species. Small amounts of heavily digested
materials less than 5 g which should not be regarded as food were recorded as"trace" in weight. Weights of each food species in each stomach are summed
and index was represented as a percentage of summed weight against combined
weight of each item of the total stomachs examined.
Occurrence index: Regardless of number of individuals, if at least one foodspecies occurred in a stomach, this species was recorded as " one occurrence ".
This index is expressed as a percentage of number of occurrence against the
total number of stomach examined.
STOMACH CONTENTS

As shown in Table 2, the analyses of largha seal stomach contents revealed thatfishes, cephalopods were the primary food in the Nemuro Strait and waters off theeast coast of Sakhalin.
Among the Nemuro strait samples, fishes was the primary food item for largha
seals, comprising 78.9% and 91. 7% in occurrence and weight indices, respectively.
Among them, Theragra chalcogramma was the dominant species at 48.9% of occurence
index and 47.0% of weight index, Pleuronectidae and Hypomesus Japonicus seemed
to be also major species.
Cephalopods was secondary item, comprising 42.6% and 6.3% in occurrence
and weight indices, respectively. It should be taken in account of under-representation in weight index of this item, because the remainder of cephalopods instomachs usually consisted of beaks, eye lenses and pens. Concerning the identification, most of cephalopods were found under the heavily digested condition,
it was considerably difficult, therefore, to identify species among the squid's beaks,
although octopus was identified to be Paraoctopus defleini by the chracteristic theirbeaks.
Euphausiids including Thysanoessa inermis were found in the ten stomachs
comprising 21.3% and 2.0% in occurrence and weight indices, respectively. There
were clearly two types in occurrence of this item; one case was very small amountof fragments of euphausiids occurred, the other was large amounts of euphausiids
occupied the most portions of the stomach contents. The latter type feeding
seemed to be more frequent in younger animals. This will be examined in thelatter chapter.
The results of stomach contents analyses in the Sakhalin samples, were almost
similar to that in the Nemuro samples. T. chalcogramma was also the most important food far from the others, comprising 72.1 % and 82.5% in occurrence andweight indices, respectively. Clupea pallasi, which is abundant species in sea ice
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF LARGHA SEAL PUPSTABLE 2.

127

FOOD COMPOSITIONS OF LARGHA SEALS IN NEMURO STRAITAND OFF THE EAST COAST OF SAKHALIN
Nemuro Strait n=47
Occurrence
index

Food species

Number
Occurred
Fishes
Theragra chalcogramma
Pleuronectidae
Eleginus gracilis
Pleurogrammus sp.
Hypomesus japonocus
Osmerus dentex
Sebastolobus macrochir
Sebastes schleigeli
Ammodytes sp.
Aptocyclus ventricosus
Gymnocanthus sp.
Gadus macrocephaliusJ.,ycogramma zesta
Clupea pallasi
Cottidae
Unidentified fish
Cephalopods
Octopus, Paraoctopus dojleini
SquidsEuphausiids
Thysanoessa inermis
T. raschii
Decapods
Pandalus borealis
Chionoecetes opitio

37
23
10
2
5
2
2

2
20
3
17
10
2

Sakhalin n = 43

Weight index

%

g

%

78.9
48.9
21.3
4.3
2.1
10.6
4.3
4.3
2.1
2.1
2.1
2.1
2.1
2.1

24,495
12,645
1,020
435
70
4,180
465
1,735
300
10
300
950
310
2,140

91.7
47.0
3.8
1.6
0.3
15.5
1.7
6.5

4.3
42.6
6.4
36.2
21.3
4.3

100
1,710
225
1,485
530
390

Occurrence
index
Number
Occurred31
23
32

Weight index

%

g

%

72.1
53.5
2.3
7.0
4.7

13,560
7,710
trace
1,585
1,460

82.5
46.9
0.0
9.6
8.9

2.3

70

0.4

14.0
4.7
11.6
34.9
27.9
7.0
27.9
9.3
11.6
16.3
7.0
2.3

2,665
70
trace
720
90
630
2,035
290
1,505
130
130
trsce

16.2
0.4
0.0
4.3
0.2
3.8
12.4
1.8
9.2
0.7
0.7
0.0

1.1

0.0
I. I
3.5
1.2
8.0

0.4
6.3
0.8
5.5
2.0
1.5

6
2
5
15
12
3
12
4
5
7
3

area in Okhotsk Sea, was ranked in second species among fishes.
It was notable, among the item of cephalopods, that octopus were more
frequent than squids in contrast with that in Nemuro samples.
Euphausiids revealed two species, T. inermis and T. raschii indicating almost
same occurrence. Two species of decapods, Pandalus borealis and Chionoecetes
opitio were found, but these were minor item as foods for largha seals.
The analyses show that T. chalcogramma are heavily used as a most importantfood for largha seals in the early spring of both areas. This fish is also importantfoods for land-breeding harbor seal, P. richardi, in the north western region of North
Pacific (Im er and Sarber, 194 7; Wilke, 1954; Kenyon, 1965 ), furthermore Pitcher(1977) found that this fish was most dominant prey for P. richardi throughout
the year in Prince William Sound.
Table 3 shows the fishing yields statistics in the Nemuro Strait during MarchSci. Rep. Whales Res. Inst.,
No. 34, 1982

128

KATO
TABLE 3.

FISHING YIELD STATISTICS FOR 1973 MARCH-MAY FROMNEMURO STRAIT AND FOR 1975 MAY FROMANIVA AND TERPENIYA BAY
Nemuro Strait
March-May, 1973

Species

tons
Gadus macrocephalus
Theragra chalcogramma
Eleginus gracilis
Pleurogrammus sp.
Clupea pallasi
Pleuronec tidae
Hypomesus sp.
Sebastolobus sp.
Other fishes
OctopusSquid
ShrimpOthers(%)

4,455.3 (13.3)
18,029.1 (55.8)
773.6 (0.2)
5.1 (0.0)
1,872.1 (5.6)
177.5 (0.5)
8,269.5 (24.6)
10.0 (0.0)
1.5 (0.0)

Aniva and Terpeniya Bay
May, 1975
tons

(%)

2.2 (0.1)
1,425.3 (81.5)
17.9 (1.0)
0.1 (0.0)
0.1 (0.0)
205.4 (11.4)
0.1 (0.0)

0.4 (0.0)
9.0 (0.5)
98.5 (5.5)

and May 1973 and in the waters off the east coast of Sakhalin in May 1975 (Hokkaido suisanbu, 1974; 1976), approximately coinciding with the sampling seasons
and areas in the present study. The catch of T. chalcogramma was also dominant
far from those of others. Although there are still several problems, assuming thefisheries catch shows fish-fauna in the both of two waters, largha seals feed primarily on abundant species. This suggests no preference on species if the organisms are available size and behavior for seals as foods. Generally speaking in
the trends of stomach contents, most of food species which occurs in stomachs arebasically in the category of coastal species in this season inhabiting from the surface
to the bottom, moreover, schooling fishes such as T. chalcogramma, Hypomesus japonocus
contributed as major food species for this seal. The only few informations of fishes,
cephalopods and others are available in the ice areas, but largha seals can possibly
use the most of nekton inhabiting ice areas as their foods.
CHANGES IN FOOD WITH AGE
Spalding (1964) pointed out an increase in food size and suggested changes infood species with age in northern fur seals, Callorhinus ursinus. Moreover specialized
feeding habits of newly weaned pups in P. richardi has been reported by Havinga(1933), Fisher (1952), Bigg (1973) and Pitcher (1977). Therefore, substantialchanges in food with age would be expected in the samples of the present study.
For the convenience of this examination, " growth stage " which was classified
into four categories, pups, youngs, maturings and adults, based on primarily ages
was adopted instead of age classes due to small sample size. Among the samples ofno age data, however, growth stages were classified tentatively by their bodylength based on age-length relations in Tikhomilov (1964) and Naito andSci. Rep. Whales Res. Inst.,
No. 34, 1982

129

FOOD OF LARGHA SEAL PUPS

Nishiwaki (1972).

As a result, following criteria were used in this examination:
Body length (cm)

Stage

Age

Pups
YoungsMaturings
Adults

0
1-2
3-4

Male

Femaledistinguishable from other stages
-130
-127
131-145
128-141
146142-

5-

The 26 stomach samples with age data obtained in Nemuro Strait in 1970 wereadded to the present study examined in previous section, then the total of 116 stomachs were available in this examination.

Food compositions
Food compositions in each growth stage are indicated in Table 4.
Pups: 16 stomachs were examined in this stage, revealing fishes, cephalopods, euphausiids and decapods. Among them, euphausiids are the dominant
TABLE 4.

COMPOSITION OF FOOD ITEMS IN RELATION TO THE GROWTH
STAGE IN HARBOUR SEAL

Food items
Fishes
Theragra chalcogramma
Clupea pallasi
Pleuronectidae
Eleginus gracilis
Pleurogrammus sp.
Hypomesus japonicus
Osmerus dentex
Sebastolobus macrochiorSebastes schleigeli
Sebastes sp.
Ammoqytes sp.
Aptocyclus ventricosus
Gymnocanthus sp.
Lycogramma zesta
Unidentified fish
Cephalopods
Octopus
Squid
Euphausiids
Thysanoessa inermis
T~ysanoessa raschii
Decapods
Panda/us borealis
Chionoecetes opitio

Pups
Oc.%

N=16
W.%

Young
Oc.%

N=35
W.%

18.8
6.3

1.0
0.2

6.3

0.0

74.3
34.3
8.6
8.6
11.4

90.9
36.4
3.5
9.4
4.5

6.3
6.3

0.8
0.8

6.3
81.3
25.0
31.3
12.5
6.3

0.8
95.5
24.0
67.8
2.7
1.2

Oc. % =percentages of frequency of occurrence
W. % =Percentages of weight composition
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

8.6
5.7
8.6

18.7
8.9
7.8

2.9

0.1

5.7
54.2
22.9
31.4
25.7

1.6
6.7
0.2
6.5
2.4

Maturing N = 16
Oc.%
W.%
75.0
56.3
6.3
31.3

88.7
58.7
0.7
8.7

6.3

0.9

12.5

19.7

75.0
25.0
50.0
18.8

9.6
4.7
4.9
1.7

Adult
Oc.%

N=49
W.%

91.8
65.3
6.1
12.2
4.1
2.0
2.1
6.1
4.1
4.1
8.2

95.8
53.7
7.2
3.5
8.2
0.2
1.6
1.7
0.4
3.7
4.4

4.1
6.1
2.0
2.0
50.0
30.6
24.5
6.1

1.3
1.0
6.9
1.0
4.0
1.2
2.8
0.0

12.2

0.2

2.0

0.0

130

TO
KA

s
i
1
1
1
r
e
1
1
si
a
s
e
1
a
s
，
sofpupscon凶 ningηり
t
n
e
t
n
o
. Stomach c
.2
g
i
F

‑
e
,r
s
e
ic
d
n
ti
gh
e and wei
nc
e
r
r
cu
c
no
5% i
.3% and 95.
1
8
s(
e
ic
d
n
hi
n bot
em i
t
i
e
l
b
a
t
o
n
s
a
w
t
I
.
m
e
t
i
s
i
h
t
n
i
d
e
i
f
i
t
n
e
d
i
e
r
e
iw
i
l
z
c
s
a
.r
sand T
i
m
r
e
n
.i
,T
)
y
cl
v
i
t
c
pe
s
ods"
o
ef
ru
ly t
ar
e
l
howing c,s
dsii
uphausyelnd on o
e
sf
6 pup
f1
to
3ou
hat1
t
.
h (T
rhand，日shetheo
ig.2. Ont
nF
howni
ss
ds"a
o
o
alf
t
n
de
han"acci
rt
he
t
a
r
und
o
ef
sewer
he
,andt
e
g
a
t
iss
h
nt
em i
t
ri
opodsweremino
cphal
)andc
ma
am
・
1
g
o
c
l
a
z
l
c
.
y
a
M
7
1
n
i
d
e
t
c
e
l
o
c
h
c
ma
o
t
s
e
n
o
y
l
n
no
i
em
t
yi
r
ima
h was pr
s
e. Fi
g
a
t
iss
h
nt
ei
abl
il
eava
r
chswe
oma
t
: 35s
Young
.
T
,
r
e
v
e
w
o
h
,
s
e
c
i
d
n
i
s
t
h
g
i
e
w
d
n
ea
e
n
陀
r
u
c
c
o
n
i
%
9
.
.3% and 90
4
ng 7
i
is
ompr
c
d
n
a
e
c
n
e
r
r
u
c
c
o
n
i
%
4
.
6
3
d
n
a
%
5
.
4
3
y
l
・don
刊
¥
hO
ss
e
i
c
e
p
ogrammaofdominants
c
l
a
z
l
c
r
e
d
l
o
n
i
t
a
h
t
n
a
h
t
e
u
l
a
v
r
e
w
o
l
y
l
ab
dr
i
ons
】gc
r
i
at
ic
nd
,i
ly
e
iv
ct
e
p
s
e
,r
s
e
ic
nd
ti
gh
wei
s
p
u
p
han
uet
owerval
dl
e
al
e
v
e
sr
d
i
i
uphaus
sofe
e
ic
d
n
rhand,ihetheos. Ont
e
g
a
t
s
s
al
e
houghtwos
t
l
,a
e
g
a
t
iss
h
nt
od"i
o
uef
r
t"t
obeno
emedt
e
cs
r
ea
s
he
geandt
a
t
s
.
s
d
i
si
u
upha
sofe
t
n
geamou
ar
yl
l
e
v
i
at
el
donr
e
f
most
g al
n
ti
a
ic
nd
,i
chs
oma
t
6s
he 1
nt
mi
te
yi
ar
sprim
h wa
s
: Fi
ng
i
r
Matu
y
l
t
n
e
u
q
e
r
f
d
e
r
r
u
c
c
o
s
d
o
p
o
l
a
h
p
e
c
t
a
h
t
e
l
b
a
t
o
n
s
a
w
t
I
.
e
g
a
t
s
s
ou
vi
e
spr
ea
u
ameval
s
.
s
e
g
a
t
hs
owt
lgr
heal
0%)amongt.
75(.8% and
ng 91
i
at
ic
d
n
si
d
o
o
antf
t
mpor
ei
s mor
da
e
but
ri
t
on
he
is
: F
t
l
u
Ad
l
l
swe
i
c
pe esa3st1s
aey. Atl
l
ve
i
ct
pe
s
e
,r
s
e
ic
d
n
eandweighti
enc
r
r
cu
c
no
8% i
95.
e
hre
nt
di
e
r
cur
c
dso
i
i
s
uphau
sofe
gment
e
. Thes
d
自e
i
nt
de
ei
mmawer
a
r
g
o
c
L
a
z
l
.c
sT
a
.
ds
o
o
alf
nt
de
i
c
c
ya
edear
ewer
s
he
,butt
omachs
t
s
od
o
alf
i
ant
ubst
sas
da
e
y us
l
n
e mai
idswers, euphau
e
v
o
ng ab
zi
Summari
r
e
d
l
o
r
e
h
t
o
e
h
t
n
i
d"
o
o
f
l
a
t
n
e
d
i
c
c
a
"
s
a
r
o
n
i
m
s
a
w
m
e
t
i
s
i
h
t
s
a
e
r
, whe
orpups
f
‑
u
a
h
p
u
e
f
o
s
t
n
u
mo
a
e
g
r
a
l
y
l
e
v
i
t
a
l
e
r
n
o
d
e
f
e
g
a
t
s
nyoung
si
l
a
e
ws
e
ghf
ou
h
t
,al
s
e
g
a
t
s
r
the
heo
. Ont
s
npup
dsi
ii
phaus
ngoneu
i
ed
e
df
e
iz
al
ci
e
p
ds
e
st
e
g
g
u
es
s
. The
ds
i
i
s
e
e
r
h
t
r
e
d
l
o
n
i
ms
e
t
i
r
o
j
s ma
da
e
ut
b
i
r
t
on
opodsmuch claphes and csheihand,f
3
・
t
s
n
s.I
sRe
.Whale
.Rψ
i
c
S
982
,1
4
.3
o
λr

FOOD OF LARGHA SEAL PUPS

100

131
r:--:-:1

L..:...:...lEuphausiids
r.n
(!)

Cl

....C1l~D0Decapods

c

Q)

(,)

.... 50(!)

c.
Cephalopods

....

..c
O'l
(!)

~

Fishes

0
100
r.n
(!)

Cl

....C1l
c

Q)
(,)

,_;

'\

~
0

Q)

c.
(!)
(,)

50

c
Q)
....
....

Cephalopods

::I
(,)

u

- -·--a..

0_.-IJ Dec a pods...:::-<..-0 Euphausiids
0

PUPS

YOUNG

MATURING

ADULT( 1 6)(35)( 1 6)(49)

Fig. 3. Changes of food composition in relation to the growth stages in largha seal. upper: weight index, below: occurrence index.

stages. It was notable that the values in both indices of T. chalcogramma seem toincrease with growth stages. Fig. 3 shows changes in foods composition basedon food items with growth stages. These changes were confirmed by the statistical
test in both indices. In the case of weight index, 2-n test utilizing z 2 values was
adopted so as to examine changes between nearest two growth stages. The test
revealed the significant difference between pups and young stages (X 2ca1=26.26>z 2= (0. 05, 3) ), whereas any differences were not detected between the other stages.
For the convenience of statistical test in occurrence index, 2-2 test utilizing z 2
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

132

KATO

v
a
l
u
e
swasadopted. Thet
e
s
tr
e
v
eal
ed s
i
gn
i
f
icantd
i
f
f
e
r
e
n
c
e
s between pupsand
χ
2
叫 1
=
you
ngss
t
a
ge
si
ni
t
emsofeuphaus
i
i
ds (
X
2
c
a
i
=l
3
.
8l>x2(
0
.
0
5
, 1)
)
,f
is
hes （
13.
8
1>x2(
0.
0
5
, 1)
)a吋 cephalopods(
x2
r
a
1
=1
0.
63>x2(
0.
0
5
,1
)
).
Both oftestsc
onfirmedd
i
f
f
e
r
e
n
tfood composition betweenpupsando
t
h
e
r
s
t
a
g
e
s
,t
h
a
ti
s
,pupspreferredeuphaus
i
i
dst
of
i
she
sandcepha
l
opod
s
.

Fo
o
ds
i
z
e
I
tseemst
h
a
tf
o
o
ds
i
z
e probably changed with growth s
t
a
g
e
sw
i
th changesinfoodspecies. However,i
ti
ss
l
i
gh
t
l
yd
i伍 c
u
l
tt
omea
surefoods
i
zed
i
re
c
t
l
yut
i
l
i
z
‑
.c
h
a
l
o
c
o
g
r
ammawasdominantfood s
peci
e
si
nt
hes
t
om‑
i
ng s
t
omachcont
e
nt
s
. T
ach contents examinationoft
hi
ss
e
al
,andoccu
r
re
d ina
l
lgrowth stages. Then,assuming t
hatt
h
i
sf
i
s
hi
st
h
er
e
p
r
e
s
ent
a
t
i
vefooditem,foodsizewas examined.
hi
sf
i
s
h hasveryuniques
hapea
ss
howni
nFig.4,andi
tof
t
e
n
Thes
ubopercl巴 oft
c
o
n
t
ri
b
u
te
dt
ot
hei
de
nt
i
f
i
c
a
ti
onoft
h
i
sf
i
sh i
nt
h
es
t
omach contents. M or
e
o
v
e
r
,

:lc
m
.
F
ig
.4
. S
u
b
o
p
cr
c
l
eo
fηieragraclwlcogrammaf
o
un
di
ns
t
o
m
a
cho
fl
a
r
g
has
e
a
l
s.

"
"
I
'
'川
（ζ2
)

川
、I
l
日
（1
1
=2
2
)
、
:
，

園圃

卑

0

二
d

．．

ー
品
》J

．

¥
b
1
u
r
i
n
g
、（
n
=
S
)

主

E・』圃且τ

~

}
.
20

.
¥du
l
l
>(
n
=105)

J
O

）
｛

1
0

1
5

2
0

~5

.
:
H
I

I
A日
比l
hofMil（）pe
rch1
1111111

F
ig
.5
. S
i
z
ed
i
st
r
i
b
ut
i
o
n
so
fs
u
b
op
e
r
c
l
e
so
f Theragra clwlcogramma f
ou
n
di
nt
h
e
s
t
o
ma
chc
o
n
t
e
n
t
si
ne
a
c
hg
r
o
w
ths
t
a
g
e
.
S
c
i
.Re
p
.WhalesRe
s.I
n
s
t
.
,
λr
o
.3
4
,1982

FOOD OF LARGHA SEAL PUPS133

at the counts of number of individuals, this character appears to be better thanthat of otolith.
The length distributions of undamaged subopercles in each growth stage areshown in Fig. 5. The means and variances (95% confidence limits) of those ineach stage were:pups,
7.00 (mm)youngs,25.09±7.55
maturing, 25.50±5.10
adult,
25.15±6.96
The differences of mean length of subopercles between stages were examined utilizing t-values. The test revealed no significant difference between three older stages.
Yoshida and Kato (1981) examined the relation between length of subopercle andstandard length of T. chalcogramma, following relation was made:y =0.0936 X 0 • 958
where, X=length of fish and Y =length of subopercle.
Utilizing above relation, stnadard length of T. chalcogramma can be reproduced asfollows:
pups
90.35 (mm)youngs 342.51±97.78
maturing 348.36±64.93
adults343.37±89.82
From the above estimations, it is clear that pups fed on smaller size of T.
chalcogramma compared with older animals in other three stages.
Taking account of sizes of other food organisms, T. chalcogramma was in
the largest category of food size in each older three stage. It was notable that all
food species found under the fresh condition retained whole body. These suggest swallowing feeding type rather than gnawing. Therefore, there is nodifference in available food size among the three older stages.
DISCUSSIONAs mentioned previously, sample collections in the present study were carried out
during the post breeding seasons, where is front of sea ice area when sea ice weremelting and retreating toward the north. The chronological reproductive behaviorof largha seal in this period have been reported by Naito and Nishiwaki (1972).
According to their reports, the parturition took place between middle and endof March, moulting of the white coat and weaning occurred 2-3 weeks after birth.
It is also notable in their report that independence of pups from their mothers
occurred suddenly compared with land-breeding harbour seal, suggesting nomother's care of feeding to pups. Although the behavior of pups of early stageof life after weaning is still not known, even for such pups as never experienced
and learned diving and feeding, available food would be only euphausiids whichis stational and smaller organisms in the ice area. Moreover, T. inermis andSci. Rep. Whales Res. Inst.,
No. 31, 1982

134

KATO

T. raschii found in stomachs of pups usually formed patch distribution near thesurface (Ponomareva, 1963 ), these would be also convenient for pups. Furthermore, Naito and Nishiwaki (1Q72) found the decreasing in the thickness of blubber among the after weaning pups compared with suckling animals. If the euphausiids or similar organisms were absent in the pack ice area, most of pups would
not be able to survive in such a critical period above. It appears, therefore, thatthe presence of euphausiids in the area and zone in which newly weaned pups canswim and dive guarantees survival of pups in the early life stage of this species.
Fay (1974) pointed out that one of the major role of sea ice for pagophilic
seals was food supply. In this connection, generally speaking, specialized ice
community of organisms are formed under inner parts of ice floes (McRoy, 1974;
Horner, 1976), and the zoo plankton such as euphausiids which used organisms
above as food are concentrated in the pack ice area (Fukushima and Meguro,1966). Therefore, specialized feeding on euphausiids of pups seems to utilize fully
above phenomena.
However, specialized feeding of pups would be only continued during limited
periods in post breeding season, that is, this feeding may be transitional feeding,until pups can feed on fishes and cephalopods with increasing of feeding experience.
This would be supported by the result of stomach contents of pup collected in latest
periods among the stomach samples from pups, and also would be closely related tothe behavior of sea ice in this season. Moreover, considerably short suckling periodsof this seal reported by Naito and Nishiwaki (1972) possibly related to the specialized feeding on euphausiids of pups. After the specialized feeding in pups, itappears that young seals forage over a larger feeding area with development andincreasing in feeding experience, select a greater number of food species andtake prey of larger size. As a result, throughout their life, largha seals use organisms in very wide range inhabiting the pack ice area.
Finally, the pack ice served not only reproductive grounds but also foodsupply for largha seals, especially in early stage of their life. In other words,
largha seals have evolved feeding habits adapted to the ice condition.
ACKNOWLEDGMENTS

This paper originally consisted some parts of a thesis which was submitted for an
M.A. degree in Fisheries at Hokkaido University. It has been slightly modified
for the present publication.
During the course of above thesis, Drs T. Tsuji ta, S. Mishima, K. Shimazaki,
T. Nishiyama (present, University of Alaska) and H. Ogi of RINPF of Faculty
Fisheries, Hokkaido University made helpful suggestions and gave facilities. Drs
T. Igarashi and A. Kawamura of Hokkaido University also made valuable suggestions in draft of thesis.
I wish to express my thanks to Dr Y. Naito of National Polor Research Institute for his valuable instructions in the treatment of seal's materials and suggestionin making draft. My sincere thanks also are due to Mr T. Itoh of Gifu dental
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

FOOD OF LARGHA SEAL. PUPS

135

college for the permission to use his stomach collections and valuable suggestion.
Dr K. Wada of Kyoto University and member of Marine Mammal ResearchGroup encouraged to develop my thesis.
Finally, I was not able to carry out sample collecting without the co-operationof those mentioned below: Mr K. Shibuta of Shibuta Kaijyu Gyogyo Co. Ltd.,crew of Dairin maru No. 5, and Messrs N. Kanazawa and S. Sasamori of Kanazawa
fur skin Co. Ltd.

REFERENCES
Fay, F. H., 1974. The role of ice ecology of mammals of the Bering Sea. pp. 383-399. In: D. W. Hoodand E.J. Kelly (ed.) Oceanography of the Bering Sea, Inst. Mar. Sci. Univ. Alaska, Fair banks, 623 pp.
Fisher, H. D., 1952. The status of the harbour seal in British Columbia with particular reference to the
Skeena River. Bull. Fish. Res. Board. Can., 93: 1-58.
Fukushima, H. and H. Meguro, 1966. The plankton ice as basic factor of the primary production in the
Antarctic Ocean. Antarctic Res., 27: 99-101.
Harner, R. A., 1976. Sea ice organism. Oceanogr. Mar. Biol. Ann. Rev., 14: 167-182.
Havinga, B., 1933. Der Seehund in den Hollandischen Gerwassern. Tijdschr. Ned. Dierk. Verreen., 3: 79111.
Hokkaido Suisanbu, 1974. Hokkaido Suisan Gensei, Hokkaido-cho, Sapporo, 301 pp. (in Japanese).
Hokkaido Suisanbu, 1976. Hokkaido Suisan Gensei, Hokkaido-cho, Sapporo, 300 pp. (in Japanese).
Hotta, H., 1961. Comparative study of the axial skeleton of Japanese taleostei. Nippon Gyogaku Shinkokai,
Tokyo 155 pp.+Pl. LXX.
Imler, R.H. and H. R. Sarver, 1947. Harbor seals and sea lions in Alaska. USDI. Fish and Wildlife Ser.
Sepe. Sc. Rep. 28, 23 pp.
Inukai, T., 1942 Hair seals in our northern waters (I). Shoukubtsu Oyobi Dobutsu, 10 (10): 927-932. (inJapanese).
Kenyon, K. W., 1965. Food habits of harbor seals at Amchitku Island, Alaska. J. Mamm., 46 (!): 103104.
Matsubara, K., 1955. Fish morphology and hierarchy. Ishizaki-shoten, Tokyo, 1,605 pp.+ Pl. 135. (in Japanese).
McRoy, C. P. andJ.J. Goering, 1974. The influence of ice on the primary productivity of the Bering Sea.
pp. 401-421. In: D. W. Hood and E.J. Kelly (ed.) Oceanography of the Bering Sea, Inst. Mar. Sci. Univ.
Alaska, Fairbanks, 623 pp.
Naito, Y. and S. Konno, 1980. The post breeding distributions of ice-breeding harbour seal (Phoca largha)
and ribbon seal (Phocofaciata) in the southern sea of Okhotsk. Sci. Rep. Whales Res. Inst., 31: 105-119.
Naito, Y. and M. Nishiwaki, 1972. The growth of two species of harbour seals in the adjacent waters of
Hokkaido. Sci. Rep. Whales Res. Inst., 24: 127-144.
Pitcher, K. W., 1977. Population productivity and Food habits ofharbor seal in the Prince William SoundCopper River Delta Anea, Alaska. MMC-75/03, PB 266 935, 36 pp.
Ponomareva, L. A., 1963. The euphausiids of the North Pacific, Their distribution and ecology. (Translated from
Russian by S. Nemchonok, 1966), 1.P.S.T., Jerusalem, 154 pp.
Spalding, D.J., 1964. Comparative feeding habits of the fur seal, sea lion and harbour seal on the British
Columbia Coast. Bull. Fish. Res. Board Can. 146: 1-52.
Tikhomirov, E. A., 1968. Body growth and development of reproduction organs of the North PacificPhocids. pp. 213-241. In: V. A. Arsen'ev and K. I. Panin (ed.) Pinnipeds of the North Pacific. (Translated
from Russian by J. Sal Kind, 1971), 1.P.S.T., Jerusalem., 275 pp.
Watanabe, M., 1958. Nipponsan Kajika-ka gyorui no kenkyu. kagaku Shikenjo Hokoku, 6,013: 1-146. (inJapanese).
Wilke, F., 1954. Seals of northern Hokkaido.]. Mamm., 35 (2): 218-224.
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

136

KATO

Yoshida, H. and H. Kato, 1981. The relationship between the Subopercle size and body length of walleye pollock, Theragra Chalcogramma (Pallas). Bull. Fae. Fish. Hokkaido Univ., 31 (2): 169-174. (inJapanesewith English abstract).

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

RECENT SURVEY ON THE DISTRIBUTION
OF THE AFRICAN MANATEE
MASAHARU NISHIWAKI, MASASHI YAMAGUCHI,SHIGEMITSU SHOKITA
Faculty of Science, University of the Ryukyus, Okinawa

SENZO UCHIDA
Okinawa Ocean EXPO Memorial Park Aquarium, Okinawa

AND

TERUO KATAOKA
Toba Aquarium, Mie

ABSTRACTThe survey was made in travelling west African countries in 1980 and 1981
mainly on the distribution of African manatee, Trichechus senegalensis.
It was confirmed that the manatees were inhabiting the Senegal Riversystem.
Manatees were distributed sparsely between Guinea-Bissau and Liberia
through Sierra Leone and abundantly from Ivory Coast to Nigeria extending
to Mali. Considerable numbers were in Cameroon and Gabon. The mostabundant area was in the Niger River and its tributaries with connected swamps.
According to the literature, the southern limit of the distribution is in
Angola, but we were not able to enter the country to confirm it.
INTRODUCTION

A fundamental thing for the study of an animal distribution is to determine whether only one or more than one species are present. In an attempt to answer the
species question, the senior author examined the sirenia collection at the British
Museum (Natural History) in 1973. Also, through the kind cooperation of Dr.
Chales Roux (Museum Nationale d'Histoire Naturelle, Paris), the senior author
studied the skeleton of a male manatee in Abidjan, Ivory Coast and found no evidence that more than a single species of African manatee exists. This agrees withprevious findings (Hatt, 1934; Kaiser, 1974; Rice, 1977; Husar, 1978).
Since then, the senior author has visited Dakar and Abidjan twice for preparatory survey on the status of the animals. In the summer (July-August) of 1980
and the winter (January-March) of 1981, the present authors shared in area toperform extensive field survey.
Brief report on the survey was aurally presented by the senior author at themarine mammal symposium, International Theriological Congress III on 17 August 1982 in Helsinki. The present report was rewritten with some corrections,particularly the estimation of living numbers were to be left to the future studies.
Sci. Rep. Whales Res. Inst.,

No. 34, 1982, 137-147

NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

138

Jo· ~
4D"E 30'N

SAUDI
ARABIA

(,rJ

SUDAN

·-~

:
·'

ATLANTIC

CENTRAL
AFRICAo·__ ,.---:.

ZAIRE

OCEAN

INDIAN
OCEAN

\,
/-

.....

10·s +----'~---t----'~--~H------'"7---fl---10·s':..----.....
:____ Jo•·---...... -,'·- . :··-----;;:~:;:->\,("-----,

,,
·'

20 E

Fig. 1.

\-~-,

30'

Traveling route of the survey.

METHOD
The principal method of survey was to collect information through interviewing
local zoologists or biologists, fishermen at market places and general inhabitants byshowing photographs of the animal. Information on the climate and other environmental conditions were also recorded. The group members often walked
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

139

into the river valley, swamps or other places where manatees might occure. One of
the most difficult problem was to identify the animals in muddy colour who quietly
submerged in the water for most of the day and surfaced to breathe by exposing
only a small portion of the muzzle tip.
DATA COLLECTION

Senegal (Republique du Senegal)
Investigation on geographical and environmental conditions along the Senegal River was made to determine the northern and western limit of the distribution of
the manatee. Two group members flew from Dakar to Saint Louis and one ofthem further proceeded to Richar<l Toll, Podor, Matan along the border between
Senegal and Mauritania.
The Senegal River is very broad at its mouth where sand bar stretches to thesea and blocks high waves, so the water around the estuary is calm. Since thearea (Saint Louis as its center) is heavily industrialized, it seemed difficult for manatees to inhabit. Naturally no report of manatee sightings were obtained in thisarea. Similarly, we were unable to collect data of recent years in Dakar district.
This area which used to be a quiet lagoon has now turned to dry land. Recent
extreme dry weather apparently affected the river and subsequently the manatee
habitat.
Survey at Richard Toll was greatly facilitated by Dr. Morel, French ornithologist stationed there, through the cooperation of Dr. Alioune Ndiaye of Dakar.
According to Dr. Morel's information, manatees are decreasing, but a considerable
number of animals are still inhabiting Lac de Cuiers. At Matan, no report was
obtained to indicate the existence of manatee.
The Senegal River meets a flow from Lac de Cuiers and winds widely on its
way to Podor. The river is incredibly dark brown in colour and flowing further tothe vast land of savannah. There seemed to be little possibilities of the animals feeding on water grass, because no forage would be available in this area.
Therefore it seemed that manatees were not able to live there, at least from Lac deCuiers to Matan except in the secluded parts of Lake Lac de Cuiers and swamps.
Native people of Matan gave us no report of living manatees. Matan is so hot inJuly that even Dakar people feel it too hard. Environmental condition seemed to
be too severe for manatees to survive in summer. However since the head watersof Senegal River is said to be connected with that of the Niger River in the vicinityof Bamako during rainy seasons, there is possibility of some manatees are recruitedfrom the Niger to the Senegal. Based on what we have heard and on the examination of local conditions, a rough estimate of the manatee population in Senegal,
would be a few hundred.
Gambia (Republic of the Gambia)-Liberia (Republic of Liberia)
We only collected data that manatees were inhabiting the Gambia River.
To collect clear evidences of manatees existance there, our stay was too limited in
Sci. Rep. Whales Res. Inst.,
No. 34, 1982

140

NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

Bissau (Republica da Guine-Bissau), Conarkry (Republique Populaire Revolutionaire deGuinee), Freetown (Republic of Sierra Leone) and Monrovia (Republic of Liberia).

Ivory Coast (Republique de Cote D' Jvoire)In the Ivory Coast geographical feature altered during August under influence of tropical rainbelt which shifts to the north in summer in the northernhemisphere (Beadle, 1978). In Abidjan, we exchanged all available informationand knowledge on manatees with Dr. Francis Laugine, French veterinarian anddirector of the Abidjan Zoo. With his assistance, we used cars and a small
plane of Cesna type for survey. We sighted considerable number of manatees invarious rivers, swamps and lagoons. This area holds a large population of manatees as well as the Niger does. The number of the animals in this country may
amount to several thousands. There were some suspicions that manatees were caught
and eaten by native people. Catch of manatees had been prohibited since the timeof French domination and was still in effect. But poachers catch and eat manatees
without leaving any evidence of carcass or bones and keep the fact secret for longtime. So there is no effective procedure of conservation. The situations are similar to dugong catch regulation in Indo-Pacific (Nishiwaki et al., 1981). Dr. Laugine plans a project of manatee research which may start in near future.
Ghana (Republic of Ghana) with information about Togo (Republique Togolais) andBennin (Republique Populaire du Bennin)
Investigation in Ghana was enhanced through the cooperation of Dr. Kazumori Minami of the Noguchi Memorial Institute for Medical Research, Universityof Ghana, and Dr. R. Kumar, Indian entomologist, of the Department of Zoology,
University of Ghana. Survey in the Lake Volta area was carried out under theirguidance. According to Dr. J. Vanderpuye, Ghanian researcher of Volta Basin
Research Project, no manatee inhabits the Akosombo dam area. Mr. A. K. Opoku
of the Volta River Development Authority, informed us that he heard a few years
ago that there had been abundant manatees in Asukawkaw River Arm, east coastof Lake Volta, about 9 km north to Akosombo. Dr. E.Q.A. Asibey of the Department of Game and Wildlife, Ministry of Forestry, told us that manatee catch was prohibited by law, and because of that, reports oflocal manatee catches hardly reachedto the government officer. However, one catch was reported in the West Arm of
Lake Volta in 1964 and another in Central Three Corner area in 1980, and someanimals were seen in the River Tano (west Ghana) sometime before, but none atpresent. During the construction of Akosombo dam which was completed in 1965,(Obeng, 1969), series of manatee skeletons were excavated, which are kept at the
Department of Zoology, University of Ghana: photographs of them were taken.
In the former description (Rappold, 1975), the manatee distribution was reported along the coast line of Ghana, but no fisherman in Cape Three Point, Elmina, Cape Coast, Accra, and of Terna, reported occurences of the animal in thesea. Although someone told us that an individual or individuals of such animal
were caught by fishing net in Angola, th_ere was no dependable evidence of the inSci. Rep. Whales Res. Inst.,
No. 34, 1982

RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

141

cident. It was suspected, therefore, that the report might have been of dolphinsor sharks. Togo and Bennin seemed to be quite different in political, economic
and other features. There is little possibility of the manatee distribution, partly
because there is no big river such as the Niger or the Congo (Zaire) Rivers in theirterritories.
Through the assistance of Japan International Cooperation Agency (JICA),
we were able to obtain some information in a relatively short period of time.

Mali (Republique du Mali) and Niger (Republique de Niger)
In the vast desert area of extremely dry Mauritania (Republique Islamiquedu Mouritanie), northern Mali and the major land of Niger, exceptional green
patches can be seen in Mandingo Plateau in the up stream of the Senegal River.
The upper Niger River also reaches to this high plateau area with its central town
named Bamako, Mali. Although the river is not very wide at Bamako area, volumeof the river water fluctuates largely between dry and rainy seasons. The Niger
River flows to northeast and continues into the wilder area, forming Inland Niger
Delta, and reaches to Tombouctou (Timbuktu). After Tombouctou, the river
gradually turns to southeast and crosses the border to Niger.
Collected data in the area indicate that considerable number of manatees arein the Inland Niger Delta, and some are inhabiting the lower stream neigbouring
to Neamey, but the population size is scarcely known. The river basin is the only
place in the dry desert area for manatees to survive.
Nigeria (Federal Republic of Nigeria)
Investigation in this country resulted us something through the help of local
scientists. Dr. C. B. Powell of the School of Biological Sciences, University of Port
Harcourt, gave us a valuable report that abundant population of manatees had beenin Lake Kainji located in the middle flow of the Niger River and its tributary of the
Benue River. However, over killing caused the manatees to decrease in number
and now there may be a few hundred in the lake.
An important and reliable information was provided to us by Mr. A. B. Wilsonof the Nigerian Institute for Oceanography and Marine Research. He told usthat there were still many manatees in the Benue River. Although Dr. Powellspoke as a few hundred, his estimation was likely a few thousand. Dr. Akihiro
Takihara, Medical Officer of the Embassy of Japan to Nigeria, told us that he sawsome manatees kept alive by local people near by Makurde located on the side of
the Benue River.
People said that occurrences of manatees had been counted before (Rappold,
1975 ), but the number has been decreasing. Mr. Wilson informed us that an animal
was tangled in a fisherman's net at Port Harcourt. He identified the animal as amanatee by seeing our photographs. If it is true, his report sounds like a manatee
was taken from the sea, but the fact was that, Port Harcourt is located on the riverside, a little up stream from the mouth. Brackish waters may be flowing in fromtime to time, but salinity of waters is low in the very wide estuary. Some individSci. Rep. Whales Res. Inst.,
No. 34, 1982

142

NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

uals might be washed out to the sea with strong current, against the animal's swimming effort.

Cameroon (Republique Unie du Cameroun)
The coastline of Cameroon faces the Gulf of Guinea, and it may be divided
geographically into two sections; high rocky coast of volcanic lava in the northwest
and low swampy and sandy coasts in the south (Ngwa, 1967). Because of this difference in topography, the west section (former British Cameroon) appears to haveno manatees in small and rapid rivers flowing down from the Mount Cameroon(altitude 4070 m, active volcano). A small Zoo (Zoological Garden) has been
estab.lished at Victoria, but its caretakers knew nothing about manatees in the district (South-West Cameroon). Fishermen in this town had some knowledge of theanimal, called " Maiga ", but they denied its occurrences.
There is a well-developed estuary, near the commercial capital of Douala,
into which two rivers (R. Mungo and R. Wouri) are flowing, and the local residents
informed us that there were manatees in the upstream of the River Mungo. However, the littoral district is heavily populated and urbanized, so it is hardly considered that there are large number of manatees. The Museum of Douala has apictorial display of a manatee as one of the significant components of the local fauna.
There may remain a considerable number of manatees in the Sanaga River
System, which is the largest in the country. Local residents interviewed at a riverside market at Edea described that the animal, called " Maga'', lived along theentire river except in the rapids, and that the manatees were eating grasses in theriver. Although it is prohibited to kill manatees by law, they occasionally catchthem for meat in order to entertain visiting dignitaries, with special permissions.
It appeared that, from what the people described, there were wide-spread incidents
of poaching activities, at least near the population centers. It is also told that there
was a licensed manatee hunter, Mr. Ngoye Samuel, at Mal Jeown near Mouanko
village, south of Douala, who possessed a special permit for manatee hunting, whichmight be for local festivity.
Gabon (Republique Gabonaise)
In the vicinities of Libreville, the capital of Gabon, manatees had been caught
very rarely from Baie de Mondah and Estuaire du Gabon. This report is based on
personal communication between the group members and the missionary people at
Donguila, and Dr. Domart, Direction des Chasses et Piches, Ministerie de !'Agriculture. The manatee is called as " Manga " in Gabon.
Approximately 150 km south to Libreville lies the city of Port-Gentil which islocated at the mouth of River Ogoue, the largest river in Gabon. Mr. Bayona ofOgoue Marine Service, who regularly commute between the city and off-shore oilrigs for servicing, informed us that he had not seen any manatee at sea, althoughseen large number of whales and dolphins passing in dry seasons. The local fishermen at Port-Gentil and also those at the neighbouring place of Ntchengue village
mentioned that manatees were common in the River Ogoue and in the several conSci. Rep. Whales Res. Inst.,
No. 34, 1982

RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

143

nected lakes located· between Port-Gentil and Lambarene. Several individual
persons informed equally that the manatees were also common in the southerncoastal lagoons, such as Lagune Nkomi or Fernan Vaz. near Omboue and Lagune
Ndogo, near Sette Gama. According to Mr.Jean Wack of Libreville, who worked
as a timber merchant soon after the World War II and travelled frequently along
the River Ogoue, manatees were abundant there before. He described that someexperienced fishermen would lie in ambush for the animals in the river because
manatees had moved onto a certain particular route every time in search of the food,species of aquatic plants.
Since Gabon is less extensively developed, it holds vast rain-forest area andriver basins with relatively smaller population of about 1.3 million people in about
270,000 km 2 (density about 5/km 2 ) (Hancock, 1978), there may be large population of manatee in some of the above-mentioned localities. One of the group member went into the wilder swampy Ivendo River area where manatees may inhabit
abundantly. One of our problems was that though experienced scientists may findthe muzzle tip or a part of the body in muddy water and estimate abundance in thearea, it is very difficult for them to count number of the animals. Relatively dense
distribution of animals was presumed. A rough estimate of manatees may be several thousands.
The government has prohibited manatee hunting, but the situation was thesame as everywhere, there seemed to have no efficient measures to prevent local
poachings.

Angola (Republica Populare de Angola) and Congo (Republique Populaire du Congo)
As we were refused to enter into Angola and Congo because of political unstability due to the civil war, no survey was carried out in those two countries.
Only information collected through Dr. Akihiro Takihara was that manatees wereseen in Stanley Pool, a lake nearby Kinshasa, Zaire (Republique du Zaire). No
manatee was said to be seen in the Ubangi River, a big tributary of the Congo (orZaire) River, which flows from the territory of Central African Republic (Enpire
Centrafrzcain ), passing through Bangui, crossing the border to Congo and flowing
into Stanley Pool.
The town of Lubumbashi is located near the border of Zambia (Republic ofZambia). A report came from the area that manatees, called " Manga " were seen
in remote rivers and swamps. However, since the body length of the animals reported were 30-150 cm, it was so doubtful that we concluded the report was false.
The southern and the eastern limit of manatee distribution is still unconfirmed.
DISCUSSION AND SUMMARY

As a result of the recent survey in the west African countries, it is clear that the mostabundant distribution of manatee is in the Niger River and its tributaries and associated swamps. The rivers which hold secondarly abundant populations are the
Sanaga and the Ivindo Rivers, in Cameroon and Gabon, respectively. The norSci. Rep. Whales Res. Inst.,
No. 34, 1982

1440u• -- - ' - -- -· -" --~: - ·- - - -- - - - - - .. - - - - - ~' - - .. -'······---------+--~~~~~~~%~~

C'

e- -1

+

.
... .. __ _--· -· ----------:---------,'

distributed area::-.: more abundan t area

1s·w

I O.

5·

·------:~::;:~.;;-~offthe
AfricanFig. I. Distribut10n
Sci. Rep.

Whales Res. Inst.,
No. 34, 1982

145

•lt111J

'

pULF

OF

GUINEA
T'nncif'~__ .~ _____________ ·-..
';

t>a.~.,. Lb,~,;11- +------------ ---p5·
manatee ( Trichechus senegalensis ).

Sci. Rep. Whales Res. Inst.
No. 31- ,1982

•

I o·

146

NISHIWAKI, YAMAGUCHI, SHOKITA, UCHIDA & KATAOKA

them and the western limit of distribution is in the Senegal River system. However, dispersing and fading distribution in both the western and the northernparts of the river were so scarce that we had once thought that it might be better toreport the Inland Niger Delta in Mali as the northern limit and the Gambia Riveras the western limit.
The African manatee was proved to have a delicate sense to avoid salt water,which unlike the American manatee, Trichechus manatus, which inhabits marine
environment as well as estuarine and freshwater habitat (Odel et al., 1978; Erdman,
1970; Hartman, 1979). Some local reports telling manatees were observed at sea
were supposedly false and disregarded in our records. We thought that dolphins,
whales or sharks might have been mistaken for manatees in those cases.
Based on the all collected data, we drew a distribution map of the African
manatee in west Africa trying to show recent status of the animal and hoping that
it would be a reference to some conservation measures.
The Niger River flows through extensive areas crossing the borders of countries, merges with other rivers, and is very long. If conservation of the African
manatee would be planned, conservation strategy by a single country would not beeffective. A conserved population in one country may be poached in other territories. Only properly organized extensive and long standing project would workfor this purpose. Almost every country we visited, prohibits the manatee hunting
by law. But we were informed in many places that the actual status and conditionof manatees and poaching incidents had scarcely reached Government Officials because of people's fear of punishment. It should be noted that research projects byscientists stationing in the field for long periods, and who are able to establish goodterms with tribal chiefs and general local people of the district, are most desirable,
Dr. Laugini in Abidjan is a good example. Sufficient collection of local reports
and workable conservation plans would be available by those people.
While travelling many lands of severe natural conditions where many people
were nearly starved, we realized that the conservation of this species must be very
difficult because of delicious meat and easy hunting by local people. Saving thosepeople from poor status by developing agricultural and other improvement andprogress must have superior priority than establishment of conservation measureson manatee. However if we wait until these conditions are fulfilled, it should be
too late for conservation of the African manatee.
ACKNOWLEDGMENT

We should like to express our sincere gratitude to the number of people, scientists,
local residents, fishermen and so on, who gave us help in collecting information as
the greater part of study was based on those hearings. We specially appreciatefollowing people who kindly gave us particular helps and were able to have names
during the survey; Dr. Alioune Ndiaye, Director du Projet P.N.U.D. R.A.F.,
Senegal, Dr. G. J. Morel, Orstom, Richard-Toll, Senegal, Dr. F. Laugine, Zoo
D'Abidjan, Cote D'Ivoire, Dr. K. Minami and Dr. K. Minakami, Noguchi MemoriSci. Rep. Whales Res. Inst.,
No. 34, 1982

RECENT SURVEY ON THE DISTRIBUTION OF AFRICAN MANATEE

147

al Institute for Medical Research, Accra, Ghana, Dr. R. Kumar, Department of
Zoology, University of Ghana, Legon, Ghana, Dr. E.QA. Asibey and Mr. C. K.
Manu, Department of Game and Wildlife, Ministry of Forestry, Ghana, Dr. J. N.
Raybould, Volta Lake Research and Development Project, Akosombo, Ghana, Mr.
D. N. Quaynor, Fishery Research Unit, Terna, Ghana, Dr. C. B. Powell, School of
Biological Science, University of Port Harcourt, Mr. A. B. Wilson, Nigerian Institute for Oceanography and Marine Research, Nigeria, Dr. Akihiro Takihara,
Messers Akikazu Nakamura, Norihiro Kobayashi, Daiko Okura, the Embassy ofJapan to Nigeria, Mr. James B. Ndeffo, Douala, Cameroon (guide, taxi-driver),Dr. Domart, Ministerie de I' Agriculture, des Eaux et Forets, Gabon, Dr. Jean
Wack, Libreville Gabon, Mr. Jean-Pirre Bayona, Port-Gentil, Gabon, Dr. Jean L.
Deval, IRAF, Gabon, Prof. T. Kano and Mr. T. Takeda, University of the Ryukyus,
Japan, and from the preparatory survey by the senior author, till the end of thisstudy, Miss Marie-Jeanne Ndiaye of the Broad Casting Station, Dakar, Senegal,
has given us generous help in collecting information, contact among group members while travelling and valuable advices for our survival in the countries quite
different from home, who has understandings in Japan and Japanese since she has
been in Japan for technical study.
REFERENCES
BEADLE, L. C., 1978. The inland waters of tropical Africa. Longman, London, 368 pp.
ERDMAN, D.S., 1970. Marine mammals from Puerto Rico to Antigua. J. Mamm., 5(3): 636-639.
HANCOCK, G. (ed) 1978. African guide. World of information. England., 366 pp.
RAPPOLD, D.C.D., 1975. Large mammals of west Africa. Longman Group Ltd., London.
HARTMAN, D.S., 1979. Ecology and behavior of the manatee (Trichechus manatus) in Florida. Special publication No. 5, The American society of mammalogists.
HATT, R. T., 1934. The American museum Congo expedition, manatee and other recent mammals. Bull.
Amer. Mus. Nat. Hist., 66: 533-566.
HusAR, S. L., 1978. Trichechus senegalensis, Mammalian species No. 89, The Amer. Soc. mammalogists., Institut
Pedagogique Africa et Malagache ed., 1975. Geographie. Classiques Hachette.
KAISER, E. K., 1974. Morphology of the sirenia. S. Karger.
NrsHIWAKI, M., T. KASUYA, T. ToBAYAMA, N. MIYAZAKI and T. KATAOKA., 1981. Distribution of the dugong in the world. Sci. Rep. Whales Res. Inst., 31: 133-141.
NGWA, J. A., 1967. A new geography of Cameroon. Longman, London, 151 pp.
OBENG, D. K., 1969. Man-made lakes. Ghana Univ. Press.
0DEL, D. K.,J. E. REYNOLDt and G. WAUGH., 1978. New records of the west Indian manatee Trichechusmanatus from the Bahama Islands. Biol. Conserv., 14: 289-293.
RrcE, D. W., 1977. A list of the marine mammals of the world. NOAA Tech. Rep. NMSF. SSRF. US Dept.
qfCommerce, Washington D. C., 711: 1-15.

Sci. Rep. Whales Res. Inst.,
No. 34, 1982

THE SCIENTIFIC REPORTS OF THE WHALES RESEARCHINSTITUTE, TOKYO, JAPANNUMBER 1, JUNE 1948
Akiya, S. and S. Tejima. Studies on digestive enzyme in whale. 3-7
Akiya, S., Y. Ishikawa, S. Tejima, and T. Tanzawa. Studies on tryptase from a whale (Balaenoptera borealisL.). 8-10
Akiya, S., S. Tejima, and Y. Ishikawa. Studies on the utilization of whale meat by the use of pancreatic
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. 61-66

NUMBER 3, FEBRUARY 1950
Ogawa, T. and T. Shida. On the sensory tubercles oflips and of oral cavity in the sei and the fin whale.
1-16
Ohe, T. Distribution of the red marrow in bones of the fin whale. 17--22
Hosokawa, H. On the cetacean larynx, with special remarks on the laryngeal sack of the sei whale andthe aryteno-epiglottideal tube of the sperm whale. 23-62
Akiba, T., T. Tsuchiya, M. Umehara, and Y. Natsume. Bacteriological studies on freshness of whale
meat. (Report No. 1). 63-70
Ishikawa, Y. Protein digestive power of sperm whale pancreatic enzyme. II. 71-78
Mori, T. and M. Saiki. Properties of fats and oils contained in various parts of a sperm whale body. 7984
Tawara, T. and R. Fukazawa. Studies on kitol. I. Preparation of kitol from whale 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 of histidine from whale blood using 3,4-dichlorobenzene sulfonic acid.
41-47
Tawara, T. and R. Fukazawa. Studies on kitol. IV. Purification ofkitol by chromatographic. 49-51
Ishikawa, S., Y. Omote and H. Okuda. Substances related to vitamin A in the whale liver oil. 53-59
Ishikawa, S., Y. Omote, M. Kijima and H. Okuda. Thermal decomposition ofkitol. 61-69
Mizue, K. Grey whales in the east sea area of Korea. 71-79
Mizue, K. Food of whales (In the adjacent waters of Japan). 81-90
Nishiwaki, M. and T. Ohe. Biological investigation on blue whales (Balaenoptera musculus) and fin whales(Balaenoptera pliysalus) 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 theJapanese 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_vseter catodon) found :u 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 of kitol (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/ 5 I. 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 (Prodelphinuscaeruleo-albus). 215-218

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

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

NUMBER 10, JUNE 1955
Hosokawa, H. Cross-sections of a 12-mm. dolphin embryo. 1-68
Nemoto, T. White scars on whales (I) Lamprey marks. 67-77
Omura, H. and T. Nemoto. Sei whales in the adjacent waters of Japan. III. Relation between movement and water temperature of the sea. 79-87
Omura, H., K. Fujino and S. Kimura. Beaked whale Berardius bairdi of Japan, with notes of -?,iphiuscavirostris. 89-132
Fujino, K. On the body weight of the sei whales located in the adjacent waters of Japan (11.) 133-141
Nishiwaki, M. On the sexual maturity of the Antarctic male sperm whale (Physeter catodon L.). 143-149
Ohta, K., T. Watarai, T. Oishi, Y. Ueshiba, S. Hirose, T. Yoshizawa, Y. Akikusa, M. Sato and K. Okano,Composition of fin whale milk. 151-167

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

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

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

NUMBER 14, SEPTEMBER 1959
Omura, H. Bryde's whale from the coast ofJapan. 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 ! labelled antibody.
101-106
Ichihara, T. Formation mechanism of ear plug in baleen whales in relation to glove-finger. 107-135
Nasu, K. Surface water condition in the Antarctic whaling Pacific area in 1956-57. 137-143
Ohsumi, S. (Kimura). A deformed fin whale foetus. 145-147
Nemoto, T. Food of baleen whales with reference to whale movements. 149-290
Yamada, M. and F. Yoshizaki. Osseous labyrinth ofcetacea. 291-304
Nakai, T. Distribution of amino acid in proteins from various parts of whale body. 305-326

NUMBER 15, NOVEMBER 1960
Nishiwaki, M. Ryukyuan humpback whaling in 1960. 1-16
Ohsumi, S. Relative growth of the fin whale, Balaenoptera ph_ysalus (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
Ichihara, T. Prenatal dead foetus of baleen whales. 47-60
Nishiwaki, M. Mesoplodon bowdoini stranded at Akita Beach, Sea ofJapan. 61-77
Nishiwaki, M. Observation on two mandibles of Mesoplodon. 79-82
Sinclair, John. An early dolphin embryo (Stene/la 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 ofdentinal growth layers in the maxillary tooth of the sperm whale. 15-35
Ichihara, 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. Calaprice. 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 feedi_ng areas. 89-110.
Okutani, T. and Nemoto, T. Squids as the food of sperm whales in the Bering Sea and Alaskan Gulf.
111-122
Ohsumi, S. Comparison of maturity and accumulation rate of corpora albicantia between the left andright ovaries in cetacea. 123-148
Omura, H. A systematic study of the hyoid bones in the baleen whales. 149-170
Nishiwaki, ?\.·I. Revision of the article "Taxonomical consideration on genera of Delphinidae " in No. 17.
171-172
Tsuyuki, H. and U. Naruse. Studies on the lipids in brain of black right whale in the northern Pacific
Ocean. 173-180

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

NUMBER 20, SEPTEMBER l 966
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
lchihara, T. and M. Nishiwaki. External measurements and weight of a southern elephant seal. 211-212

viii
Tsuyuki, H. and S. Itoh.

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

213-221

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 ofvarginal 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
Mol, T. and P.J.H. van Bree. A short contribution to the history of whaling in Japan during the l 7th
century. 125-129
Tsuyuki, H. and S. Itoh. Fatty acid composition of finless porpoise oil. 131-135.
Tsuyuki, H. and S. Itoh. Fatty acid composition of many toothed pilot whale oil. 137-141

NUMBER 22, JUNE 1970
Omura, H., T. Ichihara and T. Kasuya. Osteology of pygmy blue whale with additional information on
external and other characteristics. 1-2 7
Nishiwaki, M. and T. Kasuya. Recent record of gray whale in the adjacent waters of Japan and a consideration on its migration. 29-37
Kasuya, T. and D. W. Rice. Note on baleen plates and on arrangement of parasitic barnacles of graywhale. 39-43
Nishiwaki, M. and T. Kasuya. A Greenland right whale caught at Osaka Bay. 45-62
Nasu, K. and Y. Masaki. Some biological parameters for stock assessment of the Antarctic sei whale.
63-74
Ohsumi, S., Y. Masaki and A. Kawamura, Stock of the Antarctic minke whale. 75-125
Kawamura, A. Food ofsei whale taken by Japanese whaling expeditions in the Antarctic season 1967/68.
127-152
Nemoto, T. and K. I. Yoo. An amphipod, Parathemisto gaudichaudii as a food of the Antarctic sei whale.
153-158
Tobayama, T., S. Uchida and M. Nishiwaki. Twin foetuses from a blue white dolphin. 159-162
Machida, S. A sword-fish sword found from a North Pacific sei whale. 163-164
Tsuyuki, H. and S. 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 den tin. 103-110

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

NUMBER 24, NOVEMBER 1972
An osteological study of the Cuvier's beaked whale, :(,iphius cavirostris, in the northwest Pacific.
1-34
Nishiwaki, M. and N. Oguro. Catch of the Cuvier's beaked whales off Japan in recent years. 35--41
Nishiwaki, M., T. Kasuya, K. Kureha and N. Oguro. Further comments of Mesoplodor. gingkodens. 43-56
Kasuya, T. Growth and reproduction of Stene/la caeruleoalba based on the age determination by means ofdentinal growth layers. 57-79
Kasuya, T. and N. Oguro. A new tagging method of dolphins. 81-85
Kasuya, T. Some informations on the growth of the Ganges dolphin with a comment on the Indus 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

Omura, H.

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 Stenella caeruleoalba. 265-275
Nishiwaki, M. Possible vestigial teats of killer whale. 277-278
Williamson, G. R. Counting and measuring baleen and ventral grooves of whales. 279-292
Tsuyuki, H. and S. Itoh. Fatty acid component of blubber oil of Amazon River dolphin. 293-299
Naito, Y. Comparison in colour pattern of two species of harbour seal in adjacent waters of Hokkaido.

301-310x

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

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

NUMBER 28, OCTOBER 1976
Kawamura, A. and Y. Satake. Preliminary report on the geographical distribution of the Bryde's whalein the North Pacific with special reference to the structure of the filtering apparatus. 1-35
Pivorunas, A. A mathematical consideration. on the 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 l;yamus scammoni (Amphipoda: Cyamidae), ectoparasite of gray whale, witha remark on the associated species. 153-160
Kagei, N., T. Tobayama and Y. Nagasaki. On the helminthum of Franciscana, Pontoporia blainvillei.
161-166
Tsuyuki, H. and S. Itoh. Fatty acid component of lipid of Euphausia superba. 167-174
Naito, Y. The occurrence of the phocid seals along the coast ofJapan and possible dispersal of pups. 175185
Naito, Y. and M. Oshima. The variation in the development of pelage of the ribbon seal with reference
to the systematics. 187-197

NUMBER 29, DECEMBER 1977
Kasuya, T. Age determination and growth of the Baird's beaked whale with a comment on the feta!
growth rate. 1-20
Miyazaki, N. On the growth and reproduction of Stene/la coeruleoalba off the Pacific coast ofJa pan. 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 behaviourand 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
Orci11us orca. 107-111
Nishiwaki, M. and A. Sasao. Human activities disturbing natural migration routes of whales. 113-120
Yoshida, K., N. Baba, M. Oya and K. Mizue. On the formation and regression of corpus luteum in thenorthern fur seal ovaries. · 121-128
Abe, H., Y. Hasegawa and K. Wada. A note on the air-sac of ribbon seal. 129-135
Kawamura, A. and T. Furuno. On the northern extremes of pack ice observed by whaling vessels in thesummer of the Antarctic seasons 1957/58-1962/63. 137-141

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

xii

245-247
Yamamoto, Y. and H. Hiruta. Stranding of a black right whale at Kumomi, southwestern coast of Izu
Peninsula. 249-251
Klima, M. Comparison of early development of sternum and clavicle in striped dolphin and in humpback
whale. 253-269
Omura, H. Preliminary report on morphological study of pelvic bones of the minke whale from theAntarctic. 271-279
Kamiya, T., F. Yamasaki and S. Komatsu. A note on the parathyroid glands ot Ganges susu. 281-284
Yamasaki, F., S. Komatsu and T. Kamiya. Taste buds in the pits at the posterior dorsum of the tongueof Stene/la coeruleoalba. 285-290
Kawamura, A. On the baleen filter area in the South Pacific Bryde's whales. 291-300
Kasuya, T. and M. Nishiwaki. On the age characteristics and anatomy of the tusk of Dugong dugon.
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,
Pontoporia blainvillei. 45-67
Jurasz, C. M. and V. P. Jurasz. Feeding modes of the humpback whale, Megaptera novaeangliae, insoutheast Alaska. 69-83
Omura, H. and T. Kasuya. A skull of baleen whale dredged from the Inland Sea of Japan. 85-92
Kamiya, T., T. Tobayama and M. Nishiwaki. Epidermal cyst in the neck of a killer whale. 93-94
Major, P. F. An aggressive encounter between a pod of whales and billfish. 95-96
Kato, H. Carotenoid colored minke whale from the Antarctic. 97-99
Kato, H. Unusual minke whale with deformed jaw. 101-103
Naito, Y. and S. Konno. The post breeding distributions of ice-breeding harbour seal (Phoca largha)
and ribbon seal (Phoca fasciata) in the southern sea of Okhotsk. 105-119
Naito, Y. A record of the bearded seal wandering with special reference to the wandering speed.
121-123
Miyazaki, N., K. Itano, M. Fukushima, S. Kawai and K. Honda. Metals and organochlorine compounds in the muscle of dugong from Sulawesi Island. 125-128
Kamiya, T., S. Uchida and T. Kataoka. Organ weights of Dugong dugon. 129-132
Nishiwaki, M., T. Kasuya, N. Miyazaki, T. Tobayama and T. Kataoka. Present ditribution of the dugong
in the world. 133-141

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

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

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

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

SUBJECT INDEX

Taxonomy, Body proportionand Osteology
Balaena mysticelus 22: 45-62, 34: 49-57
Eubalaena glacialis 13: 1-52, 21 : 1- 78, 21 : 79-84,
23: 71-81, 30: 249-251
Eschrichtius robustus 22: 29-37, 26: 1-14
Balaenoptera musculus 7: 125-183
B. musculus brevicauda 22 : 1-2 7
B. physalus 7: 125-183, 9: 121-163, 12: 127-189,
15: 17-84, 16: 29-34
B. borealis 9: 89-103, 14: 1-33, 23: 83-89
B. edeni 9: 89-103, 14: 1-33, 16: 1-5, 16: 7-18,
31: 85-92, 33: 1-26
B. acutorostrata II: 1-37, 12: 1-21, 19: 37-43, 22:75-125, 27: 1-36, 28: 57-68, 28: 69-72
Megaptera novaeangliae 7: 125-183, 14: 49-87
Physeter catodon 7: 125-183, II: 47-83, 16: 35-45,
17: 1-14
Kogia sp. 9: 37-58
K. breviceps 33: 119-124
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
M. bowdoini 16: 61-77
M. sp. 16: 79-82-?,iphius cavirostris 24: 1-34
BrBerardius 27: 111-137
B. bairdii 10: 89-132
Hyperoodonplanifrons 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
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
Platanistoidea 34: 93-108
Platanisla gangetica 24: 87-108
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

Anatomical and Histological study
Brain, Physeter 6: 49-72
Stenella 26: 245-253
Platanista 32 : 105-126
Spinal cord, Esbalaena 13: 231-251
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: 41-47
Sensory tubercle, lip 3: 1-16
Lingual margin 28: 137-140
Taste buds, Stenella 30: 285-290
Tongue, Sirenia 32: 127-144
Head section, Stenella 19: 105-133
Extrinsic eye muscle 6: 1-33
Masseter, Megaptera 17: 49-52
Heart, conducting system 9: 11-35
cardiac nerve, Berardius 7 : 1-22
Larynx 3: 23-62
Air-sac, Histriophoca and Phoca 29: 129-135
Lung 6: 35-47
Parathyroid, Platanista 30: 281-284
Abdominal cavity, iconography 5: 17-39
Stomach 23: 91-101, lnia 33: 69-81
Renculi 13: 253-267
Anal tonssil, Platanistidae 29: 95-100
Corpus luteum, Callorhinus 29: 121-128
Red bone marrow, B. physalus 3: 17-22
Embryo, Stenella 10: 1-68, 16: 83-87
Size of cell 13: 269-30 I
Epidermal cyst 31 : 93-94

Body and organ weight
Eubalaena glacialis 13: 1-52, 21: 1-78
Balaenoptera musculus 3: 132-190, 4: 184-209, 125-

ii
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
Platanistagangetica 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
Balaenoptera physalus I 3 : I 55-I 69, 18: 49-88-, 20:
17-82
Physeter catodon 13: 135-153, 17: 15-35, 20: 1-16
Berardius bairdii 29; 1-20
Tursiops truncatus 32: 39-66
Stene/la ceruleoalba 8: 133-1461 24: 57-79, 28: 73106, 29: 21-48
S. attenuata 26: 157-226, 28: 73-106
Platanista gangetica 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
Eubalaena glacialis 13: 1-52, 21: 1-78
Eschrichtius robustus 5: 71-79, 13: 201-205, 22: 2937, 22: 39-43, 26: 1-14
Balaenoptera musculus 3: 132-190, 4: 27-113, 5: 91167, 6: 73-131, 7: 125-183, 8: 147-213
B. physalus 3: 119-131, 3: 132-190, 4: 27-113, 5:
91-167, 6: 73-131, 7: 125-183, 8: 14-7-213, 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
B. borealis 3: 119-131, 4: 27-113, 9: 89-103, 22:
63-74, 34: 59-91
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
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
Physetercatodon 3: 106-118, 3: 119-131, 4: 27-113,
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
,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
Odontoceti 34; 1-4 7
Oreinus orca 13 : 85-96
Globicephala macrorhynchus and G. melaena 27; 95110
Stenella coeruleoalba 12; 191-192, 22; 159-162, 24:
57-79, 26: 227-243, 28: 73-106, 29: 21-48, 30:
65-115S. attenuata 26: 157-226, 26: 227-243, 28: 73-106
Lagenodelphis hosei 30: 231-244
Phocoenoides dalli 30: 1-64
Neophocaena phocaenoides 3 I : 1-44Cephalorhynchus commersonii 32: 149-154
Platanista gangetica 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
Foods, Phoca 34: 123-136
Pelage, Historiophoca 28: 187-197
Occurrence, phocid seals 28 : 17 5-185
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

iii

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: 157-170, 19: 4551, 20: 109-155, 34: 59-91
Balaenoptera borealis 22: 127-152, 22: 153-158, 25:
219-236, 25-144
B. edeni 7: 79-85, 29: 49-58, 32: 1-23
Megaptera novaeangliae 31 : 69-83
Eschrichtius robustus 22 : 39-43
Physetercatodon 5: 81-90, 11: 139-151, 11: 153-161,
18: 111-122, 28: 145-151, 32: 199-218
Orcinus orca 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 23:
27-36
Energy budge 27: 61-79

Whaling ground, environmental
9: 179-187, 11: 163-179, 12:91-101, 12:209-224,
13: 215-229, 14: 137-143, 15: 143-158, 16: 105119, 17: 105-155, 20: 157-210, 26: 271-287, 27:
141-157
Statistical review 25: 105-203
Pack-ice limit 29: 137-141
Sighting
By boat 25: 205-217, 26: 289-302, 30: 117-178,
30: 179-195
By air 23: 37-60

Parasite, scar and skin disease
4: 14-26, 11: 99-132, 13: 185-191, 29:
101-105, 32: 97-103
Cyamus 28: 153-160
Barnacle 22 : 39-43
White scar 10: 69-77, 26: 145-155
Skin di;ease 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
DiatomChemical study
Enzyme, stomach l: 3-7
pancreas l : 8-10, l : '11-14, 2: 55-60, 3 :71-78

Whale meat, peptone 1: 15-16
freshness I: 17-26, I: 28--30, 2: 31-

34, 3: 63-70, 5: 1-4, 6: 167-176,
7: 23-30, 7: 31-36, 9: 1-10
tryptophane 2 : 51-54
digestion 2 : 61-66
nutrition 7: 51-67
amino acid 13: 303-317, 14: 305326
methionine 3: 102-105
Whale blood 1: 38-40, 3: 96--101, 5: 41-47
Wale milk 10: 151-167.
Vitamin l: 31-37, 2: 35-41, 5: 53-59, 6: 187-191,
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: 213-221
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 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
Prenatal dead fetus 16-47-60
Nalformed 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

AUTHOR INDEX
49-51
A

Abe, H. 29: 129-135
Abe, T. 12: 225-233
Aguayo L., A. 28: 127-128, 30: ll7-l77
Aguilar, A. 33: 125-126
Akiba, T. 3: 63-70, 5: 1-4
Akikusa, S. 10: 151-167
Akiya, S. l: 3-7, l: 8-10, l: 11-14, l: 15-16, 2:
51-54, 5: 41-47, 7: 23-30, 7: 31-36
Aminul Haque, A.K.M. 24: l09-ll5, 29: 87-94
Antinoja, R. C. 29: 59-85
Arai, Y. 7: 51-67
Arifuku, S. 2: 1-20
Asano, K. 30: 311-313
BBaba, N. 29: 121-128
Best, P. B. 32: 97-103
Bou,]. 32: 145-148
Brownell, R. L.Jr. 28: 127-128, 28: 129-129-135,
29: 101-105, 31: 45-67c
Calaprice, N. 17: 67-77
Casinos, A. 32: 145-148
Castello, H.P. 26: 255-258, 28: ll9-l26, 29:
107-1 ll
Clarke, R. 30: 117-177
Cushing, John E. 14: 89-100, 14: 101-106, 17:
67-77
DDairokuno, A. 12: 209-224
Dawbin, W. H. 26: 157-226
de!Campo,S.B. 30:117-177
E

ECG Research Group

15: 159-165
F

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, ll: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:iv

GGianuca, N. M. 28: 119-126
Goodall, R.N.P. 30: 197-232
Grau, E. 33: 125-126
H

Randa, C. 13: 85-96
Hasegawa, Y. 21: 79--84, 29: 129-135
Hayashi, K. 3: 132-190
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: 249-151
Hohn, A. A. 32 : 39-66
Honda, K. 31: 125-128
Hoshina, T. 11: 133-138
Hoshino, 0. 5: 41-47, 7: 23-30, 9: 1-10
Hosokawa, H. 3: 23-62, 5: 5-15, 6: 1-33, 10: 168, 13: 269-301, 19: 105-133, 21: 95-123, 23:
91-101
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: 1-27,
24: 145-148
Igarashi, S. 21: 95-123
Iguchi, K. 8: 147-213
Ishikawa, S. l: 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
lshimaru, K. 32: 97-103
Ishimaru, T. 29: 101-105
Itano, K. 31: 125-128
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
Iwai, E. 11: 139-151, 11: 153-161

J
Jimbo, H. 3: 119-131
Jover, L. 33: 125-126
Jurasz, C. M. 31: 69--83
Jurasz, V. P. 31: 69-83

v

K

M

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:
285-290, 31: 93-94, 31: 129-132, 32: 105-126,
32: 127-144, 33: 69-81, 33: 127-129
Kaneko, A. 2 : 46-50
Kanno, H. 2: 42-45
Kashita, K. 23: 139-140
Kasuya, T. 16: 35-45, 17: 15-35, 19: 37-43, 19:45-51, 19: 65-90, 20: 83-88, 20: 89-91, 21: 1-27,
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, ?6: 157-226,
26: 227-243, 27: 81-94, 27. 95-108, 28: 57--68,
28: 73-106,28: 141-143,29: 1-20,29:87-94,30:
1-63, 30: 301-310, 31: 1-44, 31: 45-67, 31: 8592, 31: 133-141, 32: 67-95, 33: 1-26
Kataoka, T. 31: 129-132, 31: 133-141, 34: 137147
Kato, H. 31: 97-99, 31: 101-103, 33: 1-26, 34:
123-136
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, II: 39-46,
11: 181-189, 12: 103-125
Kijima, M. 5: 61-69
Klima, M. 30: 253-269
Kobo, F. I: 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

Machida, S. 22: 163-164, 26: 271-287, 26: 289302, 27: 141-159
Maeda, T. 17: 1-14
Major, P. F. 31: 95-96
Masaki, Y. 22: 63-74, 22: 75-125
Matsui, S. 32: 67-95
McCann, C. 26: 145-155, 27: 111-137, 28: 107117
Mermoz, J. F. 32: 149-154
Mizue, K. 3: 106-118, 3: 119-131, 5: 71-79, 5:
81-90, 6: 73-131, 23: 123-128, 29: 121_:_128
Miyazaki, N. 25: 265-275, 26: 157-226, 26: 227243, 26: 259-263, 28: 141-143, 29: 21-48, 30:
65-115, 30: 179-195, 30: 231-244, 31: 125-128,
31: 133-141, 33: 27-67, 33: 127-129
Mo!, T. 21: 125-129
Mori, T. 3: 79-84
Motohashi, N. 7: 23-30, 9: 1-10
Murata, T. 6: 35-47, 6: 73-131

L

Leung, Y. M. 28: 153-160
Lugassy, A. A. 23: 103-110

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: 121123
Nakai, T. I: 17-26, I: 27-40, I: 41-47, 2: 31-34,
6: 167-176, 6: 177-185, 14: 305-326
Nakajima, M. 17: 191-195, 19: 65-90, 19: 91104, 20: 101-107
Naruse, U. 17: 171-190, 18: 173-180
Nasu, K. 11: 163-179, 12: 91-101, 13: 193-199,
13: 211-212, 14: 137-143, 15: 143-158, 17: 8391, 17: 105-155, 20: 157-270, 22: 63-74, 25:
205-217
Natsume, Y. 3: 63-70, 5: 1-4
Nemoto, T. 10: 67-77, 10: 79-87, 11: 132, II:
181-189, 12: 33-89, 13: 97-133, 13: 185-191, 13:
193-199, 14: 149-290, 16: 29-34, 16: 89-103, 17:79-81, 17: 83-91, 17: 191-195, 18: 89-110, 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
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: 35-

vi
46, 16: 61-77, 16: 79--82, 17: 1-14, 17: 15-35,
17: 93-103, 17: 191-195, 18: 171-172, 19: 53-64,
19: 65-90, 19: 91-104, 20: 95-100, 20: 101-107,
20: 211-212, 21: 79-84, 22: 29-37, 22: 45-62,
22: 159-162, 23: 71-81, 23: 83-89, 23: 111-122,
23: 123-128, 23: 129-137, 24: 35-41, 24: 43-56,
24: 127-144, 25: 251-263, 25: 265-275, 25: 277278, 26: 227-243, 27: 81-94, 27: 139-140, 29:
87-94, 29: 113-120, 30: 65-115, 30: 301-310, 31:
93-94, 31: 133-141, 34: 49-57, 34: 109-121, 34:
137-147
Norris, K. S. 20: 95-1000Ogawa, T. 2: 1-20 3: 1-16 7: 1-22, 8: 127-132,
9: 11-35, 12: 197-208, 13: 303-307
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: 1-2.\ 25: 237239
Ohta, K. JO: 151-167
Ohtaishi, N. 33: 131-135
Oishi, Y. 10: 15q-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, 11: 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: 25-37'
33: 1-26, 33: 119-124
Ono, H. 6: 177-185
Osawa, M. 13: 303-307
Oya, M. 29: 121-128p
Panizza, J. S. 26: 255-258
Pirlot, P. 26: 245-253, 32: 105-126
Pivorunas, A. 28: 37-55
Praderi, R. 28: 129-135

R

Rabinowits,J. L. 23: 103-110
Rice, D. W. 22: 39-43s
Saiki, M. 3: 79-84
Sakai, S. 7: 51-67
Sakiura, H. 11: 1-37
Sasao, A. 29: 113-120
Satake, Y. 26: 15-24, 28: 1-35
Sato, M. 10: 151-167
Satomi, M. 28: 137-140
Sawamura, R. 7: 31-36
Seki, Y. 13: 231-251, 25: 241-249
Sekino, T. 13: 269-301
Sergeant, D. E. 34: 1-47
Shida, T. 1: 41-47, 3: 1-16
Shiraga, S. 33: 127-129
Shokita, S. 34: 137-147
Soma, Y. 2: 35-41
Sugiura, Y. 11: 133-138
Suzuki, T. 13: 215-229, 17: 49-52
T

Takahashi, K. 2: 51-54, 14: 89-100
Takahashi, Y. (Satake) 33: 119-124
Takano, H. 32: 97-103
Takao, M. 7: 37-46
Takemura, A. 23: 123-128
Tanzawa, T. 1: 8-10
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
Tokita, K. 15: 159-165
Torno, 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: 117-125,
25: 293-299, 26: 303-306, 26: 307-311, 28: 167174

uUchida, S.

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

vii
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: 1-4v
van Bree, P.J.H.

21: 125-129

w
Wada, K. 29: 129-135
Wada, S. 30: 179-195, 30: 233-246, 33: 1-26
Watar:, T. 10: 151-167
Watkins, W. A. 33: 83-117
Williamson, G. R. 25: 279-292, 27: 37-59
yYagi, T. 8: 133-146, 17: 191-195, 32: 127-144
Yamada, M. 2: 21-30, 8: 1-79, 9: 37-58, 9: 59-

88, 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
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

zZhou, K.

34: 93-108

THE SCIENTIFIC REPORTS OF THE WHALESRESEARCH INSTITUTE

Editorial Board
HmEo OMURA; Editorial Director
MASAHARU NISHIWAKISEIJI OHSUMI
Tosmo KASUYA
TosHIRO KAMIYAy ASUHIKO NAITO
General Secretary
HIDEHIRO KATOllB fll 57 £f I2 A I5 a i::p jjjrJllB fll 57 £f 12 A 30 a ~ :ff

MN!lR.Aa ;;$: ffli !Ill $b ~

~

Wf

~

~

ffl

JI[ Jl'Clflli'I JIULk ,\1li 3 T § 32 i!f I I %*. Wf~t±FJJM\iJ_f*~~t±
Jll:Ji\~~~ !Z'.fl!!~!liP T§ 21!f t-lt!.

Printed by
Kenkyusha Printing Co.
Shinjuku-ku, Tokyo~<Pfi

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

4,000 FI ·