A CONSIDERATION ON AN AVAILABLE SOURCE OF
ENERGY AND ITS COST FOR LOCOMOTION IN FIN
WHALES WITH SPECIAL REFERENCE TO THE
SEASONAL :MIGRATIONSAKITO KAWAMURA
Whales Research Institute, Tokyo

ABSTRACTThe energy cost for locomotion and possible distance of the migrations
to and from the feeding grounds for southern fin whale were estimated being
based on the amount of whale oil by girth measurements. A 18.1 meter fin
whale keeps about 90 m 2 of the blubber area as substantially important for
expending the preserved whale oil, and about 1.8 m 3 of oil is preserved in
2.0 cm thick of the blubber. The energy cost for locomotion by swimmingin material fin whale was estimated as 0.022 Kcal- 1 ·Kg- 1 ·Km- 1 by extrapolating parameters onto the known regressions of body weight-energy cost relationships in aquatic animals, and an integrated distance of migrations whichis covered by following above mentioned parameters would be somewhere
between 20,000 and 30,000 Km. These figures lead to a consideration that
it is not unlike but generally quite possible to do have some food intake
through the breeding migrations of whales since energy budget for locomotion in large rorquals seems to be scarcely well balanced in general patternof their movements. These overall situations regarding the energy for locomotion were discussed along with the seasonal distributions of whales and alsowith the so-called problem of the breeding grounds.

INTRODUCTION
In the consideration on the seasonal changes of nutritive condition in California graywhale, Eschrichtius robustus, Rice and Wolman made a calculation on the expectedamount of energy expenditure throughs wimming locomotion being based on the
body weight difference due to the combustion of tissue before and after theirmigratory journey, and the weight loss was assumed as a function of oxidation of fat(Rice and Wolman, 1971). Being found that the overall energy budget for locomotion seems well balanced, Rice and Wolman (1971) concluded that gray whalemust be able to perform migrations of such large distance as invade far deep into
the Bering Sea and/or the Chukchi Sea without causing any malnutrition, anddescribed, " there is no reason to assume that gray whale must feed while on
the winter grounds ". Since gray whale is one of a well known regular migrators
among large whales, the above mentioned result itself would be appropriate in
the subject of controversy concerning to energy budget of migrating whales. VerySci. Rep. Whales Res. Inst.,
No. 27, 1975, 61-79

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KAWAMURA

recent aerial observations, however, revealed that gray whale clearly feed on small
fishes on the way of their southbound migrations (Sund, 1975).
On the other hand, however, the baleen whales other than gray whale actuallydistribute with more larger numbers in the world oceans. They are balaenid andbalaenopterid species of which the latter would be historically most important
relating to human activities as an industorial resource. The general ecology aroundbalaenopterid whales especially in so-called rorquals much differs from that ingray whale, that is to say, we are still in need of a verification in rorquals on thismatter whether or not we will find similar conclusion to the results by Rice and
Wolman. Under these circumstances I made a calculation and assessed the energy
cost in relation to the swimming locomotion along with the overall energy budget
through the seasonal migrations in southern fin whale, Balaenoptera physalus, andthen extended a consideration to the seasonal distribution of whales.
NOTES ON THE SEASONAL MIGRATIONS OF WHALESThe conception that large whales are very likely to make seasonal migrations
which extend over those vast oceans seems to have come in general knowledge as aresult of accumulating a great deal of fragmental evidences brought on by navigators,
fishermen and whalemen through many past years, but its substantial features
remains still obscure even today. One of well dealt descriptions on the seasonal
distributions in a north and south direction in the North Atlantic balaenopterids
species was worked out by Scoresby (1820), by which our knowledge on the migrations of whales made much progress. Discussing on the evidences of whale sightingsin nineteenth centuries, Scammon (1874) could describe only a possible north- andsouthbound migratory habits for humpback whale, Megaptera novaeangliae, andright whale, Eubalaena gracialis in northern hemisphere is unlikely to migratecrossing over the equator. There are another evidence that some blue whale,
Balaenoptera musculus remains in the waters off California throughout the year. The
seasonal migrations and the movements of whales are such variable and complicatedby each whale species and place from time to time that the matter cannot be said
as the comprehensively well explained subject.
Although it was not the aim in his discussion, True ( 1904) described that some
North Atlantic humpback whale migrates down to at least l8°N latitude. Kellogg(1929) well reviewed on the migrations of six species of baleen whales based on theavailable evidences by that time. Although his descriptions were mainly confinedto the northern species of whales, he (Kellogg, 1929) also mentioned but briefly on
the migrations in southern species. By his above mentioned review the generalidea concerning to the migrations of whales became much clear but still mysterious
especially in recognizing the movements of whales as a large scaled and successive
event performed through a life span of each whale individual, that is, the migrations of animals in broad sence. The comparative field study by Mackintosh andWheeler (1929) on the biological and morphological characters in southern blueand fin whales of both South Georgia and Saldanha Bay made our knowledge on
Sci. Rep. Whales Res. Inst.,
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LOCOMOTION ENERGY AND MIGRATIONS

63

the migrations of whales much concrete. Shortly, it can be said that pattern of
the whale migrations to the extent as have currently been recognized conception
may be basically established by their work. However, movements of whales andwhere they may stay during winter or so-called non-feeding seasons are almost
unknown even today except those traditional expressions of somewhere of " warm
temperate or tropical waters."
According to Mackintosh and Wheeler (1929) connective tissue lies beneath thevery surface skin of whales is the main body for depositing fatty substances, andthe thickness of the blubber itself varies by season in southern species, that is, morethin layered blubber is found just after the winter and get more fat by an approachof autumn as a result of voracious feeding through the past several months in the feeding ground, whereas little feeding takes place in South African waters. With thesefacts along with a possible identity of whale populations which occur in both South
Georgian and South African waters, it was obvious that both blue and fin whales
are likely to make meridional migrations by season through which they do not
feed but can continue swimming around by expending the blubber oil as the energy
source for their locomotion. The general idea of the seasonal migrations of large
baleen whales became clear to such somewhat fixed forms as having been recognized.
At the same time the reason why they have to migrate into those " warm temperate
or tropical waters " was well explained by supposing that cold feeding grounds ofalmost freezing point would be disadvantageous for parturition and for new born
calf to keep well its body temperature. The conception seems fairly well establishedand there have found no additional evidences or explanations regarding this mattereven in recently published articles which in part dealt seasonal distributions, feeding
and breeding migrations for large whale species of the world oceans (e.g. Slijper,
1958; Jonsgard, 1966; Mackintosh, 1965, 1966; Nishiwaki, 1966; Matthews, 1968).
However, Kellogg (1929) considers that there must be some fin whales throughout
winter season in the South Georgian waters, and Mackintosh (1965) thinks thestatus of whale migrations as a possibly very loose and/or somewhat random
movements in general, that is, some individuals may stay in the feeding grounds
throughout a whole year while the other may not undertake those annual back andforth movements so regularly. Reviewing on the geographic ranges and seasonal
distributions for large whales in the North Atlantic, Jonsgard (1966) consideredthat some whales may stay in the boreoarctic part of the North Atlantic, but he
did not deal much about the breeding migrations by reason of less documented
subjects. On the other hand, Mackintosh (1966) described two kinds of interestingand suggestive ideas on the status of migrating whales whether they are apt to concentrate or disperse in the breeding grounds. Matthews (1968) explained the seasonal migrations of whales schematically but he remained within showing a " warm
temperate or tropical seas " as the destination of migrating whales. Recent description by Gaskin (Gaskin, 1972) concerning to whales migrations made a subject
clear in a concrete form that the sea region where the reproduction of fin whaletakes place would be found in the offshore waters within 150 miles or thereabouts.
Where are the large whales during winter or reproductive season is still mysSci. Rep. Whales Res. Inst.,
No. 27, 1975.

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KAWAMURA

terious subject which could be approached only by accumulating a scattered evidenceson whale sighting. In the North Pacific region, for instance, a possible place forover wintering in fin and sperm whales seems to be still beyond of our scientificknowledge. Although an approximate movements of migrating whales may berecognized after the general principle as mentioned above, it seems still in need offurther investigations and considerations to prove the matter more clearly. For

@®

CD©

®

®

Fig. 1. Points for girth measurements.
Table 1 and Fig. 3.
TABLE 1.

Encircled numerals correspond to those in

GIRTH MEASUREMENTS IN THE SOUTHERN FIN AND

Ser. No.
1656t

167ltt

1673

1676

Sex
Body length (m)Thickness of blubber (cm)

F
21.1
7.0

F
17.5
6.5

M
17.6
6.5

M
17.5
5.0

Date of catch (month/day)

3/11
49-09
77-42

3/12
49-16
79-32

3/12
49-16
79-32

3/13
49-28
80-31
200

810

900

860
850

780

644

560

496

286

238

674
560
448
330
208

630
530
464
300
208

Position of catch ~ ~ ~Highest point of lip
Center of blow hole
Eye
Angle of gape
Anterior base of flipper
Tip of flipper
Posterior end of ventral grooves
Unbilicus
Center of genital apertureAnus
11 Center between dorsal fin and base of tail flukes
12 Base of tail flukes
2
3
4
5
6
7
8
9
10

* Measurement at 140 cm anterior from the base of tail flukes
110
**
150
***
1) Measurement at 238 cm posterior from the base2) Posterior margint) Pregnant: foetus of 281 cm, femalett) Not pregnant

Sci. Rep. Whales Res. Inst.,
No. 27, 1975.

65

LOCOMOTION ENERGY AND MIGRATIONS

instance, whether or not non-feeding activity during seasonal migrations explains or
actually fills overall locomotion energy required for migrating into those "warmtemperate or tropical seas" only by expending the blubber oil without causing
malnutrition.
MATERIAL AND METHOD
During the course of 1971/72 Antarctic whaling season when I was on boad of themother ship " Tonan Mam No. 2 " of the Nippon Suisan Co. Ltd., girth of fin andminke whales was measured at three to nine points of the carcasses (Fig. 1). True
(1904) noted several girth measurements on the basis of one side or whole of carcasses, and Captain Roys gave 39 ft. of girth for 95 ft. blue whale in 1800's (Scammon, 1874). However, since very little girth measurements have been done in
the ordinal program of the biological examinations on whale carcasses, I would like
present here the whole row data of the girth measurements in nine fin whales (6male and 3 female) and four male minke whales for the convenience of later use(Table 1). As shown in Table 1 both fin and minke whales were caught in the
mid March of 1972. Two-meter measure was used for actual measurement by
MINKE WHALES CAUGHT IN 1971/72 ANTARCTIC SEASON
Fin

Minke

1678tt
F
19.3
6.5

1679

1692

1702

1705

16-1

M
17.4
5.5

M
20.9
6.0

M
17.7
5.5

M
18.1
7.0

3/13
49-28
80-31

3/13
49-28
80-31

3/14
49-46
80-03
240

3/14
49-46
80-03
180

3/14
49-46
80-03
220
7702'

M
8.4
4.6
(Avg.)
3/16
53-58
85-16

16-2
M
8.2
4.6
(Avg.)
3/16
53-58
85-16

4.6
(Avg.)
3/16
53-58
85-16

26-2
M
8.4
4.6
(Avg.)
3/16
53-58
85-16

316

316

314

354

420
480

426
492

408
448

412
470

490
450
372
296
234
100

500
480
376
290
216
108

440
426
346
262
200
108

452
432
356
280
216
100

23-1
M

310
860

596
558
380*
268

560
480
296**
186

Sci. Rep. Whales Res. Inst.,
No. 27, 1975.

720
626
560
354
232

794
854
8041'

790

640
540
470
300*
192

920
600
532
320***
220

66

KAWAMURA

sliding the scale like a looper. The air which had been filled in the ventral cavity
to make the carcasses afloat was discharged when the carcasses were pulled up
onto the £lensing deck except no. 1673 fin whale which kept some amount of air
but not fully. Each girth measurements given in Table 1 are obtained by doubling the actual figure from one side measurement. Measurements at nos. 1 and 3
points show only the upper half, that is, only a part of the skull.
Since no measurement for so-called body proportion analysis on the carcasses
concerned in Table 1 was conducted, the proportion data obtained in the South
Georgian fin whales by Mackintosh and Wheeler (1929) were adopted as the pos-

t'

l.18
1.07)
18.86
(18.94)24.45(24.83)28.51
44.57 (28.71)(44.35) 45.82(45.59)Fig. 2. Average body proportions (in percentage figures) for the southern fin
whales. Figures for female are given in brackets (Calculated from the data by
Mackintosh and Wheeler, 1929).
SQUARE METER

I· 17.97 + 17.39 +

®
I
I

®

®

19.67

+ 14.36 .j:·o~1 • 9.42 •I• 4.05 ·!

0

®@

@

@
I

"II

1+-----------13.57 M - - - - - - - - + t

Fig. 3.

Surface area of body trunk for a southern fin whale (18.l m, male).

sibly most well representing figures to know relative position of the girth measurements (Fig. 2). Of six fin whales 18.1 meters of male individual (no. 1705 specimen
in Table 1) which was most well measured was selected for the calculation of bodysurface area, and consequently, the volume of the blubber. By this treatment thewhole body surface area was calculated section by section as given in Fig. 3. Anterior part from blow hole and tail flukes were excluded from the calculation sincethese two are considered unlikely to relate to the question to be discussed here. DisSci. Rep. Whales Res. Inst.,
No. 27, 1975.

LOCOMOTION ENERGY AND MIGRATIONS

67

tance between notch of flukes and the anterior base of tail flukes was hardly determined clearly, and 4.0 percent was adopted tentatively for its proportion: thenthe actual body length which concerns to a consideration is 13.57 meters, and thewhole body surface area corresponds to 13.57 meter body length is calculated as
89.924 square meters (ea. 90 m 2 ).
The thickness of the blubber with connecting tissue beneath the epidermis anddermis considerably varies with the seasons. In southern fin whales caught in theSouth Georgian waters averaged difference in the thickness of the blubber against
body length in percentage figures was 0.37 for summer and 0.27 for winter respectively (Mackintosh and Wheeler, 1929). The material of 18.1 meter fin whale
showed 7.0 cm thick blubber, that is, 0.39 percent against its body length while it
was only 5.0 thickness (ea. 0.29 percent) in another material of 17.5 meter male fin
whale. Comparing these figures with those obtained in South Georgian waters,
TABLE 2.

DATA AND ASSUMED CONSTANTS CONCERNING TO THE
CALCULATIONS FOR FIN WHALE LOCOMOTION*

Species
Position of catch
Date of catch
Body length
Sex
Thickness of blubber
Area of blubber concerned**
Body weight***

Fin whale : Balaenoptera physalus
49°46'S, 80°03'E
March 14, 1972
18.l mMale
7.0cm
89.9 m 2
34.0 tons

Thickness of blubber expended
Caloric value for blubber oil
Specific gravity of blubber oil
Energy cost for locomotion
Efficiency of muscle in performing
external work
Condition of swimming
Estimated migration distance

2.0cm
9.34-9.45 Kcal/gr.
0.92
0.022 Kcal/gr./Km
25%
10 knots, laminar flow
2.1x10'-2.3X10 4 Km

* for further detail see Schmidt-Nielsen (1970, 1972) and Kawamura (1973a, b)** body trunk proper: anterior part from blow hole and appendages are excluded*** after the formula by Ash (1952)

the 7.0 cm thick blubber in 18.1 meter fin whale would possibly be at its upper
most extremes as the function of depositing whale oil, and similarly, 5.0 cm thickblubber would be at its lower extremes. These facts suggest that the blubber oil
which corresponds to 2.0 cm difference in the thickness of the blubber is likely to
be consumed through the migratory journey. According to Slijper (1958) about
40.0 percent of the blubber is in general consisted of connecting tissues. So if wetake this figure into considerations the total volume of whale oil preserved in the
2.0 cm thick blubber for 18.1 meter fin whale would be calculated as about 1.80
cubic meters. Assuming five months between May and September as for the duration of whale migrations, the blubber oil as the energy source for locomotion would
Sci. Rep. Whales Res. Inst.,
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KAWAMURA

be about 0.36 m 3 ·month-1, or 1.2 X 10 4 ml·day- 1 • Since generally known caloric
value and specific gravity of fin whale oil is 9.34-9.45 Kilocalories • gram-1 and 0.92
respectively, the unit volume of consumable whale oil could be converted to 1.1 X
104 gram·day-1, or 10.27Xl04 -10.39xl0 4 Kilocalories·day-1 • The grand totalof consumable energy during five month migrations in 18.1 meter fin whale
would be about 1.55X10 7 -1.57 X 10 7 Kilocalories. Data and some constants concerning to above mentioned calculations are given in Table 2.
ENERGY COST FOR LOCOMOTION IN FIN WHALESThe energy cost for swimming locomotion in large whales is still unknown. However, it seems possible to speculate the energy cost for locomotion by the aid of known
data in small toothed whales and in some another kind of aquatic animals (e.g.
Schmidt-Nielsen, 1970, 1972). As I showed previously (Kawamura, 1972), theenergy cost in large whales seems to be very less expensive when it is comparedwith the case found in another species of aquatic animals. Only four percent orthereabouts in daily feeding rate in sei whale (Kawamura, 1974) and possibly
similar figures in another species of baleen whales would support very less energy
expenditure for locomotion in those large whales. According to Schmidt-Nielsen(1972) the energy cost in a dolphin of 100 Kilogram body weight is about 0.1
Kilocalories·Kilogram- 1 °Kilometer-1 when it swims through laminar flow of waterover the body at 10 knots in speed if we assume its conversion efficiency of muscle
in performing external work would be 25.0 percent whereas 22.0 percent was assumed by Gawn (1948). In general the energy cost for locomotionin animals is
closely related to the body weight of animals, and changes by following after the
exponential like curve (Schmidt-Nielsen, 1970, 1972). Then the energy cost or
metabolic rate such as 0 2 ml·gr-1 ·h-1 in relation to the body weight of animals canbe expressed under logarithmic scale by three different regressions each of whichshows difference by the kind of living media; whether the animal flys, runs, and/or
swims. Since these corelations can be followed in aquatic animals and seems to
be not unreasonable for extrapolating treatment, the energy cost for locomotion ( =swimming) in large whales would be known reasonably by extrapolating theirbody weight onto known energy cost-body weight relationships.
Then the energy cost for swimming in 18.1 meter fin whale which weighs about
34 tons is estimated as 0.022 Kilocalories·Kilogram- 1 °Kilometer-1 if the same
parameters are assumed as in the case of dolphins, that is, the animal swims at the
speed of 10 knots under laminar flow of water over the body and 25 percent in theefficiency of muscle in performing external work. (See Schmidt-Nielsen, 1972,
fig. 7) Similarly a blue whale of 100 tons of body weight would expend about
0.014 Kilocalories°Kilogram-1 °Kilometer-1 as its energy cost for swimming. The
data indicate that the large rorquals seem to expend some 1/5 to 1/7 times of energy
cost than the dolphins.
The actual energy cost in 18.1 meter and 34 tons of fin whale may be 7.48 X
102 Kilocalories • Individual- 1 • Kilometer-1, and some 2.10X10 4 -2.36 X 104 times
Sci. Rep. Whales Res. Inst.,
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LOCOMOTION ENERGY AND MIGRATIONS

69

of these cost would be required for five months migration since its totaled energy
corresponds to 1.55 X 10 7 -1.57 X 10 7 Kilocalories. These facts indicate that the18.1 meter fin whale can migrate for the distance of some 2.1X10 4 -2.3x10 4
Kilometers by expending its blubber oil preserved in 2.0 cm thickness of the blubber.
Actually, however, slightly more energy expenditure must be took into considerations since the metabolic rate as examined in human body increases for 10-20 times
according to the physical conditions whether he moves vigourously or rests (Yoshikawa, 1959). Jumping, leaping or breaching (Racovitza, 1903) behaviours in large
whales are often observed on high seas, and several times of these kind of violent
movements which may be induced by playing, chasing, and/or escaping from theenemy would possibly be a quite daily event in the wild life. All of these areresponsible for increasing the energy expenditure, since whales were assumed as
migrate constantly under 10 knots of swimming speed throughout their migratory
journey. In gray whale, however, Rice and Wolman (1971) have found well- balanced energy budget being based on the "actively swimming animal", and 10
knots in swimming speed would also be allowed for general considerations as a
totally averaged figure in energy expenditure.
CONSIDERATION ON THE AMOUNT OF WHALEOIL AND THE ENERGY COST
The calculation as has been described in previous section was introduced by following after the several assumptions: 1) Whale oil preserved in the blubber aroundhead and ventral grooves, and that in bones and internal tissues are not utilized
as the energy source for locomotion, 2) Whale oil which corresponds to 2.0 cm
thickness of the blubber which covers over main body trunk is consumed as theenergy source for locomotion, 3) Energy cost for swimming locomotion in large
rorquals was estimated by extrapolating the parameters into the known regression
line in aquatic animals and, 4) As it was assumed in the case of dolphins, the efficiency of muscle in performing external work would be 25 percent, and the animal
swims at 10 knots under laminar flow of water over the body.
Concerning to an absolute amount of whale oil itself, the whales body under
alive would contain much more than that considered in this report. For instance,
Omura et al. (1942) showed that the 18 m meter fin whale caught in the coastal
waters of Ja pan yielded 0. 73., 0.5 and 0.5 tons of whale oil from the blubber, bones
and internal organs respectively. Arai et al. (1950), on the other hand, showedthat 53 percent of the blubber around whales head contained whale oil and 65
percent was in the blubber around the back. Following to these oil rich parts themuscle around lumber to tail flukes, ventral grooves and/or abdomen contains ratherrich (Feltmann et al. 1948) but less than 20 percent or so of whale oil. That is, thepotential in preserving the whale oil as the energy source would be reduced toabout 1/3 when it is compared with oil rich parts, and the amount of whale oilfrom an individual must be more greater than usually expected, whereas theirimportance as the energy source for locomotion would be less than the blubber oil,
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KAWAMURA

since most of whale oil preserved in bones or some other parts other than the
blubber is considered to be unlike from physiological reasons to be consumed forthe purpose of locomotion.
It is well known fact that whales caught in the beginnings of Antarctic whaling
season show slender body trunk due to not only their thin layered blubber but also
possible consumption of oil and fatty substances preserved in the whole body.
Considering on this fact along with a comparison in metabolic physiology found inanother animals, the whale oil preserved in the tissues other than the blubber
would be consumed to some extent as the energy source for locomotion. And if
we assume some physiological analogy between whales and human body (Yoshikawa, 1959), whales under some peculiar occasions or situations may consume
not only their oil but also do even proteins of body tissues.
Whale bones also contain a considerable amount of whale oil, but it is presumably not consumable as the energy source for locomotion by reason of thefunction of bones themselves. The strength of animal bones is the function of theirsectioned area and it increases only by following after a square number relations withbody length whereas body weight of animals which must be suspended by the bones
increases by cube number relations. Although the whales, a typically well adapted
animals for aquatic environment, do not need such strength as terrestrial animals, andthe bones of whales are not structured well like those animals. Then the function
or physiological process which makes the strength of bones reduce much by consuming the contained whale oil may have to be kept as little as possible. Still
more, the deposit of whale oil among many organs seems to occur firstly in the internal organs, fatty layer and then in the bones by this order (Omura et al. 1942).
This fact also supports the assumption that whale oil preserved in the bones seems
to be hardly consumed as the energy source for locomotion.
From these discussions it would be reasonable to consider that there are somestill more amount of consumable whale oil in living animals while some are notavailable as the energy source for locomotion. As it was described previously thewhale oil only from the blubber can make the whales swim for 20,000 km or thereabouts. Then if some additional energy source for locomotion is expected, thedistance could be moved potentially without reducing any physiological functions
such as a malnutrition in large rorquals would be somewhere between 20,000 Km
and 30,000 Km. On the other hand, Mackintosh (1966) supposed the migrating
distances covered by large rorquals must be somewhere between 1,000 and 3,000
miles. These figures, however, correspond to only about 17 to 50 degrees of latitudes, and are considered rather under estimations.
There are no ways to prove how much extent the energy cost obtained by an
extrapolation for large rorquals is appropriate or not. The estimated energy costof about 1/5 of dolphins, however, can be discussed little more in the point of
metabolism of animals. The basal metabolism of animals closely relates to the bodysurface area. Bottlenosed dolphin, Tursiops truncatus which weighs 100 Kg. has
1.85 m 2 of body surface area (Ridgway, 1972). If it is assumed that the surface
around its head occupies about 20 percent of the whole, the surface around body
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LOCOMOTION ENERGY AND MIGRATIONS

71

trunk would be 1.5 m 2 • On the other hand, 18.1 meter fin whale has about 90 m 2
of body surface area which actually corresponds to 13.5 meter long of body trunk
only, and weighs 34 tons. Comparing with these figures of both bottlenosed dolphin and fin whale, the ratio in body weight shows 340 times larger in fin whale
whereas only 60 times in the ratio of body surface area. The well averaged numberof respiration in dolphins and phocids is 2 to 3 respirations •minute-1 while it is 1 to
2 respiration(s)·minute-1 in fin whales (Scholander, 1940). The large whales
consume comparatively little amount of oxygen than the dolphins, and are able toswim under very well controlled energy coefficient. In this respect a slight change
in body length or body surface area affects well on the whole metabolism of animals
by following after the Rubner's surface law. Actually, since the body surface areaof fin whale would reduce to some extent while they are enroute through migrations, the energy cost for locomotion may also reduce. This may be one of thereasons why large rorquals perform seasonal migrations by less energy expenditurethan the dolphins and also possibly than the figures estimated by extrapolation. It
is possible, therefore, that the energy cost and body weight relationships in large
whales may not expressed by a simply extended regression lines but by a slightly
curved or the folded lines with different coefficient.
However, these relations which have been known in another animals are well
expressed by setting up a simple regression even for between mouce and horse. Concerning to this extrapolating problem, Schmidt-Nielsen (1972) described as "Although we have no inherent right to extrapolate from the salmon to the dolphin, we
can safely assume that both animals are hightly adapted and effective swimmers,
and extrapolating from a I-kilogram salmon to a 90-kilogram dolphin is not unreasonable ". Similarly it was considered that large whales also could be extrapolated onto the regression line. In concluding this section the followings may
give a standards: the energy cost for swimming locomotion in average sized fin
whales is 0.02 Kcal.·Kg- 1 °Km-i, and overall distance which could be moved
without feeding both on breeding grounds and on the way would be somewhere
between 20,000 km and 30,000 km.
MIGRATIONS OF WHALES AND ESTIMATEDDISTANCE TO BE PERFORMED
Generally recognized destination for migrating rorquals is " warm temperate or
tropical seas" if not exclusively. Therefore, it would be worth to discuss whether
or not the distance which was estimated by the available amount of energy forlocomotion and its cost for swimming in fin whales is an accessible distance alongwith the known evidences regarding the migrations of whales to the warmer waters.
If we assume that the whales leave the Antractic feeding grounds at 60°S andstart their northbound migrations heading for the equator and again return to thestart line along the same meridional pathways, the distance covered by this round trip
is 13,320 km. That is, the whales are able to move or play around more for only
7,000 km or corresponding energy expenditure. Since little is known on the pattern
Sci. Rep. Whales Res. Inst.,
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of daily life in large whales except several but fragmental observations (e.g. Schevill
and Watkins, 1966; Cousteau and Diole, 1972), it seems still in some difficulty toestimate even an integrated distance performed by a whale in a day. It is, however, reasonable to consider that whales are unlike to swim straight but trace aquite complicated pathways which gives far more doubled distance than is consideredby an actual situation, since the daily behavior of animals may possibly have notnecessarily any objects from one end to the other.
Following fact is very suggestive concerning to the daily movements of whales.
In the whaling ground which is one of the terminal places in whales migrations, where
the whales stay for some duration within a certain range to feed by moving backand forth, it is often experienced that the whales having been spotted in the previous evening are hardly found again in the next day. In this case it is well supposedthat the whales had moved for a considerable distance during the previous night.
To make the matter clear it would be convenient to assume the case that thosewhales were sighted again after 3 hour scouting through surrounding waters at the
speed of 15 knots. Then about 2 hours out of 3 hour scouting would be the component giving away from the starting point, that is, the whales moved at least for 2
hours as to give the distance between catcher boat and themselves. J.-Y. Cousteau
attached a specially designed marks on the back of a fin whale to make him easy forchasing it through the night, and he observed that the whale usually continued tomove at the speed of 6 to 7 knots though the whale stopped several times during theobservations (Cousteau and Diole, 1972, p. 72). Their observations give us aknowledge that the whale may considerably move around even through a night.
From these facts it would be quite natural to consider that the whales are apt tomove at least for several tenth miles within a night. If the whale migrates from
60°S to the equator at 10 knots in swimming speed, 15 days would give them enoughtime to get to their destination; the terminal sea regions of so-called "warm temperate or tropical seas " where the whales stay for the rest 4 to 5 months. Thereis no reason to doubt that the daily behaviour of whales differs much both in feeding
and breeding grounds. The estimated distance for nocturnal movements in large
whales, 30 miles per 10 hours agrees well with the swimming speed found under
the natural or undisturbed conditions, and that distance would be a minimum or
close to the lower extremes, since it was estimated being based upon a possible
zigzag movements. The whales seem to move at least about 72 miles ( = 130 km)
in a day, and 15,000 to 16,000 km would be the integrated distance covered during
4 month stay in the terminal sea regions.
Accordingly the grand totaled distance which is performed through 5 monthround trip migrations would be at least some 28,000 to 30,000 km. As it was shown
previously the 18.1 meter fin whale is able to move only for 20,000 km or thereabouts by expending its blubber oil of 2.0 cm thickness, and may have to face ashortage of locomotion energy unless the whale oil or fat of another source wasconsumed supplementally. These estimations suggest that even well adapted
whales for aquatic environment are hardly possible to perform migratory journeyto those " warm temperate or tropical seas ".
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73

However, if the supply of whale oil from the muscle and connecting tissues in
addition to that from the blubber could be considered, and/or if slightly more than
2.0 cm thick of the blubber oil was consumed, the budget of energy expenditure
required for those migrations would be well balanced. Actually the large rorquals
distribute all over the world oceans and most of them sternly keep 4 to 5 cm thickof the blubber even after a very long journey for 5 to 6 months. On the other
hand, there are actually the whales which keep very thin blubber even in late March,
the time they have to leave the feeding grounds for breeding. These very slenderbodied whales seem unlike to consume their blubber oil any more as the energy source
for locomotion, since it may cause some physiological difficulties to reduce their
blubber oil deposit, and the statistics on the thickness of the blubber also suggest
its unlikelihood. Then slender bodied whales have to change or modify theirmigratory pattern and fashion of life, which may somewhat different substantiallyfrom that of the majority of normally fatted whales. For instance, poorly fatted
whales cannot but remain within some migratory range and/or have to migrate intosome productive and organism rich coastal waters where they can feed to a certain
extent. The whales may have to swim so economical basis as to reduce theenergy expenditure as little as possible since the energy for locomotion in any kindof whales does not seem to have been provided sufficiently. It is well known fact in
the Antarctic feeding grounds that the whales move longitudinally for rather widely
ranged zone extending for two or three of six sectors, whereas they are apt to follow
the cource along the continent or islands in breeding migrations, and little of themmigrate into the real mid oceans. These general tendencies are well observed bywhale sighting at high seas and by the recovery of whale marks (e.g. Dawbin, 1959;
Ivashin, 1971; Mozer, 1971). Whales which have distributed rather randomly
within the feeding grounds are apt to concentrate along their migratory pathways but
it is far sparce and loosely packed gatherings like a stream and is hardly comparable
to so-called school or herd of animals. Humpback whale apparently shows somegatherings as a unit of local populations enroute their breeding migration (Daw bin,
1964; 1966), but these kind of whale movements if not clear like the humpback
whale may also be found in rorquals. These general tendency in whale movementsor migratory habits may closely related to the productive seas or the occurrence ofrich standing stocks of organisms, and most of which is found in the marginal waters
along the continent or islands. A fertile zone such as an equatorial divergenceregions too attracts whales even if it is found on high seas. Considering on thefood and feeding of baleen whales, Nemoto (1959, p. 281) concluded that the movement of whales in the North Pacific and Bering Sea regions is closely related to thegeographical characters such as the shape of the sea, and fin whale occurring in
those waters can be considered as " ocean and marginal denizen ".
The energy for locomotion in rorquals migrations seems to be balanced on thewhole. It is, however still desirable to minimize the energy expenditure as little
as possible since an amount of whale oil preserved in a body is far less for a luxuariant
consumption. Therefore, it would be better and/or appropriate for most of migrating whales to take linear like pathways both in north- and south-bound migrations.
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For instance, little number of whales in the southern waters of Australia would
migrate to the tropical African coast by crossing the Indian Ocean diagonally.
Sperm whales evidently swim at least 600 miles within 8 days between the Antarctic
and South African coast (Clarke, 1972). This fact strongly suggests that the whaleson the whole, once they begin the migrations, can travel very rapidly even though
they feed on squids on the way.
The migrating whales are considered to be apt to invade into the almost sameor very close region of terminal seas every season. In the coastal waters off Abashiri,
Hokkaido, there once was a fin whale which was easily identified by its characteristically well damaged dorsal fin, and this animal used to be spotted if not entirely inthe same place at least in the beginning of season (Omura and Kawamura, 1968).
Similar evidence or possibility is also documented in the Antarctic fin whale ofArea II based on the recovery of whale marks (Brown, 1962, p. 14), and, thesesituation was expressed as "something like a migration route" (Mackintosh, 1966)
which is somewhat similar to "corridors" called in the migration of birds (Orr,
1970). Since it would be hardly possible to modulate the season and place of
migrations with considerable accuracy, the migration of whales as a everlasting
phenomenon could be recognized only when the migrations of whales were assumed
as follows; in order to perform the migration with those above mentioned kinds ofaccuracy, the whales may have to migrate at full or near at full speed without
wasting time on the way by following well known migratory pathways along withthe aid of well experienced navigation.
GENERAL CONSIDERATIONS IN CONNECTION WITH
THE DISTRIBUTION OF WHALESAs it has been discussed in the previous section, the budget of energy expenditure
for locomotion in large rorquals seems rather complicated, and cannot but consider the subject analogically by the aid of some assumptions, since there are so
little suggestive evidences which were obtained in the field observations. For instance, it is still beyond of our knowledge where and when the perturition andmating of rorquals will actually take place in those vast " warm temperate or
tropical seas ". No other evidences except those have been refered to seem to beleft for the further discussion, and following discussions are a kind of conclusive
view points in which the movements of whales is considered along with the generalfeatures of the distribution of whales.
In rorquals the pattern, habits and the behaviours in the way of life are quite
naturally and generally recognized as a regular migrators which move between coldpolar seas and warm temperate or tropical seas, and these are considered appropriate from the overall budget of their energy expenditure for locomotion, sincemajority of whales are likely to be well balanced in this instance. However, anamount of whale oil or fatty substances preserved in the whales body considerably varies with the physiological status or biological characters endowed with eachwhale species. Still more, the wild animals would presumably have to keep afford
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75

in the energetic budget to make their behaviour more fruitsfull under the wild
environment whereas the budget in energy expenditure actually seems to be very
tight. In this instance, it would be reasonable and natural to suppose that thewhales usually must feed to a certain extent even if they are on the way of migrations. California gray whale which are supposedly well balanced in the energy
expenditure can perform seasonal migration without taking any foodstuff throughtheir round trip migrations (Rice and Wolman, 1971 ). Even in gray whale, however, feeding activity seems to be not unusual at least in their southbound migration close to the regions of their breeding grounds (Sund, 1975). The idea that
more rorquals do not seem to feed or be under almost starved condition during
their migrations (e.g. Jonsgard, 1966; Mackintosh, 1966) would be hard to believe if not exclusive. In general the metabolic rates increase high in the warmer
environment than in the colder one, and this may become serious in small younger
animals since they swim under relatively high energy cost for locomotion than thewell aged animals. That is why large rorquals do not concentrate much in mid
oceans where a monotonous but well stabilized environment prevails, but morecommonly found in some coastal or offshore waters of structural complexity, thatis, the region of high production or rich in standing stocks of organisms whichis undoubtedly advantageous for occasional feeding. Two ways of the possible
status for migrating rorquals whether they concentrate or disperse in the breeding
grounds (Mackintosh, 1966) are quite suggestive on the whole. In the latterinstance the evidence that many whales are spotted in offshore waters within acertain ranges in lower latitudes strongly suggests a possible feeding activity of
whales as the case explained by Clarke (1962). Even planktivorous species ofbaleen whales apt to feed on shoaling small fishes and their larvae according to thetime and place. A typically similar situation is found in the comparison for food
habits between the North Pacific and the Antarctic (Nemoto, 1959; Kawamura,
1973, 1974). That is, there reason to believe that the baleen whales in breeding
grounds may feed on some organisms such as the larvae of skipjacks, tunas and ofmany other warm water fishes. By taking these general situations along with
presumed physiological conditions and feeding habits in large rorquals into consideration, it seems reasonable to believe the food intake during breeding migrations as the comments by Dr. Sergeant. (Mackintosh, 1966, pp. 143-44).
One of explanations why rorquals migrate to those " warm temperate or
tropical seas " is an advantage for breeding especially for the safety of newborn
calf of very thin blubber and make them easy to keep body temperature from chilly
environment. Antarctic minke whale, Balaenoptera bonaerensis, likely to show rather
irregular breeding cycle (Ohsumi, personal communication) than the other rorquals
which show an approximately one-year cycle. In this instance some individuals of
the Antarctic minke whale may have perturition during their stay within thecolder region, and how is the case for the calving in bowhead whales, Balaena mysticetus, explained. In this respect the Kellogg's pointing out that "it is not the sea
temperature but the food conditions that induce whale migrations " would be quite
suggestive itself (Kellogg, 1929, p. 45). Kellogg's idea also make us consider that
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the migrations of whales is desirable to be treated by each whale species.
Results of whale sighting in the Atlantic and Indian Oceans show the year
round distribution oflarge whales in the temperate and tropical regions (e.g. Town: end, 1933; Brown, 1957, 1958; Zenkovich, 1962). In those waters populationof whales may be consisted of the several different origins: some may come fromnewly migrated population and the other may somewhat from endemic or locallyseparated population such as the fin whales in the East China Sea (Fujino, 1954;
Ichihara, 1957) and sei/bryde's whales in the northern waters off North Island of
New Zealand (Dawbin, 1959, p. 15). Those locally separated whales seem to staythere throughout the year, and consequently, may have to feed on regardless theseasons. Then it is quite unlikely that the only newly migrated whales do not feedon among those taking food in those local waters. In the waters off California blue
whales are usually seen throughout the year (Kellogg, 1929), and they can feedon sardine and prawn in San Quentin region, lower California (Scammon, 1874).
Apart from the seasons, great number of large whales are apt to concentratein the zones between 30° and 40° of both south and north latitudes of the Atlantic
and Indian Oceans (Brown, 1957; 1958), and humpback whale, Megaptera novaeangliae stay in the offshore waters of lower latitudes throughout the year along the west
coast of South America. In the Arctic regions of the North Atlantic some humpback whales stay throughout the winter (Kellogg, 1929). One of another instances
is Pacific black right whale, Eubalaena gracialis which are found close to the ice-packin the Okhotsk Sea and Bering Sea regions, and then fin whale in Queen Charlot
Sound, north of Vancouver Island of approximately 50°N during February (Scammon, 1874). These facts indicate that the actual pattern of distributions in large
baleen whales, if not entirely, do not always coincide with those ideas generally
known as migration cycles. The " tropical seas " is considered unlikely for mostwhales as to be a destination being invaded after the painstaking long journey, andthis make us even doubt whether or not those habits are inevitable for carrying out
an appropriate life of whales. In the general fashion of the distribution of whales,
however, age, sex, and physiological status of each whales would relate to theirmigrating movements though the details on this subject have been known little
except the case in sperm whales, Physeter catodon, which once had caught in all over
the world oceans and are known as very highly socialized animals in the mode ofline among large whales (e.g. Mackintosh, 1965; Gaskin, 1970; Berzin, 1972).
Then the structure of population in baleen whales which occur in " warm temperate or tropical seas" may be a subject to be known in future. The baleen
whales may have to feed to a certain extent in food rich waters regardless seasons,kind and origin of whales stocks. Some blue whales are believed to feed actively
in the waters south and south east of Madagascar, which are located far northfrom the Antarctic feeding ground proper (Gambell et al, 1974). The ideas ofboth non-feeding activity and seasonal migrations in large whales are not primarily
the phenemon of two sides of a thing but independent each other, if not, the actualfeatures in the distribution of whales would hardly be explained.
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77

CONCLUSION
Some whales keep rather sufficient energy source to perform the migration
between cold feeding ground and warm breeding ground while others are hard toaccomplish their migrations unless they take food to some extent on the way. Migrating population of whales is composed of individuals which greatly vary in energy
potentials. On the whole the budget of energy for locomotion does not always
balance well or clearly unbalanced. Under these circumstances some whales may
migrate to the tropical seas and others may have to take different pathways of less far
or, have to modulate the ways of life although some of them will be fatty in anotheryear and can migrate much distance as the standards. It would be convenient tosuppose that whales feed primarily on the way of their breeding migration to getan additional energy for locomotion although the extent of feeding may actually
vary with each individuals. Some whales which had not preserved much whale
oil cannot but follow the ways along more productive and food rich waters, and/or
have to remain within the waters of rather higher latitudes throughout their breeding
migration. The migrations of whales, therefore, seem to be a stream like movements of animals as called by Mackintosh (1965), and may be performed withmuch flexibility from variable fashions of migratory movements. The " warm
temperate or tropical seas " which have been believed as the destination of breeding migration still remains as an ambiguous conception. As it has been discussed,
however, whales keep potential for making a round trip which corresponds to 120
degrees or more of latitudes, and consequently,. the whales in the archipelago of
Micronesia, for instance, cannot always be considered as the stray from local population but also possible to consider as the migrants from the polar regions. In thisinstance, mingling of the populations between northern and southern hemispheresat one of their terminal sea regions would be quite possible but considered the caseto be very little. Kellogg (1929), however, suggested much the possibility ofmingling in the case of blue whale populations.
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