Studies of the Whaling Grounds in the Northern
Sea-Region of the Pacific Ocean in Relation
to the Meteorological and Oceanographic
Conditions. (Part I)
By
MICHITAKA UDA(The Tokyo University of Fisheries)

andKEIJI NASU

Introduction

Hitherto there were very few researches on the environmental conditions of whale shoaling and whaling. M. Uda already reported on
the concentration of whales in the core of cyclonic eddies along thefrontal boundary of different water masses in the adjacent seas of Japan1 J.
In the present paper the relation between the northern whaling grounds
in 1954 and weather conditions (cyclone, sea-fog etc.) together with seaconditions was studied.

I.

Whaling Conditions in Relation to the Passage of Cyclone.

1) Cyclone hitted to the whaling grounds in the Northern Sea Regionof Pacific Ocean.
The cyclones in question may be divided into two types i.e. cyclones
started from Siberia and those appeared in the neighbouring waters ofJapan.
First in the beginning period of whaling season, cyclone occurs
frequently in the region adjacent to the Maritime Province of Siberia.
In the middle season of whaling, the path moves to north a little. The
former enters in the Bering Sea after passing through Saghalien and
Kurile Islands, and the latter proceeds into the Bering Sea through the
Kamchatka Peninsula, after crossing the Okhotsk Sea. All of thesecases do not accompany with their storms in general. Especially thecyclones appeared in the vicinity of Kamchatka Peninsula in the period
from June to July, are rarely accompanied by storms.
2) Cyclone originated in the adjacent waters of Japan.
Those cyclones in the temperate latitudes developing during their

M. UDA and K. NASU

164

procession to NE direction arrive in Bering Sea and are accompaniedby storms.
3) Relation between the whaling conditions and the cyclone.
The amount of whaling catch was analysed by the statistical method
already taken in case of yellow-tail 2 l by M. Uda.
Taking the day of nearest approach by the cyclone center to themother boat of a whaling set as zero day, and denoting those 2 days
and 1 day before the zero day, 2 days and 1 day, after the zero day
as -2, -1, + 1 and + 2 respectively and then the distribution curveof the amount of whaling catch for each 5 days was plotted in fig. 1.
The analysis was made on the data
Amount_:of catch
during the 20 days in 1954, which is too
few to get concrete results and only
capable to infer trend of the matter.
First as a general consideration, foreach species of whales the amount ofcatch was summed up separately on the-2, -1, 0, +1 and +2 day. Thenas we see in fig. 1 and table 1 on the+ 1 day the catch shows its maximum
and on the -1 day its minimum showing almost similar value on the - 2 and+ 2 day. On the zero day the amountofwhale catch is more abundant than/\/\that of the -1 day and lower than those\of the + 2 and - 2 day. Accordingly\
on the days adjacent to the + 1 day
after the cyclone passage, it showsfavourable whaling conditions.
Such considerations were paid forFig. 1. The amount of whale
catch accumulated for each species
each species of whales. Fin whale andon -2, -1, o, +1 and +2 resperm whale having abundant catch
spectively ·show the tendency similar to the total
catch, i.e. on the -1 day, it shows the minimum catch and on the +1
day the maximum.
Although for humpback whale and blue whale, the relations are
obscure. Owing their poor catches, for humpback whale the curve
seems to show the maximum on about the - 2 day and the minimumon the + 1 day and similar curve for the catch of blue whale, however
for sei whale the case almost reverse to those of blue whale and humpback whale, i.e. the curve showing the minimum on the -2 day andthe maximum on the + 1 day.
Fon
- - --·-·
Sperrr - · - · -

Humr

-----

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 165

4)

On the relation between the shoaling amount of whales and thecyclone.
The shoaling amount of whales should be conjectured by theircatches together with the oceanographic and meteorological conditions.
Here we can put the following relational formula on the amount of
whale catch.

F=K. V.S.O.
where• .. (1)

F: amount of the whale catch.
V: the rate of discovery by ordinary look-out.
S: shoaling amount of whales.
0: rate of whaling operation.
K: proportional constant, depending on the characteristics of planktonic, topographic and other elementsof the whaling ground.

Since the amount of the whale catch is varied by the approach of
the cyclone, the writers studied this relation statistically during thewhaling season in 1954.
Hence the shoaling amount of whales is the fundamentally importantfactor to determine the amount of catch.
The rate of whaling operation and rate of discovery can be known
easily, and the amount of catch is known too. Thereby, the writers
intended to carry quantitative analysis on the shoaling condition ofwhale in relation to cyclone passage.
(a) The shoaling condition of whale: S
It is evident that due to the influence of the cyclone, the sea condition become unfavourable, whereas (S) increase with the approach of
the cyclone, and is proportional to (F).
(b) The rate of discovery by ordinary look-out: V
When the cyclone approaches to the whaling ground, the southerly
wind blows and arouses the dense sea-fog, so that the rate of discovery
decreases. Since naturally the amount of catch (F) may be proportional
to (V), it may be lowered as the consequence of the (F)-decrease inspite of the shoaling amount of whales (S) increases.
(c) The rate of whaling operation: 0
The rate of operation including the meaning of the rate of gun
hits and it may be the main factors of the rate of whaling. Here, we
may assume the ability of gunners as constant. The rate of gun hits
is inversely proportional to the sea condition such as wind-wave or
swell. While the rate of whaling operation is also inversely proportional
to the sea condition.

166

M. UDA and K. NASU

Since this can apply not only to the case of whaling, but also to
the cases of other fisheries, so the fishing operation in general are influenced negatively by the sea condition due to the cyclone passage.
In the above mentioned formulation, however, F=K. S. V. 0. can
not represent well the shoaling condition of whales as affected one by
the sea condition, but in the first approximation this equation was
adopted and tentatively studied. It is obvious that the rate of gun
hits is the function of the sea condition. Thus (F) is considered to be
inversely proportional to the rate of whaling operation (0) (accordingly
rate of whaling). Consequently, we can estimate the shoaling amountof whales (S) by the computed value of F/KVO. The rate of operation (0) is determined by sea condition (W), hence, the (0) is inversely
1 .
proportional to (W), i.e. 0 (/) · W ·F=K'. V. ~S.

.(2)

S=FW
. . . (2)'K'V
The curve of (S) estimated by (2)', named as " The Whale Shoaling
Curve" is shown in fig. 2, using the average of sea conditions, therate of discovery and amount of catch are obtained for the days of theAmount of catch
cyclone in table 1.
Accordingly,orf

199=K' x 4.2 x S_ 2/3.6
157 =K: x 4.3 x S_if3.7 S_2 :S_1: So: S+1 :_S+2
184=K x 4.2 x S 0 /5.1
=170.6: 135.1:
223.4: 211.6: 148.5
238=K' x 4.5 x S+ 1/4.0
198=K' x 4.0 x S+ 2/3.0

~

\

\
\

Table 1.

v- -- - --0-··-··-

Fig. 2.

""The whale shoaling
curve.

The value of W. V. and F. in before andafter days of the cyclone passage.

Day

-2

-1

0

+1

+2

(W)

3.6

3.7

5.1

4.0

3.0

(V)

4.2

4.3

4.2

4.5

4.0

(F)

199

157

184

238

198

Glancing in fig. 2, We can see at once
that the shoaling amount of whales decreaseson the days of about -1 and + 2, and shows
the maximum value on the day of about

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean167+ 1 and the minimum on the -1 day. Perhaps it occurs because
before the cyclone approach, the rate of discovery became to fall down
to low level and also the sea became worse. We can suppose, however,that the shoaling of whales does not decrease, by the approach of
cyclone. The amount of the whaling catch before and after the cyclone
passage, summed up for the species separately.
The total amount of catch ( -2, -1, + 1 and + 2 day) is 540 individuals of whales on the before days, 620 of whales on the after days
(the amount of. catch on the zero day involved in the both periods).
The total heads in the after days are about 7 ofo more than that in the
before days.
As shown in fig. 2, on the before days, the curve of the rate ofdiscovery falls with the rise of curve of the sea condition, bad condition to the whaling operation. It may be reasonable that we can notexpect better catch on the before days than that on the after days ofthe cyclone passage. Similarly the catch for each species of whale isshown separately for the -2, -1, 0, +1 and +2 day in table 1,
table 2 and fig. 3.
Table 2. The amount of whale catch accumulated
for each species on -2, -1, 0, + 1 and + 2 day
respectively.
Around the nearest day (0 day) of cyclone
Amount of catch

~-2

-1

0

+1

+2

5
24

16
5
13
42

------·

Humpback

20

15
8
14

40

31

5
13
16
54

97

89

Total No. of
199
indiv.

157

Sei
Blue
Sperm
Fin

39
3

96

9
76
124

122

184

238

198

The catch of 0 day
added to both
Sp. whale.
Humpback

Before
days

After
days

59
24

26
42
38

its percentage
%

%

63.6
43.2
57.9
54.8
53.4

Sei
Blue
Sperm
Fin

282

In
342

69.4
36.4
56.8
42.1
45.2

Total No. of
indiv.

540

620

46.5

50
125

30.6
BeforeFig. 3. The amount of whale
catch accumulated for each species
on before and after days of thecyclone passage.

11

I'

168

M. UDA and K. NASU

i

( i)

Fin whale (Balaenoptera physalus)
The abundance of the catch on the before and after days of thecyclone passage is 282 and 342 respectively.
The percentage for total catch before and after days of the cyclone
passage is 45.2% and 54.8% respectively. In this case the one in theafter days are 9.6% more than that in the before days.
(ii) Humpback whale (Megaptera nodosa)
The abundance of the catch on the before and after days is 59 and
26 respectively, (i.e. 69.4% and 30.6% ). Therefore in the former days
it is 38.8% more than that in the latter days. which is seemingly opposite phenomenon to the other species, but the data too few to certify
the conclusion.
(iii) Sei whale (Balaenoptera borealis)On the before and the after days of the cyclone passage, the amountof the accumulated catch and its percentage are 24, 42 and 36.4%, 63.6%
respectively. In the after days, however, it shows some what goodcatch, but also in this case, data too few to conclude it.
(iv) Blue whale (Balaenoptera musculus)
During the before and the after days of the cyclone passage, theheads of the whale catch are 50 and 38, and its percentages are 56.8%
and 43.2% respectively. On the before days, it is 13.6% more thanthat in the after days.
(v) Sperm whale (Physeter catodon)
The abundance of the catch on the before and after days of thecyclone passage is 125 and 172 (i.e. 42.1% and 57.9%) respectively.
On the after days, it is 15.8% more than that on the before day.
II.

(1)

Whaling Conditions in Relation to Weather Elements especiallyto Sea Fog, and to the Distribution of Dichothermal Water.

Whaling Grounds in the North-Eastern Sea Region of Japan in
Relation to Sea Fog in Summer of 1953.
Basing on the data obtained by the whaling catcher boats, one of
the authors (M. Uda) plotted the charts of whaling grounds for each
decade during the period from the beginning of July to the end of
August in 1953 in which the isotherms, the distribution of the rate offog occurrence ( % of fog observed stations among the whole stationsin the 1° rectangle of latitude and longitude) and the localities of whale
caught included. (See Fig. 4 a, b, c, d, e and f).
We can find at once the relative abundance of whales in the dense
fog zones corresponding to the boundaries of cold and warm water
masses and to the southward extending cold current areas. The limitof the sea-fog zone lies very near to the Oyasio Front (water tempera-

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 169

N
45°

44°

195 3
EARLY JULY

41°
12°

40°

•

180

- - Isotherms=-'i> Cold Current---+Warm Current

0

•

@

£:,.

©

Sperm
Sei
Fin
Blue
Sea Fog observed

39°

38°

37-

Rate of Fog occurrence

,146°

1 8°E

Fig. 4. (a) The distribution of whaling grounds in the North-Eastern Sea Region,water temperature, cold-warm water masses and sea-fog.

170

M. UDA and K. NASU

44°

19 5 30

MI DOLE AUGUST

43°

18°

40°

39°

38°
24°

146°

E
o
1480 37

Fig. 4. (b) The distribution of whaling grounds- in the North-Eastern Sea
Region, water temperature, cold-warm water masses and sea-fog.
(Notice) Notations used in the map are the same as in Fig. 4a.

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 171

N

45°

44°

19 5 3
LATE JULY

I

40°

39°

38°'

144°

146°

148°

.E

Fig. 4. (c) The distribution of whaling grounds in the North-Eastern Sea
Region, water temperature, cold-warm water masses and sea-fog.
(Notice) Notations used in the map are the same as in Fig. 4 a.

37~

172

M. UDA and K. NASU

N
45°

0

440

41°

40°

39°-

38°

f44"

146°

Fig. 4. (d) The distribution of whaling grounds in the North-Eastern Sea
Region, water temperature, cold-warm water masses and sea-fog.
(Notice) Notations used in the map are the same as in Fig. 4 a.

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 173

N
45°

44°

19 5 3
MIDDLE JULY

41°__ .20% ·---..

40°
18°

39°

38°

3136°
22°

142°

144°

146°

Fig. 4. (e) The distribution of whaling grounds in the North-Eastern Sea
Region, water temperature, cold-warm water masses and sea-fog.
(Notice) Notations used in the map are the same as in Fig. 4 a.

M. UDA and K. NASU

174

0

60 Ii

4~'16°~0%
1s·, 'f 16°', -~-/I 0%

44°

19 5 3
LATE AUGUST

41°

40°

39°

22°

38°

24°

37°
144°

146°

Fig. 4. (f) The distribution of whaling grounds in the North-Eastern Sea
Region, water temperature, cold-warm water masses and sea-fog.
(Notice) Notations used in the map are the same as in Fig. 4 a.

ture lower than 20°C), Sea-fog occurs rarely in the zone near to Kurosiwo
Front and also in the area of water temperature higher than 20°C.
The rate of discovery for whales and the rate of gun-hit on whales
are inversely proportional to the degree of visibility, consequently pro-Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 175

portional to the frequency of sea-fog occurrence.
During the occurrence of sea-fog the sea (wind-wave) is not roughin general. However, the shoals of whales found and the amount of thewhale catch concentrate to the zone of plenty food organisms (such as
squids for sperm whales, copepods and euphausia for fin-, sei- whalesetc.) which has densely multiplied and assembled together.
In conclusion since the shoal of densely concentrated whales migrates there, notwithstanding the lower rate of discovery due to the badvisibility, the catch of whales increases consequently.
(2) Whaling Grounds in the Northern Pacific Ocean near AleutianIslands in 1954 in Relation to the Weather Conditions.
By our inspection in tables 3, 4, 5, 6 and 7 (based on the data supplied by the Mother Whaling Ship Kinzyo-maru, Baikal-maru, the catcher
boat Koyo-maru and Seki-maru), we can find clearly the whale catch in
the whaiing season from middle May to middle September corresponding
to the dense sea-fog season and the main whaling grounds lies at about
dense sea-fog districts. The weather elements corresponding to theTable 3.

Number of Whale Caught for Each Weather Elementin the Adj. Waters of Aleutian Is. in 1954.
(The Whaling Mother Boat Kinzy6-maru)

~

B

c

0

16

34
23
8

39
216
201
84

57

65

540

BC

Mont
May
June
July
Aug.

5
36

Total

F
D
(Mist included)
14
1
175
29
80
134
403

30

Observed Chance

4

10

68

57

4

No. per Chance

14

6.5

8

7.2

7.5

Table 4.

-~atherMonth----.___________

Number of Whales Caught for Each Weather Elementin the Adj. Waters of Aleutian Is. in 1954.
(The Whaling Mother Boat Baikal-maru)
B

BC

c

0

F

D

Sum

1
65
98
41
37

11

24

23
190
177
23
157

32
7
12

46
266
307
216
250

24

570

241

63

1085

22

May
June
July
Aug.
Sept.

121
48

Total

191

Obs. Chance

22

2

86

40

12

8.7

12

6.6

6.0

5.2

No. per Chance

176

M. UDA and K. NASU
Table 5.

The Difference betw. Air Temp. and Water Temp.
(Air Temp.-Water Temp.) °C.
(K6y6-maru) (7. May-27. Sept. in 1954)~ather

2.8

Mean
Table 6.

c

BC

B

Month~-May
June
July
Aug.
Sept.

3.3
2.9

4.3

3.0

4.3

0

F

D

R

I. 7
2.9
3.4
1.3
2.4

4.3
3.7
3.4
2.1
1.3

-1.3
3.6
3.2
-0.7
2.1

-0.6
3.5

2.3

3.0

1.4

1.5

Number of Whales discovered in the Adj. Waters of Aleutian in 1954.
(The Catcher Boat Seki-maru)~ibility

1

2

3

4

5

6

7

8

9, 10

May
June
July
Aug.

1
3
5

1
0
48
12

5
1
119

3
17
10

22
23
124
3

1
31
12

32
24
62

7
35
116

215
304
439
226

Total

9--.- 6170

118--....-158
276

1284

Mont~-----

Table 7.

125 ,____ 30
155

1

172 ......--47
219

Number of Whales discovered in the Northern Waters in 1954.
(The Whaling Research Boat K6y6-maru)

Species

Sum (No. pereach chance)

Fin

Sei

Humpback

Sperm

0

0

0

1

1

1

2

2

0

2

0

2

5

5

11

2

0

3

36

2

5

4

0

4

9

0

34

11

0

5

26

17

3

6

1

6

181

6

53

18

0

116

6

10

5

0

8

243

21

74

19

1

9

174

9

1

4

0

2
(1)
6
(2)
23
(3)
47
(2.5)
54
(4.5)
53
(2.6)
258
(7)
137
(6)
357
(6)
188
(24)

10

0

2

0

0

0

2
(1)

Total

792

70

192

72

1

Blue

Visibility

7

L ___ ,

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 177

most frequent catch are overcast, cloudy, mist, fog, foggy drizzle in
the period of (May), June, July, (Aug.), (Sept.). The whaling grounds
were occupied mainly by fin whales, mingling with sperm whales andhumpback whales. Of course the whale catch increases with the increase of visibility. In the case of Koyo-maru shows its maximum inthe range of visibility 6-9 Fin whale occupies its main part, and Humpback the next, Sperm whale and Sei whale in the same order, and in
the case of Seki-maru the catch gradually increasing with visibility.
In this sea-region the difference between air temperature and watertemperature is commonly 1°-4°C (about 3°C) and during the season
June-July usually the value more than 3°C corresponding to the fogregion.
(3) The Distribution of Dichothermal Water and Whaling Ground in
1954. (See Fig. 5 a, b).
The author (M. Uda) studied recently the fluctuation of Oyasiwo
current in relation to the atmospheric circulation and to the distributionof the (represented by the dichothermal water) dichothermal waters in
170E

170\V

180

•·•• ....~ •· •' ~ Whal;orr Grn""f~: 1.9;~
!f..

• •·.

.1 <rt~o -m'>j'.ve:"'-©_i.,..o::;::r;r
o•<'~

0

oao "'(ooe« •...

soi--------+----+-----+-----+--+
N©

•
11'G""oE_ _ __,____ ___,,"7,oE_ _ _ _ - - - ·1'a"o---~~

Fig. 5. (a) Whaling grounds in the Northern Sea-Region of the
Pacific Ocean in 1954.

the north Pacific ocean during the years 1933-19533 ). Glancing at Fig.
5 a, b for that in summer of 1954 in the adjacent waters of AleutianIslands, we can recognize the main localities of whaling grounds lying
at the fronts of the cold watermass and the mixed warm water mass,
such western (I), central (II) and eastern (III) whaling grounds in thewaters adjacent to Aleutian Islands, where planktons are abundant inthose regions 4\ (See Fig. 5 b).

N

50 1

N

55

N

r:P

"<]

I SOE

'~

:
170E

1,/
,1'

,-,

---,,

.'is·

l

v

\

\

~
-?"
'
~i.::-,\\

I// )11"'--.. . . . . __11;}.\l.li'- ......
\

\

180
0

170W

---·-· Layer Level of-D1chothermal Core Water(m))l3Dtherms of D1chothermal Core Waterl8-Minimum'cl=3"o e ® e <D

e

®

9

<D

160W

l"SO I o l • I $ I e I <!>SHOO 0P1iisB1ue Fin Hump Se1 Sperm""'5' (l~Ov1e""'-:.·;::."?

cl

l60W

50
N

5N5

N

-~--~soFig. 5. (b) The distribution of dichothermal core water (e-minimum C), layer level of dichothermalcore water (m) and localities caught in 1954.

·2·,\ .'lOOffi--~~~- ---<\~)''·-----..,__' -JQ_Offi~,~---'
- ..,

I

rY

oo~~~~~~~l~6~0E:__~~~~~~~~~~~l,7~0~E~~~~~~~~~~~-1~8_0~~~~~~~~~~~~~17~0~W~~~~~

,_.

c::::

~

~

z

r

5.

!lO

>

I:)

~

C1:J

""

Studies of the Whaling Grounds in the Northern Sea-Region of the Pacific Ocean 179

Summary(1) Cyclones hitted to the whaling grounds in the Northern SeaRegion of Pacific Ocean may be divided into two types i.e. (i) cyclones
started from the Siberian Continent and (ii) those originated in theadjacent waters of Japan.
(2) In general, on the days adjacent to a day after the passage of
cyclone it shows favourable whaling condition, and contrary to it adjacent
to a day before the passage of cyclone it shows poor whaling condition.
(3) At first we established the relational formula on the amount of
whale catch F = K. V. S. 0. and concluded the following: Shoaling
condition of whales on the days after the passage of cyclone was better
than that on the days before the passage of cyclone.
(4) Concerning whaling grounds in the North-Eastern Sea-Regionof Japan we found the relative abundance of whales in the dense fog
corresponding to the boundary zone of cold and warm waters.
(5) Generally whaling period in the Northern Pacific Ocean near
Aleutian Is. corresponds to the dense sea-fog season and its main whaling ground lies at about denser sea-fog districts.
(6) Main localities of whaling ground in the adjacent waters of
Aleutian Islands were found near at the boundary of the dichothermal
water masses (intermediate cold water.)
Literature
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)

M. Uda: Studies of the relation between the whaling grounds and the hydrographicalconditions (1). The Sci. Rep. of the Whales Res. Inst., No. 9, pp. 179-187, 1954.
M. Uda: Statistical study of the influence of cyclone motion upon the fishing (1).
Journ. of Imp. Fish. Inst. 23 (3): 113-120, 1927.
M. Uda: Researches on the fluctuation of the north pacific circulation (1). Recordsof Oceanographical Works in Japan, 2 (2): 43-55, 1955.
Biological investigation of the northern pacific whales in 1954. Japanese Whaling
Association 1955.
Report of Baikal-maru fleet operation. Japanese Fisheries Agency, 1954.
Report of Kinjo-maru fleet operation. Japanese Fisheries Agency, 1954.
Report on discovery of whale appearance. Japanese Fisheries Agency, 1954.
On the weather forecast of the neighbourhood of Aleutian Islands (1952 May-Middleof July). Central Meteorological Observatory of Japan, 1953.
Report of northern sea region weather observation in 1952. Central MeteorologicalObservation of Japan, 1953.
Report of Japanese Fisheries Agency, 1954.