SC/F16/JR9

Distribution of blue (Balaenoptera musculus), fin (B. physalus),
humpback (Megaptera novaeangliae) and north pacific right(Eubalaena japonica) whales in the western North Pacificbased on JARPN and JARPNII surveys (1994 to 2014)
Koji Matsuoka1, Takashi Hakamada 1 and Tomio Miyashita 2
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Institute of Cetacean Research, 4-5, Toyomi, Chuo, Tokyo 104-0055, Japan
National Research Institute of Far Seas Fisheries, Fisheries Research Agency, 2-12-4, Fukuura, Kanazawa, Yokohama,236-8648, Japan
Contact e-mail:matsuoka@cetacean.jp

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ABSTRACTWe report here the Density Index (DI: individuals / 100 n.miles) and monthly distribution pattern of blue, fin, humpback
and North Pacific right whales from May to September in the western North Pacific based on JARPN and JARPNII(1994-2014) sighting data. A total of 269,728.1 n.miles were surveyed. Among four species, fin whales were mostfrequently sighted, and next were blue, humpback and right whales in order. Monthly maps of the DI by 1oX 1osquareare provided, using all primary effort and sightings data. Northward migration patterns of whales were observed forthese species. Blue whales were mainly distributed north of 35oN and east of 157oE (374 schools and 508 individuals;
Mean schools size (Mss) was 1.36 individuals including 23 mother and calf pairs). The DI of this species was 0.19. A
high density area was observed north of 45oN between 157oE-170oE. Surface temperature (ST) ranged from 3.0 oC to
25.8o C. Fin whales were mainly sighted between 150oE and 170oE (799 schools and 1,125 individuals; Mss: 1.41,
including 37 mother and calf pairs). Distribution patterns were similar to blue whales. DI of this species was 0.42. A
high density area was observed north of 45oN. The ST ranged from 2.9 oC to 26.9oC. Humpback whales were mainly
distributed north of 37oN (492 schools and 685 individuals; Mss: 1.39, including 42 mother and calf pairs). DI was 0.25.
The ST ranged from 2.8 oC to 24.1oC. Right whale was the rarest baleen whale species sighted in the research area.
They were mainly distributed north of 40oN (48 sch. and 68 ind.; Mss: 1.42, including 9 mother and calf pairs). The DI
was 0.03. Surface temperature ranged from 2.7 oC to 17.0oC. Based on the additional data during 2008 to 2014,
distribution pattern of these species during May to August are more obvious and this new information will contribute tomarine ecosystem studies in the western North Pacific where information has been lacking since the cessation ofcommercial whaling. Further continuation of the systematic sighting surveys including in foreign EEZ areas are
required to improve information on seasonal distribution of baleen whales.
KEY WORDS: PACIFIC OCEAN, SURVEY VESSEL, DISTRIBUTION, BLUE WHALE, FIN WHALE,HUMPBACK WHALE, RIGHT WHALE

INTRODUCTION
The JARPNII (Japanese Whale Research Program under special permit in the western part of North Pacific-Phase II）
was designed with the aim to elucidate the a) feeding ecology and ecosystem studies, b) Monitoring environmental
pollutant in cetaceans and the marine ecosystem, c) Stock structure of large whales (Common minke, Bryde’s, sei andsperm whales).

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The JARPN (1994-1999) and JARPNII (2000-2014, ongoing) have conducted systematic whale sighting
surveys with and without the sampling activity. Research area of the JARPN and JARPNII is the Pacific waters north of
35oN in sub-areas 7, 8 and 9 except the 200 n.miles EEZ of foreign countries. In the Sea of Okhotsk, it covered only
sub-area 11 also except the Russian EEZ. All whale species sighted are recorded during the sighting surveys. Details of
the outline of the JARPN and JARPNII surveys were reviewed by Fujise (2000), Tamura et al. (2009) and Kiwada et al.,(2009). Sighting data by JARPN and JARPNII (1994-2007) for blue (Balaenoptera musculus), fin (B. physalus),
humpback (B. musculus), North Pacific right (Eubalaena japonica) and common minke whales (B. acutorostrata) werereported to the JARPNII review meetings which were held by the IWC/SC in 2000 and 2009 (Matsuoka et al., 2000,
Okamura et al., 2001, Matsuoka et al., 2009). In this paper, we examined the blue, fin, humpback and right whale
distribution patterns including new JARPNII sighting data (from 2008 to 2014).

MATERIAL AND METHODS
Sighting data used in this analysis
In this paper, we used all JARPN (1994-1999) and JARPNII (2000-2014) systematic sighting survey data (effort andprimary sightings) collected by sighting and sampling vessel (SSV) and dedicated sighting vessel (SV). Outline ofsighting survey are followings;
Sighting procedure
The sighting procedure of JARPNII (2008-2014) was not significantly changed during the JARPN (1994-1999) andJARPNII surveys (2000-2007) with some minor changes of the sighting procedure, which were reviewed by Bando etal. (2016: SC/F16/JR4) and Matsuoka et al. (2016: SC/F16/JR9). The research vessels were equipped with a barrel,
where three top men conducted sighting observations. On the upper bridge, a captain, a gunner, a helmsman and a
researcher also conducted the sightings. The sighting activity was continued if weather permitted during daytime from30 minutes after sunrise to 30 minutes before the sunset.
Survey modes
Searching was conducted under closing mode. Furthermore, two survey modes were adopted as NSC (Normal Search
Closing, effort code was BC) mode and NSS (Normal Search closing with Special, effort code was BS) modes bytaking into consideration the sea condition at the time of the searching. The NSC (BC) mode was conducted under thenormal weather conditions defined as visibility of 2 n.miles or more and wind velocity 4 or below. The NSS (BS) was
conducted under the unfavorable conditions defined as except the BC mode, but under which, the collection of whale
samples was possible (Tamura et al., 2009, Bando et al., 2016: SC/F16/JR9). Searching was conducted using two
survey modes (closing (ASP) and passing (NSP) modes) by the dedicated sighting vessel (SV) (Kiwada et al. 2009,
Matsuoka et al. 2016: SC/F16/JR2).
Cruise track (Main survey and SMS)
For the Main survey, the zigzag-shaped track line was established to cover the survey area. Furthermore, the ‘Special
Monitoring Survey (SMS)’ was adopted in area where the density of whales was expected to be high in order to takesamples of whales efficiently. The vessels conducted the sighting surveys 6 and 4 n.miles away from each other in theMain survey and the SMS survey, respectively.
Confirmation of the sightings
When the cetacean school of which species seemed to be minke whales or other large cetaceans was sighted in the
research area, the ship closed to the school immediately in order to identify the species, estimate the school size and getother biological information (number of calf, estimated body length etc.). To improve the estimation of the distance tothe school and the angle from the bow, training was conducted in the early part of each cruise by each vessel. Distance2SC/F16/JR9
was estimated by referring to the scale in the binoculars and angle was estimated referring the angle board. Surface
temperatures were recorded by each whale sighting.

RESULTS AND DISCUSSIONS
Primary searching efforts
A total of 269,728.1 n.miles were surveyed mainly in the sub-areas 7, 8 and 9 between 1994 and 2014. Figures 1a and1b show the research area and the primary searching effort (n.mile) of JARPN and JARPNII by Lat.1°× Long.1°square.
Research area was covered completely during the surveys.
Distribution pattern of whales in sub-areas 7, 8 and 9
Table 1 shows the summary of all the primary whale sightings in the JARPN and JARPNII during 1994 to 2014. Table 2
shows the summary of primary whale sightings in the sub-areas 7, 8 and 9. Figures 1a and 1b show the distribution of
the density index (number of the primary sightings of individuals / 100 n.miles) using primary searching efforts andnumber of primary sightings (individuals) of blue, fin, humpback and right whales in the research area between 1994
and 2014. Figures 2a, 2b, 2c and 2d show the monthly change in the density index for these species during the surveys.
Northward migration pattern of whales
Figures 2a, 2b, 2c and 2d show the monthly changes of the whale distributions with the search effort from May to
September. As a whole, the main distribution areas of blue, fin, humpback and North Pacific right whales moved
northward from 35oN to 45oN from May to August in Pacific sub-areas, which coincided with the previous large-scale
distribution pattern reported by Miyashita et al. (1995).
Blue whale
Blue whales were mainly distributed north of 35oN in the sub-areas 8 and 9 from May to September (374 schools and508 individuals). Density index of this species was 0.19 (DIW: individuals / 100 n.miles) during the surveys. Mean
schools size was 1.36 individuals including 23 mother and calf pairs (Table 1). A high density area was observed northof 45oN in sub-area 9. Surface temperature was ranged from 3.0oC to 25.8oC. A northward migration pattern of whales
was observed. The main distribution areas from 35oN to 40oN during May to June moved northward to north of 40oN
during July to August in the sub-areas 8 and 9.
Blue whales were previously caught around the rim of the Western North Pacific. In summer they
concentrated along the edge of the continental shelf and along the south side of the Aleutian Archipelago. There was a
distribution gap between sub-areas 7 and 9 for this species using previous catch data in summer (Nishiwaki, 1966).
However, JARPNII data show that there is no gap between sub-areas 7 and 9. The previous gap may have been causedby regulation of the whaling operations between coastal (land base type) and offshore (mother ship type) whaling.
Further, according to the JSV sighting data collected between 1966 and 1990, blue whales were not sighted in sub-areas
7, 8 and 9 in June. On the other hand, this species was widely distributed in these sub-areas in June between 1994 and2014.
Fin whale
Fin whales were most frequently sighted compared to blue, humpback and right whales. This species was mainly
sighted in sub-areas 8 and 9 of which distribution patterns were similar to blue whale distributions. This species was
mainly distributed north of 37oN in the sub-areas 7, 8 and 9 from May to September (799 schools and 1,125 individuals).
The DIW of this species was 0.42. Mean schools size was 1.41 individuals including 37 mother and calf pairs (Table 1).
A high density area was observed north of 45oN in sub-area 9. Surface temperature was ranged from 2.9oC to 26.9oC.
A northward migration pattern of whales was observed. The main distribution areas from 35oN to 40oN during May toJune moved northward to north of 40oN during July to August in the sub-areas 8 and 9.

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Fin whales were widely distributed in summer in the Western North Pacific and were previously caught along
the outer shelf and south of the Aleutian Islands. A distribution gap between sub-areas 7 and 9 was previously
observed for this species in summer (Nishiwaki, 1966). However, present results show that there is no gap observed
between sub-areas 7 and 9. This species was widely distributed in these sub-areas between 1994 and 2017.
Humpback whale
Humpback whales were mainly distributed north of 37oN in the sub-areas 7, 8 and 9 from May to September (492schools and 685 individuals). The DIW of this species was 0.25. Mean schools size was 1.39 individuals including 42
mother and calf pairs (Table 1). High density areas were observed north of 35oN in the sub-areas 7 and 8, and north of
45oN in the sub-area 9. Surface temperature was ranged from 2.8oC to 24.1oC. A northward migration pattern of whales
was observed. The main distribution areas from 37oN to 43oN in the sub-area 7 during May to June moved northward tonorth of 45oN during July to August in the sub-areas 8 and 9.
Present results confirm that distribution pattern of this species is similar to the previous knowledge on
distribution pattern. However, new information shows that, although humpback whales were not sighted in sub-areas 7
and 8 in May and June by the JSV sighting data (1966-1990), this species was widely distributed in these sub-areas in
May and June between 1994 and 2014.
North Pacific right whale
Right whale was most rare baleen whale species sighted in the research area. The DIW of this species was 0.03, whichis 13 % of that for blue whales (Table 1). This species was mainly distributed north of 37oN in the sub-areas 7, 8 and 9
from May to September (48 schools and 68 individuals). Mean schools size was 1.42 individuals including 9 motherand calf pairs. Surface temperature was ranged from 2.7oC to 17.0oC. A northward migration pattern of whales wasobserved. The main distribution area was north of 42oN during July to August in the sub-area 9.
Distribution pattern of this species was reported using catch and JSV data (Omura, 1986, Miyashita and Kato,
1998, Clapham et al., 2004), present results confirm existence of this species in the sub-area 7, 8 and 9 during
1994-2014, and distribution pattern is similar to the previous pattern during May to September.
New information and further survey requirements
Distribution information of blue, fin, humpback and right whales in the western North Pacific had been reported using
commercial whaling catch data (e.g. Nishiwaki, 1966) and sighting survey data (e.g. JSV data; 5oX 5osquare analyses;
Miyashita et al., 1995). Present information of whale distributions based on the additional new data during 2008 to
2014, provided by JARPN and JARPNII during 1994 to 2014 is valuable as new information for these species. Overall,this information is more detailed than previous data. This new information indicated that sighting areas of these species
were expanded compared to the previous information, and will contribute to marine ecosystem studies in the western
North Pacific.
The latest sighting data for the foreign 200 n.miles EEZ in the Sea of Okhotsk and the east of Kurile Islands
during July and August were reported by Buckland et al., (1992) using sighting data from surveys conducted by the
National Research Institute of Far Seas Fisheries in Japan. Further surveys are required to improve our knowledge ofthe seasonal distribution of baleen whales.

ACKNOWLEDGMENT
We would like expressing our thanks to all Cruise leaders, Captains, officers, crew and researchers involved on the
JARPN and JARPNII surveys. Our gratitude also to Hiroshi Hatanaka, Seiji Ohsumi, Yoshihiro Fujise, Tsutomu Tamura,and Shigetoshi Nishiwaki for their help in the preparation of this paper.

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REFERENCES
Bando, T., Yasunaga, G., Tamura, T, Matsuoka, K., Murase, H., Kishiro, T. and Miyashita, T., 2016. Methodology andsurvey procedures under the JARPNII -offshore component- during 2008 to 2014 with special emphasis on whale
sampling procedures. Paper SC/F16/JR4 presented to the JARPNII special permit expert panel review workshop,
Tokyo, February 2016 (unpublished).**pp. [Paper available from the Office of this Journal].
Buckland, S.T., Cattanach, K.L. and Miyashita, T., 1992. Minke whale abundance in the Northwest Pacific and the
Okhotsk Sea estimated from 1989 and 1990 sighting surveys. Rep. Int. Whal. Commn. 42:387-90.
Clapham, P.J., Good, C., Quinn, S.E., Reeves, R.R., Scarff, J.E. and Brownell, R.L. 2004. Distribution of North Pacificright whales (Eubalaena japonica) as shown by 19th and 20th century whaling catch and sighting records. J.
Cetacean Res. Manage. 6 (1):1-6.
Fujise, Y., 2000. Outline of the research activities under the Japanese Whale Research Program under a special permit in
the North Pacific (JARPN) from 1994 to 1999. Document SC/F2K/J8 presented to JARPN Review Meeting, 7-10
February 2000 (unpublished). 30pp. [Paper available from the Office of this Journal].
Kiwada, H., Kumagai, S. and Matsuoka, K., 2009. Methodology and procedure of the dedicated sighting surveys in
JARPNII –Offshore and coastal component of Sanriku and Kushiro-. Paper SC/J09/JR2 presented at the JARPNII
Review Meeting, 26-30 January 2009 (unpublished). 16pp. [Paper available from the Office of this Journal].
Matsuoka, K., Hakamada, T., Fujise, Y. and Miyashita, T. 2000. Distribution pattern of minke whales based on sighting
data during the JARPN 1994-1999. Paper SC/F2K/J16 presented at the JARPN Review Meeting, 7-10 February 2000
(unpublished). 17pp. [Paper available from the Office of this Journal].
Matsuoka, K., Kiwada, H., Fujise, Y. and Miyashita, T., 2009. Distribution of blue (Balaenoptera musculus), fin(B.physalus), humpback (Megaptera novaeangliae) and North Pacific right (Eubalaena japonica) whales in thewestern North Pacific based on JARPN and JARPNII sighting surveys (1994 to 2007). Paper SC/J09/JR35
presented at the JARPNII Review Meeting, 26-30 January 2009 (unpublished). 12pp. [Paper available from the
Office of this Journal].
Matsuoka, K., Hakamada, T. and Miyashita, T. 2016. Methodology and procedure of the dedicated sighting surveys in
JARPNII - Offshore component -, 2016. Paper SC/F16/JR2 presented to the JARPNII special permit expert panel
review workshop, Tokyo, February 2016 (unpublished).**pp. [Paper available from the Office of this Journal].
Miyashita, T., Kato, H. and Kasuya, T. (Eds), 1995. Worldwide Map of Cetacean Distribution based on Japanese
Sighting Data (Volume 1). National Research Institute of Far Seas Fisheries, Shimizu, Shizuoka, Japan.140pp.
Miyashita, T., Kato, H. 1998. Recent data on the status of right whales in the NW Pacific Ocean. Paper SC/M98/RW11
presented to the IWC Special Meeting of the Scientific Committee towards a Comprehensive Assessment of Right
Whales Worldwide, 16-25 March, Cape Town, South Africa.
Nishiwaki, M., 1966. Distribution and migration of the larger cetaceans in the North pacific as shown by Japanesewhaling results. In K.S. Norris, ed., Whales, dolphins, and porpoises. University of California Press, Berkely. CA.
pages 171-191.
Okamura, H, Matsuoka K, Hakamada T, Okazaki M, and Miyashita, T., 2001. Spatial and temporal structure of thewestern North Pacific minke whale distribution inferred from JARPN sightings data. J. Cetacean Res. Manage. 3(2):193-200.
Omura, H. 1986. History of right whale catches in the waters around Japan. Rep. int. Whal. Commn (special issue)
10:35-41.
Tamura, T., Matsuoka and Fujise, Y., 2009. Methodology and survey procedure under the JARPNII - offshore
component- with special emphasis on whale sampling procedures. Paper SC/J09/JR4 presented to the JARPNII
Review Workshop, Tokyo, January 2009 (unpublished). 16pp.

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Table. 1. Summary of all primary sightings of blue, fin, humpback and North Pacific right whales during the JARPN
and JARPNII (1994-2014) including transit surveys to and from the research areas. Sch.: Number of the
primary sightings of schools. Ind.: Number of the primary sightings of individuals. Calf: Number of calves
including Ind.. Mss: mean school size (Ind. / Sch.). DIS: Density Index (schools / 100 n.miles). DIW: Density
Index (individuals / 100 n.miles). WT: Range of surface temperature of the species sighting position.
Western North pacific (all primary sightings)
Species
Sch.

Ind.

Calf

Mss

DIS

DIW

WT

Blue whale

374

508

23

1.36

0.14

0.19

3.0 - 25.8oC

Fin whale

799

1,125

37

1.41

0.30

0.42

2.9 - 26.9oC

Humpback whale

492

685

42

1.39

0.18

0.25

2.8 - 24.1oC

N.P. right whale

48

68

9

1.42

0.02

0.03

2.7 - 17.0oC

Table. 2. Summary of all primary sightings restricted by the sub-areas 7, 8 and 9 during the JARPN and JARPNII(1994-2014).
Sea
Sub-area

Western North pacificSub-area 7

Sub-area 8

Sub-area 9

Latitude35N-43N

35N - 45N

35N - 51N

Longitude

Japanese coast - 150E

150E - 157E

157E - 170E

Depth (m)200-4000m<

4000 m <4000 m <Species

Sch.

Ind.

Sch.

Ind.

Sch.

Ind.

Blue whale
Fin whale
Humpback whale
N.P. right whale

20
93
165
7

23
124
225
9

59
231
191
7

77
323
274
9

271
464
148
34

377
676
213
52

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Figure 1a. Distribution of the Density Index (number of primary sightings of individuals / 100 n.mile ) of whales during
JARPN and JARPNII from 1994 to 2014 surveys by Lat.1°× Long.1°square. Upper: blue whale, Bottom: Fin whale.

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Figure 1b. (continue). Upper: humpback whale, Bottom: North Pacific right whale.

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Figure 2a. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of blue whales
during JARPN and JARPNII from 1994 to 2014 surveys by Lat.1°× Long.1°square. Top left: April. Top right: May.
Middle left: June. Middle right: July. Bottom left: August. Bottom right: Sep.

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Figure 2b. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of fin whales
during JARPN and JARPNII from 1994 to 2014 surveys by Lat.1°× Long.1°square. Top left: April. Top right: May.
Middle left: June. Middle right: July. Bottom left: August. Bottom right: Sep.

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Figure 2c. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of humpback
whales during JARPN and JARPNII from 1994 to 2014 surveys by Lat.1°× Long.1°square. Top left: April. Topright: May. Middle left: June. Middle right: July. Bottom left: August. Bottom right: Sep.

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Figure 2d. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of North Pacificright whales during JARPN and JARPNII from 1994 to 2014 surveys by Lat.1°× Long.1°square. Top left: April.
Top right: May. Middle left: June. Middle right: July. Bottom left: August. Bottom right: Sep.

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