SC / J 09 / JR 35

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 JARPN II sighting surveys (1994 to2007)
Koji Matsuoka1, Hiroshi Kiwada 1, Yoshihiro Fujise 1 and Tomio Miyashita 2
1

The 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
2

ABSTRACTWe report here the Density Index (DI: individuals / 100 n.miles) and monthly distribution pattern of blue, fin, humpback
and right whales from May to September in the western North Pacific based on JARPN (1994-1999) and JARPN II(2000-2007) sighting data. A total of 200,317.4 n.miles were surveyed in the sub-areas 7, 8 and 9. Among four species,
fin whales were most frequently sighted, and next were blue, humpback and right whales in order. Monthly maps of the
DI by 1 ﾟ X 1 ﾟ square are provided, using all primary effort and sightings data. Northward migration pattern of whales
were observed for these species. Additionally, sighting areas of these species were spread out compare to the previous
information except for right whales. Blue whales were mainly distributed north of 35 ﾟ N in the sub-areas 8 and 9 (275schools and 387 individuals; Mean schools size (Mss) was 1.41 individuals including 17 mother and calf pairs). The DIof this species was 0.20. A high density area was observed north of 45 ﾟ N in sub-area 9. Surface temperature (ST)ranged from 3.0 to 21.6 ﾟ C. Fin whales were mainly sighted in sub-areas 8 and 9 (506 schools and 740 individuals;
Mss: 1.46, including 28 mother and calf pairs). Distribution patterns were similar to blue whales. DI of this species was
0.38. A high density area was observed north of 45 ﾟ N in sub-area 9. The ST ranged from 3.4 to 24.1 ﾟ C. Humpback
whales were mainly distributed north of 37 ﾟ N in the sub-areas 7, 8 and 9 (321 schools and 473 individuals; Mss: 1.47,
including 29 mother and calf pairs). DI was 0.16. The ST ranged from 3.6 to 22.7 ﾟ C. Right whale was the most rarebaleen whale species sighted in the research area. They were mainly distributed north of 37 ﾟ N in the sub-areas 7, 8 and
9 (28 schools and 40 individuals; Mss: 1.43, including 6 mother and calf pairs. The DI was 0.02. Surface temperature
ranged from 3.0 to 17.0 ﾟ C. This new information will contribute to marine ecosystem studies in the western North
Pacific where information has been lacking since the cessation of commercial whaling. Further continuation of thesystematic sighting surveys including in foreign EEZ areas are required to improve information on seasonal distributionof baleen whales.
KEY WORDS: PACIFIC OCEAN, SURVEY VESSEL, DISTRIBUTION, BLUE WHALE, FIN WHALE,HUMPBACK WHALE, RIGHT WHALE

INTRODUCTION
The JARPN II (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 and1SC / J 09 / JR 35
sperm whales).
The JARPN (1994-1999) and JARPN II (2000-2007, on going) have been conducted the systematic whalesighting survey with and without the sampling activity. Research area of the JARPN and JARPN II is the Pacific waters
north of 35 ﾟ N 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 JARPN II surveys were reviewed by Fujise (2000), Tamura et al.
(2008) and Kiwada et al., (2008). Sighting data by JARPN for blue (Balaenoptera musculus), fin (B. physalus),
humpback (B. musculus), right (Eubalaena japonica) and common minke whales (B. acutorostrata) were reported to
the JARPN review meeting which held by the IWC/SC in 1999 (Matsuoka et al., 2000, Okamura et al., 2001). In thispaper, we examined the blue, fin, humpback and right whale distribution patterns using the JARPN and JARPN II
sighting data as a contribution other than the original objectives of JARPN II.

MATERIAL AND METHODS
Sighting data used in this analysis
In this paper, we used all JARPN (1994-1999) and JARPN II (2000-2007) 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 JARPN II (2000-2007) was not largely changed during the JARPN (1994-1999) surveys withsome minor changes of the sighting procedure, which were reviewed by Fujise (2000), Tamura et al. (2008) and Kiwada
et al. (2008). The research vessels equipped with barrel, where three top men conducted sighting observation. On theupper bridge, a captain, a gunner, a helmsman and a researcher also conducted the sighting. The sighting activity wascontinued if weather permitted during daytime from 30 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 under the normal
weather conditions defined as visibility of 2 n.miles or more and wind velocity 4 or below. The NSS (BS) was under theunfavorable conditions defined as except the BC mode, but under which, the collection of whale samples was possible(Tamura et al. ,2008). Searching was conducted two survey modes (closing (ASP) and passing (NSP) modes) by the
dedicated sighting vessel (SV) (Kiwada et al. 2008).
Cruise track (Main survey and SMS)
The Main survey, the zigzag-shaped track line was established to cover 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 takesample 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, the training was conducted in the early time of each cruise by each vessel.
Distance was estimated by referring the scale in the binocular and angle was also estimated referring the angle board.

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Surface temperatures were recorded by each whale sighting.

RESULTS AND DISCUSSIONS
Primary searching efforts
A total of 200,317.4 n.miles were surveyed in the sub-areas 7, 8 and 9 between 1994 and 2007. Figure 1 show the
research area and the primary searching effort (n,mile) of JARPN and JARPN II by Lat.1°× Long.1°square. Researcharea was covered completely during the surveys.
Distribution pattern of whales in sub-areas 7, 8 and 9
Table 1 shows the summary of the primary whale sightings in the JARPN and JARPN II during 1994 to 2007. Table 2
shows the summary of primary whale sightings in each sub-area. Figures 2a and 2b show the distribution of the density
index (number of the primary sightings of individuals / 100 n.miles) using primary searching efforts and number ofprimary sightings (individuals) of blue, fin, humpback and right whales in the research area between 1994 and 2007.
Figure 3a, 3b, 3c and 3d show the monthly change in the density index of these species during the surveys.
Northward migration pattern of whales
Figures 3a to 3c 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 right whales were moved northward from 35 ﾟ N to 45 ﾟ
N from May to August in Pacific sub-areas, which coincided with previous large-scale distribution pattern by Miyashita
et. al. (1995).
Blue whale
Blue whales were mainly distributed north of 35 ﾟ N in the sub-areas 8 and 9 from May to September (275 schools and
387 individuals). Density index of this species was 0.20 (DIW: individuals / 100 n.miles) during the surveys. Mean
schools size was 1.41 individuals including 17 mother and calf pairs (Table 1). High density area was observed north of
45 ﾟ N in sub-area 9. Surface temperature was ranged from 3.0 ﾟ C to 21.6 ﾟ C. Northward migration pattern of whales
were observed. The main distribution areas from 35 ﾟ N to 40 ﾟ N during May to June moved northward to north of 40 ﾟ
N during July to August in the sub-areas 8 and 9.
Blue whales are 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. This gap may be caused by a regulation of thewhaling operation 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 were widely distributed in these sub-areas in June between 1994 and 2007.
Fin whale
Fin whales were most frequently sighted compare to blue, humpback and right whales. This species were mainly
sighted in sub-areas 8 and 9 of which distribution patterns were similar to blue whale distributions. This species weremainly distributed north of 37 ﾟ N in the sub-areas 7, 8 and 9 from May to September (506 schools and 740 individuals).
The DIW of this species was 0.38. Mean schools size was 1.46 individuals including 28 mother and calf pairs (Table 1).
High density area was observed north of 45 ﾟ N in sub-area 9. Surface temperature was ranged from 3.4 ﾟ C to 24.1 ﾟ C.
Northward migration pattern of whales were observed. The main distribution areas from 35 ﾟ N to 40 ﾟ N during May toJune moved northward to north of 40 ﾟ N during July to August in the sub-areas 8 and 9.
Fin whales were widely distributed in summer in the Western North Pacific and were caught along the outer
shelf and south of the Aleutian Islands, and distribution gap between sub-areas 7 and 9 was observed for this species in3

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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 2007.
Humpback whale
Humpback whales were mainly distributed north of 37 ﾟ N in the sub-areas 7, 8 and 9 from May to September (321schools and 473 individuals). The DIW of this species was 0.16. Mean schools size was 1.47 individuals including 29
mother and calf pairs (Table 1). High density areas were observed north of 35 ﾟ N in the sub-areas 7 and 8, and north of
45 ﾟ N in the sub-area 9. Surface temperature was ranged from 3.6 ﾟ C to 22.7 ﾟ C. Northward migration pattern ofwhales were observed. The main distribution areas from 37 ﾟ N to 43 ﾟ N in the sub-area 7 during May to June moved
northward to north of 45 ﾟ N 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 is provided that, although humpback whales were not sighted in
sub-areas 7 and 8 in May and June by the JSV sighting data (1966-1990), but this species were widely distributed inthese sub-areas in May and June between 1994 and 2007.
Right whale
Right whale was most rare baleen whale species sighted in the research area. The DIW of this species was 0.02, which
is 10 % of the blue whales (Table 1). This species were mainly distributed north of 37 ﾟ N in the sub-areas 7, 8 and 9
from May to September (28 schools and 40 individuals). Mean schools size was 1.43 individuals including 6 motherand calf pairs. Surface temperature was ranged from 3.0 ﾟ C to 17.0 ﾟ C. Northward migration pattern of whales wereobserved. The main distribution area was north of 42 ﾟ N during July to August in the sub-area 9.
Distribution pattern of this species were reported using catch and JSV data (Omura, 1986, Miyashita andKato, 1998, Clapham et al., 2006), present results confirm existence of this species in the sub-area 7, 8 and 9 during
1994-2007, 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; 5 ﾟ X 5 ﾟ square analyses;
Miyashita et al., 1995). Present information of whale distributions provided by JARPN and JARPN II during 1994 to2007 is valuable as new information for these species. Overall, this information is more detailed rather than previous
data. These new information indicated that sighting areas of these species were expanded out compare to the previous
information except right whales, and will contribute to marine ecosystem studies in the western North Pacific.
The latest sighting data of 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 Japanese whale sighting survey data conductedby the National Research Institute of Far Seas Fisheries in Japan. Further surveys are required to improve for seasonal
distribution of baleen whales.

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

REFERENCES
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.

4SC / J 09 / JR 35
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 submitted to JARPN review meeting.
Kiwada, H., Kumagai, S. and Matsuoka, K., 2009. Methodology and procedure of the dedicated sighting surveys in
JARPN II –Offshore and coastal component of Sanriku and Kushiro-. Paper SC/J09/JR2. 16pp.
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].
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:
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 JARPN II - offshore
component- with special emphasis on whale sampling procedures. Paper SC/J09/JR4.16pp.

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Table. 1. Summary of baleen whale sightings during the JARPN and JARPNII (1994-2007). 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 (sub-areas 7, 8 and 9)
Species
Sch.

Ind.

Calf

Mss

DIS

DIW

WT

Blue whale

281

396

17

1.41

0.14

0.20

3.0 - 21.6oC

Fin whale

514

750

28

1.46

0.26

0.37

3.4 - 24.1oC

Humpback whale

323

476

29

1.47

0.16

0.24

3.6 - 22.7oC

Right whale

28

40

6

1.43

0.01

0.02

3.0 - 17.0oC

Table. 2. Summary of baleen whale sightings by sub-area during the JARPN and JARPNII (1994-2007).
Sea

Western North pacificSub-area

Sub-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

7

8

40

59

234

329

Fin whale

34

37

140

197

340

516

Humpback whale

97

139

103

158

123

179

Right whale

6

7

4

6

18

27

Figure 1. Distribution of the primary searching effort (n.mile) during JARPN and JARPN II (1994 to 2007) surveys by
Lat.1°× Long.1°square.

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Figure 2a. Distribution of the Density Index (number of primary sightings of individuals / 100 n.mile ) of whales during
JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.
Upper : blue whale, bottom : fin whale.

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Figure 2b. Distribution of the Density Index (number of primary sightings of individuals / 100 n.mile ) of whales during
JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.
Upper : humpback whale, bottom : right whale.

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Figure 3a. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of blue whales
during JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.

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Figure 3b. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of fin whales
during JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.

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Figure 3c. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of humpback
whales during JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.

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Figure 3d. Monthly change of the Density Index (number of primary sightings of whales / 100 n.mile ) of right whales
during JARPN and JARPN II from 1994 to 2007 surveys by Lat.1°× Long.1°square.

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