SC/61/O5

SC/61/O5

Cruise report of the second phase of the Japanese Whale Research Program
under Special Permit in the Western North Pacific (JARPN II) in 2008
(Part II) - Coastal component off Kushiro.
HIDEYOSHI YOSHIDA1, HIDEHIRO KATO2, TOSHIYA KISHIRO1, TOMIO MIYASHITA1, TOSHIHIDE IWASAKI1,
YU KANAJI1, GENTA YASUNAGA3, HIROYUKI OIKAWA3, TAMEO RYONO3, SHIGEO TABATA3, RYOSUKEOKAMOTO2, HIKARI MAEDA2, AKIRA MATSUMOTO2, NATSUKO OGAWA2, SYOKA NAGATSUKA2, SATOKOINOUE2, HISOKA HIRUDA3, AKIHIRO GOKITA2, HAYATA MATSUNAGA2, AND KEI YAMASAKI2
1

National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa-ku, Yokohama,
Kanagawa 236-8648, Japan
2
Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-0075, Japan
3
The Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan.

Contact e-mail:hideka@fra.affrc.go.jp
ABSTRACTThe sixth survey of the JARPN II coastal component off Kushiro, northeast Japan (northern part of the sub-area7) was conducted from 9 September to 20 October 2008, using four small-type whaling catcher boats as
sampling vessels. Searching and sampling of common minke whales was conducted in coastal waters within 50
nautical miles from Kushiro port. All the whales collected were landed at the JARPN II research station forbiological examination. During the survey, a total of 5,381.4 nautical miles (521.3 hours) was searched, all the
108 schools (110 individuals) of common minke whales were detected, and 50 individuals were sampled.
Average body length of the animals was 5.97 m (SD=1.12, Range=4.50-7.72 m, n=32) for males and 5.61 m(SD=1.14, Range=3.87-7.94 m, n=18) for females. Ten of the 32 males were sexually mature and three females
attained maturity, one of which was pregnant. The dominant prey species found from whale forestomach waswalleye pollock (Theragra chalcogramma, 58.0%), followed by Japanese anchovy (Engraulis japonicus, 34.0%),
krill (Euphausia pacifica, 4.0%), and Japanese common squid (Todarodes pacificus, 2.0%). Pacific saury(Cololabis saira) was also had, but only two individuals were detected from whale forestomach. The ratio of
whales feeding on walleye pollock was highest in the present survey, in comparison with the previous surveys in
2002-2007 (3.4-30.0%). Results of the previous surveys off Kushiro suggest that feeding habit is different
between immature and mature whales: immature animals tend to take walleye pollock, while mature whales
mainly have Pacific saury and common squid. In the 2008 survey, all but one whales taking walleye pollock
were immature, while most of mature whales fed on Japanese anchovy. Furthermore, immature and mature
animals fed on different prey species, even if they were sampled at the same positions. These results also indicate
the difference in feeding habit between immature and mature common minke whales off Kushiro in autumn
season.
KEYWORDS: COMMON MINKE WHALE; NORTH PACIFIC; COASTAL WATERS OF JAPAN; FOOD/PREY;ECOSYSTEM; SCIENTIFIC PERMITS.

BACKGROUND
The full-scale survey of the second phase of the Japanese Whale Research Program under Special Permit in
the Western North Pacific (JARPN II) was started in 2002. The survey mainly aimed at i) feeding ecology
and ecosystem studies, involving prey consumption by cetaceans, prey preferences of cetaceans andecosystem modeling, ii) monitoring environmental pollutants in cetaceans and the marine ecosystem, andiii) elucidation of stock structure of whales (Government of Japan, 2002a).
The full-scale JARPN II consists of two survey components, i.e., offshore and coastal components. The
JARPN surveys (1994-1999) and the JARPN II feasibility study (2000-2001) revealed that common minke
whales are widely distributed from offshore waters into coastal waters and feed on various prey species
such as Japanese anchovy, Pacific saury, and walleye pollock (Government of Japan 2002b; Tamura andFujise 2002). Both the waters are very important fishing grounds. Thus, it is thought that the waters are also
very important area for the full-scale JARPN II program. However, the Nisshin Maru research vessels can
not be operated in near shore areas, because of their movement restrictions in shallow waters and the1Yoshida, et al.: Report of the JARPN II in 2008 - Coastal Component off Kushiropresence of fishing gear and many boats. Furthermore, the research vessels are not available from lateautumn to early spring. In order to cover the temporal and spatial gap of these vessels, in the full-scale
JARPN II, sampling of common minke whales in coastal waters using small-type whaling catcher boats
was planned (Government of Japan, 2002a).
In the first two years of the full-scale JARPN II, feasibility studies were conducted, to examine the logistic
aspects of the methodology. The first feasibility study was conducted in coastal waters off Kushiro inautumn 2002 and the second one was in coastal waters off Sanriku in spring 2003 (Kishiro et al. 2003,
Yoshida et al. 2004). Since no logistic problem occurred in the studies, it was concluded that the coastal
survey could be continued as the component of the full-scale JARPN II, using the same methodology(Government of Japan 2004b, Kato et al. 2004), while the survey was revised to be conducted twice a year
and to collect 60 common minke whales in each of spring and autumn (Government of Japan 2004a).
The first revised full-scale survey was carried out in coastal waters off Kushiro in autumn 2004 (Kishiro etal. 2005), then the coastal survey was conducted annually from 2005 to 2007 (Kishiro et al. 2006, 2008,
Yoshida et al. 2007). Here, we show results of the sixth survey conducted off Kushiro, from 9 September to
20 October 2008. The survey was authorized by the Government of Japan in compliance with Article VIIIof the International Convention for the Regulation of Whaling. At the request of the Institute of Cetacean
Research (ICR), the National Research Institute of Far Seas Fisheries (NRIFSF), of the Fisheries Research
Agency, took the lead in the planning and conduct of the survey, under cooperation of the ICR, Tokyo
University of Marine Science and Technology, and the Japan Small-type Whaling Association.
In January 2009, the JARPN II review workshop was carried out in Japan under the IWC/SC, where theprogress made in the first six years of the full-scale JARPN II (2002-2007) was reviewed by the scientificspecialists. Although the present survey was conducted after the first six years period, the survey was
carried out under the original revised plan (Government of Japan 2004a) because it was started before theworkshop.
MATERIALS AND METHODS
Research area
Research area was set in the same waters where the previous JARPN II coastal surveys off Kushiro wereconducted in 2002-2007 (Kishiro et al. 2003, 2005, 2006, 2008, Yoshida et al. 2007): the area was incoastal waters within 50 nautical miles from Kushiro port, southeastern Hokkaido (Fig. 1). This is includedin the northern part of the sub-area 7, established by the IWC.
Research vessels, station, and period
Four small-type whaling catcher boats were used as sampling vessels: Taisho Maru No. 28 (hereinafterreferred as 28T; 47.3GT), Koei Maru No. 75 (75K; 46.0GT), Katsu Maru No.7 (7K; 32.0GT), andSumitomo Maru No.31 (31S; 32.0GT). All the common minke whales sampled were landed at the JARPN
II research station established in the Kushiro port, for biological examination. Research period was set for
42 days, from 9 September to 20 October, 2006.
Searching and sampling methods
Searching and sampling methods were almost same with those for the first coastal survey off Kushiro in2002 (Kishiro et al. 2003). The research head office established in the research station controlled thesampling vessels during the survey. In order to avoid concentration of searching effort, the office
determined searching areas and routes of the vessels every day, from weather conditions, whale distribution,and information on fishing grounds of coastal fisheries. Searching activity was carried out during thedaytime and the vessels returned to the port every night. A researcher was on board each of the vessels andrecorded sighting and sampling information, e.g., coordinates and time of common minke whale sighting
and sampling made, weather conditions, and vessel activity. Sighting information was also recorded forother baleen whales and sperm whales. Searching was conducted by crews and researchers from the top
barrel and upper bridge of vessels running at around 10.5 knots. All common minke whales sighted weretargeted for sampling, except cow-calf pairs. When a school consisted of more than 1 animal, an individual
was selected randomly from the school and then collected. Once a vessel caught a whale, it returned to theKushiro port as soon as possible, to transport the animal sampled to the research station. While returning to
the port, even if the vessel sighted other common minke whales, it did not catch the animals. At the port,2

SC/61/O5

animals were lifted from the vessel by the crane, using a wire net and then carried to the station by the
11-ton freight trailer. At that time, body weight of animals was measured with the truck scale.
Biological research on common minke whales collected
All the whales sampled were examined by biological researchers at the research station. Research items arelisted in Table 2. These data and samples were collected for studies on feeding ecology, stock structure, life
history and pollutants.
RESULTS
Searching effort made by sampling vessels
Of the 42 days period predetermined for the 2008 survey, the sampling vessels could conduct searching
only for 24 days (57.1% of the predetermined days), from bad weather conditions, e.g., low atmosphericpressure and thick fog. Cruise tracks made by the vessels are shown in Figure 2. Searching distance andtime are given in Table 1. Here, searching distance and time are defined as distance and time recorded
under searching activity conducted by crews from the top barrel of the vessels. During the survey, a total of
5,381.4 nautical miles (521.3 hours) was searched.
Common minke whale sightings made by sampling vessels
All the 108 schools (110 individuals) of common minke whales were detected during the searching (Table 1,
Fig. 2). No cow-calf pairs were encountered. Sightings of a humpback and two sperm whales were also
made. Cruise tracks were widely distributed in coastal waters south of Kushiro port, whereas sightings ofcommon minke whales concentrated in waters along 200m isobath, particularly on the continental slope
southeast of Kushiro. Density index of common minke whales was calculated as 1.67 for DI (the number ofprimary sightings of schools per 100 nautical miles searching) and 0.17 for SPUE (the number of primarysightings of schools per 1 hour searching).
Sampling of common minke whales
Of the 110 common minke whales sighted, 50 animals were collected for biological examination. In thesampling process, struck and lost occurred in one case. Sighting positions of animals collected are shown in
Figure 2.
Sex ratio, body length and weight of animals caught
Research items of biological examination for the 50 individuals are summarized in Table 2, with thenumber of data and samples collected. The animals consisted of 32 males and 18 females. Sex ratio ofmales to all the animals was 0.64, which is almost same with ratios recorded in the previous surveys off
Kushiro in 2002-2007.
Average body length was 5.97 m (SD=1.12, range=4.50-7.72 m) for males and 5.61 m (SD=1.14,
range=3.87-7.94 m) for females (Table 3). In males, large animals with body length of 7 m or more werecollected in all the period. However, occurrence frequency of the large males was lowest in the present
survey, in comparison with the previous Kushiro surveys in 2002-2007. In the previous surveys, males withbody length of 7 m were recorded most frequently, whereas animals with body length of 4.5m werecollected most in the 2008 survey (Fig. 3). For females, obvious difference could not be found in bodylength frequency among animals collected in all the 2002-2008 surveys, possibly from their small sample
size. Sexual maturity of animals collected is shown in Table 4. In males, 10 of 32 animals were sexuallymature (31.3%), and three of 18 females attained sexual maturity (16.7%), of these a female was pregnant.
The male maturity ratio was lowest in the present survey, when it is compared with the ratio recorded in theprevious 2002-2007 Kushiro surveys (45.2-68.1%).
Prey species found from common minke whale forestomach
Stomach contents of the 50 animals collected were examined. Following the same methods used in the
JARPN II feasibility survey conducted in 2001 (Fujise, et al., 2002), stomach contents were weighed to thenearest 0.1 Kg, by each of four chambers. Weights were recorded both including and excluding liquid
contents. A small quantity of stomach contents was collected and frozen for laboratory analysis. Weight offorestomach contents including liquid ranged from 2.68 kg (walleye pollock) to 72.92 kg (Japanese
anchovy). Forestomach contents found from the 50 whales are listed in Table 5. Empty stomach wasobserved in one case. Dominant prey species was walleye pollock (Theragra chalcogramma)(58.0%,

3

Yoshida, et al.: Report of the JARPN II in 2008 - Coastal Component off Kushiroobserved in 29 animals), followed by Japanese anchovy (Engraulis japonicus)(34.0%), krill (Euphausia
pacifica)(4.0%), and common squid (Todarodes pacificus)(2.0%). Pacific saury (Cololabis saira) was also
taken, but only two individuals were detected from whale stomach. The ratio of whales feeding on walleye
pollock was highest in the present survey, in comparison with the previous Kushiro surveys(3.4-30.0%)(Fig. 4). In the 2008 survey, all but one whales taking walleye pollock were immature, whilemost of mature whales fed on Japanese anchovy (Fig. 5). Sighting positions of whales collected in the 2008
survey are shown by their maturity stage and prey species (Fig. 6).
DISCUSSION
The present survey was the sixth survey of the JARPN II coastal component off Kushiro. No practicalproblems occurred in the present survey, whereas bad weather conditions, e.g., low atmospheric pressure
and thick fog, often disturbed the research activities. Of the 42 days period predetermined for the 2008
survey, sampling vessels could conduct searching only for 24 days (57.1% of the predetermined days). Thisratio was lowest, in comparison with the previous Kushiro surveys in 2002-2007. Furthermore, the present
survey was 10 days shorter in the survey period than the last 2007 survey. Nevertheless, we could collectthe same number of animals as sampled in the last survey.
In the present survey, young and small animals were collected most frequently. Occurrence frequency oflarge males with body length of 7 m or more was lowest in the 2008 survey, when it is compared with theprevious 2002-2007 Kushiro surveys, where the large males collected most frequently (Fig. 3). In the 2008
survey, small animals with body length of 4.5m were collected most. Furthermore, male maturity ratio wasalso lowest. These results imply that, in the 2008 autumn season, younger and smaller males are relatively
abundant in coastal waters off Kushiro. For females, such tendency could not be detected, possibly fromsmall sample size (see, Fig. 3).
The present results show that the dominant prey species found from whale forestomach was walleye
pollock. The ratio of whales feeding on walleye pollock was about over twice or more in the present survey
as high as the animals collected in the previous surveys (Fig. 4). Kishiro et al. (2008) suggested that feeding
habit is different between immature and mature common minke whales off Kushiro in autumn season:
immature animals tend to take walleye pollock, while mature whales mainly have Pacific saury andcommon squid. In the 2008 survey, all but one whales taking walleye pollock were immature, while mostof mature whales fed on Japanese anchovy (Fig. 5). Furthermore, immature and mature animals fed on
different prey species, even if they were sampled at the same positions (Fig. 6): immature animals fed onwalleye Pollock, while mature whales took Japanese anchovy there. These results indicate the difference infeeding habit between immature and mature common minke whales off Kushiro, as Kishiro et al. (2008), in
which it is suggested that immature animals tend to take walleye pollock, while mature whales mainly have
Pacific saury and common squid.
The present survey indicates that immature males appear to be relatively abundant off Kushiro in theautumn of 2008 (see, Fig. 3). Possibly, this resulted in high frequently of whales feeding on walleye pollock
in the present survey (Fig. 4). From the 2008 survey, we could accumulate further information on feeding
habits of common minke whales migrating off Kushiro in autumn season.
ACKNOWLEDGMENTS
We acknowledge Dr. Hiroshi Hatanaka (ICR), Dr. Seiji Ohsumi (ICR), and Mr. Shigeki Takaya (theFisheries Agency of Japan), for their guidance in the survey design and support. Crew of research vessels,
staff of the research station in Kushiro, and the Japan Small-type Whaling Association assisted in important
aspects of the survey. We also thank all the members of the Kushiro fisheries cooperative association, themunicipal office of Kushiro, Hokkaido government Kushiro sub-prefectural office, and Hokkaido
government office, for their kind assistance.
REFERENCES
Fujise, Y., Tamura, T., Bando, T., Watanabe, H., Kiwada, H., Otani, S., Kanda, N., Yasunaga, G., Mogoe, T.,
Konishi, K., Inamori, M., Shigemune, H. and Tohyama, D. 2002. Cruise report of the feasibility study of
the Japanese Whale Research Program under Special Permit in the western North Pacific-Phase II(JARPN II) in 2001. Paper SC/54/O16 submitted to the 54th IWC Scientific Committee, 51pp.
Government of Japan, 2002a. Research plan for cetacean studies in the western North Pacific under special

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permit (JARPN II). Paper SC/54/O2 submitted to the 54th IWC Scientific Committee.
Government of Japan (Fujise, Y., Kawahara, S., Pastene, L.A. and Hatanaka, H. eds.), 2002b. Report of2000 and 2001 feasibility study of the Japanese Whale Research Program under Special Permit in thewestern North Pacific-Phase II (JARPN II). Paper SC/54/O17 submitted to the 54th IWC ScientificCommittee, 202pp.
Government of Japan, 2004a. Revised research plan for cetacean studies in the western North Pacific under
special permit (JARPN II). Paper SC/56/O1 submitted to the 56th IWC Scientific Committee, 14pp.
Government of Japan (Fujise, Y., Tamura, T., Kato, H. and Kawahara, S. eds.), 2004b. Some considerationsof the feasibility components of the JARPN II research plan. Paper SC/56/O2 submitted to the 56th IWC
Scientific Committee, 36pp.
Kato, H., Kishiro, T., Yoshida, H. and Kawahara, S. 2004. Feasibility of coastal surveys in the JARPN II,
from the viewpoint of logistics. Appendix 1, pp4-12. In: Government of Japan (Fujise, Y., Tamura, T.,
Kato, H. and Kawahara, S. eds.), Some considerations of the feasibility components of the JARPN II
research plan. Paper SC/56/O2 submitted to the 56th IWC Scientific Committee, 36pp.
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Hara., T., Hayashi, T., Miyashita, T., Fukudome, K., Kiwada, H., and Kawahara, S. 2003. Report of the2002 JARPN II survey in the western North Pacific. Part II: Coastal component - Coastal Survey off
Kushiro, northeast Japan. Paper SC/55/O8 submitted to the 55th IWC Scientific Committee, 26pp.
Kishiro, T., Kato, H., Yoshida, H., Miyashita, T., Ryono, T., Tabata, S., Okamoto, R., Yasui, K., Sato, H.,
Morita, Y., Saino, S., Hara, T., Ebisui, T., Kuroishi, H., Nishiwaki, S., and Kawahara, S. 2005. Cruise
report of the coastal survey on common minke whales off Kushiro, northeast Japan: the 2004 JARPN II
survey (Part II) - Coastal component. Paper SC/57/O4 submitted to the 57th IWC Scientific Committee,
37pp.
Kishiro, T., Kato, H., Yoshida, H., Miyashita, T., Ryono, T., Tabata, S., Yasui, K., Sato, H., Morita, Y.,
Kumagaya K., Tokuda, D., Nakai, K., Funabashi, N., Ebisui, T., Wakatsuki, T., Sakaguchi, M., Houhana,T., Nishiwaki, S., and Kawahara, S. 2006. Cruise report of the second phase of the Japanese Whale
Research Program under Special Permit in the Western North Pacific - Coastal component off Kushiro in2005. Paper SC/58/O10 submitted to the 58th IWC Scientific Committee, 32pp.
Kishiro, T., Kato, H., Yoshida, H., Miyashita, T., Iwasaki, T., Kanaji, Y., Ryono, T., Tabata, S., Morita, Y.,
Okamoto, R., Maeda, H., Nagatsuka, S., Ogawa, N., Nakai, K., Ebisui, T., Matsumoto, A., Gokita, A.,
Kiwada, H. and Kawahara, S. 2008. Cruise report of the Second phase of the Japanese Whale Research
Program under Special Permit in the western North Pacific (JARPN II) in 2007 - Coastal component off
Kushiro. Paper SC/60/O7 submitted to the 60th IWC Scientific Committee, 33pp.
Tamura, T. and Fujise, Y. 2002. Geographical and seasonal changes of the prey species on minke whale in
the Northwestern Pacific. ICES Journal of Marine Science, 59:516-528.
Yoshida, H., Kato, H., Kishiro, T., Iwasaki, T., Miyashita, T., Ryono, T., Tabata, S., Sakakibara, M., Saino,
S., Hara, T., Hayashi, T., Tomizawa, Y., Tamai, K., Okamoto, R., Fukuoka, M., Watanabe, H., Tsunekawa,
M. and Kawahara, S. 2004. Report of the coastal survey on common minke whales off Sanriku coast,
northeast Japan: the Japanese whale research program under special permit in the western North Pacific– Phase II (JARPN II) in 2003 (Part II) – Coastal component. Paper SC/56/O14 submitted to the 56th
IWC Scientific Committee, 31pp.
Yoshida, H., Kato, H., Kishiro, T., Miyashita, T., Iwasaki, T., Minamikawa, S., Ryono, T., Tabata, T.,
Morita, M., Sato, H., Okamoto, R., Toyoda, Y., Nakamura, G., Ebisui, T., Nakai, K., Matsumoto, A.,
Nishiwaki, S., and Kawahara, S. 2007. Cruise report of the second phase of the Japanese Whale Research
Program under Special Permit in the Western North Pacific (JARPN II) in 2006 - Coastal component off
Kushiro. Paper SC/59/O7 submitted to the 59th IWC Scientific Committee, 43pp.

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Yoshida, et al.: Report of the JARPN II in 2008 - Coastal Component off Kushiro

Table 1. Searching days, distances, hours, and number of cetacean sightings made during the 2008 JARPN II
coastal survey off Kushiro.
Number of sightings*
PeriodDays Distances
Hours
SpeciesPrimary
Secondary
Total(n. miles)(Ind/Sch)(Ind/Sch)（Ind/Sch）
9/9-10/20
245381.4
521.3
Common minke
92/90
18/18
110/108
whale
Like minke whale
24/24
1/1
25/25
Humpback whale
1/1
0/0
1/1
Sperm whale
2/1
0/0
2/1
Unidentified large
2/2
0/0
2/2
whale
*: The number probably includes some duplicated sightings made by plural vessels.

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Table 3. Statistics of body length (m) of common minke whales sampled during the 2008 JARPN II
coastal survey off Kushiro.
PeriodMale
FemaleMean S.D. Min. Max.
n
Mean S.D.
Min. Max. n
9/9 - 9/20
5.70
1.13
4.50
7.55
15
5.72
1.23
4.57
7.94
9
9/21 - 9/30

5.83

1.20

4.64

7.51

4

5.17

0.32

4.84

5.61

4

10/1 - 10/10

6.45

1.30

4.95

7.72

5

5.30

1.27

3.87

6.30

3

10/11 - 10/20

6.26

1.00

4.70

7.50

8

6.47

1.92

5.11

7.82

2

Total

5.97

1.12

4.50

7.72

32

5.61

1.14

3.87

7.94

18

Table 4. Composition of sex and sexual maturity of common minke whales sampled during the 2008 JARPN II
coastal survey off Kushiro.
PeriodMale
FemaleIm M Total Maturity(%)
Im R P Total Maturity(%) Pregnancy(%)*
9/9 - 9/20
11
4
15
26.7
7
1 1
9
22.2
50.0
9/21 - 9/30

3

1

4

25.0

4

0

0

4

0.0

-

10/1 - 10/10

2

3

5

60.0

3

0

0

3

0.0

-

10/11 - 10/20

6

2

8

25.0

1

1

0

2

50.0

0.0

Total
22 10
32
31.3
Im: Immature; M: Mature; R: Resting; P: Pregnant.
*: Apparent pregnancy ratio.

15

2

1

18

16.7

33.3

Table 5. Number of common minke whales by major prey species found in forestomach,sampled during the 2008 JARPN II coastal survey off Kushiro.
Number of whales (%)
Japanese
Pacific
Walleye
Krill
CommonEmpty
Periodanchovysaury*
Pollocksquid
9/9 - 9/20
3 (12.5)
0 (0.0)17 (70.8)
2 (8.3)1 (4.2)
1 (4.2)

Total
24

9/21 - 9/30

2 (25.0)0 (0.0)6 (75.0)0 (0.0)0 (0.0)0 (0.0)8

10/1 - 10/10

6 (75.0)0 (0.0)2 (25.0)0 (0.0)0 (0.0)0 (0.0)8

10/11 - 10/20

6 (60.0)0 (0.0)4 (40.0)0 (0.0)0 (0.0)0 (0.0)10

2 (4.0)1 (2.0)1 (2.0)50

Total
17 (34.0)
0 (0.0)29 (58.0)*: Only two individuals were found from whale stomach.

7

Yoshida, et al.: Report of the JARPN II in 2008 - Coastal Component off Kushiro

Kushiro50n. miles

Figure 2. Cruise tracks (upper) and sighting positions (lower) ofcommon minke (circle), humpback (star), and sperm (triangle)
whales made by sampling vessels during the 2008 JARPN II
coastal survey off Kushiro. Black circles are sighting
positions of common minke whales sampled.
Isobaths are 100m, 200m, 1000m, and 2000m.

Figure 1. Research area set for the 2008 JARPN II coastal survey
off Kushiro. The area is contained in the northernpart of the sub-area 7 established by the IWC.
Isobaths are 100m, 200m, 1000m, and 2000m.

8SC/61/O5

2002

Number of individuals

2004

2005

2006

2007
2006

2008

Body length (m)Figure 3. Body length frequency of common minke whales sampled during the 2008 JARPN II
coastal survey off Kushiro, with comparison to results of the previous 2002-2007 surveys.

Figure 4. Composition of prey species of common minke whales sampled during the 2008 JARPN II
coastal survey off Kushiro, with comparison to results of the previous 2002-2007surveys.

9

Yoshida, et al.: Report of the JARPN II in 2008 - Coastal Component off Kushiro

Figure 5. Sexual maturity and body length frequency of common minke whales by their prey species
found in forestomach in the 2008 JARPN II coastal survey off Kushiro.

Immature animal

Mature animal

Walleye pollock
Krill
Japanese anchovy
Common squid
Empty

Figure 6. Sighting positions of common minke whales sampled during the 2008 JARPN II coastal survey off
Kushiro, shown by their maturity stage and prey species. Isobaths are 100m, 200m, 1000m,
and 2000m.

10