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Cruise Report of the Second Phase of the Japanese Whale
Research Program under Special Permit in the Western North
Pacific (JARPN II) in 2011 - (Part II) - Coastal component off
Kushiro, spring survey
GENTA YASUNAGA1), NOBUYUKI, ITOH2), ATSUSHI WADA1), HIROSHI KIWADA1), HITOMI SATO2), HIKARI MAEDA3), GEN
NAKAMURA3), SATOKO INOUE3), NAOKO MIYAKAWA3), KAZUYA KITAYAMA3), YUICHIRO ISHIKAWA3), NOBUYUKI
SUZUKI3), TAICHI TSUTSUMI3), ICHIRO KADOWAKI3), HIDEHIRO KATO3)

1) Institute of Cetacean Research, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
2) Association for Community-Based Whaling, 2-5-28, Hakata-eki-higashi, Hakata-ku, Fukuoka, 812-0013, Japan
3) Tokyo University of Marine Science and Technology 4-5-7 Konan, Minato-ku, Tokyo 108-0075, Japan
Contact e-mail:yasunaga@cetacean.jp

ABSTRACTOn March 11 2011 the Ayukawa town, including all research facilities of JARPN II there, was destroyed by a large
earthquake and tsunami. For this reason the spring coastal survey in 2011 could not be conducted in Ayukawa. Instead
the spring survey was conducted in Kushiro. While the main reason for this change was logistic, we expected that thesurvey in a different season in this locality (Kushiro/spring) would provide new information on the feeding ecology of
the common minke whales. The survey was conducted from 25 April to 10 June, using three small-type whaling catcher
boats. Sampling of common minke whales was conducted in coastal waters within 50 n. miles from Kushiro port, andall animals collected were landed on the JARPN II research station established for biological examination. A total of
3,867.4 n.miles (375.2 hours) was surveyed and 36 schools (43 individuals) of common minke whales were sighted. A
total of 17 animals was sampled. Average body length of the animals was 6.70 m (SD: 0.84, n=9) for males and 6.29 m(SD: 1.02, n=8) for females. Dominant prey species found in the forestomach were walleye pollock (Theragra
chalcogramma) throughout all survey period, and krill (Euphausia pacifica), which was observed less frequently. This
spring survey revealed that walleye pollock is one of the most important food items for common minke whales inKushiro in both spring and autumn seasons. Distribution of the common minke whales appear to differ between spring
and autumn surveys in Kushiro, at least for some of the years surveyed.
KEYWORDS: COMMON MINKE WHALE; NORTH PACIFIC; FEEDING ECOLOGY; SCIENTIFIC PERMITS.

INTRODUCTION
After the two-year feasibility study in 2000-2001, 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 objectives ofthe program are 1) Feeding Ecology and Ecosystem Studies, involving prey consumption by cetaceans, prey preferencesof cetaceans and ecosystem modeling; 2) Monitoring environmental pollutants in cetaceans and the marine ecosystem;and 3) Stock structure of whales (Government of Japan, 2002).
The JARPN II coastal component using small-type whaling catcher boats started to complement the temporal andspatial gap of the offshore components using the Nisshin Maru research vessels since 2002. In the original JARPN II
plan, the coastal component was presented as the two-year feasibility study to examine the logistic aspects of themethodology (Government of Japan, 2002). First feasibility survey was carried out in the coastal waters off Kushiro in

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autumn 2002 (Kishiro et al., 2003) and then the second feasibility survey was conducted in the coastal waters off
Sanriku district in spring 2003 (Yoshida, et al., 2004). In each of the surveys, 50 common minke whales were caught.
From detailed examination of logistic aspects in the surveys, it was concluded that no substantial problem occurred andthat the coastal survey could be continued as a component of the JARPN II using same kind of vessels (small-typewhaling catcher boats) and methodology (Government of Japan, 2004a, Kato, et al., 2004). However, re-calculation ofrequired sample size from the survey data suggested that the size should be modified to 60 individuals in eacharea/season (Tamura, et al., 2004), and from the possible geographical and/or temporal variations of prey consumptionof the whales, the coastal surveys thought to be needed on a yearly bases in each local area (Government of Japan,
2004b). The revised survey off Sanriku was carried out in spring during 2005 and 2010 year (Yoshida et al., 2006; Goto
et al., 2007; Bando et al., 2008, 2011; Yasunaga et al., 2009, 2010).
On March 11 2011 the Ayukawa town, including all research facilities of JARPN II, was destroyed by a large
earthquake and tsunami. For this reason the spring coastal survey could not be conducted in Ayukawa in 2011. Instead
the spring survey was conducted in Kushiro. While the main reason for this change was logistic, we expected that thesurvey in a different season in Kushiro will provide new information on the feeding ecology of the common minke
whales. There is no data of feeding ecology of common minke whales off Kushiro in spring through JARPN, JARPN II
and past commercial whaling.
Here we report the survey carried out in coastal waters off Kushiro from 25 April to 10 June in 2011. This survey was
authorized by the Government of Japan in compliance with Article VIII of the International Convention for the
Regulation of Whaling. The Institute of Cetacean Research (ICR) planned and conducted the survey in cooperation with
National Research Institute of Far Seas Fisheries and Tokyo University of Marine Science and Technology and the
Association for Community-Based Whaling.

MATERIALS AND METHODS
Research area
The research area was set in the same way as in previous surveys in Kushiro (Yoshida et. al, 2011). The area was incoastal water within 50 n. miles from Kushiro port, south eastern Hokkaido (Figure 1). The research area corresponds tothe northern part of sub-area 7CN, established by the IWC (1994).
Whale samplingThree small-type whaling catcher boats were used as sampling vessels: Seiwa Maru (here in after referred as SW;
15.2GT), Katsu Maru No.7 (7K; 32.0GT), and Sumitomo Maru No.51 (51S; 30.0GT). All the animals sampled werelanded on the JARPN II research station established in the Kushiro port for biological examination.
BIOLOGICAL RESEARCH
All common minke whales collected were examined biologically by researchers at the research station. Research items
are summarized in Table 1. These items are related to studies on feeding ecology, stock structure, life history andpollutions.

RESULTS
Searching effort
The whale sampling survey was conducted in the period from 25 April to 10 June, 2011. Cruise tracks by the sampling
vessels SW, 7K and 51S are shown in Figure 2. The tracks covered widely the coastal waters of Kushiro. Searching
distance and time are listed in Table 2, by sampling vessel. Searching distance and time are defined as distance and time
recorded under searching activity conducted from the top barrel of the vessels. Total searching distance and time madeby the three vessels were 3,867.4 n. miles and 375.2 hours, respectively (Table 2).

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Sightings
The cruise tracks covered widely distributed the coastal waters of Kushiro (Figure 2). A total of 36 schools (43individuals) of common minke whales was sighted during searching (Table 3, Figure 3). No cow-calf pair was observed.
Density index (DI, the number of primary sightings of schools per 100 n.miles searching) of common minke whales
was calculated as 0.83 (Table 4). Three schools (four individuals) of fin whales were sighted during the searching.
Sampling of common minke whales
A total of 17 common minke whales was sampled. No situation of struck and lost occurred. The sighting positions ofsampled animals are shown in Figure 3.
Biological examination
Sex ratio, body length and weight
Research items for the biological examination are summarized in Table 1. The sampled animals consisted of 9 males
and 8 females. Sex ratio of males was 0.53. Average body length was 6.70 m (max=7.86, min=5.28, SD: 0.84) for
males and 6.29 m (max=8.11, min=4.39, SD=1.02) for females (Table 5). The sexual maturity of animals collected islisted in Table 6. For males and females 67% and 13% of the animals sampled, were sexually mature, respectively. The
mature female was pregnant.
Prey species of common minke whale
Following the same methods used in the JARPN II feasibility survey conducted in 2001 (Fujise, et al., 2002), stomach
contents were weighted to the nearest 0.1 kg, in each of the four chambers, for both cases including and excluding
liquid contents. In addition a small sample of forestomach contents was collected and frozen for laboratory analysis.
Forestomach contents are listed in Table 7. Dominant prey species were walleye pollock (Theragra chalcogramma)(71.4%, 10 from 14 stomaches examined). Krill (Euphausia pacifica) was observed in four animals. The maximum net
weight of forestomach contents was 105.3 kg, consisting of walleye pollock (Table 8).

DISCUSSION
The present survey was the first coastal survey carried out in coastal waters off Kushiro in spring. A total of 17 animals
were sampled of 60 planned for this survey. Limited sampling can be explained by the migration pattern of minke
whale. Less minke whales migrate to Kushiro coastal area in spring than they do in fall. In addition low atmosphericpressure often disturbed the research activities during the 2011 survey and changeable weather condition and big waves
obstructed sampling activities in offshore waters.
The sighting positions of the common minke whales in this survey were concentrated along the Kushiro canyon ofnorth-south orientation (Figure 4). In contrast whales were distributed widely on the shelf region and along the 200500m isobaths on the continental slop in the autumn surveys of 2010 and 2011 (Yoshida et al., 2011; Kishiro et al.,2012).
Figure 5 shows the histogram of body length of whales sampled in the 2011 spring survey and those in autumn surveys
in the years 2011-2012 (Yoshida et al., 2011; Kishiro et al., 2012). Average body lengths in the spring 2011 survey(male=6.70m; female=6.29m) were higher than those in the 2010 autumn survey (male=5.80; female=5.44, Yoshida etal., 2011) and similar to those in the 2011 autumn survey (male=6.24; female=6.05, Kishiro et al., 2012).
Sexual maturities of whales sampled in Kushiro in the 2011 spring survey (male=67%; female=13%) were higher thanthose in the 2010 autumn survey (male=22% female=0%, Yoshida et al., 2011) and similar to those in the 2011 autumn
survey (male=54% female=12%, Kishiro et al., 2012). These results reflect the migratory nature of minke whales bysex and reproductive classes.
Walleye pollack and krill were observed in the forestomach of common minke whales in this research, whereas
walleye pollack, anchovy and Japanese saury had been observed in previous autumn surveys (Yoshida et al., 2011;
Kishiro et al., 2010). The results in the spring survey suggest that walleye pollock is one of the most important food3

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items for common minke whales in Kushiro in both the spring and autumn seasons. Common minke whales feeding on
walleye pollock in the 2011 spring survey were concentrated along the Kushiro canyon of north-south orientation, while
those in 2010 autumn survey were concentrated along the 200-500m isobaths on the continental slope region.
In summary during the present survey, which involved a new area/season combination, new valuable information on
feeding ecology of common minke whales was obtained.

ACKNOWLEDGMENTS
We acknowledge Luis Pastene (ICR), Tomio Miyashita (NRIFSF) and Tatsushi Matsuo (Fisheries Agency of Japan),for their guidance in the survey design and support. Crewmen, staff of the research station in Kushiro and the
Association for Community-Based Whaling assisted greatly during the survey. We also thank the members of themunicipal office of Kushiro, Kushiro sub-prefectural office, and Hokkaido government office, for their kind assistance.

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Kishiro, T., Kato, H., Ohizumi, H., Yoshida, H., Saito, T., Isoda, T., Tabata, S., Sakakibara, M., Saino, S., Hara., T.,
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SC/55/O8 submitted to the 55th IWC Scientific Committee, 26pp.
Kishiro, T., Kato, H., Ito, N., Yasunaga, G., Hara, T., Nakamura, G., Maeda, H., Inoue, S., Miyakawa, N., Ishida, K.,
Kadowaki, I., Oikawa, H., Miyashita, T., Iwasaki, T., Kanaji, Y., Minamikawa, S., Watanabe, H., Kumagai, S., Sato,H. and Kitayama, K. 2012. Cruise report of the second phase of the Japanese Whale Research Program under Special
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Recalculation of sample size of common minke whales in coastal areas required for estimating consumption of various
prey items based on results of JARPN II. Appendix 2, pp13-17. 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. Paper SC/56/O16 submitted to the 56th IWC
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Yasunaga, G., Kato, H., Kishiro, T., Yoshida, H., Nishiwaki, S., Saito, T., Tabata, S., Okamoto, R., Maeda, H.,
Nakamura, G., Inoue, S., Otani, S., Iwasaki, T., Kanaji, Y., Mogoe, T., Murase, H., Wada, A., Nakai, K., Matsumoto,A., Gokita, A., Yamazaki, K., Oikawa, H., Onodera, K., Shiraishi, K. and Nagashima, H. 2009. Cruise report of thesecond phase of the Japanese Whale Research Program under Special Permit in the Western North Pacific (JARPN II)
in 2008 - Coastal component off Sanriku. Paper SC/61/O6 submitted to the 61th IWC Scientific Committee, 20pp.
Yasunaga, G., Kato, H., Kishiro, T., Yoshida, H., Ishikawa, H., Goto, M., Tabata, S., Maeda, H., Nakamura, G., Inoue,
S., Miyakawa, N., Tamura, T., Kumagai, S., Iwasaki, T., Kanaji, Y., Watanabe, H., Hiruta, H., Yamazaki, K.,
Yonehara, Y., Oikawa, H. and Onodera, K. 2010. Cruise report of the second phase of the Japanese Whale Research
Program under Special Permit in the Western North Pacific (JARPN II) in 2009 - (Part II) - coastal component off
Sanriku. Paper SC/62/O5 presented to the IWC Scientific Committee, May 2010 (unpublished). 20pp.
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., Iwasaki, T., Miyashita, T., Saito, T., Tabata, S., Morita, Y., Sato, H., Okada, A.,
Tomizawa, Y., Saino, S., Kuroishi, H., Ebisui, T., Nakai, K., Nishiwaki, S. and Kawahara, S. 2006. Cruise report ofthe second phase of the Japanese Whale Research Program under Special Permit in the Western North Pacific (JARPNII) in 2005- Coastal component off Sanriku. Paper SC/58/O9 submitted to the 58th IWC scientific Committee, 30pp.
Yoshida, H., Kato, Ito, N., Kishiro, T., Miyashita, T., Iwasaki, T., Minakawa, N., Kanaji, Y., Oikawa, H., Tabata, S.,
Kumagai, S., Nakamura, G., Maeda, H., Inoue, S., Miyakawa, N., Ishikawa, Y., Shimizu, K., Yonehara, Y., Kitayama,K., Tsutsumi, T. and Kato, H. 2011. Cruise report of the second phase of the Japanese Whale Research Program underSpecial Permit in the Western North Pacific (JARPN II) in 2010 (Part III)- Coastal component off Kushiro. Paper
SC/63/O4 submitted to the 63th IWC scientific Committee, 10pp.

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Table 1. Summary of biological data and samples collected during the 2011 JARPN II coastal survey off
Kushiro in spring
Number of animals
Male Female Total

Samples and data
Body length and sex
External body proportion
Photographic record and external character
Diatom film record
Body scar record
Measurements of blubber thickness (5 points)
Whole body weight
Skin tissues for DNA study
Muscle, liver, kidney, spleen, blubber, heart and ventral groove for various analysis
Urine for various analysis
Muscle, liver, kidney, and blubber for heavy metal analysis
Muscle, liver, kidney, and blubber for organochlorine analysis
Collection of blood plasma
Mammary grand; lactation status, measurement and histological sample
Uterine horn; measurements and endometrium sample
Collection of ovary
Photographic record of fetus
Fetal length and weight
External measurement of fetus
Muscle, liver, kidney, heart, blubber and skin tissues of fetus
Collection of fetus
Testis and epididymis; weight and histological sample
Stomach contents, convenient record
Volume and weight of stomach content in each compartment
Observation of marine debris in stomach
Collection of stomach contents for feeding study
Record of external parasites
Earplug for age determination
Tympanic bulla for age determination
Eye lens for age determination
Largest baleen plate for morphologic study and age determination
Baleen plate measurements (length and breadth)
Photographic record of baleen plate series
Length of baleen series
Vertebral epiphyses sample
Number of ribs
Skull measurement (length and breadth)
Skull measurement (43 points)
Collection and measurement of pelvic bone

6

9
9
9
9
9
9
9
9
9
6
9
9
8
0
0
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
7
9

8
8
8
8
8
8
8
8
8
2
8
8
7
8
8
8
1
1
0
0
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
6
8

17
17
17
17
17
17
17
17
17
8
17
17
15
8
8
8
1
1
0
0
1
9
17
17
17
17
17
17
17
17
17
17
17
17
17
17
17
13
17

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Table 2. Searching days, hours and distances by three sampling vessels in the 2011 JARPN II coastal
surveys off Kushiro in spring
Sampling vessels*
Period

SW

07K

51S

Total

Early period（25 April-17 May）

Days
Hours
Distance(n.mile)

12
70.6
708.8

12
67.3
688.0

9
55.0
582.6

33
192.9
1,979.4

Late period（18 May-10 June）

Days
Hours
Distance(n.mile)

3
22.8
224.8

12
79.0
783.5

12
80.5
879.7

27
182.3
1,888.021
135.5
1,462.3

60
375.2
3,867.4

Total

Days
15
24
Hours
93.4
146.3
Distance(n.mile)
933.6
1,471.5*: SW:Seiwa Maru, 07K; Katsu Maru No.7, 51S; Sumitomo Maru No.51.

Table 3. List of cetacean species and number of sightings made by three sampling vessels in the 2011
JARPN II coastal surveys off Kushiro in spring
PeriodEarly period（25 April17 May）
Late period（18 May10 June）
Total

SpeciesPrimary
Sch.
Ind.
12
12

Secondary
Sch.
Ind.
1
1

Sch.
13

Ind.
13

3

3

0

0

3

3

Common minke
whale
Like minke whale

20

27

3

3

23

30

2

2

0

0

2

2

Common minke
whale
Like minke whale

32

39

4

4

36

43

5

5

0

0

5

5

Common minke
whale
Like minke whale

Table 4. Density index of common minke whales by sampling vessels in the 2011
JARPN II coastal survey off Kushiro in spring
PeriodSPUE*1
0.062
Early period （25 April-17 May）
0.11
Late period （18 May- 10 June）
Total
0.085
*1
: No. of primary school sightings per 1 hour searching.

DI*2
0.61
1.06
0.83

*2

: No. of primary school sightings per 100 n. miles searching.

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Total

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Table 5. Body length (m) of common minke whales collected during the 2011 JARPN II coastal survey off Kushiroin spring
Male
FemalePeriodmean
S.D.
Min. Max.
n
mean
S.D.
Min.
Max.
n
Early period（25 April-17 May）
6.68
1
6.22
1.19
4.39
8.11
6
Late period（18 May-10 June）
6.70
0.90
5.28 7.86
8
6.51
6.23
6.79
2
Total
6.70
0.84
5.28 7.86
9
6.29
1.02
4.39
8.11
8

Table 6. Sex and sexual maturity status of common minke whales collected by the 2011 JARPN II coastal survey off
Kushiro in spring
Male
Period

Im

M

Uk

Total

FemaleMaturity
(%)
1.00

Im.

R

P

P&L

Uk

Early period
0
1
0
1
5
0 1
0
0
（25 April-17 May）
Late period
3
5
0
8
0.63
2
0 0
0
0
（18 May-10 June）
Total
3
6
0
9
0.67
7
0 1
0
0
Im: Immature, M: Mature, R: Resting, P: Pregnant, P&L: Pregnant and lactating, Uk: Unknown

6

Maturity
(%)
0.17

2

0.00

8

0.13

Total

Table 7. Prey species found in forestomach of common minke whales collected by the 2011 JARPN II coastal survey
off Kushiro in spring (removing animals with broken stomach by harpoon.)
Prey species

No. of whales
observed

PeriodEarly period（25 April-17 May）
Late period（18 May-10 June）
Total

6
8
14

Number
Occurrence (%)
Number
Occurrence (%)
Number
Occurrence (%)

8Walleye pollack

Krill

3
50.0
7
87.5
10
71.4

3
50.0
1
12.5
4
28.6

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Table 8. Weight (kg) of forestomach content of common minke whales collected by the 2011 JARPNⅡ
coastal survey off Kushiro in spring

Early period（25 April-17 May）
Late period（18 May-10 June）
Total

averagerange
averagerange
average
range

Walleye pollack

Krill

10.0
(2.6-22.1)
52.4(3.7-105.3)
36.5(2.6-105.3)

9.6(1.2-18.0)
4.7
7.98(1.2-18.0)

Figure 1. Research area of the 2011 JARPNII coastal survey off the Kushiro in spring.

Figure 2. Cruise tracks by three sampling vessels in the 2011 JARPNII coastal survey off Kushiro in spring

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Kushiro port

43N

30 n.mile

50 n.mile

Sighting and sampled
Only sighting
42N
143E

144E

145E

Figure 3. Sighting positions of common minke whales made by sampling vessels in the 2011 JARPNⅡ coastal
survey off Kushiro in spring (●:sighting and sampled; ○: only sighting)2010 Autumn

2011 Autumn

2011 Spring●：Walleye pollock▲：Krill★：Japanese anchovy

Figure 4. Sighting position of common minke whales sampled in Kushiro during spring 2011 and autumn 2010,2011, by major prey species.

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Figure. 5. Frequency of body length of common minke whales sampled in Kushiro in spring 2011, by sex

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