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SC/62/O6

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 Kushiro
TOSHIYA KISHIRO1, HIDEHIRO KATO2, HIDEYOSHI YOSHIDA1, GENTA YASUNAGA3, SHIGEO TABATA4, GEN
NAKAMURA2, HIKARI MAEDA2, SATOKO INOUE2, NAOKO MIYAGAWA2, RYOSUKE OKAMOTO2, HIROYUKIOIKAWA3, HIKARU WATANABE1, TOSHIHIDE IWASAKI1, YU KANAJI1, SHINGO MINAMIKAWA1, SEIJI OTANI3,
HAJIME ISHIKAWA3, NAOHISA KANDA3, AKIHIRO GOKITA2, KEI YAMAZAKI2,YUTA YONEHARA2
1

National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 2368648, 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

4

Fisheries Agency of Japan, 1-2-1, Kasumigaseki, Chiyoda-ku, Tokyo, 100-8907, Japan

Contact e-mail: kishiro@affrc.go.jp
ABSTRACTThe seventh survey of the JARPN II coastal component off Kushiro, northeast Japan (northern part of the sub-area 7) was
conducted from 5 September to 17 October 2009, using four small-type whaling catcher boats as sampling vessels. The
sampling was conducted in the coastal waters within the 50 nautical miles from the Kushiro port, and all whales sampledwere landed on the land station in the Kushiro port for biological examination. During the survey, a total of 5,136.2 n. miles(493.8 hours) was searched, 106 schools/ 107 individuals of common minke whales were sighted and 59 whales were
sampled. Average body length of sampled whales was 6.13m (SD=1.10, n=36) for males and 5.12m (SD=0.60, n=23) for
females, respectively. In males, 12 out of 36 animals were sexually mature, while all females (23 animals) collected were
sexually immature. The dominant prey species found in the forestomach contents was walleye pollock Theragra
chalcogramma (40.7%), followed by krill Euphausia pacifica (32.2%), Japanese anchovy Engraulis japonicus (22.0%), andJapanese common squid Todarodes pacificus (1.7%). Pacific saury Cololabis saira was not found. Both the ratio of thewhales fed on walleye Pollock, and the ratio of immature whales were high as same as the previous survey conducted in 2008,
and these results indicated the difference in feeding habit between mature and immature individuals in the coastal waters off
Kushiro in autumn season, as suggested in the previous surveys.
KEYWORDS: COMMON MINKE WHALE; NORTH PACIFIC; COASTAL WATERS OF JAPAN; FOOD/PREY;ECOSYSTEM; SCIENTIFIC PERMITSBACKGROUND
The full-scale surveys of the second phase of the Japanese Whale Research Program under Special Permit
in the western North Pacific (JARPN II) started in 2002 (Government of Japan, 2002). The objectives ofthe surveys are: i) feeding ecology and ecosystem studies, involving prey consumption by cetaceans, prey
preferences of cetaceans and ecosystem modelling, ii) monitoring environmental pollutants in cetaceans
and marine ecosystem, and iii) stock structure of whales (Government of Japan, 2002).
The full-scale JARPN II involves two survey components; ‘offshore’ which is covered by the Nisshin Maru
research vessels and ‘coastal’ which is covered by small-type whaling catcher boats, and the latter one is1

Kishiro, et al.: Report of the JARPN II in 2009 – Coastal Component off Kushiro

necessary to cover the temporal and spatial gaps, which cannot be covered by the Nisshin maru research
vessels (Government of Japan, 2002).
Based on the results of the two-year feasibility study of the coastal survey component conducted in 2002
off Kushiro and 2003 off Sanriku district (Kishiro, et al., 2003, Yoshida, et al., 2004, Government of Japan,
2004a), the coastal component has been revised to be conducted twice a year, with 60 common minke
whales being sampled in each of spring off Sanriku and autumn off Kushiro (Government of Japan, 2004b).
After the first revised survey carried out off Kushiro in autumn 2004 (Kishiro, et al., 2005), the coastal
survey off Kushiro was conducted annually from 2005 to 2008 (Kishiro, et al., 2006, 2008, Yoshida, et al.,2007, 2009).
In January 2009, the expert workshop to review the ongoing JARPN II programme was carried out in Japan
under the IWC/SC, and results of the first six years of the full-scale JARPN II (2002-2007) was reviewed
by the scientific specialists (IWC, 2009). Because there was no critical problem in the survey methodology,
the survey off Kushiro in 2009 was carried out in principle under the original research plan (Government ofJapan 2004b).
This paper presents results of the seventh survey conducted off Kushiro, from 5 September to 17 October in2009. The survey was authorized by the Government of Japan in compliance with Article VIII of theinternational convention for the Regulation of Whaling. The National Research Institute of Far Seas
Fisheries (NRIFSF), Fisheries Research Agency, planned and conducted the survey cooperate with theInstitute of Cetacean Research (ICR) and Tokyo University of Marine Science and Technology.

MATERIALS AND METHODS
Research area
The research area was same to the previous surveys (Kishiro, et al., 2003, 2005, 2006, 2008, Yoshida, et al.,2007, 2009), i.e. the coastal waters off Kushiro, within the 50 nautical miles from the Kushiro port (Fig. 1).
This area is included in the northern part of the sub-area 7 determined by the IWC.

Research vessels and land station
Four small-type whaling catcher boats (Taisho Maru No. 28 (hereafter referred as 28T; 47.3GT), Koei
Maru No.75 (75K; 46.0GT), Sumitomo Maru No.31 (31S; 32.0GT) and Katsu Maru No.7 (7K; 32.0GT)
were used as the whale sampling vessels. The sampling survey was conducted from 5 September to 17
October. All whales sampled were landed on the land station (the JARPN II research station) in the Kushiro
port for biological examination.

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 was placed in the research station and controlled thesampling vessels during the survey. All catcher boats were engaged as the sampling vessels. To avoid theconcentration of sampling location, the research head office arbitrarily determined the searching area androute (direction from the port) for each sampling vessel in every day, based on the information of the whale
distribution. Weather conditions and information on fishing grounds of prey species were also considered.
In each vessel, a researcher was on board and recorded the cruise tracks, searching time on effort, sea
weather conditions and sighting data. Sighting data would be collected for all baleen whales and sperm
whales. The vessel principally continued to cruise and search along the predetermined direction until
arrived at 10-30 n. miles from the port, and then freely cruised in the waters within the 50 n. miles radius2

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from the port. Searching was carried out during the day and the vessels returned to the port every night.
Sighting was conducted from the top barrel and upper bridge by all the crews and researcher with vessel
speed at about 11 knots. All common minke whales sighted were targeted for sampling, except for the cowcalf pair. When a sighting consisted of more than one animal, first targeted animal was selected following
the random sampling digits. Sampling was made by 50 mm whaling cannon. Once a vessel caught a whale,
it returned to the Kushiro port to transport the animal to the research station. While returning to the port,other common minke whales sighted were also targeted for sampling, if the situation allowed. At the port,
the sampled whale was lift up from the vessel using wire nets and a crane and transported to the station by
an 11 tons freight trailer. At that time, body weight of the whale was measured with the truck scale.

Biological research on common minke whales collected
All the whales sampled were biologically examined by researchers at the research station. Research itemsof the biological studies were summarized in Table 2, with the number of data and samples obtained. These
items were related to studies on feeding ecology, stock structure, life historical biology and pollutions.

RESULTS
Searching effort made by sampling vessels
The cruise tracks made by the sampling vessels (28T, 75K, 31S and 7K) during the survey are shown in
Fig.2. The searching areas covered widely coastal waters within 30 nautical miles from the Kushiro port.
Searching distance and time are shown in Table 1. Here, we defined the searching distance and time as thatwith sighting effort, i.e. the periods of the searching conducted from the top barrel. During the research
period, total searching distance and time were 5,136.2 n. miles and 493.8 hours, respectively.

Sightings and sampling of common minke whales
Fig.3 shows distribution of common minke whales sighted by the sampling vessels. Sighting positions
widely distributed in inshore areas off Kushiro port to the waters in around 30 n. miles from the port, andrelatively concentrated in the southeastern side of the research area on the continental shelf and slope.
During the survey, a total of 106 schools/ 107 individuals of common minke whales were sighted,
consisting of 97 schools/ 98 individuals of primary sightings and 9 schools/ 9 individuals of secondarysightings (Table 1). These figures probably include some duplicated sightings because sampling vessels
searched almost same areas in every day. Density index of common minke whales was calculated as 1.89
for DI (the number of primary sightings of schools per 100 nautical miles searching) and 0.20 for SPUE
(the number of primary sightings of schools per 1 hour searching). Of the 107 common minke whales
sighted, 59 common minke whales were sampled. In the sampling process, there were no struck and lostanimals. Fig.3 showed sighting positions of sampled whales. Distribution of these whales almost covered
all of the areas where the sightings were made during the survey period.

Sightings of other large cetaceans
During the survey, a total of 20 schools/ 51 individuals of fin whales, 2 schools/ 5 individuals of sei whales,
and 19 schools/ 22 individuals of humpback whales were sighted (Table 1). Sighting positions of thosewhales were shown in Fig.4.

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Kishiro, et al.: Report of the JARPN II in 2009 – Coastal Component off Kushiro

Sex ratio, body length and maturity of common minke whales caught
The 59 sampled whales were consisted of 36 males and 23 females (sex ratio of males was 0.61). Average
body length of the whales was 6.13m (max=8.05, min=4.18, SD=1.10) for males and 5.12m (max=7.00,
min=4.54, SD=0.60) for females, respectively (Table 3). Composition of sex and sexual maturity of thewhales is listed in Table 4. Male with a single testis weight of 290g or more, and female had at least one
corpus luteum or albicans in their ovaries were determined as sexually mature. In males, 12 of 36
individuals (33.3%) were sexually mature. This figure was lower than that of the previous surveys, e.g.
45.7% in 2007, 52.0% in 2006 and 66.7% in 2005, but almost same with last year survey (31.3% in 2008).
All females sampled were immature (n=23), and sexually mature females was not observed.

Prey species of common minke whale found in the stomach contents
Stomach contents of all collected animals were examined except for two, which was broken by harpoon(Table 5). Following the same methods used in the JARPN II feasibility surveys (Fujise, et al., 2002),
stomach contents were weighted to the nearest 0.1 Kg by each four chamber in both cases of including andexcluding liquid. Then, a sub-sample of stomach contents was collected and frozen for the later laboratory
work. Four prey species, walleye pollock Theragra chalcogramma, krill Euphausia pacifica, Japanese
anchovy Engraulis japonicus, and Japanese common squid Todarodes pacificus were found in theforestomach contents. Among them, walleye pollock was the most dominant prey species. Ratio of thewhales mainly fed on walleye pollock was 40.7% or 24 out of 59 whales. Next dominant prey species was
krill (32.2% or 19 whales), followed by Japanese anchovy (22.0%) and Japanese common squid (1.7%).
Pacific saury Cololabis saira was not found. The weights of forestomach contents ranged from 3.72Kg(Japanese anchovy) to 97.6Kg (krill) and average weight was 26.9Kg.

DISCUSSION
The present survey was the seventh survey of the JARPN II coastal component in the autumn season off
Kushiro. As same as the previous surveys, bad weather conditions such as typhoons, low atmosphericpressures and thick fog often disturbed research activities. Of total 43 day survey period from 5 September
to 17 October, sampling vessels could conduct the research for 25 days or 58.1% of the predetermined days.
This figure was almost same in the last year survey (57.1% in 2008). However, we could collect almost
same number of a planned sample size of common minke whales in this year. One of the reasons wasthought to be the migration of common minke whales. The density index of common minke whales
recorded by the sampling vessels in 2009 (DI=1.89) was higher than that of the last year survey (DI=1.67,
Yoshida et al., 2009), and this suggested that the migration of common minke whales in 2009 was moreabundant than that in 2008. A logistical minor improvement of sampling method (additional sampling
while returning to the port) was thought to be also contributed to the progress in catch.
Frequency distribution of body length of common minke whales collected in 2009 was similar to
those in 2008, but young and small females with body length of 4.5m were collected most, and ratio oflarge animals with body length of 7m or more was low when it’s compared with the previous 2004-2005
surveys (Fig. 5). These results suggested that immature animals were frequently distributed in the researcharea, and the migration of mature animals into the research area was scarce in the 2009 season.
As same as the results of the 2008 survey, the most dominant prey species found from whale
forestomach was walleye pollock, but the composition of prey species was different and next dominant
prey was krill in the 2009 survey (Fig. 6). All whales taking walleye Pollock were sexually immature anddistributed in the waters southeast coast off Kushiro along 200-500m isobaths on the continental slop
region (Fig. 7 and 8). Krill and Japanese anchovy were taken by both immature and mature whales, andcommon squid was taken by mature whale (Fig. 7). These results were thought to be indicated thedifference in feeding habit between mature and immature common minke whales in the coastal waters off4

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Kushiro in autumn season, as suggested by the results of the previous 2002-2007 surveys (Kishiro et al.,2008, 2009), i. e. immature animals tend to take walleye pollock on the continental shelf and slope regions,while mature whales mainly have Pacific saury and common squid, and both immature and mature whales
consumed Japanese anchovy. In the present survey, Pacific saury was not observed in the stomach ofsampled whales, and maturity ratio of sampled whales was low. This might be due to a small migration ofPacific saury in the restricted research area in 2009, and as a result, the visit of mature whales that prefer
Pacific saury might have been also few in the research area.
One of the features in this year was that there were a lot of sightings of large baleen whales such as
fin and humpback whales compared with the ordinary years. In 2009, a total of 51 fin, 5 sei, and 22
humpback whales were sighted (Table 1), but during the total periods from 2002-2008, a total of only threefin, one sei, and six humpback whales sightings were recorded (Kishiro, et al., 2003, 2005, 2006, 2008,
Yoshida, et al., 2007, 2009) Although these figures probably include some duplicated sightings, the numberof sightings in 2009 was obviously more than that of the previous 2002-2008 surveys. The sighting
positions of these whales were overlapped with those of commom minke whales (Fig. 4) and stomach
contents of minke whales sighted near those whales were krill (Fig.8). Furthermore, krill was the next
dominant prey species found in the stomach of common minke whales in 2009. These results implied thatthe local migration of large baleen whales observed in 2009 might be related to the distribution of krill, andkrill might be more abundant in the research area in 2009, as compared with the previous years. However,it was uncertain what those whales were actually eating, and further analysis is needed.
There was no serious practical problem in conducting the surveys and the 2009 coastal survey off
Kushiro was conducted successfully.

ACKNOWLEDGMENTS
The authors are greatly indebted to Dr. Hiroshi Hatanaka, the Institute of Cetacean Research (ICR), Dr.
Seiji Ohsumi (ICR) and Mr. Shigeki Takaya, the Fisheries Agency of Japan for their guidance andimplementation of the research. We thank to all crew of the research vessels and all staff of the land stationand the Japanese small-type whaling association. We also thank to the staff of the Kushiro City and theKushiro Fisheries Cooperative Union for their kind assistance in the implementation of the research.

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 studyof 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, 2002. Research plan for cetacean studies in the western North Pacific under special
permit (JARPN II). Paper SC/54/O2 submitted to the 54th IWC Scientific Committee.
Government of Japan (Fujise, Y., Tamura, T., Kato, H. and Kawahara, S. eds.), 2004a. Someconsiderations of the feasibility components of the JARPN II research plan. Paper SC/56/O2 submitted
to the 56th IWC Scientific Committee, 36pp.
Government of Japan, 2004b. 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.
International Whaling Commission, 2009. The Report of the Expert Workshop to review the ongoing
JARPN II Programme. Paper SC/61/Rep1 submitted to the 61th IWC Scientific Committee, 57pp.
Kishiro, T., Kato, H., Ohizumi, H., Yoshida, H., Saito, T., Isoda, T., Tabata, S., Sakakibara, M., Saino, S.,
Hara., T., Hayashi, T., Miyashita, T., Fukudome, K., Kiwada, H., and Kawahara, S. 2003. Report of the5

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2002 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.
Kishiro, T., Yoshida, H., Tamura, T., Konishi, K., Kanda, N., Okamoto, R. and Kato, H. 2009. Relationshipbetween body size, maturity, and feeding habit of common minke whales off Kushiro in autumn season,
from 2002-2007 whale sampling surveys under the JARPN II coastal component off Kushiro. Paper
SC/J09/JR13 submitted to theIWC SC JARPN II review workshop, 25pp.
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
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Kushiro. Paper SC/59/O7 submitted to the 59th IWC Scientific Committee, 43pp.
Yoshida, H., Kato, H., Kishiro, T., Miyashita, T., Iwasaki, T., Kanaji, Y., Yasunaga, G., Oikawa, H.,
Ryono, T., Tabata, T., Okamoto, R., Maeda, H., Matsumoto, A., Ogawa, N., Nagatsuka, S., Inoue, S.,
Hiruda, H., Gokita, A., Matsunaga, H., and Yamazaki, K.2009. Cruise report of the second phase of theJapanese Whale Research Program under Special Permit in the Western North Pacific (JARPN II) in2008(Part II) - Coastal component off Kushiro. Paper SC/61/O5 submitted to the 61th IWC ScientificCommittee, 10pp.

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Table 1. Searching days, hours, distances, and number of sightings made by the whale sampling survey inthe 2009 JARPN II coastal component off Kushiro.

Table 2. Summary of biological data and samples collected during the 2009 JARPN II coastal survey off Kushiro.

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Kishiro, et al.: Report of the JARPN II in 2009 – Coastal Component off Kushiro

Table 3. Body length (m) of common minke whales sampled by the 2009 JARPN II coastal survey off
Kushiro.

Table 4. Composition of sex and sexual maturity of common minke whales sampled by the 2009 JARPN II
coastal survey off Kushiro.

Table 5. Number of common minke whales by major prey species found in their forestomach contents
sampled by the 2009 JARPN II coastal survey off Kushiro.

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Fig.1. The IWC sub-area for western North Pacific minke whales (upper) andresearch area for the 2009 JARPN II coastal component off Kushiro (lower).

Fig.2. Cruise tracks of the whale sampling survey in the 2009 coastal component off Kushiro.

9Kishiro, et al.: Report of the JARPN II in 2009 – Coastal Component off Kushiro

Fig.3. Sighting positions of common minke whales made by the whale sampling survey in the 2009
coastal component off Kushiro. Closed circle indicates sighting position of sampled whale.

Fig.4. Sighting positions of fin whales (closed triangle), humpback whales (grey square), and sei whales(open circle) made by the whale sampling survey in the 2009 coastal component off Kushiro.

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Fig 5. Body length frequency of common minke whales sampled during the 2009 coastal survey off
Kushiro, with comparison to results of the previous 2002-2008 surveys.

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Kishiro, et al.: Report of the JARPN II in 2009 – Coastal Component off Kushiro

Fig. 6. Composition of prey species of common minke whales sampled during the 2009 coastal survey off
Kushiro, with comparison to results of the previous 2002-2008 surveys.

Fig.7. Sexual maturity and body length frequency of common minke whales by their major prey species
found in the forestomach in the 2009 coastal survey off Kushiro.

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Fig.8. Sighting positions of common minke whales in the 2009 coastal survey off Kushiro
by their sexual maturity and major prey species found in the forestomach

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