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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 I) – Offshore component –TSUTOMU TAMURA 1), TOSHIHIRO MOGOE 1), KAZUYOSHI NAKAI 1), MASAKATSU MORI 2), MASAOMI TSUNEKAWA 2),
ISAMU YOSHIMURA 2), YUICHIRO ISHIKAWA 3), SHINYA KAWABE 2), FUTOSHI YAMAGUCHI 2), MASAHIRO YAMAZAKI 2),
EISEI UETA 2), HIKARU WATANABE 4), AND KOUJI EGUCHI 2)

1) Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan,2) Kyodo Senpaku Co. Ltd., 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan,
3) Tokyo University of Marine Science and Technology, Faculty of Marine Science, 4-5-7, Konan, Minato-ku, Tokyo, 108-8477, Japan
4) National Research Institute of Far Seas Fisheries, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648,
Japan

Contact e-mail: tamura@cetacean.jp

ABSTRACTThe tenth cruise of the full-scale Second Phase of the Japanese Whale Research Program under Special Permit in theWestern North Pacific (JARPN II) -offshore component- was conducted in sub-areas 7, 8 and 9 of the western North
Pacific. There were three main research components: whale sampling survey, dedicated sighting survey and whale
prey species survey. A total of five research vessels was used: two sighting/sampling vessels (SSVs) (whale sampling
survey component), one research base vessel (whale sampling survey component), one whale prey survey vessel
equipped with scientific echo sounder (PSV) (whale prey survey component) and three dedicated sighting vessels(SVs) (dedicated sighting survey component), The whale sampling survey was carried out from 11 June to 5
September 2011. A total of 5,156 n.miles was surveyed in a period of 76 days by the SSVs. A total of 53 common
minke, 476 sei, 149 Bryde’s, 295 sperm, 66 fin and eight blue whales were sighted by the SSVs and NM. A total of 49
common minke, 95 sei, 50 Bryde’s and one sperm whale was sampled by the SSVs. All whales sampled were
examined on board the research base vessel. In July, common minke whales fed mainly on Japanese anchovy near
Syiriya, and they fed mainly on walleye pollock around east of Hokkaido. There were geographically changes of preyspecies of minke whales in sub area 7. Sei whales fed mainly on copepods and Japanese anchovy from June to August
in sub areas 8 and 9. Bryde’s whales fed mainly on krill in sub area 7 in July. There were yearly changes of preyspecies of Bryde’s whales in sub area 7. Dominant prey species in the stomach of the sperm whale were various kindsof squids, which inhabit the mid- and deep-waters. The dedicated sighting surveys were carried out from 28 April and
6 June in 2011. Surveys were conducted in the sub areas 8 and 9. A total of 4,060 n.miles was surveyed by the SVs. A
total of three common minke, 51 sei, six Bryde’s, 116 sperm, 31 fin and four blue whales were sighted. The preyspecies survey was carried out from 13 to 28 June in 2011. Surveys were conducted in a part of sub areas 8 and 9 by
the PSV. Distribution and/or abundance of the whales and its prey species were investigated. The purpose of thissurvey was to estimate habitat and prey preference of sei whale in relation to oceanographic and prey environments aswell as productivity in early summer. Data obtained in this research will be used in the elucidation of the role ofwhales in the marine ecosystem through the study of whale feeding ecology in the western North Pacific.
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KEYWORDS: PACIFIC OCEAN; COMMON MINKE WHALE; BRYDE’S WHALE; SEI WHALE; SPERM WHALE; FOOD/PREY;MONITORING; SCIENTIFIC PERMITSINTRODUCTION
After the Japanese Whale Research Program under Special Permit in the Western North Pacific (JARPN) wascompleted in 1999, the second phase of Japanese Whale Research Program under Special Permit in the Western North
Pacific (JARPNII) was started in the 2000 summer season as a two-year feasibility study. Based on the success of thefeasibility study (Government of Japan, 2002a) and the increasingly strong support from international fisheriesorganizations, including FAO, for research to improve multi-species approaches to management, JARPN II started as afull-scale research program in 2002. The full-scale study aimed i) to evaluate the feeding ecology and ecosystem
studies, ii) to monitor environmental pollutants in cetaceans and the marine ecosystem and iii) to elucidate the stock
structure (Government of Japan, 2002b).
The full-scale JARPN II plan involves two survey components: the ‘offshore’ survey, which is covered by the Nisshin
Maru research unit and two ‘coastal’ surveys (Sanriku and Kushiro), which are covered by small type catcher boats.
The coastal component was necessary to cover the temporal and spatial gaps, which could not be covered by the
Nisshin Maru unit (Government of Japan, 2002b).
The research area of the offshore component is set in sub-areas 7, 8 and 9, and the target species and sample sizes forthe lethal component of the research were set as follows: 100 common minke whales; 100 sei whales, 50 Bryde’s
whales and 10 sperm whales (Government of Japan, 2002b). The survey was composed of three main components:
whale sampling survey, dedicated sighting survey and whale prey species survey.
In January 2009 IWC/SC conducted the Expert Workshop to review the ongoing JARPN II Programme (IWC, 2009)
for the first period (2002-2007). The results presented on the three main objectives of JARPN II were discussed by an
Independent Expert Panel (IEP). Constructive discussions were conducted and some recommendations were offered by
the IEP. Some of those recommendations were already responded by Japanese scientists.
This paper reports the tenth full-scale survey of the JARPN II -offshore component-, carried out in 2011.

MATERIALS AND METHODS
Whale sampling survey
Research area
Sub-areas 7, 8 and 9, excluding the EEZ zones of foreign countries, comprised the research area of the SSV vessels(Figure 1).
Research vessels
Five research vessels were used. The research base vessel Nisshin Maru (NM: 8,044GT) commanded the research andwas the platform for biological examination of whale samples and processing of by-products. The Yushin Maru (YS1:

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720GT) and Yushin Maru No.2 (YS2: 747GT) were used as the sighting/sampling vessels (SSVs), which conducted
sighting activities, sampling of targeted whale species and various experiments and observations.
Methods for setting cruise track line and sighting procedure
Track lines and allocation of vessels were made as in previous JARPN and JARPN II surveys (Fujise et al., 1995, 1996,
1997, 2000, 2001, 2002, 2003; Ishikawa et al., 1997; Zenitani et al., 1999; Tamura et al., 2004, 2005, 2006, 2009a,
2009b; Bando et al., 2010; Matuoka et al., 2007; Yasunaga et al., 2011). The zigzag-shaped track line was establishedon an arbitrary basis in each sub-area. Furthermore, some ‘special monitoring surveys’ (SMS) were conducted in areas
where the abundance of common minke whales, Bryde’s and sei whales was expected to be high. Track line in the
SMS was designed separately from the original track line. Two SSVs were allocated to these tracks with the allocation
being changed every day. The research course for the SSVs consisted of one main track and one parallel track
established 7n.miles apart from the main course.
Sighting procedure both for the whale sampling survey, dedicated sighting survey and whale prey species survey was
similar to the previous surveys of JARPN and JARPN II (Fujise et al., 1995, 1996, 1997, 2000, 2001, 2002, 2003;
Ishikawa et al., 1997; Zenitani et al., 1999; Tamura et al., 2004, 2005, 2006, 2007, 2009a, 2009b; Bando et al., 2010;
Matsuoka et al., 2008; Yasunaga et al., 2011). In the research area sighting was conducted mainly under closing mode.
Furthermore two modalities of sighting in closing mode were adopted, NSC and NSS modes, by taking into
consideration weather and sea conditions. The NSC and NSS modes were the same as BC and BS modes in the previous
JARPN surveys, respectively. The conditions to conduct surveys under NSC mode were similar to those established inJapanese sighting surveys conducted by the National Research Institute of Far Seas Fisheries (i.e. visibility of two
n.miles or more and wind force of four or below). The NSS mode was used under bad weather conditions such as
heavy rain and fog when the collection of whale samples was still possible. This NSS mode was used only by SSV
vessels. These two mode surveys were recorded separately for future analysis. Also an ASP mode was used (closing
mode survey without sampling activities under normal sighting conditions). Closing was performed mainly onsightings of common minke, Bryde’s, sei and sperm whales. Furthermore closing was made on sightings of other large
whales, such as blue, humpback, right and fin whales. In these cases, closing was done in order to confirm species andschool size and in order to conduct some experiments.
Sampling numbers and procedure of targeted whales
The target species and sample sizes in the 2011 JARPN II offshore component were set as follows: 100 common
minke whales; 100 sei whales, 50 Bryde’s whales and 10 sperm whales.
Most of the whales sighted on the track line were approached for sampling. Furthermore sampling effort was applied
outside the established research hours (Main time: 06:30-18:30 (12 hrs)), if collection of whale samples wasconsidered possible. For schools consisting of two or more animals, numbering was made for all the whales in theschool; to set sampling order randomly in accordance with the table of random numbers (Kato et al., 1989). Cow andcalf pairs were not targeted for sampling. Sampled whales were immediately transported to a research base vessel,
where biological measurements and sampling were carried out.
Experiments
The following experiments and observations were conducted by the SSV vessels and the NM:
1. Sighting distance and angle experiments to examine the precision of sighting data (YS1 and YS2).
2. Biopsy sampling on gray, blue, fin, humpback and right whales (YS1 and YS2).
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3. Photographic records of natural marks on blue, humpback and right whales (YS1 and YS2).
4. Feeding behaviour patterns of large whale species (blue, fin, sei, Bryde’s, common minke, humpback, right andsperm whales) (YS1 and YS2).
5. Excretion and vomiting behaviour patterns of large whale species (sei, Bryde’s, common minke and sperm whales)(YS1 and YS2).
6. Marine debris observation during transit (NM). Record of large marine debris in the research area (YS1, YS2 andNM), which were expected to be frequent after the earthquake and tsunami that affected Japan in March 2011.
Dedicated Sighting survey (see Matsuoka et al., 2012)
A report of the dedicated sighting surveys was presented by Matsuoka et al. (2012). In this document, the summary ofthese surveys was described.
Research area
The dedicated sighting surveys were set in sub areas 8 and 9.
Research vessel
The YS1, YS2and Yushin Maru No.3 (YS3: 742GT) were used as dedicated sighting vessel (SV).
Methods for setting cruise track line and sighting procedure
An independent track line for dedicated sighting survey was designed in the research area. A detailed report of thissurvey was presented in Document SC/64/O6.
Experiments
The following experiments and observations were conducted by the SVs.
1. Sighting distance and angle experiments to examine the precision of sighting data.
2. Biopsy sampling on gray, blue, fin, humpback and right whales.
3. Photographic records of natural marks on blue, humpback and right whales.
4. Feeding behaviour patterns of large whale species (blue, fin, sei, Bryde’s, common minke, humpback, right andsperm whales).
5. Marine debris observation as explained above.
Whale prey species survey (see Appendix 1)
A report of this whale prey species survey was presented in Appendix 1. In this section, the summary of the survey
was described. The objective of the survey was to examine habitat and prey preference of sei whale in early summer.
Research area
The whale prey species survey was set in sub area 8 and 9.
Research vessel
The Hokko Maru (HK: 1,246GT) was used as whale prey species survey vessel (PSV).
Methods for setting cruise track line and survey procedure

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The survey was conducted concurrently at the same track line of whale sampling survey within 15 hours in 2011. It
was conducted the whale prey species survey by Conductivity–Temperature–Depth (CTD), water irradiance, midwater
trawl, Matsuda–Oozeki–Hu–Trawl (MOHT, Oozeki et al. 2004), North Pacific Standard (NORPAC) nets, andquantitative echosounder. To estimate relationship between distribution of each whale species and environmental andbiological parameters, whale sighting survey from upper bridge was also conducted by HK. A detail report of thissurvey was presented in Appendix 1 in this paper.
Experiments
The following experiments were conducted by the PSV,
1. Sighting of cetaceans from upper bridge.
2. Observations of oceanographic conditions and biological productivity by the Conductivity–Temperature–Depth(CTD), chlorophyll, and underwater irradiance surveys Oceanographic observations using Conductivity–
Temperature–Depth (CTD) and water irradiance.
3. Estimation of abundance of prey species using an echo sounder system as well as mid-water trawl, MOHT andtwin NORPAC nets.

RESULT
Whale sampling survey
Actual survey periods, track lines and searching distances
Cruise period: Between 11 June and 5 September (87 days)
Research period: Between 16 June and 30 August (76 days)
Track line: Track line set by the two SSVs is shown in Figure 2.
Searching distance: The total searching distance for SSVs was 5,156 n.miles
Sightings of common minke, Bryde’s, sei and sperm whales
A total of 52 schools (53 individuals) of common minke whales was sighted, consisting of 14 schools (14 individuals)of primary and 38 schools (39 individuals) of secondary sightings. For sei whale, 198 schools (476 individuals) weresighted, consisting of 46 schools (63 individuals) of primary sightings and 152 schools (413 individuals) of secondarysightings. For Bryde’s whale, 122 schools (149 individuals) were sighted, consisting of 77 schools (98 individuals) ofprimary sightings and 45 schools (51 individuals) of secondary sightings. For sperm whale, 181 schools (295individuals) were observed, consisting of 135 schools (231 individuals) of primary sightings and 46 schools (64individuals) of secondary sightings (Table 1).
Sightings of other large cetacean species
Table 1 also shows the number of sightings for other large whale species made by the SSVs, including large baleen
whales such as blue (7 schs./8 inds.), fin (52 schs./66 inds.), and humpback whales (11 schs./15 inds.).
Sampling numbers and biological research for common minke, Bryde’s, sei and sperm whales
A total of 49 common minke whales (Male: 38 individuals, Female: 11 individuals), 95 sei whales (Male: 54
individuals, Female: 41 individuals), 50 Bryde’s whales (Male: 20 individuals, Female: 30 individuals) and one female
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sperm whales were sampled. Struck and lost occurred in one case (sei whale) in this research. Table 2 summarizes the
biological data and samples collected from whales. A total of 36 research items was covered. These items are related tothe studies conducted under the three main objectives of the JARPN II: study on feeding ecology of whales and marine
ecosystem, pollution studies and elucidation of stock structure.
Composition of sex and sexual maturity status of common minke, sei and Bryde’s whales are shown in Table 3.
Statistics of body length of common minke, sei, Bryde’s and sperm whales is shown in Table 4. Mean body length ofcommon minke whales was 6.98m and 7.33m for males and females, respectively. For sei whales, those were 13.42m
and 13.87m for males and females, respectively. For Bryde’s whales, those were 11.65m and 12.00m for males andfemales, respectively. For sperm whales of females, body length was 10.15m.
Geographical distribution of common minke, sei, Bryde’s and sperm whale samples are shown in Figure 3 based on
the sighting positions.
Distribution and food habits of whales
During the research period (from June to August), common minke whales fed mainly on Japanese anchovy (Engraulisjaponicus) (68.1%) and walleye Pollock (Theragra chalcogramma) (17.0%) (Table 5). In this research, almost
common minke whales were sampled in the sub-area 7. In July, minke whales fed mainly on Japanese anchovy near
Syiriya, and they fed mainly on walleye pollock around east of Hokkaido.
Sei whales were distributed widely in the offshore area. In this survey, almost sei whales were sampled in the subareas 8 and 9, they fed mainly on copepods (58.0%) and Japanese anchovy (23.2%) (Table 5).
Bryde’s whales were distributed in the southern part of the research area. In this survey, almost all Bryde’s whales
were sampled in the sub-area 7, they fed on krill (71.0%) and Japanese anchovy (29.0%) in July (Table 5).
Sperm whales were also distributed widely in the research area. In this survey, one sperm whale was sampled in the
sub-area 7.Main prey was deep sea squids.
Experiments
Sighting distance and angle experiment
A sighting distance and angle experiment was performed on 28 and 27 June 2011 by YS1 and YS2, respectively. The
results of this experiment will be used in calculation of abundance estimates.
Photo-ID and biopsy samplingThree blue whales were photographed by the SSVs. A total of three biopsy samples were collected from two blue andone Bryde’s whales by the SSVs.
Feeding behaviour
No case was observed in the research.
Observation of marine debris
A total of 17 fisheries boats, two large containers, one fishing gear and one other large object were observed andreported to the Japan Maritime Safety Agency and Fisheries Agency. In addition to these, several other marine debris
such as refrigerators, lumber, parts of fishing gear, rubble etc. were seen in all research area. The large numbers ofdebris observed were due to earthquake and tsunami.

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Dedicated Sighting survey (see Matsuoka et al., 2012)
Actual research periods and searching distance
Cruise period:
YS1, YS2: Between 28 April and 6 June (40 days)
YS3: Between 13 May and 6 June (25 days)

Research period:
YS1, YS2: Between 5 May and 31 May (27 days)
YS3: Between 17 May and 31 May (15 days)

Searching distance:
YS1: 1,466.0 n.miles.
YS2: 1,492.8 n.miles.
YS3: 1,101.5 n.miles.
Sightings of common minke, Bryde’s, sei and sperm whales
A total of three schools (three individuals) of common minke whales was sighted, consisting of three schools (three
individuals) of primary sighting. For sei whale, 32 schools (51 individuals) were sighted, consisting of 31 schools (50individuals) of primary sighting and one school (one individual) of secondary sighting. For Bryde’s whale, threeschools (six individuals) were sighted, consisting of three schools (six individuals) of primary sighting. For sperm
whale, 60 schools (116 individuals) were observed, consisting of 56 schools (112 individuals) of primary and four
schools (four individuals) of secondary sighting.
Sightings of other large cetacean species
Large baleen whales such as blue (four schools/four individuals), fin (23 schools/31 individuals), humpback (27schools/35 individuals), and right whales (13 schools/20 individuals) were sighted.
Experiments
Photo-ID and biopsy samplingThree blue, five humpback and 19 right whales were photographed by the SVs. A total of 20 biopsy samples werecollected from two blue, two fin, two humpback and 14 right whales by the SVs.
Feeding behaviour
No case was observed in the research.
Observation of marine debris
One fisheries boat was observed and reported to the Japan Maritime Safety Agency.
Whale prey species survey (see Appendix 1)
Actual research period and searching distance
Cruise period: Between 13 and 28 June (16 days)
Research period: Between 16 and 23 June (8 days)
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Searching distance: 592 n.miles.
Sightings of common minke, Bryde’s, sei and sperm whales
A total of 24 schools (27 individuals) of sei whales was sighted, consisting of 19 schools (24 individuals) of primary
and two schools (three individuals) of secondary sightings. For sperm whale, three schools (four individuals) ofprimary sighting were observed.
Sightings of other large cetacean species
No other large whale species were observed.
Experiments
Midwater trawl: Six points
MOHT survey: Six points
MOCNESS net sampling: Two points
NORPAC net sampling: Eight points

DISCUSSION
Prey species and food habits of common minke, sei, Bryde’s and sperm whales in the 2011 survey is discussed below
in the context of previous survey results.
Common minke whale
From the JARPN and JARPN II surveys from 1994 to 2010, common minke whales fed on various prey species such
as Japanese anchovy, Pacific saury Cololabis saira, walleye pollock and Japanese common squid Todarodes pacificus,
and the main prey species changed seasonally and geographically. For example, they fed on Japanese anchovy in
May/June and Pacific saury in July/August (Tamura et al., 2009c).
In the 2011 survey, it was confirmed that walleye pollock is an important prey species for minke whales around east of
Hokkaido during feeding season (From April to October), which was also confirmed by the coastal surveys (Yasunaga
et al, 2012; Kishiro et al. 2012). Minke whales fed mainly on Japanese anchovy near Syiriya. In 1980’s, their
dominant prey was Japanese sardine (Sardinops melanostictus) around Sanriku region (Kasamatsu and Tanaka, 1992).
After depletion of Japanese sardine resources in late of 1980’s, minke whales switched their dominant prey fromJapanese sardine to Japanese anchovy in early summer. It is reasonable to assume that minke whales do not have astrong preference for a particular prey species, changes in the prey of minke whales probably reflect changes in theabundance of available prey species in this area.
Sei whale
From our research results of past JARPN II (2000 to 2010), they fed on Japanese anchovy and copepods dominantly
during survey season in most of years (Tamura et al., 2009c). According to the result of prey species survey conductedin early summer in sub-areas 8 and 9 in the present survey, sei whales were found mainly in the transition zone southof the subarctic boundary where Japanese anchovy was significantly abundant. Sei whales were less frequent in theadjacent areas including both transition zone and transitional domain. These results suggest that sei whales occur at the
distribution centre of Japanese anchovy in early summer in sub-areas 8 and 9 (main feeding habit).

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Bryde’s whale
From our research results of past JARPN II (2000 to 2010), the dominant prey species of Bryde’s whale was Japanese
anchovy and krill during May to September. There was seasonal change of prey species. In early season (May andJune), the dominant prey species was krill. In late season (from July to September), the dominant prey species was
Japanese anchovy in sub-areas 7 and 8. In the south eastern part of sub-area 9 in August, oceanic lightfish were also
important prey species. In previous research, Bryde’s whale fed mainly on Japanese anchovy (Tamura et al., 2009c).
During the present survey Bryde’s whale fed mainly on krill in July in the sub area 7. This result suggested that theJapanese anchovy was not abundant in this area in this year and whales selected krill as their prey species. It is also
reasonable to assume that Bryde’s whales do not have a strong preference for a particular prey species.
Sperm whale
From our research results of past JARPN II (2000 to 2010), the following information was obtained: (1) sperm whales
feed mainly on deep-sea squids. Some of these are reported as prey species of the sperm whale for the first time; (2)Squids found in the sperm whale stomach are relatively fresh suggesting that sperm whale feed on these prey during
daytime; (3) At least some fish species (walleye pollock, bottom fishes) was identified in the diet of the sperm whale(Tamura et al., 2009d). During the present survey the food habit of sperm whale was the same as in previous surveys.

ACKNOWLEDGMENTS
The authors are greatly indebted to Tatsushi Matsuo, Toshinori Uoya and Hiroshi Kawamura of the Fisheries Agencyof Japan, Hidehiro Kato, Tokyo University of Marine Science and Technology, and Yoshihiro Fujise, Hiroshi
Hatanaka, Seiji Ohsumi, L.A. Pastene, and Shigetoshi Nishiwaki of the Institute of Cetacean Research (ICR) for theirguidance in the design and implementation of the research. We thank research technicians, Messrs. Tatsuo Sasaki,
Teppei Hattori and Takaaki Murakami of Kyodo Senpaku Kaisya Ltd. for their contribution. Mr. Takayuki Suetsugu of
the Government of Japan, served as onboard inspector. We thank all crew of the research vessels (NM, YS1, YS2 andHK) and the staff of the ICR, Kyodo-Senpaku Co. Ltd and NRFSF.

REFERENCES
Bando, T., Kiwada, H., Mogoe, T., Isoda, T., Mori, M., Tsunekawa, M., Yoshimura, I., Nakai, K., Sato, H., Tanaka, H.,
Inagaki, M., Tamahashi, K., Yoshida, K., Morine, G., Watanabe, H., Fujiwara, G., Eguchi, K. and Tamura, T. 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 I) - Offshore component – Paper SC/62/O4 presented to the IWC ScientificCommittee, June 2010 (unpublished). 34pp.
Fujise, Y., Kishiro, T., Zenitani, R., Matsuoka, K., Kawasaki, M. and Shimamoto, K. 1995. Cruise report of theJapanese whale research program under a special permit for North Pacific minke whales in 1994. Paper SC/47/NP3
presented to the IWC Scientific Committee, May 1995 (unpublished). 29pp.

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THIS PAPER CAN NOT BE CITED WITHOUT THE WRITTEN CONSENT FROM THE AUTHORS

SC/64/O3

Fujise, Y., Iwasaki, T., Zenitani, R., Araki, J., Matsuoka, K., Tamura, T., Aono, S., Yoshida, T., Hidaka, H., Nibe, T.
and Tohyama, D. 1996. Cruise report of the Japanese whale research program under a special permit for North
Pacific minke whales in 1995 with the results of a preliminary analysis of data collected. Paper SC/48/Np13
presented to the IWC Scientific Committee, June 1996 (unpublished). 39pp.
Fujise, Y., Shimada, H., Zenitani, R., Goto, M., Tamura, T., Lindstrøm, U., Uchida, A., Yoshida, H., Shimamoto, K.,
Yuzu, S., Kasai, H., Kinoshita, T., Iwata, T. and Tohyama, D. 1997. Cruise report of the Japanese Whale Research
Program under a Special Permit in the North Pacific (JARPN) in 1996 with some preliminary analysis of datacollected during the 1994-1996 JARPN surveys. Paper SC/49/NP8 presented to the IWC Scientific Committee,
September 1997 (unpublished). 38pp.
Fujise, Y., Zenitani, R., Tamura, T., Bando, T., Ohtani, S., Takeda, S., Kitajima, A., Kimura, T., Masaki, T. andTohyama, D. 2000. Cruise report of the Japanese whale research program under special permit in the North Pacific(JARPN) in 1999. Paper SC/F2K/J9 presented to the JARPN review meeting, February 2000 (unpublished). 32pp.
Fujise, Y., Pastene, L.A, Tamura, T., Bando, T., Murase, H., Kawahara, S., Watanabe, H., Ohizumi, H., Mogoe, T.,
Kiwada, H., Nemoto, K. and Narita, H. 2001. Progress Report of the Feasibility study of the Japanese whale research
program under special permit in the western North Pacific-Phase II (JARPN II) in 2000. Paper SC/53/O10 presented
to the IWC Scientific Committee, July 2001 (unpublished). 77pp.
Fujise, Y., Tamura, T., Bando, T., Hikaru Watanabe, Hiroshi Kiwada, 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 Japanesewhale research program under special permit in the western North Pacific – Phase II (JARPNII) in 2001. Paper
SC/54/O16 presented to the IWC Scientific Committee, May 2002 (unpublished). 51pp.
Fujise, Y., Tamura, T., Bando, T., Yasunaga, G., Konishi, K., Murase, H., Yoshida, T., Itoh, S. Ogawa, R., Oka, T.,
Sasaki, T., Fukutome, K., Isoda, T., Birukawa, N., Horii, N., Zharikov, K.A., Park, K.J., Tohyama, D. and Kawahara,
S. 2003. Cruise report of the Japanese whale research program under special permit in the western North Pacific –Phase II (JARPNII) in 2002 (Part I). Paper SC/55/O7 presented to the IWC Scientific Committee, May 2003
(unpublished). 41pp.
Government of Japan. 2002a. Report of the 2000 and 2001 feasibility study of the Japanese whale research program
under special permit in the western North Pacific-phase II (JARPN II). Paper SC/54/O17 presented to the IWC
Scientific Committee, May 2002 (unpublished). 202pp.
Government of Japan. 2002b. Research Plan for Cetacean Studies in the Western North Pacific under Special Permit(JARPN II) Paper SC/54/O2 presented to the IWC Scientific Committee, May 2002 (unpublished). 115pp.
International Whaling Commission. 2009. The report of the Expert Workshop to review the ongoing JARPN II
Programme. Paper SC/61/Rep 1 presented the IWC Scientific Committee, May 2009 (unpublished). 57pp.
Ishikawa, H., Yuzu, S., Shimamoto, K., Bando, T., Ohshima, K., Kasai, H., Kinoshita, T., Mizushima, Y., Iwakami, H.,
Nibe, T., Hosoyama, T., Kuramochi, T., Numano, K. and Miyamoto, M. 1997. Cruise report of the Japanese Whale
Research Program under a Special Permit in the North Pacific (JARPN) in 1997. Paper SC/49/NP9 presented to the
IWC Scientific Committee, September 1997 (unpublished). 28pp.
Kasamatsu, F. and Tanaka, S. 1992. Annual changes in prey species of minke whales taken off Japan 1948-87. Nippon
Suisan Gakkaishi. 58:637-51.

10

THIS PAPER CAN NOT BE CITED WITHOUT THE WRITTEN CONSENT FROM THE AUTHORS

SC/64/O3

Kato, H., Hiroyama, H., Fujise, Y. and Ono, K. 1989. Preliminary report of the 1987/88 Japanese feasibility study ofthe special permit proposal for Southern Hemisphere minke whales. Report of the International Whaling Commission,
39: 235-248.
Kishiro, T., Kato, H., Ito, N., Yasunaga, G., Takahiro, H., Nakamura, G., Maeda, H., Inoue, S., Miyagawa, N., Ishida,K., Kadowaki, I., Oikawa, H., Miyashita, T., Iwasaki, T., Kanaji, Y., Minamikawa, S., Watanabe, H., Kumagai, S.,
Sato, H., Kitayama, K. 2012. Cruise report of the Second Phase of the Japanese Whale Research Program underSpecial Permit in the Western North Pacific (JARPN II) in 2010 (part II) - Coastal component off Kushiro, autumn
survey –. Paper SC/64/O5 presented to the IWC Scientific Committee, June 2012 (unpublished). 14pp.
Konishi, K., Tamura, T. 2009. Feeding strategies and prey consumption of three baleen whale species within the
Kuroshio-current extension. J. Northw. Atl. Fish. Sci., 42: 27–40.
Matsuoka, K., Otani, S., Isoda, T., Wada, A., Kumagai, S., Ohshima, T., Yoshimura, I., Sugiyama, K., Aki, M., Kato,
K., Bhuiyan M.M.U., Funasaka, N., Suzuki, Y., Sudo, R., Motohashi, Y., Mori, M.,Tsunekawa, M., Inagake, D.,
Murase, H. and Ogawa, T. 2008. Cruise report of the second phase of the Japanese Whale Research Program underSpecial Permit in the Western North Pacific (JARPN II) in 2007 - Offshore component -. Paper SC/60/O5 submitted
to the 60th IWC Scientific Committee Meeting.
Matsuoka, K., Tsunekawa, M., Nishiwaki, S. and Miyashita, T. 2012. Cruise report of the Japanese cetacean sighting
survey in the western North Pacific, sub areas 8 and 9, May 2011. Paper SC/64/O6 presented to the IWC ScientificCommittee, June 2012 (unpublished). 9pp.
Tamura, T., Fujise, Y., Bando, T., Yasunaga, G., Konishi, K., Kiwada, H., Isoda, T., Itoh, S. Machida, S., Tsunekawa,
M., Konagai, T., Takamatsu, T., Ohshima, T., Honjo, K., Matsuoka, T., Zharikov, K.A., Yong, Rock AN, Tohyama,
D. and Kawahara, S. 2004. Cruise Report of the Japanese Whale Research Program under Special Permit in thewestern North Pacific -Phase II (JARPN II) in 2003 (part I) – Offshore component –. Paper SC/56/O13 presented to
the IWC Scientific Committee, June 2004 (unpublished). 46pp.
Tamura, T., Fujise, Y., Mogoe, T., Kanda, N., Yasunaga, G., Konishi, K., Kiwada, H., Ogihara, M., Hasegawa, A.,
Kitajima, M, Sugiyama, T., Sasaki, T., Mori, M., Teraoka, T., Tsunekawa, M., Fukutome, K., Zharikov, K.A , NA,
Jong-Hun., Tohyama, D, Inagake, D. and Kawahara, S. 2005. Cruise Report of the Japanese Whale Research
Program under Special Permit in the western North Pacific -Phase II (JARPN II) in 2004 (part I) – Offshore
component –. Paper SC/57/O3 presented to the IWC Scientific Committee, June 2005 (unpublished). 33pp.
Tamura, T., Otani, S., Kiwada, H., Mori, M., Konishi, K., Isoda, T., Wada, A., Ogihara, M., Hasegawa, A., Kumagai,
S., Komatsu, W., Hayasaka, K., Fukutome, M., Siozaki, M., Zharikov, K.A, NA, Jong-Hun., Ogawa, T, Watanabe, H.,
Yonezaki, S, Inagake, D. and Kawahara, S. 2006. Cruise report of the second phase of the Japanese Whale Research
Program under Special Permit in the Western North Pacific (JARPN II) in 2005 – Offshore component –. Paper
SC/58/O8 presented to the IWC Scientific Committee, June 2006 (unpublished). 52pp.
Tamura, T., Otani, S., Isoda, T., Wada, A., Yonezaki, S., Mori, M., Tsunekawa, M., Fukutome, K., Nakai, K., Satoh,
H., Nomura, I., Nagatsuka, S., Umatni, M., Koyanagi, T., Takamatsu, T., Kawabe, S., Kandabashi, S., Watanabe, H,
Kumagai, S., Sato, H. and Ogawa, T. 2009a. 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 I) - Offshore component –.
Paper SC/61/O4 presented to the IWC Scientific Committee, May 2009 (unpublished). 49pp.

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THIS PAPER CAN NOT BE CITED WITHOUT THE WRITTEN CONSENT FROM THE AUTHORS

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Tamura, T., Matsuoka, K. and Fujise, Y. 2009b. Methodology and survey procedure under the JARPN II - offshore
component- with special emphasis on whale sampling procedures. Paper SC/J09/JR4 presented to the JARPN II
review meeting, January 2009 (unpublished). 36pp.
Tamura, T., Konishi, K., Isoda, T., Okamoto, R. and Bando, T. 2009c. Prey consumption and feeding habits ofcommon minke, sei and Bryde’s whales in the western North Pacific. Paper SC/J09/JR16 presented to the JARPN II
review meeting, January 2009 (unpublished). 36pp.
Tamura, T., Kubodera, T., Ohizumi, H., Konishi, K. And Isoda, T. 2009d. Feeding habits of sperm whales and theirimpact on neon flying squid resources in the western North Pacific. Paper SC/J09/JR17 presented to the JARPN II
review meeting, January 2009 (unpublished). 22pp.
Yasunaga, G., Kiwada, H., Mogoe, T., Wada, A., Nakai, K., Mori, M., Tsunekawa, M., Kasai, H., Ohshima, T.,
Yoshimura, I., Sato, H., Sakamoto, N., Watanabe, H., Fujiwara, G., Tamura, T. and Ogawa, T. 2011. Cruise report of
the Second Phase of the Japanese Whale Research Program under Special Permit in the Western North Pacific(JARPN II) in 2010 (part I) - Offshore component –. Paper SC/63/O2 presented to the IWC Scientific Committee,
June 2011 (unpublished). 38pp.
Yasunaga, G., Itou, N., Wada, A., Kiwada, H., Sato, H., Maeda, H., Nakamura, G., Inoue, S., Miyakawa, N., Kitayama,
K., Ishikawa, Y., Suzuki, N., Tsutsumi, T., Kadowaki, I. and Kato, H. 2012. Cruise report of the Second Phase of theJapanese Whale Research Program under Special Permit in the Western North Pacific (JARPN II) in 2011 (part II) Coastal component off Kushiro, spring survey –. Paper SC/64/O4 presented to the IWC Scientific Committee, June2012 (unpublished). 13pp.
Zenitani, R., Fujise, Y., Matsuoka, K., Tamura, T., Bando, T., Ichihashi, H., Shimokawa, T., Krasnenko, A.S., TaguchiF., Kinoshita, T., Mori, M., Watanabe, M., Ichinomiya, D., Nakamura, M., Sakai, K., Matsuzaka, K., Kamei, H. andTohyama, D. 1999. Cruise report of the Japanese Whale Research Program under a Special Permit in the North
Pacific in 1998. Paper SC/51/RMP7 presented to the IWC Scientific Committee, May 1999 (unpublished). 20pp.

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Table 1. Whale species and number of sightings in the 2011 JARPN II survey (no. schools/no. individuals)

Cetacean species

PrimarySch. Ind.

SecondarySch. Ind.

Total
Sch. Ind.

Common minke whale

14

14

38

39

52

53

Like minke whale

0

0

2

2

2

2

Sei whale

46

63

152

413

198

476

Bryde's whale

77

98

45

51

122

149

Sperm whale

135

231

46

64

181

295

Blue whale

5

5

2

3

7

8

Fin whale

33

41

19

25

52

66

Humpback whale

8

11

3

4

11

15

13

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Table 2. Summary of biological data and samples collected during the 2011 JARPN II survey.

Common minke

Research items
Body length and sex
External body proportion
Photographic recoed and external character
Diatom film recoedStandaed measurements of blubber thickness (five points)
Detailed measurements of blubber thickness (eleven points)
Body weight
Body weight by parts
Blubber tissues for DNA study
Blubber, muscle, liver and kidney tissues for heavy metal/organochlorines analysis

Blubber, muscle, liver and kidney tissues for various analysis
Tissue for nutritional compornent analysis
Lung tissue for air monitoring
Tissues for various analysis
Tissues for virus test
Mammary gland; lactation status and measurement
Collection of ovary
Photographic record of foetus
Foetal sex (identified by visual observation)
Foetal length and weight
Foetal blubber tissuyes for DNA study
Testis weight and histological sample
Collection of plasma sample
Stomach content, conventional record
Volume and weight of stomach content in each compartment
Stomach contents for feeding study
Record of external parasites
Record of internal parasites
Earplug for age determination
Tympanic bulla for age determination
Maxillally teeth for age determination
Lens for age determination
Largest baleen plate for morphologic study and age determination
Vertebral epiphyses sample
Brain weight
Skull measurements (length and breadth)*: Including fetus of sex unknown.

14

F M T
11 38 49
11 38 49
11 38 49
11 38 49
11 38 49
1 0 1
11 38 49
1 0 1
11 38 49
11 38 49
11 38 49
1 3 4
0 8 8
11 38 49
NA 38 38
11 NA 1111 NA 11
3 1 4
3 1 4
3 1 4
3 1 4
NA 38 38
10 35 45
11 38 49
11 38 49
11 38 49
11 38 49
11 38 49
11 38 49
1 0 1
0 0 0
11 38 49
11 38 49
11 38 49
0 0 0
11 38 49

Sei whale
F M T
41 54 95
41 54 95
41 54 95
41 54 95
41 54 95
1 0
141 54 95
1 0
141 54 95
41 54 95
41 54 95
3 2
5
0 10 1041 54 95
NA 54 54
41 NA 41
41 NA 41
8 10 18
8 10 18
8 10 18
8 10 18
NA 52 52
41 52 93
41 54 95
41 54 95
41 54 95
41 54 95
41 54 95
41 54 95
1 0
1
0 0
0
41 54 95
41 54 95
41 54 95
1 0
141 54 95

Bryde's whale

Sperm whale

F M T
F M
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
1 0 1
1 0
30 20 50
1 0
1 0 1
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
4 1 5
0 0
6 0 6
1 0
30 20 50
1 0
NA 20 20 NA 030 NA 301 0
30 NA 301 0
2 8 11* 0 0
2 8 11* 0 0
2 8 11* 0 0
2 8 11* 0 0
NA 20 20 NA 030 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
1 0 1
0 0
0 0 0
1 0
30 20 50
1 0
30 20 50
1 0
30 20 50
1 0
1 0 1
1 0
30 20 50
1 0

T
1
1
1
1
1
1
1
1
1
1
1
0
1
1
0
1
1
0
0
0
0
0
1
1
1
1
1
1
1
0
1
1
1
1
1
1

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Table 3. Sex and sexual maturity composition of whales sampled during the 2011 JARPN II survey.

MaleSpeciesCommonminke

Sei

Bryde's

Sperm

Sub
area
SA7
SA8
SA9
Combined
SA7
SA8
SA9
Combined
SA7
SA8
SA9
Combined
SA7
SA8
SA9
Combined

FemaleMat.

Imm. Mat. Uk Total Imm.
10
0
1
11
0
4
7
11
9
1
0
10
0
0
0
0

27
0
0
27
0
12
31
43
7
0
3
10
0
0
0
0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

37
0
0
38
0
16
38
54
16
1
3
20
0
0
0
0

Ovu. Rest. Preg. Lact.

3
0
1
4
1
2
0
13
8
2
1
11
0
0
0
0

0
0
0
0
0
0
5
0
1
0
0
1
0
0
0
0

3
0
0
3
0
3
11
8
5
0
2
7
0
0
0
0

4
0
0
4
0
7
1
18
7
1
3
11
0
0
0
0

0
0
0
0
0
1
0
2
0
0
0
0
1
0
0
1

Preg.
Total
Total
Lact.
0
7
10
0
0
0
0
0
1
0
7
11
0
0
1
0
11
13
0
17
27
0
28
41
0
13
21
0
1
3
0
5
6
0
19
30
0
0
1
0
0
0
0
0
0
0
0
1

Total
47
0
2
49
1
29
65
95
37
4
9
50
1
0
0
1

Table 4. Body length (m) of whales sampled during the 2011 JARPN II survey.

Species

Sub
area
SA7

Common
minke

SA8
SA9
Combined
SA7

Sei

SA8
SA9
Combined
SA7

Bryde's

SA8
SA9
Combined
SA7

Sperm

SA8
SA9
Combined

n
37
0
1
38
0
16
38
54
16
1
3
20
0
0
0
0

mean
7.04
NA
4.66
6.98
NA
13.41
13.42
13.42
11.57
10.97
12.31
11.65
NA
NA
NA
NA

Male
S.D.
0.83
NA
NA
0.90
NA
0.70
0.96
0.89
1.46
NA
0.27
1.34
NA
NA
NA
NA

min
5.36
NA
4.66
4.66
NA
11.95
9.79
9.79
8.05
10.97
12.00
8.05
NA
NA
NA
NA

15

max
7.90
NA
4.66
7.90
NA
14.33
14.82
14.82
13.31
10.97
12.52
13.31
NA
NA
NA
NA

n
10
0
1
11
1
13
27
41
21
3
6
30
1
0
0
1

mean
7.32
NA
7.44
7.33
13.57
13.93
13.86
13.87
11.89
11.27
12.76
12.00
10.15
NA
NA
10.15

Female
S.D.
1.32
NA
NA
1.25
NA
0.83
1.21
1.08
1.71
1.88
1.84
1.74
NA
NA
NA
NA

min
4.95
NA
7.44
4.95
13.57
12.54
11.18
11.18
7.25
9.68
9.02
7.25
10.15
NA
NA
10.15

max
8.72
NA
7.44
8.72
13.57
14.97
15.97
15.97
13.94
13.35
13.74
13.94
10.15
NA
NA
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Table 5. Prey species and stomach contents weight (1st. + 2nd. stomachs) in whales sampled during the 2011 JARPN
II survey.

N%

Range of weight(kg)

Japanese anchovy
Pacific saury
Walleye pollock

6
32
1
8

12.8
68.1
2.1
17.0

4.84
6.40
33.58
13.34

-

76.50
97.15
33.58
76.35

Neocalanus spp.
Japanese anchovy
Pacific saury

10
40
16
3

14.5
58.0
23.2
4.3

23.44
8.74
4.30
4.50

-

359.21
419.65516.67151.00Japanese anchovy

22
9

71.0
29.0

19.10
58.60

- 161.12- 728.52

Dominant prey species
Common minke whale
Krill
Fish

Sei whale
Krill
Copepods
Fish
Bryde's whale
Krill
Fish

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97

8

Figure 1. Research area of the JARPN II full-scale program.

50N

45N

40N

35N
140E

145E

150E

155E

160E

Figure 2. Track-lines of the sighting/sampling vessels (SSVs).

17

165E

170E

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50N

45N

40N

35N
140E

145E

150E

155E

160E

165E

170E

Figure 3. Sighting positions of the sampled common minke (pink circle), sei (orange square), Bryde’s (green diamond)and sperm (brown triangle) whales. Red block show the survey area for the cooperative prey and whale
sampling survey. Blue lines were special monitoring surveys.

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Appendix 1.

Cruise report of JARPN II whale prey species survey inconjunction with whale sampling survey in the offshore regionof the western North Pacific in 2011
HIKARU WATANABE 1), DENZO INAGAKE 2), MAKOTO OKAZAKI 2), TSUTOMU TAMURA 3), KOUICHI SAWADA 4),
TOMOHIKO MATSUURA 4), YOSHIAKI FUKUDA 5), AND TOMIO MIYASHITA 1)

1) National Research Institute of Far Seas Fisheries, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648,
Japan2) National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648,
Japan3) The Institute of Cetacean Research, Toyomi-cho 4-5, Chuo-ku, Tokyo 104-0055, Japan
4) National Research Institute of Fisheries Engineering, Fisheries Research Agency, 7620-7 Hasaki, Kamisu, Ibaraki 314-0408, Japan
5) Graduate School of Fisheries Science, Hokkaido University, 3-1-1 Minato, Hakodate, Hokkaido 041-8611, Japan*Contact e-mail: hikaru1@affrc.go.jp

ABSTRACT
Whale prey species survey including whale sighting and oceanographic surveys as well as survey of biologicalproductivity was firstly conducted in the transition region of the western North Pacific in a part of sub-areas 8 and 9 inlate June 2011. The objective of these surveys in this year were to examine habitat selection of the sei whale
Balaenoptera borealis in relation to ecosystem information and also to accumulate quantitative data on functional
response and prey preference of the whale in this area in early summer. Hence these surveys were cooperated with thesampling survey of the whale under JARPN II program and all of these surveys were conducted concurrently at thesame area within 12 h. Sei whale was mainly found in specific area in the transition zone south of the subarctic
boundary where abundance of Japanese anchovy was significantly higher than in its adjacent areas. This area was also
corresponded to the area where both primary production and productivity of subtropical copepods, which are thought
to the prey of Japanese anchovy, increased about three times comparing with these values in the southern oligotrophic
waters. These facts suggest that distribution of sei whale was closely related to biological productivity as well as
distribution of their prey species. During cooperative survey period, a total of 14 sei whales was captured. Usingstomach content data of these individuals, together with environmental data, functional response and prey preferenceof the whale will be analyzed in the future.

KEYWORDS: SEI WHALE, HABITAT SELECTION, WHALE SIGHTING AND ECOSYSTEM SURVEYS, OFFSHORE REGION, WESTERNNORTH PACIFIC, EARLY SUMMER

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INTRODUCTION
To obtain parameter of ecosystem models mainly prey preference of the whale, we have conducted whale prey species
survey as a part of JARPN II in conjunction with whale sampling survey to estimate abundance of whale prey species
in the environment in the offshore region of the western North Pacific (Government of Japan 2002). At the
IWC/JARPN II review workshop in 2009, the Expert Panel recommended estimation of functional relationship of eachwhale species (relationship between distribution density of each prey species and dietary intake of each individual of
the whale for each prey species), which is a wide-use parameter for various ecosystem models as well as prey
preference. The Expert Panel also recommended accumulating quantitative ecosystem information in the subtropical,
transition, and subarctic regions, to construct separate ecosystem models including whales in each region, although
JARPN II modeling group built several ecosystem modes to cover the whole part of sub-areas 7, 8, and 9 (Kawahara
2009, Mori et al. 2009). Based on these comments, we newly started ‘whale prey species survey’ from 2010 or 2011
by following approach.
1.

Whale prey species and whale sampling surveys conduct on the same track lines at the same period to obtain thedata on prey abundance in environment and stomach contents of the whale simultaneously. This approach is useful
to obtain the data on functional response of the whale.

2.

Whale prey species survey vessel conducts whale sighting survey and various observation of physical andbiological conditions to obtain major ecosystem information including whales in various regions and months (seeMaterials and Methods).

These surveys are unique in the western North Pacific and characterized that the major parameters of ecosystemmodels could be obtained simultaneously and also quantitatively.
Sei whales Balaenoptera borealis are the abundant baleen whale in the western North Pacific and migrate into highlatitudinal area mainly between 40 and 47˚N during spring and summer from the low latitudinal wintering area (Fujise
et al. 2004, Kasamatsu et al. 2009). Previous studies have indicated that this whale species frequently feed on small
epipelagic fish species such as Japanese sardine Saldinops melanostictus, Japanese anchovy Engraulis japonica, and/or
Pacific saury Cololabis saira in summer, suggesting the competition between whale and fisheries (Nemoto 1962,
Kawamura 1973, Konishi et al. 2009). Subarctic copepods such as Neocalanus cristatus and N. plumchrus, andeuphausiids are also sometimes important prey for sei whale (Nemoto 1962, Konishi et al. 2009). However,quantitative data on the distribution patterns and feeding habits of this whale species in relation to oceanographic
conditions and ecosystem information are still limited (Watanabe et al. 2012). Such information is essential to estimate
its feeding impact on commercially important small epipelagic fish species and also to obtain parameters of ecosystemmodels like functional response and prey preference of the whale.
In this document, we firstly report the distribution pattern of sei whale in relation to ecosystem information in a part of
sub-areas 8 and 9. During cooperative survey period of whale prey species and whale sampling in this year, a total of
14 individuals of sei whale was captured. Using stomach contents data of these individuals and environmental data
where these individuals were captured, functional response and prey preference of the whale will be analyzed in the
future.

MATERIALS AND METHODS
Surveys were conducted in the western North Pacific enclosed by latitude from 37˚N to 43º30’N and longitude from
156ºE and 159ºE from 16 to 23 June 2011 by the trawler–type research vessel, Hokko Maru (1,246 GT, Hokkaido
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National Research Institute of Fisheries Science, Figure 1). These surveys by Hokko Maru and whale sampling survey
by Nisshin Maru and two sampling vessels under the JARPN II program were conducted concurrently at the same area
within 12 hours. All surveys were conducted during the daylight period from one hour after sunrise to one hour before
sunset. Distribution and abundance of the whale prey species were investigated with midwater trawl, Matsuda–
Oozeki–Hu–Trawl (MOHT, Oozeki et al. 2004), North Pacific Standard (NORPAC) nets, and quantitativeechosounder on the track lines as follows.
Whale sighting survey
Whale sighting survey was conducted along with acoustic survey (see below) basically in passing mode when windvelocity was less than 10 knots and visibility was more than two nautical miles. However, abeam closing survey was
also conducted within two nautical miles perpendicular to track line in case that the species of large cetaceans could
not identified by passing mode. During the survey, two primary observers were allocated to the upper bridge.
Environmental survey
A Conductivity–Temperature–Depth (CTD, Sea–Bird Co., Ltd.) profiler cast was made down to 500 m depth at eachsampling station to determine the position of the subarctic boundary and subarctic front. We also conductedchlorophyll (ACL-208DK, JFE advance) and under water irradiance (Micropro, Salantic) surveys in the 0–150 m layer
once a day during 11:00 AM to 1:00 PM in local time to obtain data on geographical distribution of primary
production and vertical distribution of illumination, respectively, in this study area. The latter data will be analysed inrelation to vertical distribution and/or migration of deep scattering layer (DSL) to estimate species composition of each
DSL, because underwater irradiance is an important parameter for discriminating among organisms especially during
their diel vertical migration periods (Matsuura et al, 2012).
Midwater trawl sampling
The midwater trawl adopted in this study had a mouth opening of approximately 30 x 30 m with a 17.5 mm liner codend. The sampling depths and the height of the net mouth were monitored by net monitor system (PI32, SIMRAD). In
this survey, trawls were made to identify species and size compositions of acoustic backscatters in the echosounders
and also aimed for collecting distribution data on species difficult to detect by the echosounders such as squids andneustonic organisms like Pacific saury. Trawling station was predetermined at generally every 20 to 30 nautical mileapart on the track lines. At each predetermined station, a trawl net was towed at 0–30 m for 60 minutes. Towing speed
was 3–4 knots. All samples were identified to the lowest taxonomic level possible and wet body weight of each species
was measured aboard the ship. For the major species, individual body length was measured from randomly selected
100 samples. When sample size was less than 100 individuals, body length was measured for all.
The biomass of Pacific saury, which was one of the prey species of the sei whale, was estimated from midwater trawl
sampling data because they are generally distributed in the sea surface layer and are difficult to detect with theechosounder. We assumed that the distribution depth of this species is 0–10 m, area of mouth opening for the trawl net
is 600 m2, and the catching efficiency of the trawl we used is 14.4 %, based on the similar sized trawl data (Ueno et al.
2004). To estimate water volume filtered in each sampling, average towing speed of midwater trawl in each sampling
were adopted.
MOHT sampling
MOHT was towed to examine species and size compositions and vertical distribution patterns of macro–
zooplanktons, especially euphausiids. The mouth opening and mesh size of this net were 5.06 m 2 and 2.0 x 2.0mm, respectively. MOHT was towed at about 2 knots in the target depths for 20 to 40 minutes. A flow meter was
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attached to net mouth to measure the volume of seawater filtered. We selected target depths using information of
DSL and patchiness in the echograms of 38, 120, and 200 kHz. Samples were preserved in 5 % formalin–bufferedseawater for later analysis in the laboratory.
NORPAC net sampling
We conducted NORPAC net samplings in the 0–150 m layer once a day to collect data for species and size
compositions of meso–zooplanktons, especially copepods, in the epipelagic zone. The mouth opening of this net was
0.15 m2 and the mesh size of the net was 0.33 x 0.33 mm. A flow meter was attached to each net to measure thevolume of seawater filtered. Samples were preserved in 5 % formalin–buffered seawater.
Quantitative echosounder survey
We collected acoustic data by quantitative echsounders, SIMRAD ER60, with operating frequency at 38, 70, 120, and200 kHz by steaming at 10 knots on the track lines. Calibrations were carried out in the coastal region off eastern
Hokkaido (42˚53’N, 144˚10’E) on 26 to 27 June using a standard sphere technique. A tungsten carbide sphere (38.1mm in diameter) was used as the standard sphere. Acoustic data was analyzed by SonarData Echoview (Sonar Data
Co., Ltd.) software. To estimate distribution density of Japanese anchovy and zooplankton (euphausiid and copepod)
preys, we adopted information of target strength reported by Amakasu et al. (2010) and Fukuda et al. (unpubl. data,
see below), respectively.
Estimate of target strength of zooplanktons
Two living copepod species, N. cristatus and N. plumchrus, and living euphausiids mainly Euphausia pacifica, were
sorted and sound speed and density contrasts of each species were measured by time of flight method and density
bottle method, respectively (Mikami et al. 2000). These experiments are essential to obtain theoretical values of target
strength of these species, which are important to estimate abundance of these preys by acoustic data. To calculate
target strength of these animals, the Distorted-Wave Born Approximation based deformed-cylinder model (DWBA
model) was adopted and dorsal-aspect target strengths as a function of the incident angle of the ensonified wave (TSpattern) were calculated. TS-pattern of euphausiid was averaged by Foote’s method (Foote 1980) using the results ofthe swimming angle measurements by Miyashita et al. (1996). TS-pattern of copepod was averaged for all swimming
angles.

RESULTS AND DISCUSSION
Summary of some survey
A total of six midwater trawl surveys, six MOHT surveys, two MOCNESS surveys, and eight NORPAC, chlorophyll,
and under water irradiance surveys were conducted (Tables 1 to 4). Sound speed contrast of copepods Neocalanus spp.
and euphausiids mainly E. pacifica was measured for three and one times, respectively. Density contrast of copepods
and euphausiids was measured 30 and 14 times, respectively. The average sound speed and density contrast values
used for the model computation were 1.016 and 1.003 (copepods), 1.014 and 1.054 (euphausiid), respectively.
Distribution of sei whale relate to oceanographic condition and biological production
In the northern North Pacific, two oceanographic fronts, subarctic front between subarctic region and transitional
domain, and subarctic boundary between transitional domain and transition zone are distributed (Favorite et al. 1976,
Pearcy 1991). According to Kawai (1972) and Murakami (1994), subarctic front is defined by a water temperature
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lower than 5˚C at 100 m. Sub-arctic boundary is defined by 34.0 PSU salinity front in the epipelagic zone (Favorite etal. 1976). According to our CTD data, water temperature at 100 m was higher than 5˚C in all area and 34.0 PSU
salinity front in the epipelagic zone was found in the area between 39˚30’ and 40˚N, indicating that this study area was
located in the transitional domain north of ca. 40˚N and the transition zone to the south (Figure 2a, b).
A total of 592 nautical miles was searched. A total of 28 animals of 22 schools of large cetacean species was found by
primary sighting (Table 5). Of these, sei whale was the most abundant in this study area (Table 5). This whale species
was found mainly in the transition zone between 38˚10’ and 39˚40’N south of the subarctic boundary in late June
(Figure 2). During late July and early August, sei whale was reported to be densely distributed in the transitional
domain around 44˚N in the western North Pacific enclosed by longitude from 163ºE and 166ºE (Watanabe et al. 2011).
According to Fujise et al. (2004) and Konishi et al. (2009), sei whale was mainly captured in the transition zone southof 40˚N in May and June and in the transitional domain between 40˚ and 45˚N from July to September. These dataprobably indicate that sei whale migrate into the transitional domain from the transition zone in July just after ourstudy period.
The present result also indicated that the most of sei whale was found in the area where density of chlorophyll a at sea
surface rapidly increased from 0.6 to 0.9 mg m-3 (Figure 2c), which was probably corresponded to the surface
convergence, where cool surface waters from the north containing high levels of chlorophyll a sink beneath warm andoligotrophic waters to the south (Polovina et al. 2001). Because distribution of surface chlorophyll density could beobserved from satellite, satellite data would be useful to estimate distribution of sei whale in early summer. This
chlorophyll front area was well corresponded to the distribution area of subtropical copepod species, euphausiids, andJapanese anchovy (Figure 2e, f, g). In this area, high primary production probably led increase of subtropical copepod
abundance. Planktivorous Japanese anchovy may therefore migrate into and/or stay in this area from the southern
oligotrophic waters, and sei whale, which is predator of euphausiids and Japanese anchovy, also seemed to migrate
into and/or stay in this area for feeding. The mechanisms of high concentration of sei whales in this area could be
explained by these processes, suggesting that distribution of sei whale was closely related to the biological productivity
and directly related to the distribution of Japanese anchovy (see below).
Distribution of sei whale relate to prey environment
Among prey species, copepods Neocalanus spp. (most of which were N. cristatus and N. plumchrus), euphausiids,
Pacific saury, Common squid Todarodes pacificus, Pink salmon Oncorhynchus gorbuscha, Chum salmon O. nerka,
and Pacific pomfret Brama Japonica were mainly distributed in the northernmost region of the transition zone and/orin the transitional domain north of the main habitat of sei whale (Figure 2d, h-l). Contrasting with these species,
euphausiids and Japanese anchovy were abundantly distributed in the main distribution area of sei whale, althougheuphausiids were also abundant in the southern and northern parts of transitional domain (Figure 2f, g). These datasuggest that the distributions of euphausiids and Japanese anchovy greatly affect the distributions of sei whale.
However, no euphausiids were found in the stomachs of sei whale and this whale species mainly fed on Japanese
anchovy in their main habitat (Tamura et al. unpubl. data). These results might indicate that sei whale preferredJapanese anchovy prey and this prey species affect the distribution of the whale more significantly than euphausiid
prey in early summer in a part of sub-areas 8 and 9.
According to Watanabe et al. (2011), sei whale was also mainly distributed in the distribution centre of Japanese
anchovy where was located in the transitional domain and preferred Japanese anchovy prey in late July in the western
North Pacific. Because Japanese anchovy undertake northward migration from the transition zone to the transitional
domain during summer (Pearcy et al. 1996, Ichii et al. 2004), sei whale possibly migrate to the northward following
northward migration of Japanese anchovy and continued to depend on Japanese anchovy prey from early to mid
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summer. In the future, data on the relationship between distribution density of sei whale and prey preference of thewhale should be accumulated in each month in the more wide area of the western North Pacific to examine thishypothesis, which is essential to estimate role of sei whales as predator.

ACKNOWLEDGEMENT
A special thank is given to Captain S. Toishi and crews of Hokko Maru for their skilful assistance in collecting data. D.
Kitagawa and O. Yamamura of Hokkaido National Research Institute of Fisheries Science and H. Sugisaki of National
Research Institute of Fisheries Science kindly allowed us to use their sampling gears. T. Ichii and H. Murase of
National Research Institute of Far Seas Fisheries gave us valuable comments.

REFERENCES
Amakasu, K., Sadayasu, K., Abe, K., Takao, Y., Sawada, K. and Ishii, K. 2010. Swimbladder shape and relationshipbetween target strength and body length of Japanese anchovy (Engraulis japonicus). J Mar Acoustics Soc Jpn 37: 4659 (in Japanese with English abstract).
Favorite, F., Dodimead, A. J. and Nasu, K. 1976. Oceanography of the Subarctic Pacific Region, 1960-1971. INPFC33,
Vancouver, 187pp.
Foote, K. G. 1980. Averaging of fish target strength functions. J. Acoust. Soc. Am. 67: 504-515.
Fujise, Y., Tamura, T., Bando, T., Konishi, K. and Yasunaga, G. 2004. Sei and Bryde’s whales. Geiken Sousyo No. 11(in Japanese).
Government of Japan. 2002. Research Plan for Cetacean Studies in the Western North Pacific under Special Permit(JARPN II). Paper SC/54/O2 presented to the IWC Scientific Committee, May 2002 (unpublished). 115pp.
Ichii, T., Mahapatra, K., Sakai, M., Inagake, D. and Okada, Y. 2004. Differing body size between the autumn and thewinter-spring cohorts of neon flying squid (Ommastrephes bartramii) related to the oceanographic regime in the
North Pacific: a haypothesis. Fish Oceanogr 13: 295-309.
Kasamatsu, F., Miyashita, T. and Yoshioka, M. 2009. Field guide to whales, dolphins, and porpoises in the western
North Pacific and adjacent waters (new edition, Ohsumi S. ed). Tokyo: Tokyo University Press (in Japanese).
Kawahara, S. 2009. A minimum realistic model in the JARPN II offshore survey area. A document presented to the
IWC/JARPN II review workshop held at National research Institute of Fisheries Science in Yokohama from 26-30
January 2009, SC/J09/JR22 (unpublished). 22pp.
Kawai, H. 1972. Hydorography of the Kuroshro and the Oyashio. In: Physical oceanography II. Fundamental Lecturesof Oceanography (Masuzawa, J. ed), 129-321. Tokyo: Tokai University Press (in Japanese).
Kawamura, A. 1973. Food and feeding of sei whale caught in the waters south of 40˚N in the North Pacific. Sci Rep
Whales Res Inst, Tokyo 32: 155-197.
Konishi, K., Tamura, T., Isoda, T., Okamoto, R., Matsuoka, K. and Hakamada, T. 2009. Feeding strategies and prey
consumption of three baleen whale species within the Kuroshio-Current extension. J. Northw. Atl. Fish. Sci. 42: 2740.
24

THIS PAPER CAN NOT BE CITED WITHOUT THE WRITTEN CONSENT FROM THE AUTHORS

SC/64/O3

Miyashita, K., Aoki, I. and Inagaki, T. 1996. Swimming behavior and target strength of isada krill (Euphausia
pacifica). ICES J. Mar. Sci. 53: 303-308.
Mori, M., Watanabe, H., Hakamada, T., Tamura, T., Konishi, K., Murase, H. and Matsuoka, K. 2009. Development ofan ecosystem model of the western North Pacific. A document presented to the IWC/JARPN II review workshop heldat National research Institute of Fisheries Science in Yokohama from 26-30 January 2009, SC/J09/JR21(unpublished). 49pp.
Mikami, H., Mukai, T. and Iida, K. 2000. Measurement of sound speed and density rates of euphausiids to estimate
their target strength by theoretical model. Nippon Suisan Gakkaishi, 66: 682-689. (in Japanese with English abstract).
Murakami, M. 1994. On long-term variations in hydrographic conditions in the Tohoku area. Bull Tohoku Natl Fish
Res Inst 56: 47-56. (in Japanese with English abstract).
Nemoto, T. 1962. Prey items of baleen whale. Report of Institute of Cetacean Research 4, 136 pp. (in Japanese).
Oozeki, Y., Hu, F., Kubota, H., Sugisaki, H. and Kimura, R. 2004. Newly designed quantitative frame trawl forsampling larval and juvenile pelagic fish. Fish. Sci. 70: 223-232.
Pearcy, W. G., Fisher, J. P., Anma, G. and Meguro, T. 1996. Species associations of epipelagic nekton of the North
Pacific Ocean. Fish Oceanogr 5: 1-20.
Polovina, J. J., Howell, E., Kobayashi, D. R. and Seki, M. P. 2001. The transition zone chlorophyll front, a dynamic,
global feature defining migration and forage habitat for marine resources. Prog Oceanogr 9: 71-82.
Ueno, Y., Suyama, S., Kurita, Y. and Kumazawa, T. 2004. Design and operation methods of a mid-water trawl for
quantitative sampling of a surface pelagic fish, Pacific saury (Cololabis saira). Fish Res 66: 3-17.
Watanabe, H., Fujiwara, G., Sawada, K., Matsuura, T., Fukuda, Y., Okazaki, M., Inagake, D., Yasunaga, G., Kiwada,
H., Yoshida, H. and Tamura, T. 2011. Cruise report of whale sighting and prey species surveys in the offshore
reguion of the western North Pacific in 2010. Paper SC/63/O2 Appendix 1 presented to the IWC ScientificCommittee, June 2011 (unpublished). 13-28.
Watanabe, H., Okazaki, M., Tamura, T., Konishi, K., Inagake, D., Bando, T., Kiwada, H. and Miyashita, T. 2012.
Habitat and prey selection of common minke, sei, and Bryde’s whales in mesoscale during summer in the subarctic
and transition regions of the western North Pacific. Fisheries Science. (in press).

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Figure 1. Research track line of whale sighting and prey species surveys in late June 2011.

Figure 2. Sighting positions of sei whales, vertical temperature and salinity profiles, and geographical distribution of
biological productivity and each fish and squid species including whale prey species along track lines in early summer(late June) 2011. Shaded area indicates main distribution area of sei whale. Sampling position of sei whale was also
depicted (Tamura unpubl. data). TZ: transition zone. TD: transitional domain.

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Table 1. Sampling data of midwater trawl survey.

Sampling
SST Latitude (N)Longitude (E)Sampling depth (m)duration
Stn Year Month Day (˚C) Degree Minute Degree Minute Shallowest Deepest(min)
2 20116
16 17.3
37
20.4
156
40.4
0
30
60
4 2011617 16.7
38
30.9
158
37.0
0
30
60
7 20116
19 13.4
39
36.8
156
47.5
0
30
60
8 20116
20 11.8
40
28.6
156
57.3
0
30
60
10 20116
21 10.3
40
59.4
157
58.5
0
30
60
12 20116
22 11.0
42
33.2
156
54.2
0
30
60

Table 2. Sampling data of MOHT survey.

Stn
3
4
7
9
10
13

Year
2011
2011
2011
2011
2011
2011

SST Latitude (N)Longitude (E)TargetSampling duration at
Month Day (˚C) Degree Minute Degree Minute depth (m) the target depth (min)6
17 16.0
38
16.8
158
24.8
150
20
6
17 16.7
38
28.1
158
33.2
120
40
6
19 12.4
39
39.4
156
41.7
175
20
6
20 10.5
40
50.2
157
39.9
20
20
6
21 10.2
41
0.7
158
7.9
110
20
6
23 11.6
42
39.3
156
41.6
170
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Table 3. Sampling data of MOCNESS survey.

Stn
11

14

SST Latitude (N)Longitude (E)Sampling depth (m)Year Month Day (˚C) Degree Minute Degree Minute Shallowest Deepest
2011
6
22 10.5
42
17.1
157
26.6
0
30
30
50
50
105
105
140
140
210
210
255
255
400
400
500
2011
6
23
11.8 42
56.5
156
6.9
0
15
15
35
35
60
60
180
180
210
210
320
320
420
420
500

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Table 4. Research data that NORPAC net, chlorophyll, and under water irradiance surveys were conducted.

Stn
2
3
5
7
8
10
11
14

SST Latitude (N)Longitude (E)Year Month Day (˚C) Degree Minute Degree Minute2011
6
16 17.3
37
20.4
156
40.4
2011
6
17 16.0
38
16.8
158
24.8
2011
6
18 16.7
39
10.8
157
40.0
2011
6
19 12.4
39
39.4
156
41.7
2011
6
20 11.8
40
28.6
156
57.3
2011
6
21 10.3
40
59.4
157
58.5
2011
6
22 10.5
42
17.1
157
26.6
2011
6
23 11.8
42
56.5
156
6.9

Table 5. Results of sighting survey for large cetacean species.

Species
Sei whale
Sperm whale

Primary sighting
Secondly sighting
Schools Animals Schools Animals
19
24
2
3
3
4

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