SC/59/O6

Cruise report of the second phase of the Japanese Whale Research
Program under Special Permit in the Western North Pacific (JARPNII) in 2006 - Coastal component off Sanriku.
MUTSUO GOTO1, HIDEHIRO KATO2, RYOKO ZENITANI1, HIDEYOSHI YOSHIDA3, TERUO SAITO1,SHIGEO TABATA1, YUKA MORITA1, HITOMI SATO1, RYOSUKE OKAMOTO2, HIKARI MAEDA2, AYA
ODAGAWA2, TADASHI EBISUI1, KAZUYOSHI NAKAI1, AKIRA MATSUMOTO2, SOH FUJIMORI2,
SHIGETOSHI NISHIWAKI1, AND SHIGEYUKI KAWAHARA3
Contact e-mail:goto@cetacean.jp
The Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan.
Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-0075, Japan
3
National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa-ku, Yokohama,
Kanagawa 236-8648, Japan1
2

ABSTRACTThe third survey of the JARPN II coastal component was conducted from 12 April to 24 May 2006,
off Sanriku district, northeastern Japan (middle part of the sub-area 7), using four small-type whaling
catcher boats, two echo sounder-trawl survey vessels, and one dedicated sighting survey vessel.
Based on results from the two-year feasibility study conducted in 2002 and 2003, the coastal
component of JARPN II was revised to be conducted twice a year and to sample 60 common minke
whales in each of spring and autumn, and then the first revised survey was carried out off Kushiro inautumn of 2004. In the present survey, sampling of common minke whales was conducted in coastal
waters mainly within 30 nautical miles from Ayukawa port in the Sanriku district, and all animals
collected were landed on the JARPN II research station established in the port for biologicalexamination. During the survey, a total of 6340.0 nautical miles (634.1 hours) was surveyed forwhale sampling, the 139 schools (143 individuals) of common minke whales were detected, and 60
animals were caught. Average body length of the animals was 6.15m (SD: 1.12, n=26) for males and5.83m (SD: 1.04, n=34) for females. Dominant prey species found from forestomach of animals was
Japanese sand lance (Ammodytes personatus) during the first half of the survey period. However,both Japanese sand lance and Japanese anchovy (Engraulis japonicus) were dominant during second
half period. Krill (Euphausia pacifica) was observed from only one individual in the second half
period. Seasonal pattern of the dominant prey species through the survey period was different fromthe past two coastal surveys off Sanriku in 2003 in which krill was dominant, and 2005 in which
Japanese sand lance was also dominant. These results indicate that feeding habit of common minke
whales in coastal waters off Sanriku changes year by year.
KEYWORDS: COMMON MINKE WHALE; NORTH PACIFIC; COASTAL WATERS OF JAPAN;
FOOD/PREY; ECOSYSTEM; SCIENTIFIC PERMITS.

INTRODUCTION
After the two-year feasibility study in 2000-2001, the full-scale survey of the second phase of theJapanese Whale Research Program under Special Permit in the Western North Pacific (JARPN II)
was started in 2002. The purpose of the program is, i) to evaluate the feeding ecology and ecosystem
studies, involving prey consumption by cetaceans, prey preferences of cetaceans and ecosystem
studies, ii) to monitor environmental pollutants in cetaceans and the marine ecosystem and iii) to
elucidate the stock structure of whales (Government of Japan, 2002a).
The JARPN (1994-1999) and the JARPN II feasibility study (2000-2001) revealed that common
minke whales are widely distributed from offshore waters to coastal waters and feed on various preyspecies such as Japanese anchovy, Pacific saury, and walleye pollock (Government of Japan, 2002b;
1

Tamura and Fujise, 2002). The coastal waters of Japan are also very important fishing ground. Thus,
it was thought that the coastal waters are also very important research area for the full-scale JARPN
II program. However, the Nisshin Maru research vessels can not be operated in the near shore areas,
because of their movement restrictions from shallow water depth, and many fishing gears and boats.
Furthermore, the vessels can not work from late autumn to early spring because of their practicalavailability. In order to cover the temporal and spatial gap of the vessels, sampling of common
minke whales in the coastal waters using small-type whaling catcher boats was planned.
In the original JARPN II plan, the coastal component was presented as the two-year feasibility
study to examine the logistic aspects of the methodology (Government of Japan, 2002a). First
feasibility survey was carried out in the coastal waters off Kushiro in fall 2002 (Kishiro, et al., 2003)
and then the second feasibility survey was conducted in the coastal waters off Sanriku district inspring 2003 (Yoshida, et al., 2004). In each of the surveys, 50 common minke whales were caught.
From detailed examination of logistic aspects in the surveys, it was concluded that no substantial
problem occurred and that the coastal survey could be continued as a component of the JARPN II
using same kind of vessels (small-type whaling catcher boats) and methodology (Government ofJapan, 2004b, Kato, et al., 2004). However, re-calculation of required sample size from the survey
data suggested that the size should be modified to be at least 60 individuals in each area/season(Tamura, et al., 2004), and from the possible geographical and/or temporal variations of prey
consumption of the whales, the coastal surveys thought to be needed on a yearly bases in each local
area (Government of Japan, 2004a). The first revised survey off Sanriku was carried out in spring2005 (Yoshida, et al., 2006).
In the present paper, we show results of the third survey carried out in coastal waters off theSanriku district, Japan, from 12 April to 24 May 2006. This survey was authorized by theGovernment of Japan in compliance with Article VIII of the International Convention for the
Regulation of Whaling. The Institute of Cetacean Research (ICR) planned and conducted the survey
cooperate with National Research Institute of Far Seas Fisheries, Tokyo University of Marine Scienceand Technology and Miyagi Prefecture Fisheries Research and Development Center.
MATERIALS AND METHODS
Research area
Research area was set in the same waters where the 2003 and 2005 JARPN II coastal surveys off theSanriku district were conducted (Yoshida et. al, 2004; 2006). The district occupies northeastern partof the Japanese main island, Honshu (see, Fig. 1). In coastal waters off the Sanriku district, common
minke whales were taken by the past land-based coastal whaling (Miyashita and Hatanaka, 1997).
The waters are also very important fishing grounds. So, the waters were thought to be suitable forthe research area of the JARPN II, and thus the 2003 and 2005 coastal survey were conducted in thisarea. The present research area was also set in the same waters: within 50 nautical miles (mainly 30
n. miles) from the Ayukawa port in the Sanriku district (Fig. 1). The survey area is included in the
middle part of the sub-area 7 established by the IWC (1994).
Research vessels and station
Whale sampling survey
Four small-type whaling catcher boats were used as sampling vessels: Taisho Maru No. 28(hereinafter referred as 28T; 47.3GT), Koei Maru No. 75 (75K; 46.0GT), Katsu Maru No.7 (7K;
32.0GT), and Sumitomo Maru No.31 (31S; 32.0GT). The whale sampling survey was conducted in aperiod from 12 April to 24 May, 2006. All the animals sampled were landed on the JARPN II
research station established by the Ayukawa port for biological examination.
Prey species survey
The Takuyo Maru (TAK, 120.0GT) and Shunyo Maru (SHM, 887.0GT), the trawler-type research
vessels, conducted the prey species survey in research area set off northeast coast of Honshu from 10
to 25 April and from 7 to 28 April, respectively. Detail of the both of prey species surveys are shownin Appendices 1 and 2. The both research vessels TAK and SHM also carried out oceanographic
2

observation using CTD and EPCS.
Dedicated sighting survey
The Shonan Maru No.2 (SM2; 712.0GT) joined as the dedicated sighting vessel. The dedicatedsighting survey was conducted from 19 April to 2 May, following zigzag track lines pre-determinedin coastal waters off northeast coast of Honshu. Detail of the survey is shown in Appendix 3.
Sighting and sampling methods
Sighting and sampling methods by whale sampling vessels were almost same in the past two coastal
surveys conducted in Ayukawa in 2003 and 2005 (Yoshida et al. 2004, Yoshida et al. 2006). The
research head office was placed in the research station and controlled the sampling vessels during
the survey. In order to avoid concentration of sampling vessels, research area was divided into 3
small areas (Fig. 1). The office determined searching area and routes of sampling vessels everyday
by weather conditions, whale distribution and information on coastal fisheries.
A researcher was on board each of four sampling vessels, and recorded sighting and sampling
information, e.g., coordinates and time of common minke whales sighting and sampling made,weather conditions, and vessel activity. Two experienced researchers boarded on sampling vessels
for training two newcomer researchers both on 75K for first 12days and on 7K for first 9 days.
Sighting information was also recorded for other baleen whales and sperm whales. Searchingactivity was conducted from top barrel and upper bridge by crews and researchers. All common
minke whales sighted were targeted for sampling, except cow-calf pair. When a school consisted ofplural animals, an individual was selected randomly from the school and then caught. Once thevessel sampled a whale, she returned to the Ayukawa port as soon as possible, to transport the
animal to the research station. During the return cruise, even if common minke whales were sighted,
sampling was not conducted. At the port, animals taken were lift up from the vessels by a crane,using a wire net and then carried to the station by an 11-tons freight trailer. At that time, animal bodyweight was measured with the truck scale.
Biological research for common minke whales collected
All the animals collected were examined biologically by researchers at the research station. Research
items of the biological examination are summarized in Table 4. These items are related to studies on
feeding ecology, stock structure, life history and pollutions.
RESULTS
Searching effort made by sampling vessels
Cruise tracks made by sampling vessels (28T, 75K, 7K and 31S) during the present survey are
shown in Fig. 2. The sampling vessels tried to cover widely research areas within 30 n. miles from
Ayukawa port. In offshore waters, however, searching activity was very difficult from changeable
weather condition and bigger waves for small sampling vessels, which resulted in more searchingeffort in Area 1. Searching distance and time made by four sampling vessels are listed in Table 1.
Here, searching distance and time are defined as distance and time recorded under searching activity
conducted from top barrel of vessels. Total searching distance and time made by the four vessels
were 6340.0 n. miles and 634.1 hours, respectively.
Common minke whale sightings made by sampling vessels
Sighting positions of common minke whale schools made by the sampling vessels are shown in Fig.
3. All of common minke whale sightings were recorded in middle part of Sendai Bay. As shown in
Table 2, a total of 139 schools (143 individuals) of common minke whales were sighted. These were
116 primary sightings (118 animals/116 schools) and 23 secondary sightings (25 animals/23 schools).
Of 139 schools sighted, only 2 schools consisted of 2 individuals in primary sightings and 1 school
consisted of 3 individual in secondary sighting and others were solitary animals. No cow-calf pairs
were sighted.
Table 3 shows density index (SPUE: number of primary school sightings per one hour searching;3DI: number of primary school sightings per 100 n. miles searching) of common minke whales
recorded by the sampling vessels. Both SPUE and DI increased twice from the first half to second
half period of the survey.
Sampling of common minke whales
A total of 60 common minke whales were taken for biological examination. In the sampling process,two common minke whales were struck but lost due to technical failure. Sampling positions ofindividuals are shown in Fig. 4. Animals were taken evenly from whales sighted.
Prey species survey and dedicated sighting survey
The distribution and abundance of the prey species were investigated with the quantitative echosounder (EK 500 and ER 60) on board TAK and SHM. Acoustic data were acquired with operating
frequency at 38, 120 and 200 kHz. Species/size compositions of echo signs were identified bytargeting mid-water trawling. As the water temperature was high, many schools of anchovy were
distributed. Echo signs identified as adult sand lance (> 10 cm in standard length) occurred at depths
between 20m and 60m, especially off Fukushima prefecture. The echo signs were in the shape of
patches on the bottom or sticks rising from the bottom. Many echo signs identified as juvenile sandlance occurred as smaller patches in the mid-layer in the shallower area. Krill was frequently foundat depths deeper than 50 m.
The dedicated sighting survey was carried out using the sighting survey vessel (SM2). All the 29
common minke whale schools (29 animals) were sighted. Most of the sightings were obtained in
middle part of Sendai Bay, as recorded by the sampling vessels. The sighting number in the present
survey was smaller than in the 2005 survey off Sanriku, in which 49 common minke whale sightings
were obtained by the dedicated sighting survey vessel (Yoshida, et al. 2006). Results from the preyspecies survey and the dedicated sighting survey are noted in Appendices 1 and 2 (the prey species
survey) and Appendix 3 (the dedicated sighting survey).
Sex ratio, body length and weight of animals caught
Research items of biological examination are summarized in Table 4, with number of data andsamples obtained. The 60 animals taken consisted of 26 males and 34 females. Sex ratio of males toall animals was 0.43. The ratio was almost same as recorded in the 2003 (0.42) and 2005 (0.38)
coastal surveys off Sanriku.
Average body length was 6.15m (max=7.62, min=4.29, SD: 1.12) for males and 5.83m(max=8.07, min=4.08, SD=1.04) for females (Table 5). Frequency of body length of common minke
whale by sex was shown in Fig. 5. Average body weight was 2.85 tons (max=4.86, min=0.99,
SD=1.24) for males and 2.50 tons (max=7.04, min=0.86, SD=1.34) for females (Table 6).
Frequency of body weight of common minke whale by sex was shown in Fig.6. In both sexes,
average body length and weight of first half period were larger than that of second half period of thesurvey. In comparisons with females collected during the past two coastal surveys off Sanriku, in thepresent survey females showed markedly smaller values in body length and body weight (6.30 m and3.12 tons in the 2003 and 6.55m and 3.47 tons in the 2005 surveys). The both values of male were alittle smaller than that of in the 2003 (6.28 m and 2.92 tons) and 2005 (6.29m and 2.92 tons) surveys.
Composition of sexual maturity of animals collected is listed in Table 7 and frequency of sexual
maturity of male and female were shown in Fig. 7 and 8, respectively. In males, eleven of 26 animals
were sexually mature (42.3%), and 3 of 33 females attained sexual maturity (9.1%). All the mature
females were pregnant. Lactating females were not observed. Frequency of sexually mature males
was higher than that of the 2003 (38.1%) and 2005 (34.8%) surveys, but markedly lower in the 2003
(31.0%) and 2005 (37.8%) females.
Prey species of common minke whale found from forestomach
Following the same methods used in the JARPN II feasibility survey conducted in 2001 (Fujise, et4al., 2002), stomach contents were weighted to the nearest 0.1 Kg, by each of four chamber, in bothcases of including and excluding liquid contents. Then, small sample of forestomach contents wascollected and frozen for laboratory analysis.
The maximum weight of forestomach contents including liquid was 106.38kg, of which
consisted sand lance. This individual was male with body length of 7.44m and body weight of 4.00
tons. The maximum contents weight was 2.66% of her body weight.
Forestomach contents found from common minke whales during the present survey are listed inTable 8. Dominant prey species was Japanese sand lance (Ammodytes personatus) (43.3%, from 26
of 60 animals). Sand lance was detected throughout the survey. Japanese anchovy (Engraulisjaponicus) was not observed during the first half period except one individual which forestomach
contents were consisted of sand lance and Japanese anchovy, but increased during the second half
period (21.7%, from 15 of 60 animals). Krill (Euphausia pacifica) was recorded from only one
animal during the second half period. Most of unidentified fishes (35.6%) were also assumed to besand lance in the first period and sand lance and/or Japanese anchovy in the second half period(Table 8).
By-products of the whales
After biological examination, all the animals were processed according to the International
Convention for Regulation of Whaling, Article VIII. Total weight of productions including meat andblubber was 76.2 tons.
DISCUSSION
The present survey was the third coastal survey carried out in coastal waters off Sanriku district.
During the survey period, low atmospheric pressure and thick fog often disturbed the research
activities. Furthermore, changeable weather condition and bigger waves obstructed searchingactivities of sampling vessels in offshore waters. These bad whether and sea conditions were caused
to concentrate for sighting and sampling effort within Area 1.
Seasonal pattern of the dominant prey species of common minke whale found from forestomach
through the survey period was different from the past two coastal surveys off Sanriku. In the 2003
coastal survey off Sanriku, dominant species changed with time (Yoshida, et al. 2004): krill were
dominant in the first period (74.8%), then the occurrence frequency reduced with time, and in thethird period sand lance were found most frequently (92.2%). On the other hand, dominant preyspecies was Japanese sand lance (45.0%) in the 2005 coastal survey off Sanriku. Sand lance weredetected throughout the survey. Krill and Japanese anchovy were also found, but their frequency wasmuch lower (6.7%) (Yoshida et al., 2006). These results indicate that feeding habit of common
minke whales in coastal waters off Sanriku changes year by year, probably from environmental
factors, e.g., oceanographic conditions or prey species distribution.
Seasonal report of Miyagi Prefecture Fisheries Research and Development Center (fourth
information of spring fisheries in Miyagi prefecture in 2006) reported that total catch of sand lanceby fisheries in Miyagi prefecture until the end of May in 2006 was 61% lower than that of same
period in 2005. According to the results of monthly fisheries survey conducted by the TAK, both
southward cold water derived from Oyashio current and northward warm water derived from
Kuroshio current off Sanriku flew into the Sendai bay and made complicated sea circumstances ofthis region since April. After the late of April more strong northward warm water (surface
temperature of 12 ℃) off Sanriku flew into the Sendai Bay. Japanese anchovy which was
distributed in the marginal of this warm water also moved into the Sendai bay. Consequently
fisheries ground of the sand lance was dispersed and reduced by rising the sea water temperature andintrusion of Japanese anchovy to the Sendai Bay. The stomach contents revealed by present study
reflect these fisheries and sea circumstances conditions. These results indicate that common minke
whales and coastal fisheries caught adult sand lance and Japanese anchovy at the same time and area,
which indicate existence of interaction between them.
5

Density index of common minke whales recorded by sampling vessels in the present survey(0.19 for SPUE and 1.86 for DI) was lower than that of in the 2003 survey (0.47 for SPUE and 4.20
for DI) (Yoshida, et al. 2004) and 2005 survey (0.37 for SPUE and 3.26 for DI) (Yoshida, et al.
2006). One of the reasons for this result was thought to be bad weather condition in the present
survey. Another reason was assumed to be sea circumstances conditions occurred in Sendai Bay
mentioned above. Hatanaka and Miyashita (1997) hypothesized that migration pattern of western
North Pacific common minke whale was different by sex and sexual maturity: young animals
migrate into the coastal area of southern sub-area 7 (off Sanriku) in April and then disperse tonorthern sub-area 7, mature males appear widely from coastal waters to offshore waters in May,and :some of mature females distribute in sub-area 7 but they are rare in the southern sub area 7 andthe offshore waters of western North Pacific. When a comparison was made composition of sex andsexual maturity recorded in the present survey and past two surveys off Sanriku, frequency of
sexually mature males was higher than that of the 2003 (38.1%) and 2005 (34.8%) surveys, but
frequency of mature females in present survey (9.1%) was markedly lower than in the 2003 (31.0%)
and 2005 (37.8%). This lower frequency of mature female was assumed to be migrated to more
northern area at research period or migrate to more offshore area because of low prey species
abundance and/or sea circumstances conditions.
From the present survey, we could obtain valuable information including feeding ecology ofminke whales. To evaluate more precise values on food consumption of minke whales and to obtain
more information on interaction between the whales and coastal fisheries, further studies are needed.
ACKNOWLEDGMENTS
We acknowledge Dr. Hiroshi Hatanaka (ICR), the project leader of the full-scale JARPN II survey,
Mr. Hideki Moronuki, the Fisheries Agency of Japan, for his guidance and implementation to theresearch. Crewmen of research vessels, staffs of the research station in Ayukawa, and the Japan
small-type whaling association helped us. We also thank all the members of the municipal office ofIshinomaki, the Ojika fisheries cooperative association, and Miyagi prefectural office, for their kindassistance.
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 thefeasibility study of the Japanese Whale Research Program under Special Permit in the western
North Pacific-Phase II (JARPN II) in 2001. Paper SC/54/O16 submitted to the 54th IWC ScientificCommittee, 51pp.
Government of Japan, 2002a. 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., Kawahara, S., Pastene, L.A. and Hatanaka, H. eds.), 2002b. Reportof 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 submitted to the 54th IWC
Scientific Committee, 202pp.
Government of Japan, 2004a. Revised research plan for cetacean studies in the western North Pacificunder special permit (JARPN II). Paper SC/56/O1 submitted to the 56th IWC Scientific Committee,
14pp.
Government of Japan (Fujise, Y., Tamura, T., Kato, H. and Kawahara, S. eds.), 2004b. Someconsiderations of the feasibility components of the JARPN II research plan. Paper SC/56/O2
submitted to the 56th IWC Scientific Committee, 36pp.
Hatanaka, H. and Miyashita, T. 1997. On the feeding migration of the Okhotsk Sea-West Pacific
Stock of minke whales, estimates based on length composition data. Rep. int. Whal. Commn
47:557-564.
International Whaling Commission. 1994. Report of the Scientific Committee, Annex G. Report of
the Working Group on North Pacific Minke Whale management trials. Rep. int. Whal. Commn
44:120-44.
6

Kato, H., Kishiro, T., Yoshida, H. and Kawahara, S. 2004. Feasibility of coastal surveys in the
JARPN II, from the viewpoint of logistics. Appendix 1, pp4-12. In: Government of Japan (Fujise,Y., Tamura, T., Kato, H. and Kawahara, S. eds.), Some considerations of the feasibility
components of the JARPN II research plan. Paper SC/56/O2 submitted to the 56th IWC ScientificCommittee, 36pp.
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 the 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.
Miyashita, T. and Hatanaka, H. 1997. A note on whaling grounds for the western North Pacificminke whale. Rep .int. Whal. Commn 47:539-542.
Tamura, T. and Fujise, Y. 2002. Geographical and seasonal changes of the prey species on minke
whale in the Northwestern Pacific. ICES Journal of Marine Science, 59:516-528.
Tamura, T., Hakamada, T., Konishi, K., Fujise, Y., Kishiro, T., Yoshida, H., Ohizumi, H. and Kato,
H. 2004. Recalculation of sample size of common minke whales in coastal areas required for
estimating consumption of various prey items based on results of JARPN II. Appendix 2, pp13-17.
In: Government of Japan (Fujise, Y., Tamura, T., Kato, H. and Kawahara, S. eds.), Someconsiderations of the feasibility components of the JARPN II research plan. Paper SC/56/O2
submitted to the 56th IWC Scientific Committee, 36pp. Paper SC/56/O16 submitted to the 56th
IWC Scientific Committee, 36pp.
Yoshida, H., Kato, H., Kishiro, T., Iwasaki, T., Miyashita, T., Ryono, T., Tabata, S., Sakakibara, M.,
Saino, S., Hara, T., Hayashi, T., Tomizawa, Y., Tamai, K., Okamoto, R., Fukuoka, M., Watanabe,H., Tsunekawa, M. and Kawahara, S. 2004. Report of the coastal survey on common minke
whales off Sanriku coast, northeast Japan: the Japanese whale research program under special
permit in the western North Pacific – Phase II (JARPN II) in 2003 (Part II) – Coastal component.
Paper SC/56/O14 submitted to the 56th IWC Scientific Committee, 31pp.
Yoshida, H., Kato, H., Kishiro, T., Iwasaki, T., Miyashita, T., Saito, T., Tabata, S., Morita, Y., Sato,
H., Okada, A., Tomizawa, Y., Saino, S., Kuroishi, H., Ebisui, T., Nakai, K., Nishiwaki, S. and
Kawahara, S. 2006. Cruise report of the second phase of the Japanese Whale Research Program
under Special Permit in the Western North Pacific (JARPN II) in 2005- Coastal component off
Sanriku. Paper SC/58/O9 submitted to the 58th IWC scientific Committee, 30pp.

7

50 n. mails

30 n. mails

Western North Pacific23

Fig．1. Research area of the 2006 JARPNII coastal survey
off Sanriku.

HonshuArea1

Ayukawa★

Sanriku

8

Fig. 2. Cruise trucks made by four sampling vessels in the 2006 JARPNII
coastal survey off Sanriku.

Fig. 3. Sighting position of common minke whales made by sampling
vessels in the 2006 JARPNII coastal survey off Sanriku.

9Fig. 4. Sampling position of common minke during the 2006 JARPNII
coastal survey off Sanriku.

12

Female(n=34)

10
Number of animalsMale(n=26)
8
6
4
2
0
3.5 4 4 4.5 4.5 5 5 5.55.5

6 6 6.56.5 7 7 7.57.5 8 8 8.58.5

Body length （ｍ）
Fig．5. Frequency of body length of common minke whales taken in the 2006 JARPNII coastal
survey by sex.

14
12

Female(n=34)

Number of animalsMale(n=26)
10
8
6
4
2
0

11 1

22 2 33 3

44 4 55 5 66 6 77 7 88 8 99 9
Body weight （ｔ）

Fig．6. Frequency of body weight of common minke whales taken in the 2006 JARPNII coastal
survey by sex.

10

8
7

M
Im

Number of animals

6
5
4
3
2
1
0
3.5

4

4 4.5 4.5 5

5 5.5 5.5

6

6 6.5 6.5 7

7 7.5 7.5

8

8 8.5 8.5

Body length （ｍ）
Fig．7. Frequency of sexual maturity of male of common minke whales taken in the 2006
JARPNII coastal survey．Im：immature； M：mature．
12

Number of animals

10

M
Im

8

6

4

2

0

3.5 4

4 4.5 4.5 5

5 5.5 5.5

6

6 6.5 6.5

7 7 7.57.5 8 8 8.58.5

Body length （ｍ）
Fig．8. Frequency of sexual maturity of female of common minke whales taken in the 2006
JARPNII coastal survey．Im：immature； M：mature．

11

Table1. Searching days, hours, distances by four sampling vessels in the 2006
JARPNII coastal survey off Sanriku .
PeriodSampling vessels*1
28T
75K
07K
31S
First half period
Days
12
12
10
12
（12-30 April）
Hours
86.7
80.8
69.5
79.6
Distances (N. mail)
880.8
792.0
665.3
808.5
Second half period（1-24 May）

Days
Hours
Distances (N. mail)

19
88.2
866.2

19
70.3
709.2

19
88.2
871.7

19
70.8
746.3

Total
46
316.6
3146.576317.53193.5

Total

Days
31
31
29
31
122
Hours
174.9
151.0
157.7
150.4
634.1
Distances (N. mail)1747.0 1501.3 1537.0 1554.8
6340.0*1: 28T; Taisho Maru No. 28; 75K: Koei maru No. 75; 7K: Katsu Maru No. 7; 31S: Sumitomo
maru No. 31.

Table 2. List of cetacean species and number of sightings (no. schools/no. individuals)
made by four sampling vessels in the 2006 JARPN II coastal survey off Sanriku.
PeriodSpecies

First half period（12-30 April）

Common minke whale
Like minke whale
Unidentified baleen
whale
Unidentified large whale

Second half period（1-24 May）

Total

PrimarySch. Ind.
37
39
12
12

SecondarySch. Ind.
6
8
0
0

Total
Sch.
Ind.
43
47
12
12

1

1

0

0

1

1

2

2

0

0

2

2

Common minke whale
Like minke whale
Unidentified baleen
whale
Unidentified large whale

79
18

79
18

17
0

17
0

96
18

96
18

0

0

0

0

0

0

1

1

0

0

1

1

Common minke whale
Like minke whale
Unidentified baleen
whale
Unidentified large whale

116
30

118
30

23
0

25
0

139
30

143
30

1

1

0

0

1

1

3

3

0

0

3

3

12

Table 3. Density index of common minke whales by sampling vessels in
the 2006 JARPNII coastal survey off Sanriku .
PeriodSPUE*1
DI*2
First half period（12-30 April）

0.12

1.24

Second half period（1-24 May）

0.25

2.47

Total

0.19

1.86

*1: No. of primary school sightings per 1 hour searching.
*2; No. of primary school sightings per 100 n. miles searching.
Table 4. Summary of whale sampling in the 2006 JARPN II coastal survey off Sanriku.
Number of whales
Samples and data
Male Female
26
34
Body length and sex
26
34
External body proportion
26
34
Photographic record and external character
26
34
Diatom film record and sampling
26
34
Body scar record
26
34
Measurements of blubber thickness (eleven points)
26
34
Body weight0
3
Body weight by parts
26
34
Skin tissues for DNA study
26
34
Muscle, liver, and heart tissues for allozyme analysis
26
34
Muscle, liver, kidney, and blubber tissues for chemical analysis
Muscle, liver, blubber, vertebrae, and stomach contents for lipid
03
analysis
Mammary grand; lactation status, measurement and histological
34
sample34
Uterine horn; measurements and endometrium sample
34
Collection of Ovary0
3
Photographic record of foetus
03
Foetal length and weight0
3
External measurement of foetus
03Collection of foetus
24
Testis and epididymis; weight and histological sample
26
34
Stomach contents, convenient record
24
32Volume and weight of stomach content in each compartment
26
34
Observation of marine debris in stomach
26
33
Stomach contents for feeding study
26
34
Record of external parasites
26
34
Earplug for age determination
25
34
Tympanic bulla for age determination

13

Total
60
60
60
60
60
60
60
3
60
60
60
3
34
34
34
3
3
3
3
24
60
56
60
59
60
60
59

24
26
26
26
26
19
26
26
26
26

Eye lens for age determination
Largest baleen plate for morphologic study and age determination
Baleen plate measurements (length and breadth)
Photographic record of baleen plate series
Length of each baleen series
Sampling of serum
Vertebral epiphyses sample
Number of vertebrae
Number of ribs
Skull measurement (length and breadth)

34
34
34
34
34
24
34
34
34
34

58
60
60
60
60
43
60
60
60
60

Table 5. Statistics of body length (m) of common minke whales collected by the 2006 JARPN
II coastal survey off Sanriku.
PeriodFirst half period（12-30 April）
Second half period（1-24 May）
Total

Mean S.D.
7.02 0.58

Male
Min.
5.84

Max.
7.62

ｎ
8

Mean S.D.
6.06 0.75

Female
Min.
4.65

5.76

1.09

4.29

7.44

18

5.72

1.15

4.08

8.07

23

6.15

1.12

4.29

7.62

26

5.83

1.04

4.08

8.07

34

Max. ｎ7.01 11

Table 6. Statistics of body weight (tons) of common minke whales collected by the 2006 JARPN II
coastal survey off Sanriku.
PeriodMale
FemaleｎMean S.D.
Min. Max. ｎ
Mean S.D.
Min.
Max.
First half period
3.70
0.64
2.37 4.37 8
2.55
0.72
1.3
3.81
11
（12-30 April）
Second half period
2.47
1.26
0.99 4.86 18
2.47
1.56
0.86
7.04
23
（1-24 May）
Total
2.85
1.24
0.99 4.86 26
2.50
1.34
0.86
7.04
34

Table 7. Composition of sex and sexual maturity of common minke
whales collected by the 2005 JARPN II coastal survey off Sanriku.
PeriodFirst half period（12-30 April）
Second half period（1-24 May）
Total

Male

Female
Im

M

Total

11

0

11

Maturity
（％）
0.0

27.8

19

3

22**

13.6

42.3

30

3

33

9.1

Im

M*

Total

2

6

8

Maturity
（％）
75.0

13

5

18

15

11

26

Iｍ：Immature、M：Mature、P：Pregnant

14

Table 8. Prey species found in forestomach of common minke whales collected by the 2006
JARPN II coastal survey off Sanriku.

PeriodFirst half period(12-30 April)
Second half
period(1-24 May)
Total

Sample
size

Sand
lance

Japaneseanchovy

19
(%)

10
52.6

0
0.0

40

12

(%)
59
(%)

Prey species
Sand lance+Japanese
anchovy

Krill

Unidentified
fish

None

1
5.3

0
0.0

7
36.8

1
5.3

10

3

1

14

0

30.0

25.0

7.5

2.5

35.0

0.0

22
37.3

10
16.9

4
6.8

1
1.7

21
35.6

1
1.7

15

Appendix 1
2006 coastal prey species survey of JARPN II off
Sanriku-Johban
Shiroh Yonezaki1, Hiroshi Nagashima2, Hiroto Murase3, Kaoru Kohyama4, Shungo
Oshitani1, Kaoru Nemoto1, Ryuichi Matsukura5, Kenji Minami5, and Shigeyuki Kawahara6
1

National Research Institute of Far Seas Fisheries, 5-7-1 Orido, Shimizu-ku, Shizuoka 424-8633, Japan

2

Miyagi Prefecture Fisheries Research and Development Center, 97-6 Sodenohama, Watanoba,
Ishinomaki, Miyagi 986-2135, Japan

3

The Institute of Cetacean Research, 4-5 Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
Izu Mito Sea Paradaise, 3-1 Uchiuranagahama, Numazu, Shizuoka 410-0224, Japan
5
Field Center for Northern Biophere, Hokkaido University, 3-1-1 Minato-cho, Hakodata, Hokkaido
4041-8611, Japan
6

National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa-ku, Yokohama,
Kanagawa 236-8648, Japan
ABSTRACTA prey species survey was conducted in the coastal region off Sanriku-Johban, northeastern Japan, concurrently
with the coastal sampling survey for minke whale during spring 2006 as a part of JARPN II study. The
objective of concurrent surveys was to estimate the prey preference (selection) of minke whale. While thesampling survey for minke whale was conducted within 30 nautical miles (max 50 nautical miles) from
Ayukawa, Miyagi prefecture, the prey species survey was conducted in wider area at depths between 20 m and
200 m from 37º 00’ N to 38º 40’ N off Sanriku-Johban, northeastern Japan. The survey area was divided into
10 blocks with depth and latitude. The distribution and abundance of the prey species were investigated with
the quantitative echosounder (EK 500 and ER 60) on board Takuyo Maru (120 GT) and Shunyo Maru (887GT) steaming at 9 – 10 knots along the track lines during daytime. Acoustic data were acquired with
operating frequency at 38, 120 and 200 kHz. Species/size compositions of echo signs were identified bytargeting mid-water trawlings. As the water temperature was high, many schools of anchovy were distributed.
Echo signs identified as adult sand lance (> 10 cm in standard length) occurred at depths between 20m and 60m,
especially off Fukushima prefecture. The echo signs were in the shape of patches on the bottom or sticks
rising from the bottom. Many echo signs identified as juvenile sand lance occurred as smaller patches in the
mid-layer in the shallower area. Krill was frequently found at depths deeper than 50 m.

INTRODUCTION

The goal of JARPN II is to contribute to the conservation and sustainable use ofmarine living resources including whales in the western North Pacific, especially within
Japan’s EEZ (Government of Japan, 2002). The priority is put on feeding ecology andecosystem studies, involving studies of prey consumption by cetaceans, prey preference(selection) of cetaceans and ecosystem modeling. As it is difficult to cover the coastal
area, especially in spring and autumn, by the Nisshin Maru, the full-scale JARPN II has a
new coastal component, that is, the sampling survey for minke whale by small-typewhaling catcher boats. As in 2003 and 2005 surveys (Kawahara et al., 2004; Yonezaki etal., 2005), a prey species survey was conducted in the coastal region off Sanriku-Johban,
northeastern Japan, concurrently with the coastal sampling survey for minke whale during
spring 2006. In this document, the results of the 2006 prey species survey off
Sanriku-Johban are presented.

16

MATERIALS AND METHODS

While the sampling survey of minke whale was conducted in the coastal waters within
the 30 nautical miles (max 50 nautical miles) from Ayukawa, Miyagi prefecture, the preyspecies survey was conducted in wider area at depths between 20 m and 200 m from 37º
00’ N to 38º 40’ N off Sanriku-Johban, northeastern Japan, to elucidate the distribution andabundance of main prey species (Fig. 1). To avoid the conflict with set nets in the coastal
waters, the waters 10 miles from the coastal lines were excluded in principle. The survey
area was divided into 10 blocks (A, B, C, D, E, F, G, H, I, and J) at depths of 40m/100m
and 37º 40’ N/37º 54’ N/38º 15’ N. Blocks E, F, G, H, I and J south of 37º 54’ N are
located off Fukushima prefecture. A zigzag track line was set to cover each block. The
waypoints of planned track lines in each block were shown in Table 1. However, since
the width of the sea areas of Blocks H and I were narrow in the south off Fukushima
prefecture, both blocks were considered the one block, and the investigation line was set.
The prey species survey was conducted from April 11 to 27 in blocks A, B, C, D, E, F and G
by Takuyo Maru (Miyagi prefecture, 120 GT), and from April 8 to 14 in blocks H, I and J by
Shunyo Maru (National Research Institute of Far Seas Fisheries, 887 GT). The distribution
and abundance of the prey species were investigated with the quantitative echosounder (Takuyo
Maru: EK 500, Shunyo Maru: ER 60) steaming at about 9-10 knots along the track lines. The
survey was conducted during the daytime from an hour after sunrise to an hour before sunset.
Oceanographic observations were conducted with CTD-EPCS (Continuous Sea Surface Water
Monitoring System) (Takuyo Maru) and XCTD-OPCS (Continuous Sea Surface Water
Monitoring System) (Shunyo Maru). With EPCS and OPCS, temperature, salinity andchlorophyll in the surface water were measured every minute. Preliminary sighting survey
was made for marine mammals such as northern fur seals.
Acoustic data were acquired with Echoview Ver.3 (Sonar Data Co., Ltd.) with operating
frequency at 38, 120 and 200 kHz. Calibrations were carried out at a depth around 30m in
Ishinomaki Bay (Takuyo Maru,April 10 2006) in Shiogama Bay (Shunyo Maru, April 15 2006)
using the copper sphere technique described in EK 500 manual. Trawl sampling, Bongo net
sampling, Sabiki sampling (Takuyo Maru), Multiple Opening/Closing Net and Environmental
Sampling (MOCNESS) (Shunyo Maru) and Isaaca-kidd midwater trawling (IKMT) (ShunyoMaru) were conducted to identify the species and size compositions of targeting echo signs.
The trawl net had a mouth opening of 7 m width/3.5 m height and a 3 mm liner cod end. The
depth and the height of the mouth of the net were monitored with a net recorder. Towing speedof the trawl net was 2-4 knots. Catches of trawl, Sabiki, Bongo net, MOCNESS and IKMT
were identified to the species level and weighed aboard the vessel. For the major species, asample of 100 animals was taken, and lengths and weights were measured. Scaled andstandard lengths were used to anchovy and adult/juvenile sand lance, respectively. Total
length from the tip of the rostrum to the end of the telson was used for krill. Some frozen
samples were taken for further analysis in the laboratory.
RESULTS
The planned track lines were almost covered in the acoustic survey. A summary of the
midwater trawl operations, temperature by depth and catches was shown on Table 2 (TakuyoMaru) and 3 (Shunyo Maru). Targeting trawlings were made 25 times (Takuyo Maru: 15 times,
Shunyo Maru: 10 times) and CTD and XCTD observations were made at the trawling points and50 waypoints (Takuyo Maru: 39 points, Shunyo Maru: 11 points). The oceanographic
conditions are described in Appendix 2 in the report.
Acoustic data were analyzed with Echoview Ver.3 at the laboratory and the results are as
follows. The surface water temperature in the survey area was between 6.7 ºC and 13.9 ºC
based on EPCS and OPCS. The surface water temperature of survey area was higher than lastyear (Yonezaki et al., 2005), and many schools of Japanese anchovy were occurred during theprey species survey (Table 2). Echo signs identified as adult sand lance (> 10 cm in standard

17

length) occurred at depths between 20 m and 60 m in blocks B, C, E, F, H, I, and J. Especially,
many echo signs identified as adult sand lance were found in blocks F off Fukushima prefecture.
The echo signs on the echograms were in the shape of patches on the bottom or sticks risingfrom the bottom. Juvenile sand lance could be identified from the difference in average Sv
values between 38 and 120 kHz. Many echo signs identified as juvenile sand lance occurred in
the shallower area of Sendai Bay (blocks B and E). Most of the echo signs were smaller patches,
usually found in the mid-layer. Although the difference in average Sv values by frequency issimilar to that of krill, juvenile sand lance could be identified based on the distribution patterns
and the size of the echo signs. Krill was frequently found at depths deeper than 60 m. In
most cases the echo signs were large patches and in the shape of belts in the mid/bottom layers
or sticks rising from the bottom.
Hydrographic condition in this year was greatly different with last year (Yonezaki et al.,2005). According to a inflow warm water in the survey sea area from off shore division, many
patches of Japanese anchovy were confirmed and the number of krill school was less than lastyear (Yonezaki et al., 2005).
ACKNOWLEDGEMENT
A special thank is given to Captain H. Kimura (Takuyo Maru), Captain M. Onoda (ShunyoMaru), and crews of Takuyo Maru and Shunyo Maru for their dedication in collecting data.
REFERENCES
Government of Japan. 2002. Research Plan for Cetacean Studies in the Western North Pacificunder Special Permit (JARPN II). IWC/SC/54/O2: 115pp.
Kawahara, S., Watanabe, H., Ichihara, M., Suenaga, Y. and Katayama, M. 2004. 2003 preyspecies survey (coastal component) of JARPN II. Appendix 1, pp 15-20. In: 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 oncommon 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 Meeting, 31 pp.
Yonezaki, S., Nagashima, H., Murase, H., Nagaki, T., Shimizu, D., and Kawahara, S. 2006. 2005
coastal prey species survey of JARPN II off Sanriku. Appendix 1, pp 16-22. In: Yoshida,
H., Kato, H., Kishiro, T., Iwasaki, T., Miyashita, T., Saito, T., Tabata, S., Morita, Y., Sato,
H., Okada, A., Tomizawa, Y., Saino, S., Kuroishi, H., Ebisui, T., Nakai, K., Nishiwaki, S.,
and Kawahara, S. 2005. Cruise report of the second phase of the Japanese Whale
Research Program under Special Permit in the Western North Pacific (JARPN II) in
2005- Coastal component off Sanriku. IWC/SC/58/O9 submitted to the 58th IWC
Scientific Committee Meeting, 30 pp.

18

Table 1. Waypoints of planned lines.
Block A
WP
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10

Latitude
38
38
38
38
38
38
38
38
38
38

-

38
38
38
38
38
38
38
38
38
38
38
37
37
37
37

-

40.0
38.0
35.0
32.0
29.0
26.0
23.0
20.0
17.0
15.0

Longitude
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141

N
N
N
N
N
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
140
141
140
141
140
141
140
141
141

-

41.3
50.8
35.4
50.6
35.7
50.6
37.1
50.2
36.2
45.3

E
E
E
E
E
E
E
E
E
E

CourseDistance

105
256
104
256
104
254
106
255
106
TOTAL

7.7
12.4
12.3
12.1
12.1
11.0
10.7
11.4
7.4
97.0

CourseDistance

108
261
104
262
100
261
98
262
98
262
99
260
101
259
-

6.5
12.2
8.1
13.9
11.1
13.4
13.9
14.8
13.7
14.2
13.4
12.0
10.7
4.8
-

TOTAL

162.8

CourseDistance

119
254
98
264
98
262
99
261
100
261
100
261
100
262
99
261
-

3.1
5.3
10.8
13.7
11.4
10.8
9.1
9.7
8.7
9.1
8.7
9.6
8.6
10.2
10.1
3.2
-

TOTAL

142.3

Block B
WP
B1
B2
B3
B4
B5
B6
B7
B8
B9
B10
B11
B12
B13
B14
B15

Latitude
21.0
19.0
17.0
15.0
13.0
11.0
8.9
7.0
5.0
3.0
1.0
59.0
57.0
54.9
54.0

Longitude
-

16.6
24.4
9.1
19.1
1.6
15.4
58.7
16.1
57.5
14.6
56.8
13.6
58.6
11.9
6.0

E
E
E
E
E
E
E
E
E
E
E
E
E
E
E

Block C
WP
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
C11
C12
C13
C14
C15
C16
C17

Latitude
38
38
38
38
38
38
38
38
38
38
38
38
37
37
37
37
37

-

17.0
15.5
14.0
12.5
11.0
9.5
8.0
6.5
5.0
3.5
2.0
0.5
59.0
57.5
56.0
54.5
54.0

Longitude
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141

-

22.2
25.6
19.1
32.7
15.5
29.8
16.2
27.6
15.5
26.4
15.0
25.8
13.8
24.5
11.7
24.3
20.3

19

E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E

Block D
WP
D1
D2
D3
D4
D5
D6
D7
D8
D9

Latitude
38
38
38
38
38
38
37
37
37

-

15.0
13.0
10.0
7.0
4.0
1.0
58.0
55.0
53.9

Longitude
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141

-

40.7
49.3
30.3
48.9
26.8
47.9
24.9
41.0
35.0

E
E
E
E
E
E
E
E
E

CourseDistance

106
259
102
260
100
261
103
257
TOTAL

7.1
15.3
15.0
17.7
17.0
18.4
13.1
4.9
108.5

Block E
WP
E1
E2
E3
E4
E5
E6
E7
E8
E9
E10
E11

Latitude
37
37
37
37
37
37
37
37
37
37
37

-

37
37
37
37
37
37
37
37
37

-

54.0
53.5
52.0
50.5
49.0
47.5
46.0
44.5
43.0
41.5
40.0

Longitude
N
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141
141

N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141

-

4.0
0.0
12.5
2.0
13.0
2.1
8.2
2.6
9.7
3.0
11.1

E
E
E
E
E
E
E
E
E
E
E

CourseDistance

261
99
260
100
260
107
251
105
254
103
TOTAL

3.2
10.0
8.5
8.9
8.8
5.1
4.7
5.8
5.5
6.6
67.2

CourseDistance

103
257
104
259
102
258
102
258
TOTAL

4.5
8.9
8.2
10.0
9.3
10.0
9.4
4.8
-

CourseDistance

262
99
261
100
261
100
260
TOTAL

13.6
12.5
12.8
11.9
13.1
11.8
12.0
87.7

Block F
WP
F1
F2
F3
F4
F5
F6
F7
F8
F9

Latitude
54.0
53.0
51.0
49.0
47.0
45.0
43.0
41.0
40.0

Longitude
-

18.3
23.9
13.0
23.0
10.6
22.1
9.8
21.3
15.4

E
E
E
E
E
E
E
E
E

Block G
WP
G1
G2
G3
G4
G5
G6
G7
G8

Latitude
37
37
37
37
37
37
37
37

-

54.0
52.0
50.0
48.0
46.0
44.0
42.0
40.0

Longitude
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141

-

40.4
23.4
39.0
23.1
37.9
21.6
36.2
21.3

20

E
E
E
E
E
E
E
E

Block HI
WP
HI 1
HI 2
HI 3
HI 4
HI 5
HI 6
HI 7
HI 8
HI 9
HI 10
HI 11
HI 12
HI 13
HI 14
HI 15
HI 16
HI 17
HI 18
HI 19
HI 20
HI 21
HI 22
HI 23
HI 24
HI 25
HI 26
HI 27
HI 28

Latitude
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37

-

40.0
38.8
37.0
35.1
34.0
32.5
31.0
29.4
28.0
26.9
25.0
23.1
22.0
20.9
19.0
16.9
16.0
15.0
13.0
10.9
10.0
9.1
7.0
4.8
4.0
3.1
1.0
0.0

Longitude
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141
141

-

2.6
9.7
19.9
10.1
4.3
10.5
17.0
9.9
4.5
8.9
15.0
8.1
4.1
7.7
13.4
6.3
3.5
5.9
10.9
4.8
2.1
4.3
8.7
2.1
0.3
2.0
6.3
3.8

E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E

CourseDistance

102
102
256
256
106
106
254
254
109
109
251
251
111
111
249
249
117
117
246
246
118
118
245
245
122
122
243
-

5.7
8.3
8.1
4.7
5.2
5.3
5.9
4.5
3.7
5.2
5.9
3.3
3.1
4.8
6.0
2.4
2.2
4.4
5.3
2.3
1.9
4.1
5.7
1.7
1.6
4.0
2.2
-

TOTAL

117.7

CourseDistance

82
282
80
281
81
280
80
281
79
282
79
282
78
285
-

7.3
13.9
17.9
16.3
18.8
17.0
17.2
15.4
16.2
14.6
15.6
14.5
14.7
12.0
-

TOTAL

211.4

Block J
WP
J1
J2
J3
J4
J5
J6
J7
J8
J9
J10
J11
J12
J13
J14
J15

Latitude
37
37
37
37
37
37
37
37
37
37
37
37
37
37
37

-

0.0
1.0
4.0
7.0
10.0
13.0
16.0
19.0
22.0
25.0
28.0
31.0
34.0
37.0
40.0

Longitude
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141
141
141
141
141
141

-

15.7
24.7
7.7
29.8
9.7
33.0
12.0
33.3
14.3
34.3
16.3
35.6
17.8
35.9
21.3

21

E
E
E
E
E
E
E
E
E
E
E
E
E
E
E

Table 2. A summary of the sampling operations, temperature by depth and catches by Takuyo
Maru.
St-1
4/11
8:41

St-2
4/11
12:11

St-3
4/14
10:14

St-4
4/15
6:10

St-5
4/18
8:02

St-6
4/18
9:06

St-7
4/18
15:43

38-17.884
141-16.905

38-13.083
141-04.146

38-05.459
141-02.583

37-56.358
141-02.711

38-14.816
141-41.811

38-14.310
141-44.093

38-04.027
141-26.411

6.80
6.64
6.76
6.48

7.10
6.75
6.84

7.80
7.13
6.80

8.20
7.78
6.98

23
Trawl
10-20

27
Trawl
15-25

23
Trawl
15-25

10.40
10.28
10.30
10.30
10.23
9.91
7.98
6.91
6.37
148
Trawl
30-40

9.60
9.37
9.72
10.26
10.24
9.05
8.37
7.95

30
Trawl
10-20

8.60
9.52
9.79
9.74
9.72
9.72
8.60
6.85
5.59
142
Trawl
100-110Juvenile sandlance,
37,
30-50, Jelly
fish

Juvenilesand lance,
47, 34-57

Adult sandlance, 104,
98-131,Juvenilesand lance,
48, 31-57,
Jelly fish

Adult sandlance, 107,
91-132,Juvenilesand lance,
30, 24-54,
Japaneseanchovy, 70
and 78, Jelly
fish

Maurolicus
japonicus,
34, 18-37

Nothing

Krill, 17,
13-22, Jelly
fish

Catches (kg)

2.7

19.8

8.0

12.6

0.3

0.0

0.2

StationDate
Time
LatitudeLongitude
Surf. Temp.
10 m
20 m
30 m
40 m
50 m
75 m
100 m
125 m
Depth (m)

St-8
4/19
8:07

St-9
4/19
12:26

St-10
4/22
10:47

St-11
4/23
9:26

St-12
4/25
10:19

St-13
4/26
6:56

St-14
4/26
7:22

37-56.591
141-32.492

38-08.474
141-32.731

38-19.603
141-48.619

38-35.703
141-39.054

37-40.485
141-18.193

37-54.268
141-17.963

37-54.246
141-18.146

11.26
-

9.02
9.23
9.73
9.11
9.15
9.52
8.39
6.98

8.55
-

10.73
-

9.80
10.51
10.60
10.25
9.73
9.29

9.80
10.51
10.60
10.25
9.73
9.29

142
Sabiki
20-60

117
Bongo
115

207
Trawl
70-80

7.60
7.22
8.03
8.38
9.36
7.50
5.72
5.20
4.86
138
Trawl
125-135

86
Sabiki
20-70

62
Trawl
10-20

62
Trawl
15-25

Japaneseanchovy,
116, 116-128

Krill

Nothing

Krill, 16,
13-21,
Maurolicus
japonicus,
23,30,48,
etc.

Japaneseanchovy,
114, 111-117

Adult sandlance, 118,
97-144,
Jelly fish

Adult sandlance, 118,
97-144,
Jelly fish

Catches (kg)

0.17

< 0.1

0.0

10.8

0.09

0.5

0.3

StationDate
Time
LatitudeLongitude
Surf. Temp.

St-15
4/27
7:50

Depth temp.

StationDate
Time
LatitudeLongitude
Surf. Temp.
10 m
20 m
30 m
40 m
50 m
75 m
100 m
125 m
Depth (m)Sampling method

Net depth (m)Species caught,
Length modeand range (mm)Depth temp.

Sampling method

Net depth (m)Species caught,
Length modeand range (mm)37-50.549
141-33.857

11.50

22

108
Trawl
80-90

Depth temp.

10 m
20 m
30 m
40 m
50 m
75 m
100 m
125 m
Depth (m)Sampling method

Net depth (m)Species caught,
Length modeand range (mm)Catches (kg)

11.42
11.25
11.21
10.84
10.20
8.52
8.27
7.97
135
Trawl
125-135
Krill,
15-22

18,

0.1

23

Kesen-numa
MIYAGI
Ayukawa

38.40 N

IshinomakiA
38.15 N

B

Soma

E

D
37.54 NF

G
37.40 NH
FUKUSHIMA

C

I

J

37.00 N

Fig. 1. Survey area and blocks of prey species survey in 2006 off Sanriku.

24

Appendix 2
Oceanographic conditions in the coastal survey of JARPN II off Sanriku,
northeastern Japan, in April 2006
Denzo Inagake1, Makoto Okazaki1, Shiroh Yonezaki2, Hiroshi Nagashima3,
Hiroto Murase4 and Shigeyuki Kawahara2
1 National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa, Yokohama,

Kanagawa, 236-8648, Japan

2 National Research Institute of Far Seas Fisheries, 5-7-1, Orido, Shimizu-ku, Shizuoka,

Shizuoka, 424-8633, Japan
Miyagi Prefecture Fisheries Research and Development Center, 97-6, Sodenohama,
Watanami, Ishinomaki, Miyagi, 986-2135, Japan
4 The Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan
Contact e-mail: ina@affrc.go.jp
3

ABSTRACTA prey species survey was conducted in the coastal region off Sanriku, northeasternJapan, concurrently with the coastal sampling survey for minke whale during spring2006 as a part of JARPN II study. Oceanographic observations were conducted with
CTD from 11 to 27 April 2006 by Takuyo-Maru and XCTD from 8 to 13 April 2006 by
Shunyo-Maru. According to the CTD data at 39 stations and XCTD data at 11 stations,water masses in the survey area have characteristics of the Cold water (5ºC <temperature < 10ºC at 100m depth). The offshore water was affected by the Warmwater spread from the Kuroshio

Introduction
The oceanographic condition at the Tohoku area, northeastern Japan, is one of the mostcomplicated areas in the world. In this area, there are a lot of fronts and water masses.
The Kuroshio flows northward along the east coast of Japan to the southern part of the
Tohoku area with warm high-salinity water. The Oyashio flows southwestward along the
Kuril Islands to the northern part of the Tohoku area with cold low-salinity water. The
Kuroshio and the Oyashio flows eastward from the Tohoku area, and the area between the
Kuroshio and Oyashio was usually called the Kuroshio-Oyashio Inter-frontal Zone or
perturbed area. The Tsugaru warm water enters into the Inter-frontal Zone throughTsugaru Strait, and also the warm-core ring is cut off from the Kuroshio extension into theInter-frontal Zone. Each water mass is mixed with others, and make a new water mass.
The coastal area off Sanriku is the most variable in the Tohoku area, because the Kuroshio,
the warm-core ring, the Oyashio, the Tsugaru warm water and other water arrive here byturns.
A prey species survey was conducted on board Takuyo-Maru (Miyagi prefecture, 120 GT)
and R/V Shunyo-Maru (National Research Institute of Far Seas Fisheries, 887GT) in the
coastal region off Sanriku, northeastern Japan, concurrently with the coastal sampling
survey for minke whale during spring 2006 as a part of JARPN II study. Oceanographic
observations were conducted with Conductivity Temperature Depth profiler (CTD) by
Takuyo-Maru and Expendable Conductivity Temperature Depth profiler (XCTD) by
Shunyo-Maru. In this paper, we analyzed the CTD and XCTD data to make clear theoceanic environment in the survey area.

25

Data and Methods
Hydrographic observations with CTD (SBE 19) were carried out at 39 stations from 11
to 27 April 2006 in the coastal area off Sanriku, northeast of Japan (Fig. 1, upper panel).
XCTD (Tsurumi MK-130) observations were done at 11 stations from 8 to 13 April 2006 in
the southern part of the coastal area (Fig. 1, lower panel).
Oceanic fronts and water masses are usually detected by subsurface temperature map(see Table 1), because they are obscure in sea surface temperature distributions fromsummer to fall seasons and the Oyashio water spreads into the subsurface layer. So, theoceanographic conditions in April 2006 (Fig. 2) are detected by 100m and 200m
temperature maps using the monthly mean subsurface temperature in seas around Japan
from NEAR-GOOS database.
Oceanographic conditions in the survey area
Figure 3 shows the Temperature-Salinity diagrams using CTD and XCTD station data.
Almost all water mass in the survey area have characteristics of the Cold water withsurface subtropical water. A few stations show cold low-salinity water (less than 33.5 psu),
which is mixed with the Oyashio water.
Figure 2 shows the schematic hydrographic map in April 2006. The northern limit of
the Warm water spread from the Kuroshio Extension moves northward from March to
November. The position of the Warm water in April 2006 was at 38ºN on 144ºE line, which
was a slightly southward position from monthly mean location in April (38º40’N). Tsugaru
warm water was obscure because it restricted near the coastal area called by coastal modein April. The southern limit of the first Oyashio Intrusion located around 39ºN, 143ºE,
which was a little northward position from monthly mean location in April (38º30’N). All
stations in the survey area were distributed in the Cold water defined by 100 m
temperature which is over 5ºC and less than 10ºC.
Figure 4 and 5 show temperature and salinity maps at the depth of 100 m, observed by
Takuyo-Maru and Shunyo-Maru. Water of 6ºC to 10ºC and 33.7 to 34.2 psu were dominantat the depth of 100 m in Fig. 4 and 5. It means that the Cold water occupied in thesesurvey area.
Figure 6 and 7 show vertical section of temperature and salinity. Warm (over 10ºC)
high-salinity (over 34 psu) water distributed at the offshore area. Low salinity water lessthan 33 psu was dominant at the shallow layer near the coast in Fig. 6. Although the cold
water occupied in these survey area, onshore water was colder and lower salinity thanoffshore water.
All of these figures show that all stations are distributed in the cold area, but shallow
coastal area was modified by the Oyashio water and offshore area was affected by theWarm water spread from the Kuroshio.
Acknowledgment
A special thank is given to Crews of Takuyo-Maru and Shunyo-Maru for their dedication incollecting data.
References
Kawai, H. (1969):

Statistical estimation of isotherms indicative of the Kuroshio axis,

Deep-Sea Res., Suppl. to 16, 109-115.

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).

26

Table 1.

Extraction method from temperature map to determine the position of eachwater mass according to Kawai (1969) and Murakami (1994).
Target characteristics
Extraction method
Kuroshio Extension Axis
14 ºC isotherm at 200m
Warm-core ringTemperature front at 200m
Oyashio front
5ºC isotherm at 100m
Oyashio water
Area with T < 5ºC at 100m
Cold water
Area with 5ºC < T < 10ºC at 100m
Warm water
Area with T > 10ºC at 100m and T < 14ºC at 200m

27

Fig. 1.

Station map observed by Takuyo-Maru in 11 to 27 April 2006 (upper panel) andShunyo-Maru in 8 to 13 April 2006 (lower panel).

28

Fig. 2. Schematic hydrographic map in Tohoku area, northwestern Pacific, in April
2006 with station map observed by Takuyo-Maru (▲) and Shunyo-Maru (△).

29

Fig. 3. Temperature-Salinity diagrams using CTD station data observe by Takuyo-Maruin 11 to 27 April 2006 (left panel) and Shunyo-Maru in 8 to 13 April 2006 (rightpanel). Each thin line in this figure denotes a density line of sigma-t.

Fig.4.

Temperature (left panel) and salinity (right panel) maps at 100 m depth, observed
by Takuyo-Maru in 11 to 27 April 2006.

30

Fig.5.

Fig.6.

Fig.7.

Temperature (left panel) and salinity (right panel) maps at 100 m depth, observedby Shunyo-Maru in 8 to 13 April 2006.

Temperature (left panel) and salinity (right panel) sections, observed by

Takuyo-Maru in 11 to 27 April 2006.

Temperature (left panel) and salinity (right panel) sections, observed by

Shunyo-Maru in 8 to 13 April 2006.

31

Appendix 3
Cruise report of the dedicated sighting survey in 2006 JARPNII
coastal survey off Sanriku, northeast Japan
Shigetoshi Nishiwaki, Kazuki Fukutome and Keisuke KimuraContact e-mail: nisiwaki@cetacean.jp
The Institute of Cetacean Research, 4-5 Toyomi-cho, Chuo-ku Tokyo, 104-0055, Japan

ABSTRACT
A cetacean sighting survey using the line transect method was conducted concurrently with the whale
sampling survey and the whale prey survey off the Sanriku coast, Japan from 20 Apr. to 3 May, 2006.
The primary objective of the sighting survey was the abundance estimation of baleen whales in thesurvey area. Shonan-maru No.2 was dedicated to the sighting survey. Total primary searching
distance was 1003.1 n.miles, and the 34 schools (34 individuals) of primary sightings were made.

INTRODUCITON
A cetacean sighting survey using the line transect method was conducted concurrently with thewhale sampling survey and the whale prey survey off the Sanriku coast, Japan from 20 April to 3
May, 2006, as a part of coastal component of 2006 JARPN II full scale study (Government of Japan,
2002). The primary objective of this survey was to obtain information on abundance of baleen
whales in the survey area. Preliminary results of the cetacean sighting survey are presented in thispaper.

MATERIALS AND METHODS
The cetacean sighting survey area was set within Sub-area 7 (Fig. 1). Though the sampling ofwhales was conducted within the 30 n.miles from Ayukawa port, sighting survey area had larger areextent to see the overall baleen whale distribution pattern off the coast of the Sanriku, between 37N
to 39N and shorelines to 142E. Near shore area of the survey block where the water depth is lessthan 20m was not surveyed because many fisheries gears were set in there. The survey was
conducted from 20 Apr. to 3 May, 2006. Shonan-maru No.2 (SM2, 712GT) engaged in the cetaceansighting survey. Sighting survey procedures were same as offshore component of 2006 JARPN II.
The right (Eubalaena japonica), blue (Balaenoptera musculus), and humpback (Megaptera
novaeangliae) whales can be approached to obtain the Natural marking record experiments as theopportunistic basis. Large baleen whale feeding behavior visual observation was attempted. If the
behavior was observed, it was recorded on video tape.
RESULTS AND DISCUSSION
Tracklines surveyed are shown in Fig. 1. Total primary searching distance was 1003.1 n.miles. The
34 schools (34 individuals) of primary sightings were obtained and one secondary sighting (oneanimal/one school) was also made. Details of sightings are listed in Table 1. Sightings of common
minke whales were recorded. Sighting positions of these sightings are noted in the Fig. 1. No
32

feeding behavior of large baleen whales was observed.

ACKNOWLEDGEMENT
Special thanks is given to the crews and researchers for their dedication in collecting data. The
authors would like to thank Dr. Hiroshi Hatanaka (The Institute of Cetacean Research). We thank
Koji Matsuoka and Hiroshi Kiwada for the preparation and analysis of this cruise. We also express
the gratitude to Hiroto Murase for the comment on the course of preparing the English manuscriptof this paper.

REFERENCES
Government of Japan. 2002. Research Plan for Cetacean Studies in the Western North Pacific underSpecial Permit (JARPN II). IWC/SC/54/O2: 115pp.

33

Table 1. Summary of cetacean sightings made during the dedicated sighting survey in 2006 JARPNII
coastal survey.

SpeciesCommon minke whale
Like Common minke whale
Fin whale
Unidentified large cetaceans
Unidentified cetaceans
Total

PrimarySch. Ind.
28
28
1
1
1
1
1
1
3
3
34
34

SecondarySch. Ind.
1
1

1

1

Fig. 1. Survey area and predetermined tracklines, and surveyed tracklines and sighting
positions of common minke (●) and fin (▲) whales.
34