SC/58/O9

SC/58/O9

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.
HIDEYOSHI YOSHIDA1, HIDEHIRO KATO2, TOSHIYA KISHIRO1, TOSHIHIDE IWASAKI1, TOMIO MIYASHITA1,TERUO SAITO3, SHIGEO TABATA3, YUKA MORITA3, HITOMI SATO3, AZUSA OKADA3,
3

3

3

3

YASUHIRO
3

TOMIZAWA , SHIGEO SAINO , HISASHI KUROISHI , TADASHI EBISUI , KAZUYOSHI NAKAI , SHIGETOSINISHIWAKI3, AND SHIGEYUKI KAWAHARA1
Contact e-mail:hideka@fra.affrc.go.jp
1

National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa-ku, Yokohama,
Kanagawa 236-8648, Japan

2

Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-0075, Japan

3

The Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo, 104-0055, Japan.

ABSTRACTThe second survey of the revised JARPN II coastal component was conducted from 11 April to 21 May 2005, off Sanriku
district, northeastern Japan (middle part of the sub-area 7), using four small-type whaling catcher boats, one echosounder-trawl survey vessel, 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 in autumn of 2004. In
the present survey, sampling of common minke whales was conducted in coastal waters 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 biological examination. During the survey, a total of 5245.8 nautical miles (466.9 hours) was surveyed for whale
sampling, the 202 schools (205 individuals) of common minke whales were detected with sightings of 2 humpback whale
schools (2 animals), and all the 60 animals were caught. Average body length of the animals was 6.29m (SD=0.82, n=23) for
males and 6.55m (SD=1.15, n=37) for females. Dominant prey species found from forestomach of animals was Japanesesand lances (Ammodytes personatus). Krill (Euphausia pacifica) and Japanese anchovies (Engraulis japonicus) were also
observed, but their occurrence frequency was much lower. This observation was different from the 2003 JARPN II coastal
survey off Sanriku, in which krill were also dominant. These results indicate that feeding habit of common minke whales incoastal waters off Sanriku changes yearly.
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 the Japanese
Whale Research Program under Special Permit in the Western North Pacific (JARPN II) was started in
2002. The purpose of the program is, i) feeding ecology and ecosystem studies, involving prey
consumption by cetaceans, prey preferences of cetaceans and ecosystem modeling, ii) monitoring1

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

environmental pollutants in cetaceans and the marine ecosystem, and iii) elucidation of stock structure ofwhales (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 prey species such
as Japanese anchovy, Pacific saury, and walleye pollock (Government of Japan, 2002b; Tamura and Fujise,2002). The coastal waters of Japan are also very important fishing ground. Thus, it was thought that thecoastal waters are also very important research area for the full-scale JARPN II program. However, theNisshin 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 notwork from late autumn to early spring because of their practical availability. In order to cover the temporaland spatial gap of the vessels, sampling of common minke whales in the coastal waters using small-typewhaling 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 survey was carriedout in the coastal waters off Kushiro, northeast Japan, from 10 September to 12 October 2002 (Kishiro, etal., 2003) and then the second survey was conducted in the coastal waters off Sanriku district, from 8 April
to 2 May 2003 (Yoshida, et al., 2004). In each of the surveys, 50 common minke whales were caught. Fromdetailed 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 kindof vessels (small-type whaling catcher boats) and methodology (Government of Japan, 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 tobe needed on a yearly bases in each local area (Government of Japan, 2004b).

The first survey of the revised JARPNII was carried out from 13 September to 31 October, 2004, off
Kushiro and finished successfully (Kishiro et al. 2005). In the present paper, we show results of the second
survey carried out in coastal waters off the Sanriku district, Japan, from 11 April to 21 May 2005. Thissurvey was authorized by the Government of Japan in compliance with Article VIII of the International
Convention for the Regulation of Whaling. The National Research Institute of Far Seas Fisheries (NRIFSF),
Fisheries Research Agency, planned and conducted the survey, entrusted by the Institute of Cetacean
Research (ICR).

MATERIALS AND METHODS
Response to the discussion at the IWC/SC meeting
The revised JARPN II research plan was presented at the 56th IWC/SC annual meeting (Government ofJapan, 2004a).

Then, the first revised survey was conducted in 2004, off Kushiro and results was reported

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SC/58/O9

at the 57th IWC/SC annual meeting (Kishiro et al. 2005). Since serious comments and recommendations to
the plan were not noted at the both meetings, the present survey was conducted under the original revisedplan (Government of Japan, 2004a).

Research area
Research area was set in the same waters where the 2003 JARPN II coastal survey off the Sanriku district
was conducted (Yoshida et. al, 2004). The district occupies northeastern part of the Japanese main island,
Honshu (see, Fig. 1). In coastal waters off the Sanriku district, common minke whales were taken by thepast land-based coastal whaling (Miyashita and Hatanaka, 1997). The waters are also very importantfishing grounds. So, the waters were thought to be suitable for the research area of the JARPN II, and thus
the 2003 coastal survey was conducted there. 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.

Research vessels and station
Whale sampling survey
Four small-type whaling catcher boats were used as sampling vessels: Taisho Maru No. 28 (hereinafterreferred as 28T; 47.3GT), Koei Maru No. 75 (75K; 46.0GT), Katsu Maru No.7 (7K; 32.0GT), andSumitomo Maru No.31 (31S; 32.0GT). The whale sampling survey was conducted in a period from 11 April
to 21 May, 2005. All the animals sampled were landed on the JARPN II research station established in the
Ayukawa port for biological examination.

Prey species survey
The Takuyo Maru (TAK, 120.0GT), the trawler-type research vessel, conducted the prey species survey inresearch area set off northeast coast of Honshu, from 11 to 27 April. Detail of the prey species survey isshown in Appendix 1. The Takuyo maru also carried out oceanographic observation using CTD and EPCS.
Oceanographic condition revealed from the observation is shown in Appendix 2.

Dedicated sighting survey
The Shonan Maru (SM1; 712.0GT) joined as the dedicated sighting vessel. The dedicated sighting survey
was conducted from 19 April to 2 May, following zigzag track lines predetermined in 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 first coastal survey
conducted in Kushiro 2002 (Kishiro et al. 2003). The research head office was placed in the researchstation 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 androutes of sampling vessels everyday, from weather conditions, whale distribution, and information on

3

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

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, andvessel activity. Sighting information was also recorded for other baleen whales and sperm whales.
Searching activity 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 of plural
animals, an individual was selected randomly from the school and then caught. Once the vessel sampled awhale, 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 theport, animals taken were lift up from the vessels by a crane, using a wire net and then carried to the station
by a 11-tons freight trailer. At that time, animal body weight 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 itemsof 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. 2a. 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 andbigger waves for small sampling vessels, which resulted in more searching effort in Area 1. A sampling
vessel went southward out of 30 n. miles once for scouting, but no sighting was recorded there (see, Fig. 2).
Searching distance and time made by four sampling vessels are listed in Table 1. Here, searching distanceand time are defined as distance and time recorded under searching activity conducted from top barrel ofvessels. Total searching distance and time made by the four vessels were 5,245.8 n. miles and 466.9 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. 2b. At
the margin of searching area, no sightings were obtained: all of common minke whale sightings wererecorded in middle part of Sendai Bay, except a sighting obtained in Area 2. A total of 202 schools (205individuals) of common minke whales were sighted. These were 168 primary sightings (171 animals/168
schools) and 34 secondary sightings (34 animals/34 schools, Table 2). These figures probably include someduplicated sightings made by plural vessels, because the sampling vessels searched same areas. Of 202
schools sighted, only 3 schools consisted of 2 individuals and others were solitary animals. No cow-calfpairs were sighted. Sightings of 2 humpback whale schools (2 animals) were also obtained in the present

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survey, although, in the 2003 coastal survey off Sanriku, only minke whale sightings were made (Yoshida,
et al. 2004).

Table 3 shows density index (SPUE: number of primary school sightings per one hour searching; 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 from the first to second period of the survey, and thendecreased in the last period. This tendency was same as recorded in the 2003 coastal survey off Sanriku.
However, density index in the present survey (0.37 for SPUE and 3.26 for DI) was lower than that in the2003 survey (0.47 for SPUE and 4.20 for DI)(Yoshida, et al. 2004). This result was thought to be mainly
from bad weather condition in the present survey.

Sampling of common minke whales
A total of 60 common minke whales were taken for biological examination. In the sampling process, there
were no harpooned-missed animals (i.e., no struck-lost animals). Sampling positions of individuals areshown in Fig. 2c. Animals were taken evenly from whales sighted.

Prey species survey and dedicated sighting survey
The prey species survey was conducted using the trawler-type research vessel (TAK). Distribution andabundance of prey species were investigated using mid-water trawl net and quantitative echosounder(EK500). Oceanographic observation was also conducted using CTD and EPCS. Sand lances were mainly
found in 4 shallower strata of all the 7 ones set in the research area (see, Appendix 2). Especially, juvenile
sand lances were distributed in sallower waters of Sendai Bay. Krill were frequently detected at deeper
waters than 60m. The dedicated sighting survey was carried out using the sighting survey vessel (SM1). All
the 49 common minke whale schools (49 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 much larger than in the 2003 survey off Sanriku, in which only four common minke whale sightings
were obtained by the dedicated sighting survey vessel (Yoshida, et al. 2004). Results from the prey species
survey and the dedicated sighting survey are noted in Appendix 1 (the prey species survey), Appendix 2(the oceanographic observations), 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 and samples
obtained. The 60 animals taken consisted of 23 males and 37 females. Sex ratio of males to all animals was
0.38. The ratio was almost same as recorded in the 2003 coastal survey off Sanriku (0.42). Average bodylength was 6.29m (max=7.41, min=4.49, SD=0.82) for males and 6.55m (max=8.40, min=4.66, SD=1.15)
for females (Table 5). Average body weight was 2.92 tons (max=4.39, min=1.32, SD=1.71) for males and3.47 tons (max=7.26, min=1.32, SD=1.71) for females (Table 6). In both sexes, average body length andweight were largest at the second period of the survey. In comparisons with females collected during the2003 coastal survey off Sanriku, the present survey females showed larger values in body length and body5

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

weight (6.30 m and 3.12 tons for the 2003 survey females). The values were almost same between males
collected in the present survey and the 2003 survey (6.28 m and 2.92 tons). Composition of sexual maturityof animals collected is listed in Table 7. In males, eight of 23 animals were sexually mature (34.8%), and
14 of 37 females attained sexual maturity (37.8%). All the mature females except an individual werepregnant. Lactating females were not observed. Frequency of sexually mature males was higher in the 2003
survey (38.1%), but lower in the 2003 females (31.0%).

Prey species of common minke whale found from forestomach
Following the same methods used in the JARPN II feasibility survey conducted in 2001 (Fujise, et al.,2002), stomach contents were weighted to the nearest 0.1 Kg, by each of four chamber, in both cases ofincluding and excluding liquid contents. Then, small sample of forestomach contents was collected andfrozen for laboratory analysis. Weight of forestomach contents including liquid ranged from 1.86kg to
99.84kg. The maximum weight, which consisted of unidentified fish, was recorded from a female withbody weight of 5.68 tons. The maximum contents weight was 1.8% of her body weight.

Forestomach contents found from minke whales during the present survey are listed in Table 8. Dominant
prey species was Japanese sand lance (Ammodytes personatus)(45.0%, from 27 of 60 animals). Sand lanceswere detected throughout the survey. Most of unidentified fishes (48.3%) were also thought to be sandlances from remains. All the sand lances found from whales were adult, except some juveniles detectedfrom a whale. Krill (Euphausia pacifica ) and Japanese anchovies (Engraulis japonicus) were also found(Table 8), but their frequency was much lower (6.7%). Krill were recorded in the first 2 period andanchovies were found only in the last one. In the 2003 coastal survey off Sanriku, dominant specieschanged with time (Yoshida, et al. 2004): krill were dominant in the first period (74.8%), then theoccurrence frequency reduced with time, and in the third period sand lances were found most frequently(92.2%). However, in the present survey, such tendency was not observed.

By-products of the whales
After biological examination, all the animals were processed according to the International Convention forRegulation of Whaling, Article VIII. Total weight of productions including meat and blubber was 99.6 tons.

DISCUSSION
The present survey was the second coastal survey conducted under the revised JARPNII research plan and
was also the second one carried out in coastal waters off Sanriku district. During the survey period, lowatmospheric pressure and thick fog often disturbed the research activities. Furthermore, changeable weather
condition and bigger waves obstructed searching activities of sampling vessels in offshore waters. Fromthese, density index of minke whales recorded in the present survey was lower than that in the 2003 survey
off Sanriku. However, sampling vessels could collect planned sample size during the survey period from 11
April to 21 May. The present survey was finished according to the plan.

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When a comparison was made between composition of sex and sexual maturity recorded in the present
survey and the 2003 survey off Sanriku, no obvious difference was observed. However, occurrence
frequency of prey species found from animal forestomach was different between the surveys. In the 2003
coastal survey off Sanriku, dominant prey species changed with time: krill was dominant first, then theoccurrence frequency reduced with time, and lastly sand lances were found most frequently. However, inthe present survey, such tendency was not observed: the sand lance was only one dominant species and was
detected throughout the survey. Krill were found only from four whales. These results indicate that feeding
habit of minke whales changes yearly, probably from environmental factors, e.g., oceanographic conditions
or prey species distribution. The yearly change in feeding habit of minke whales is also reported in coastal
waters off Kushiro (Kishiro et al. 2006).

In the present research area, krill and sand lance are one of the most important target species of coastal
fisheries and the fisheries were operated during the survey. Main fishing ground of each of krill, juvenile
sand lances, and adult sand lances were separated (H. Nagashima, Miyagi Prefecture Fisheries Researchand Development Center). Krill fisheries were mainly operated at northern part of the research area.
Juvenile sand lances were caught along shore line of Sendai Bay. Adult sand lances were taken at middle
part of the bay. Fishing ground of adult sand lances overlapped with main sighting area of minke whales
recorded in the present survey. Furthermore, prey species observation for minke whales collected in thepresent survey revealed that the sand lance was only one dominant species and that all the sand lances
found were adult, except some juveniles detected from a whale. These results indicate that common minke
whales and coastal fisheries caught adult sand lances at the same time and area, which indicate existence ofinteraction between them.

From the present survey, we could obtain valuable information including feeding ecology of minke whales.
To evaluate more precise values on food consumption of minke whales and to obtain more information oninteraction 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, Dr. Seiji
Ohsumi (ICR), and Mr. Joji Morishita, the Fisheries Agency of Japan, for their guidance andimplementation to the research. Crewmen of research vessels, staffs of the research station in Ayukawa, andthe Japan small-type whaling association helped us. We also thank all the members of the municipal officeof Ishinomaki, the Oshika 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 the feasibility study of
the Japanese Whale Research Program under Special Permit in the western North Pacific-Phase II

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Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku(JARPN II) in 2001. Paper SC/54/O16 submitted to the 54th IWC Scientific Committee, 51pp.
Government of Japan, 2002a. Research plan for cetacean studies in the western North Pacific under special
permit (JARPN II). Paper SC/54/O2 submitted to the 54th IWC Scientific Committee.
Government of Japan (Fujise, Y., Kawahara, S., Pastene, L.A. and Hatanaka, H. eds.), 2002b. Report of2000 and 2001 feasibility study of the Japanese Whale Research Program under Special Permit in thewestern North Pacific-Phase II (JARPN II). Paper SC/54/O17 submitted to the 54th IWC ScientificCommittee, 202pp.
Government of Japan, 2004a. Revised research plan for cetacean studies in the western North Pacific under
special permit (JARPN II). Paper SC/56/O1 submitted to the 56th IWC Scientific Committee, 14pp.
Government of Japan (Fujise, Y., Tamura, T., Kato, H. and Kawahara, S. eds.), 2004b. Some considerationsof the feasibility components of the JARPN II research plan. Paper SC/56/O2 submitted to the 56th IWC
Scientific Committee, 36pp.
Hatanaka, H. and Miyashita, T. 1997. On the feeding migration of the Okhotsk Sea-West Pacific Stock ofminke whales, estimates based on length composition data. Rep.int. Whal. Commn 47:557-564.
Kato, H., Kishiro, T., Yoshida, H. and Kawahara, S. 2004. Feasibility of coastal surveys in the JARPN II,
from the viewpoint of logistics. Appendix 1, pp4-12. In: Government of Japan (Fujise, Y., Tamura, T.,
Kato, H. and Kawahara, S. eds.), Some considerations of the feasibility components of the JARPN II
research plan. Paper SC/56/O2 submitted to the 56th IWC Scientific Committee, 36pp.
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 the2002 JARPN II survey in the western North Pacific. Part II: Coastal component - Coastal Survey off
Kushiro, northeast Japan. Paper SC/55/O8 submitted to the 55th IWC Scientific Committee, 26pp.
Kishiro, T., Kato, H., Yoshida, H., Miyashita, T., Ryono, T., Tabata, S., Okamoto, R., Yasui, K., Sato, H.,
Morita, Y., Saino, S., Hara, T., Ebisui, T., Kuroishi, H., Nishiwaki, S., and Kawahara, S. 2005. Cruise
report of the coastal survey on common minke whales off Kushiro, northeast Japan: the 2004 JARPN II
survey (Part II) - Coastal component. Paper SC/57/O4 submitted to the 57th IWC Scientific Committee,
37pp.
Kishiro, T., Kato, H., Yoshida, H., Miyashita, T., Ryono, T., Tabata, S., Yasui, K., Sato, H., Morita, Y.,
Kumagaya K., Tokuda, D., Nakai, K., Funabashi, N., Ebisui, T., Wakatsuki, T., Sakaguchi, M., Houhana,T., Nishiwaki, S., and Kawahara, S. 2006. Cruise report of the second phase of the Japanese Whale
Research Program under Special Permit in the Western North Pacific - Coastal component off Kushiro in2005. Paper SC/58/O10 submitted to the 58th IWC Scientific Committee, 32pp.
Miyashita, T. and Hatanaka, H. 1997. A note on whaling grounds for the western North Pacific minke
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: Government8

SC/58/O9of 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. 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.

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Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Sanriku

Ayukawa
3
Sendai ◙◙Area 1

2

30 n. miles
50 n. miles

HonshuTokyo ◙

Western North PacificFigure 1. Research area of the 2005 JARPN II coastal survey off Sanriku.

10

b)

c)

survey off Sanriku.

11

Sighting positions of humpback whales are also shown (star).

Figure 2. Cruise tracks (a), and sighting positions (b) and catch positions (c) of common minke whales made by sampling vessels in the 2005 JARPN II coastala)SC/58/O9

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Table 1. Searching days, hours, distances made by four sampling vessels in the 2005 JARPN II
coastal survey off Sanriku.
PeriodSampling vessels*1
28T
75K
7K
31S
Total
First period
Days
10
10
10
10
40
(11 - 23 April)
Hours
44.3
51.2
51.8
50.2
197.5
Distances (n. miles)
517.2
578.1
567.0
513.9
2176.2
Second period
Days
9
9
9
9
36
(24 April – 7 May) Hours
41.6
38.3
44.8
39.9
164.6
Distances (n. miles)
496.1
434.7
500.9
434.2
1865.9
Third period
Days
8
8
8
8
32
(8 - 21 May)
Hours
28.1
25.4
26.9
24.4
104.8
Distances (n. miles)
339.2
298.1
305.4
261.0
1203.7
Total
Days
27
27
27
27
108
Hours
114.0
114.9
123.5
114.5
466.9
Distances (n. miles) 1352.5
1310.91373.31209.15245.8*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 byfour sampling vessels in the 2005 JARPN II coastal survey off Sanriku.
SpeciesPrimary*
Secondary*
Total*
Period
Sch.
Ind.
Sch.
Ind.
Sch. Ind.
Common minke whale
63
64
13
13
76
77
First period
Like minke whale
9
10
1
1
10
11
(11 - 23 April)
Unidentified baleen whale
1
1
0
0
1
1
Unidentified large whale
6
6
0
0
6
6
Common minke whale
67
69
17
17
84
86
Second Period
Like minke whale
6
6
0
0
6
6
(24 April - 7 May)
Unidentified baleen whale
1
1
0
0
1
1
Common minke whale
38
38
4
4
42
42
Third period
Like minke whale
5
5
1
1
6
6
(8 - 21 May)
Humpback whale
2
2
0
0
2
2
Common minke whale
168
171
34
34
202
205
Total
Like minke whale
20
21
2
2
22
23
Humpback whale
2
2
0
0
2
2
Unidentified baleen whale
2
2
0
0
2
2
Unidentified large whale
6
6
0
0
6
6
*: These figures probably include some duplicated sightings made by plural vessels.
Table 3. Density index of common minke whales made by sampling vessels in the 2005
JARPN II coastal survey off Sanriku.
DI*2
PeriodSPUE*1First period (11 - 23 April)
0.32
2.94
Second period (24 April - 7 May)
0.42
3.70
Third period (8 - 21 May)
0.36
3.16
Total
0.37
3.26
1
* : No. of primary school sightings per 1 hour searching.
*2; No. of primary school sightings sighted per 100 n. miles searching.

12

SC/58/O9

Table 4. Summary of whale sampling in the 2005 JARPN II coastal survey off Sanriku.
Number of whales
Samples and data
Male
Female Total
Body length and sex
233760
External body proportion
23
37
60
Photographic record and external character
23
37
60
Diatom film record and sampling
23
37
60
Body scar record
23
37
60
Measurements of blubber thickness (eleven points)
23
37
60
Body weight
23
37
60
Body weight by parts
1
2
3
Skin tissues for DNA study
23
3760
Muscle, liver, and heart tissues for isozyme analysis
23
3760
Muscle, liver, kidney, and blubber tissues for chemical analysis
23
3760
Muscle, liver, blubber, vertebrae, and stomach contents for lipid analysis
1
2
3
Mammary grand; lactation status, measurement and histological sample
37
37
Uterine horn; measurements and endometrium sample
3737Collection of Ovary
37
37
Photographic record of foetus
6413
Foetal length and weight6
4
12
External measurement of foetus
101Collection of foetus
5
4
12
Testis and epididymis; weight and histological sample
23
23
Stomach contents, convenient record
233760
Volume and weight of stomach content in each compartment
23
37
60
Observation of marine debris in stomach
23
37
60
Stomach contents for feeding study
23
37
60
Record of external parasites
23
37
60
Earplug for age determination
23
37
60
Tympanic bulla for age determination
23
37
60
Largest baleen plate for morphologic study and age determination
23
37
60
Baleen plate measurements (length and breadth)233760
Photographic record of baleen plate series
23
37
60
Length of each baleen series
23
37
60
Vertebral epiphyses sample
23
37
60
Number of vertebrae
23
3760
Number of ribs
23
37
60
Skull measurement (length and breadth)
22
35
57

13

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Table 5. Statistics of body length (m) of common minke whales collected by the 2005 JARPN II
coastal survey off Sanriku.

PeriodMaleFirst period

Female

Mean

S.D.

Min.

Max.

n

Mean

S.D.

Min.

Max.

n

5.65

0.79

4.49

6.53

7

6.63

1.20

5.06

8.25

8

6.92

0.42

6.09

7.41

8

6.68

1.18

4.66

8.40

20

6.23

0.74

5.17

7.28

8

6.17

1.09

5.08

7.81

9

6.29

0.82

4.49

7.41

23

6.55

1.15

4.66

8.40

37

（11 - 23 April)
Second period（24 April - 7 May)
Third period（8 - 21 May）
Total

Table 6. Statistics of body weight (tons) of common minke whales collected by the 2005
JARPN II coastal survey off Sanriku.

PeriodFirst period

MaleFemale

Mean

S.D.

Min.

Max.

n

Mean

S.D.

Min.

Max.

n

2.14

0.74

1.07

2.95

7

3.59

1.53

1.65

5.69

8

3.57

0.40

2.69

4.06

8

3.64

1.82

1.32

7.26

20

2.96

0.91

1.80

4.39

8

2.98

1.69

1.49

5.92

9

2.92

0.90

1.07

4.39

23

3.47

1.71

1.32

7.26

37

（11 - 23 April）
Second period（24 April - 7 May)
Third period（8 - 21 May）
Total

14

SC/58/O9

Table 7. Composition of sex and sexual maturity of common minke whales collected by the 2005 JARPN II
coastal survey off Sanriku.
PeriodFirst period

Male
Im

M

7

0

7

3

5

5

15

FemaleTotal Maturity(%)

Im

R

P

Total Pregnancy(%)*

Maturity(%)

0.0

3

0

5

8

100.0

62.5

8

62.5

13

1

6

20

85.7

35.0

3

8

37.5

7

0

2

9

100.0

22.2

8

23

34.8

23

1

13

37

92.9

37.8

（11 - 23 April)
Second period（24 April - 7 May)
Third period（8 - 21 May）
Total

Im: Immature; M: Mature; R: Resting; P: Pregnant.
*: Apparent pregnancy rate.

Table 8. Prey species found in forestomach of common minke whales collected by the 2005
JARPN II coastal survey off Sanriku.
SamplePrey species (%)
PeriodSize
Sand lance
Krill
Japanese
Unidentified
anchovy
fish
First period157(46.7)3(20.0)0( 0.0)7(46.7)(11 - 23 April)
Second period(24 April - 7 May)

28

15(53.6)1( 3.6)0( 0.0)13(46.4)

Third period(8 - 21 May)

175(29.4)0( 0.0)4(23.5)9(52.9)Total

60

27(45.0)4( 6.7)4( 6.7)29(48.3)

15

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Appendix 1
2005 coastal prey species survey of JARPN II off Sanriku
SHIROH YONEZAKI1, HIROSHI NAGASHIMA2, HIROTO MURASE3, TOSHIYUKI NAGAKI2DAISUKE SHIMIZU4
AND SHIGEYUKI KAWAHARA

5

1

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

2

Miyagi Prefecture Fisheries Research and Development Centre, 97-6, Sodenohama, Watanami,Ishinomaki, Miyagi, 986-2135, Japan

3

The Institute of Cetacean Research, Toyomi-cho 4-5, Chuo-ku, Tokyo 104-0055, Japan

4

Field Center for Northern Biophere, Hokkaido University 3-1-1 Minato-cho Hakodata Hokkaido
041-8611, Japan

5

National Research Institute of Far Seas Fisheries, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa
236-8648, Japan

ABSTRACTA prey species survey was conducted in the coastal region off Sanriku, northeastern Japan, concurrently with the coastal
sampling survey for minke whale during spring 2005 as a part of JARPN II study. The objective of concurrent surveys was toestimate the prey preference (selection) of minke whale. While the sampling 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 20m and 200m from 37o40’N to 38 o40’N off Sanriku, northeastern Japan, The survey area wasdivided into 7 blocks with depth and latitude The distribution and abundance of the prey species were investigated with thequantitative echosounder (EK500) on board Takuyo maru (120 GT) steaming at 9 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 by targeting mid-water trawlings. As the water temperature was low, a few schools of anchovy weredetected. Echo signs identified as adult sand lance (>10cm 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 thebottom. 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 60m as large patches and in the shape of belts in the mid/bottom layers or
sticks rising from the bottom.

INTRODUCTION
The goal of JARPN II is to contribute to the conservation and sustainable use of marine 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 and ecosystem studies, involving studies of prey consumption bycetaceans, prey preference (selection) of cetaceans and ecosystem modeling. As it is difficult to cover thecoastal area, especially in spring and autumn, by the Nisshin Maru, the full-scale JARPN II has a newcoastal component, that is, the sampling survey for minke whale by small-type whaling catcher boats. As in

16

SC/58/O9

2003 surveys (Kawahara et al., 2004), a prey species survey was conducted in the coastal region off
Sanriku, northeastern Japan, concurrently with the coastal sampling survey for minke whale during spring
2005. In this document, the results of the 2005 prey species survey off Sanriku are presented.

MATERIALS AND METHOD
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 prey species survey was conducted in wider
area at depths between 20m and 200m from 37º40’N to 38º40’N off Sanriku, northeastern Japan,

toelucidate the distribution and abundance of main prey species (Fig. 1). To avoid the conflict with set nets inthe coastal waters, the waters 10 miles from the coastal lines were excluded in principle. The survey area
was divided into 7 blocks (A, B, C, D, E, F and G) at depths of 40m/100m and 37º54’N/38º15’N.

BlocksE, F and G south of 37º54’N are located off Fukushima prefecture. A zigzag track line was set to covereach block. The waypoints of planned track lines in each block are shown in Table 1.

The prey species survey was conducted from April 11 to 27 in blocks B, C, D, E, F, G and A in order ofimportance. The distribution and abundance of the prey species were investigated with the quantitativeechosounder (EK500) and targeting mid-water trawling on board a stern trawler-type research vessel,
Takuyo maru

(Miyagi prefecture, 120 GT) steaming at about 9 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 and EPCS (Continuous Sea Surface Water Monitoring System).
With EPCS, temperature, salinity and chlorophyll 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 (April 11 2005)
using the copper sphere technique described in EK 500 manual. Mid-water trawlings were made to identify
the species and size compositions of targeting echo signs. The net had a mouth opening of 7m width/3.5m
height and a 3mm liner cod end. The depth and height of mouth of net were monitored with a net recorder.
Towing speed of the trawl net was 2-4 knots. Catches were identified to the species level and weighed atthe vessel. For the major species, a sample of 100 animals was taken, and lengths and weights were
measured. Scaled and standard 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 laboratory analysis.

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. Targeting trawlings were made 14
times and CTD observations were made at the trawling points and 28 waypoints. The oceanographic
conditions are described in Appendix 2 in the report.

17

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

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 5.8ºC and 12.5ºC based on EPCS. As thetemperature was lower than 15ºC which was the indicator of the occurrence of northward migrating
anchovy, a few schools of anchovy were detected during the prey species survey. Echo signs identified as
adult sand lance (>10cm in standard length) occurred at depths between 20m and 60m in blocks B, C, E
and F. Especially, many echo signs identified as adult sand lance were found in blocks E and F off
Fukushima prefecture. The echo signs on the echograms were in the shape of patches on the bottom orsticks rising from 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 theshallower area of Sendai Bay (blocks B and C). Most of the echo signs were smaller patches, usually foundin the mid-layer. Although the difference in average Sv values by frequency is similar 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 60m. In most cases the echo signs were large patches andin the shape of belts in the mid/bottom layers or sticks rising from the bottom.

ACKNOWLEDGEMENT
A special thank is given to Captain H. Kimura and crews of Takuyo maru for their dedication in collecting
data.

REFERENCES
Government of Japan. 2002. Research Plan for Cetacean Studies in the Western North Pacific under Special
Permit (JARPN II). IWC/SC/54/O2: 115pp.
Kawahara, S., Watanabe, H., Ichihara, M., Suenaga, Y. and Katayama, M. 2004. 2003 prey species 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 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, 31 pp.

18

SC/58/O9

Table 1. Waypoints of planned track lines.
Block A
WP

LatitudeLongitude

Course

A1
A2

38
38

-

40.0
38.0

N
N

141
141

-

36.6
50.9

E
E

A3

38

-

36.0

N

141

-

35.7

A4

38

-

34.0

N

141

-

50.9

A5

38

-

32.0

N

141

-

A6

38

-

30.0

N

141

A7

38

-

28.0

N

141

A8

38

-

26.0

N

A9

38

-

24.0

N

A10

38

-

22.0

N

Distance

100.1
260.5

11.39'
12.09'

E

99.5

12.10'

E

260.7

12.41'

35.3

E

99.5

12.11'

-

50.5

E

260

11.49'

-

36.1

E

99.9

11.65'

141

-

50.7

E

258.9

10.34'

141

-

37.8

E

101.3

10.19'

141

-

50.5

E

260

11.51'

A11

38

-

20.0

N

141

-

36.1

E

100.3

11.21'

A12

38

-

18.0

N

141

-

50.1

E

259.7

11.14'

100.7

5.38'

A13

38

-

16.0

N

141

-

36.2

E

A14

38

-

15.0

N

141

-

42.9

E
TOTAL

143.02'

CourseDistance

Block B
WP

LatitudeLongitude

B1
B2

38
38

-

21.2
19.0

N
N

141
141

-

20.7
13.7

E
E

248.2
110.7

5.94'
7.08'

B3

38

-

16.5

N

141

-

22.1

E

260.7

15.50'

B4

38

-

14.0

N

141

-

2.7

E

104.1

10.25'

B5

38

-

11.5

N

141

-

15.3

E

258.7

12.80'

B6

38

-

9.0

N

140

-

59.4

E

100.7

13.43'

B7

38

-

6.5

N

141

-

16.1

E

260.2

14.68'

B8

38

-

4.0

N

140

-

57.8

E

100.4

13.83'

B9

38

-

1.5

N

141

-

15.0

E

259.8

14.15'

B10

37

-

59.0

N

140

-

57.4

E

101.8

12.21'

B11

37

-

56.5

N

141

-

12.5

E

255.3

9.83'

B12

37

-

54.0

N

141

-

0.5

E
TOTAL

129.69'CourseDistance

Block CWP

LatitudeLongitude

C1
C2

38
38

-

16.0
14.0

N
N

141
141

-

25.6
19.2

E
E

248.4
101

5.43'
10.53'

C3

38

-

12.0

N

141

-

32.3

E

260.3

11.85'

C4

38

-

10.0

N

141

-

17.5

E

103.2

8.76'

C5

38

-

8.0

N

141

-

28.3

E

258.4

9.92'

C6

38

-

6.0

N

141

-

16.0

E

103.3

8.69'

C7

38

-

4.0

N

141

-

26.7

E

257.7

9.39'

C8

38

-

2.0

N

141

-

15.1

E

103.5

8.54'

C9

38

-

0.0

N

141

-

25.6

E

258.1

9.71'

C10

37

-

58.0

N

141

-

13.6

E

102.9

8.94'

C11

37

-

56.0

N

141

-

24.6

E

258.3

9.87'

C12

37

-

54.0

N

141

-

12.4

E
TOTAL

19

101.62'

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Block DWP
D1
D2

Latitude
38
38

-

15.0
12.5

Longitude
N
N

141
141

-

Course49.8
32.8

Distance

E
E

259.4
101.1

13.64'
12.95'

D3

38

-

10.0

N

141

-

48.9

E

261.3

16.62'

D4

38

-

7.5

N

141

-

28.1

E

98.1

17.64'

D5

38

-

5.0

N

141

-

50.2

E

262.5

19.14'

D6

38

-

2.5

N

141

-

26.2

E

98.8

16.41'

D7

38

-

0.0

N

141

-

46.7

E

261.9

17.67'

100.8

13.30'

D8

37

-

57.5

N

141

-

24.6

E

D9

37

-

55.0

N

141

-

41.1

E
TOTAL

127.37'Block EWP
E1
E2

LatitudeLongitude

Course
4.3
12.5

E
E

Distance

37
37

-

54.0
53.0

N
N

141
141

-

98.7
260.2

6.57'
8.85'

E3

37

-

51.5

N

141

-

1.5

E

99.3

9.32'

E4

37

-

50.0

N

141

-

13.1

E

259.7

8.38'

E5

37

-

48.5

N

141

-

2.7

E

103.5

6.45'

E6

37

-

47.0

N

141

-

10.6

E

256.9

6.60'

E7

37

-

45.5

N

141

-

2.5

E

106

5.45'

E8

37

-

44.0

N

141

-

9.1

E

253.1

5.15'

E9

37

-

42.5

N

141

-

2.9

E

102.8

6.76'

E10

37

-

41.0

N

141

-

11.2

E

256.1

4.18'

E11

37

-

40.0

N

141

-

6.1

E
TOTAL

67.71'

Block F
WP

LatitudeLongitude

CourseDistance

F1
F2

37
37

-

54.0
52.5

N
N

141
141

-

12.4
23.8

E
E

99.4
260

9.16'
8.61'

F3

37

-

51.0

N

141

-

13.1

E

100.7

8.07'

F4

37

-

49.5

N

141

-

23.1

E

261.7

10.42'

F5

37

-

48.0

N

141

-

10.1

E

98.5

10.11'

F6

37

-

46.5

N

141

-

22.7

E

262.2

11.06'

F7

37

-

45.0

N

141

-

8.9

E

98.7

9.96'

F8

37

-

43.5

N

141

-

21.3

E

260

8.63'

100

8.63'

F9

37

-

42.0

N

141

-

10.6

E

F10

37

-

40.5

N

141

-

21.3

E
TOTAL

84.66'

CourseDistance

Block G
WP
G1
G2
G3
G4
G5
G6
G7
G8
G9
G10

Latitude
37
37
37
37
37
37
37
37
37
37

-

54.0
52.5
51.0
49.5
48.0
46.5
45.0
43.5
42.0
40.5

Longitude
N
N
N
N
N
N
N
N
N
N

141
141
141
141
141
141
141
141
141
141

-

24.4
40.0
23.1
38.8
23.1
38.0
22.3
37.0
21.4
35.9

E
E
E
E
E
E
E
E
E
E

96.9
263.6
96.9
263.1
97.2
263.1
97.3
263.1
97.4
TOTAL

20

12.45'
13.48'
12.54'
12.55'
11.92'
12.55'
11.77'
12.48'
11.62'
111.37'

SC/58/O9

Table 2. A summary of the midwater trawl operations, temperature by depth and catches.
Station
調査点
ST-1
ST-2
調査日Date 2005.04.12
2005.04.12
時刻 Time
9:09
14:54
Latitude
緯度（北緯）
38°17.067' 38°07.723'
Longitude 141°20.099' 141°07.437'
経度（東経）
Surf.Temp.
表面水温
7.92
8.65
水
10m
7.99
8.13
Ｄ
温
20m
7.73
8.05
ｅ
ｐ
観
30m
7.00
ｔ
測
40m
ｈ
層
50m
(m )
75m
水深ｍ
Depth(m)35
29
Net depth(m)
曳網水深ｍ
20-30
10-20
Species
コウナゴ
コウナゴ
S p e c ie sjuvenile
juvenilecaught,caught,
採集魚種
34(26-49)
39(29-56)
sand lance, sand lance,
LengthL e n g thモード（全長範囲）
クラゲ
34(26-49),
39(29-56)mｍｍ
o d eandmode
イサダ(m m )(mm) krill, 他
othersrange
C採集重量ｋｇa tc h e s(k g )
0.7
9.5

ST-3
ST-4
ST-5
ST-6
ST-7
2005.04.13
2005.04.14
2005.04.14
2005.04.15
2005.04.15
9:32
9:58
14:04
9:41
14:38
38°05.290' 37°56.634' 38°03.332'
38°12.949'
38°12.949'
141°07.708' 141°20.404' 141°22.056'
141°25.733' 141°25.733'
8.05
7.03
8.44
8.82
8.82
8.06
7.59
7.68
8.15
7.89
8.39
7.62
7.46
7.89
7.79
7.20
7.44
7.36
7.28
7.41
6.99
7.20
7.01
7.12
6.81
6.22
6.58
6.90
6.22
33
83
62
53
57
16-30
14-30
40-50
15-25
45-55
メロード
コウナゴ
イサダ
コウナゴ
メロード
juvenile
adult
sand
adult
sand
juvenile
krill,
120(106-162)
33(29-43)
19(13-21.5) sand34(29-42)
170(170-196)
lance, 170
lance,
lance,
120
sandlance,
19(13トラフグ
クラゲ
クラゲ(170-196),
34(29-42),(106-162),
33(29-43) 21.5)
端脚類

調査点
Station
ST-8
ST-9
調査日Date 2005.04.18
2005.04.19
時刻 Time
13:28
8:12
Latitude
緯度（北緯）
38°06.673' 37°58.3053'
Longitude 141°33.758' 141°31.887'
経度（東経）
表面水温
Surf.Temp.
9.13
8.92
10m
8.64
8.73
20m
8.27
7.84
Ｄ
水
30m
7.35
6.80
ｅ
温
40m
6.58
6.69
ｐ
観
50m
6.35
6.46
ｔ
測
75m
5.98
5.79
ｈ
層) 100m
5.89
5.83
(m
125m
6.22
150m
Depth(m)
水深ｍ
123
132
Net depth(m)
曳網水深ｍ
75-85
100-120
SpeciesS
p e c ie s
イサダ
イサダ
krill,
krill,
ccaught,
aught,
採集魚種
19(15-29)
19(14-29)
19(15-29), 19(14-29)
L
e n g thモード（全長範囲）
Length
端脚類
稚魚
amphipodsmo d eand
mode
ｍｍ
稚魚
他
(m
m ) (mm)range
他C
atc h e s(k g)
採集重量ｋｇ
0.1
2.4

ST-10
ST-11
ST-12
ST-13
ST-14
2005.04.19
2005.04.24
2005.04.24
2005.04.25
2005.04.26
10:05
7:36
9:33
11:58
13:07
37°59.711' 37°48.612' 37°50.649'
37°46.249'
38°23.052'
141°44.814' 141°14.170' 141°15.9210'
141°38.616' 141°44.759'
7.19
8.63
8.72
8.14
9.72
7.03
8.76
8.55
7.65
8.43
6.77
8.42
8.34
7.10
8.20
6.71
7.87
7.90
6.32
7.71
6.61
7.05
5.93
7.34
6.74
6.85
6.51
7.31
6.68
6.93
7.35
6.97
6.79
7.45
6.93
6.60
7.21
6.89
7.20
158
41
58
147
160
80-90
25-35
30-50
175-190145-155
イサダ
メロード
キュウリエソ
キュウリエソ
adultsand pearlsides,
pearlsides,
krill,イサダ
20.5
krill,
20.5
20.5(17-23)
端脚類
150(117-198)
44(28-63)
45(24-46)
lance, 150 44(28-63), 45(24-46),(17-23)(17-24),
イサダ17.5(12-22)
稚魚
クラゲ
クラゲ
マダラ（268,190)(117-198)
krill,
17.5
amphipods
スケトウダラ（214,196)
他
カレイ稚魚
端脚類
cods
他
ホタルイカ他 (12-22)
かいあし類他
3.27
0.42
1.48
2.46
0.25

jelly fishjelly fish

4.05

1.8

21

2

1.95

0.65

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Kesen-numa
MIYAGI
Ayukawa
Ishinomaki

A

B

Soma

E

D

C

F

G

FUKUSHIMA

Fig. 1. Survey area, blocks and planned track lines of prey species survey in 2005 off Sanriku.

22

SC/58/O9

Appendix 2
Oceanographic conditions in the coastal survey of JARPN II off Sanriku,
northeastern Japan, in April 2005
DENZO INAGAKE1, SHIROH YONEZAKI2, HIROSHI NAGASHIMA3, HIROTO MURASE4, AND SHIGEYUKI KAWAHARA1
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, Shimizu-orido, Shizuoka,
424-8633, Japan

3

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

4

The Institute of Cetacean Research, Toyomi-cho 4-5, Chuo-ku, Tokyo 104-0055, Japan

Contact e-mail: ina@affrc.go.jp
ABSTRACTA prey species survey was conducted in the coastal region off Sanriku, northeastern Japan,
concurrently with the coastal sampling survey for minke whale during spring 2005 as a part of JARPN
II study. Oceanographic observations were conducted with CTD and EPCS from 11 to 27 April 2005.
According to the CTD data at 42 stations, water masses in the survey area have characteristics of thecold water (5ºC < temperature < 10ºC at 100m depth). The water on the shelf is occupied by the cold
water mixed with low-salinity coastal water.

Introduction
The oceanographic condition at the Tohoku area northeast of Japan is the most complicated area in theworld.

In this area, there are a lot of fronts and water masses.

The Kuroshio flows northward along theeast coast of Japan to the southern part of the Tohoku area with warm high-salinity water.

The Oyashio

flows southward 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 through Tsugaru Strait, and also the warm-core ring is cut off
from the Kuroshio extension into the Inter-frontal Zone.
a new water mass.

Each water mass is mixed with others, and makeThe coastal area off Sanriku is the most variable in the Tohoku area, because theKuroshio, the warm-core ring, the Oyashio, the Tsugaru warm water and other water arrive here by turns.
A prey species survey was conducted on board Takuyo maru (Miyagi prefecture, 120 GT) in the coastal
region off Sanriku, northeastern Japan, concurrently with the coastal sampling survey for minke whale
during spring 2005 as a part of JARPN II study. Oceanographic observations were conducted with CTD(Conductivity Temperature Depth profiler) and EPCS (Continuous Sea Surface Water Monitoring System).
In this paper, we analyzed the CTD data to make clear the oceanic environment in the survey area.

23

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Data and Methods
Hydrographic observations with CTD (SBE 911plus) were carried out at 42 stations from 11 to 27
April 2005 in the coastal area off Sanriku, northeast of Japan (Fig. 1).
The oceanographic conditions in April 2005 were analyzed by Tohoku National Fisheries ResearchInstitute (TNFRI), which used quasi-real-time data from several cooperative organs and prefectures, thosewere Fisheries Research Agency, Meteorological Agency, Hydrographic Department and Fisheries
Experiment Stations, etc. TNFRI published temperature maps and schematic hydrographic maps using
World Wide Web (http://www.myg.affrc.go.jp/kaiyo/temp/temp.
html).

Oceanic fronts and water masses are usually detected by subsurface temperature map (sea Table 1),

because they are obscure in sea surface temperature distributions from summer to fall seasons and the
Oyashio water spreads into the subsurface layer.

Oceanographic conditions in the survey area
Figure 2 shows the Temperature-Salinity diagrams using CTD station data.
survey area have characteristics of the cold water.

Light blue dots show the data in cold waters defined by

100 m temperature which is over 5ºC and less than 10ºC.
than 100 m depth.

Water masses in theBlack dots show the data on the shelf shallower

Because black dots are similar with light blue dots in Fig. 2, the water on the shelf is

occupied by the cold water mixed with low-salinity coastal water.
Figure 3 shows the schematic hydrographic map in April 2005, presented by TNFRI.

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 2005 was at 39ºN on 145ºE line.

Tsugaru warm water was

obscure because it restricted near the coastal area called by coastal mode in April. The southern limit of
the first Oyashio Intrusion located around 41ºN, 144ºE, which were more northern position from monthly
mean location in April (38º30’N). Although cold water cut off from the first Oyashio Intrusion distributed
around 40ºN, 143º30’E, the Oyashio Intrusion was restricted to the northern area in April 2005. 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 shows the 50 m and 100 m depth temperature map observed by Takuyo maru.
dominant at the depth of 50 m and 100 m in Fig. 4.

6ºC to 7ºC is

It means that the cold water occupied in this survey

area.
All of these figure show that all stations are distributed in the cold area and shallow coastal area
occupied by the cold water.

Acknowledgement
A special thank is given to Captain H. Kimura and crews of Takuyo maru for their dedication in collecting
data.

24

SC/58/O9

REFERENCES

Kawai, H. (1969):

Statistical estimation of isotherms indicative of the Kuroshio axis, Deep-Sea Res., 16,

109-115.
Murakami, M. (1994): On long-term variations in hydrographic conditions in the Tohoku area, Bull. Tohoku
Natl. Fish. Res. Inst., No. 56, 47-56 (in Japanese with English abstract).

Table 1.

Extraction method from temperature map to determine the positionof each water mass.

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
Warm water

Area with 5ºC < T < 10ºC at 100m
Area with T > 10ºC at 100m and T < 14ºC at 200m

25

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Fig. 1.

Station map observed by Takuyo maru in 11 to 27 April 2005.

Light blue stars and black circles

denote CTD stations in the cold area (100 m temperature was over 5ºC and less than 10ºC) andthe shallow coastal area, respectively.

Fig. 2.

Temperature-Salinity diagrams using CTD station data observe by Takuyo maru in 11 to 27 April
2005.

Each thin line in this figure denotes a density line of sigma-t.

26

SC/58/O9

Fig. 3.

Schematic hydrographic map in Tohoku area, northwestern Pacific, in April 2005 (presented

by Tohoku National Fisheries Research Institute) with station map observed by Takuyo maru.
Blue, green, yellow and red area show distributions of the Oyashio, the cold water, the warm
water spread from the Kuroshio Extension and the Kuroshio Extension, respectively.

Lightblue star and black circles denote CTD stations observed by Takuyo maru in the cold area andthe shallow coastal area, respectively.

Fig.4.

50 m (left panel) and 100 m (right panel) temperature map observed by Takuyo maru in 11 to 27
April 2005.

27

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Appendix 3
Cruise report of the dedicated sighting survey in 2005 JARPNII
coastal survey off Sanriku, northeast JapanSHIGETOSHI NISHIWAKI AND ISAMU YOSHIMURA
Contact 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 2 May, 2005. The primary objectiveof the sighting survey was the abundance estimation of baleen whales in the survey area. Shonan-maru wasdedicated to the sighting survey. Total primary searching distance was 832.8 n. miles and the 50 schools (50individuals) of primary sightings were made.

INTRODUCITON
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 April to 2 May, 2005, as apart of coastal component of 2005 JARPN II full scale study (Government of Japan, 2002). The primaryobjective 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 this paper.
MATERIALS AND METHODS
The cetacean sighting survey area was set within Sub-area 7 (Fig. 1). Though the sampling of whales was
conducted within the 30 n. miles from Ayukawa port in the Sanriku, sighting survey area had larger are extent to
see the overall baleen whale distribution pattern off the coast of the Sanriku. Near shore area of the survey block
where the water depth is less than 50m was not surveyed because many fisheries gears were set in there. The
survey block was further divided into the coastal and offshore area. Coastal area was divided into three at thetwo boundary lines, 37ºN and 39ºN. Offshore area was divided into two at the boundary lines on 38ºN. The
survey was conducted from 20 Apr. to 2 May, 2005. Shonan-maru (SM1, 712GT) engaged in the cetaceansighting survey. Sighting survey procedures were same as offshore component of 2005 JARPN II. The right(Eubalaena japonica), blue (Balaenoptera musculus), and humpback (Megaptera novaeangliae) whales canbe approached to obtain the Natural marking record experiments as the opportunistic basis. Large baleen

28

SC/58/O9

whale feeding behavior visual observation was attempted. If the behavior was observed, it was recorded onvideo tape.
RESULTS AND DISCUSSION
Tracklines surveyed are shown in Fig. 1. Total primary searching distance was 832.8 n.miles. The 50
schools (50 individuals) of primary sightings were obtained and one secondary sighting (one animal/one
school) was also made. Details of sightings are listed in Table 1. Sightings of common minke whales wererecorded. Sighting positions of these sightings are noted in the Fig. 1. Natural marking record and biopsy
sampling experiments were not in opportunity, and no feeding behavior of large baleen whales wasobserved.

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 of the cruise. We also express the gratitude to Hiroto Murase for thecomment on the course of preparing the English manuscript of this paper.

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

29

Yoshida, et al.: Report of the JARPN II in 2005 - Coastal Component off Sanriku

Table 1. Summary of cetacean sightings made during the dedicated sighting survey in 2005 JARPNII
coastal survey.

Primary

SecondarySpecies

Sch.

Ind.

Sch.

Ind.

Common minke whale

48

48

1

1

Unidentified cetaceans

2

2

Total

50

50

1

1

Fig. 1. Survey area and predetermined tracklines, and surveyed tracklines and sighting positions ofcommon minke (open circle) during the dedicated sighting survey in 2005 JARPNII coastal survey.

30