Progress Report on the Killing Method of Whales in the Second Phase ofJapanese Whale Research Program in the Antarctic Sea (JARPAII) andNorthwestern Pacific Ocean (JARPNII)
Hajime Ishikawa D.V.M.
JAPANJapanese Whale Research Programs have been conducted since the 1987/88 season in theAntarctic Sea (JARPA and JARPAII) and since the 1994 season in the Northwestern Pacific Ocean(JARPN and JARPNII). Since these programs adopt lethal methods, whale killing methods have been
examined and improved with a special interest in reducing the time-to-death (TTD) and increasing theinstantaneous death rate (IDR) of whales. This document reports major efforts and results on the whalekilling method mainly from 2005 to 2009 season in the Japanese whale research (JARPAII andJARPN II).
DATA COLLECTION, ANALYSIS and TRAINING of GUNNERS
Improvement of the whale killing method has been conducted based on the IWC Action plandeveloped at the workshop on whale killing method in 1992 (revised in 1995 and 1999). This action
plan especially encouraged improving whaling equipment and methods to reduce TTD.
Data collection
Japan has been collecting catch records including the TTD for all whales taken by samplingvessels (catcher boats). The catch records include all firing time of a whaling cannon, detail of grenade
used and the IWC criteria used for death confirmation of the whale. All firing time of a rifle and typeof bullets are also recorded, if the secondary killing (back up) method is used. Necropsies (grossanatomical observation) of whale carcasses have been conducted by a veterinarian or an experienced
biological researcher on the research base ship. The necropsy record* includes the hit point andinternal track of the whaling harpoon, explosive point of the grenade, examination of the harpoon
wounds and the effect of bullets used for the secondary killing method.
*From 2009/10 season, the necropsy record of Antarctic minke whales was simplified to record the hit point andinternal track of the explosive harpoon.

Data-feedback system and data analysis
In mother-ship type operation of the whale research, it is difficult for a gunner to examine a whale
carcass shot by him. Therefore, during the research cruise, the necropsy records obtained by aresearcher on the research base ship are sent to the gunners on the sampling vessels as soon as possible
so that they can review in detail the results of their shots while their memories are still fresh. When thewhale did not die instantaneously, the gunners learn the reason of prolonged TTD and make good useof data to correct their shooting in next time.
Firing accuracy has been improved as gunners gain knowledge about the most preferable firing
angles and shooting areas in the whale body by combining their experience with the anatomical andmedical data from a researcher on the research base ship. This rapid-analysis and data-feedback
system has been considered as the main reason for the successful improvement of the TTD and IDR in
the Japanese whale research (Ishikawa, 1999).All data was accumulated and analyzed so as to improve
killing method of whales. Gunners and crews of sampling vessels are briefed at a pre-cruise meetingon the analysis of the past research for the killing methods and are encouraged to achieve the shorter
TTD and higher IDR.
Recruitment of new gunners
Cadets for gunners were recruited in 2004. Three excellent crew of the sampling vessel were selected
as gunner trainees and were getting experience year by year. The gunner cadets are on board withregular gunners and are allocated a number of firing opportunity. The regular gunners are responsible
for the training of the cadets and report progress of training to their company in every cruise.

1IMPROVEMENT OF WHALING DEVICES
Improvement of whaling devices also contributed to reduce the TTD. Large caliber rifle withsolid bullets as the secondary killing (back up) method was introduced since 1996. As handling ofrifles was easier than that of electric lances previously used, introduction of the rifle shortened TTD
significantly. Since 2002, Japan introduced an improved grenade with refined fuse. It explodes shorter
distance after a harpoon hits the whale body with little misfiring than Japanese old grenade.
Comparative experiments with Norwegian new grenade, Whalegrenade-99, showed both Japanese
improved and Norwegian grenades reduced TTD and increase IDR significantly compared to theJapanese old grenade (Ishikawa and Shigemune, 2008).
Replacement of sampling vessels
Kyodo-Senpaku Co.Ltd, owner of research vessels, newly built and replaced three sampling vessels
from 1999 to 2007. Building of pelagic whaling boat was the first time in 26 years in Japan. Newvessels, Yushin-Maru series (No 1-3) are equipped 5280 ps main engine and variable pitch propeller.
They also have a 75 mm whaling cannon with two whaling winches, and developed whaling sonar as
whaling devices. Introduction of new whaling vessels made easy to chase whales and increasedshooting chances for gunners, resulting high shooting accuracy and improved TTD.
Design of Harpoon headIn purpose of reducing struck and lost, the design of the harpoon head was modified. The struck andlost was occurred by reason of losing out of a harpoon or breaking line of the harpoon. During thecourse of the investigation on reason of the struck and lost, it was suggested that in some cases aharpoon line was cut by large shrapnel of the grenade inside the body of a whale. As an ordinal steel
head of the explosive harpoon remained large shrapnel after explosion, design of the steel head was
modified so as to remain relatively uniform sized and light shrapnel after explosion (Fig.1).

Fig. 1. (Upper) The traditional style harpoon head and shrapnel after explosion. A large shrapnel with a heavy
weight was left in the whale body frequently. It sometimes cut harpoon line and caused “struck and lost”.
(Lower) Improved harpoon head produces fewer and smaller shrapnel than the traditional one, which isexpected to reduce possible struck and lost.

Whaling devices for larger whale species
With the second phase of JARPA and JARPN, larger whales than minke whale were targeted for lethal
2research. Whaling devices for fin, sei, Bryde’s and sperm whales were considered and increased
penthrite explosive, delayed fuse and larger caliber rifle (.458) were introduced.
Table 1 summarizes primary and secondary killing devices for each target species in the latest
season. Penthrite charge of the grenade varied from 30g to 60g according to species and estimatedbody size of the target. 60g of penthrite charge proved to be effective to kill 20 m length fin whales
instantaneously when the grenade exploded inside of thorax. Three types of fuse for the grenade (0sec,0.05sec delayed and 0.1 sec delayed) were selected after several examinations of five types of fuse.
Two types of fuse, 0.025 and 1 sec delayed fuse were not adopted because 0.025 sec. delayed fuse
exploded the grenade too fast for sei whale and 1 sec. delayed fuse exploded after penetration of thewhale body of sei and fin whales.
Rifle shot as the secondary killing method for large whales were also considered. Large caliber
rifle (.458) proved to penetrate the skull of Bryde’s whales (up to 14 m in body length). However,primary use of the second explosive harpoon was recommended for the sei whales because the riflewas not as effective for large sei whales (up to 16 m in body length) as for Bryde’s whales.
Experimental shooting to a fin whale carcass (20 m in body length) was conducted to examine
efficiency of the large caliber rifle (.458), but necropsy revealed that no bullet reached at central
nervous system. Use of the large caliber rifle to sperm whales was not adopted because it wasconsidered that their unique anatomical character of the skull would prevent penetration of the bullets.
Table 1. Summary of primary and secondary killing devices for target whale species.

Fin whale

Sei whale

SpermWhale

Bryde’swhale

Primarykilling
method (grenade )75mm harpoon
with 60g penthrite
explosive
75mm harpoon
with 60g/50g
penthrite explosive
Ditto.

Primary killing
method (fuse )0.1sec./0.05sec.
delayed75mm harpoon
with 50g/30g
penthrite explosive

0.05sec. delayedor 0sec.

(Antarctic) 75mm harpoon
minkewith 30g penthrite
Whale
explosive

Ditto.

Ditto.

0sec. fuse

Secondary killing
methodSecond harpoon
with 60g penthrite
explosive
Second explosive
harpoon and large
caliber rifle (.458)
Second explosive
harpoon with
60g/50g penthrite
explosive
Second explosive
harpoon and large
caliber rifle(.458/.375)
Second cold
harpoon or large
caliber rifle (.375)

Remarks
Rifle is not effective as
the secondary killing
method.
Penthrite amount andfuse was selected byestimated body length.
Rifle is not effective as
the secondary killing
method.
Penthrite amount andfuse was selected byestimated body length.
50mm explosive
harpoon is used forcoastal operation.

Results of the JARPAII from 2005/06 season
The JARPAII was conducted in the eastern part of Area III, Area IV and western part of Area V inthe 2005/06 and 2007/08 season, whereas in the Area V and western part of Area VI in the 2006/07and 2008/09 season. Although 850 Antarctic minke whales and 10 (50 after 2007/08) fin whales wereplanned to be taken in each season, it was not achieved. Ten and three fin whales were taken in the2005/06 and 2006/07 season respectively, whereas no fin whale was taken in the 2007/08 season. Only
one fin whale was taken in the 2008/09.
Table 2 shows the TTD and the IDR information for Antarctic minke whales from the 2005/06 to2008/09 seasons. Regression analysis revealed significant decrease of the TTD (p<0.0001) andincrease of the IDR (p<0.0001) during research years (from 1993/94 to 2008/09 season).

3Table 2. TTD and IDR from the 2005/06 to 2008/09 JARPAII. The data for fin whales was
excluded because of insufficient number of data for analysis.

SeasonSpecies

Instantdeath rate(IDR)

Time to death(TTD)

Total
numberMED

MEAN

S.D.

853

0:00

2:06

3:37

50.3 %

505

2:00

2:26

3:57

40.6 %

2007/08

551

0:00

1:57

2:33

51.0 %

2008/09

679

0:00

2:12

3:1754.2 %2005/06
2006/07

Antarctic
Minke whale

Results of the JARPNII (offshore operation) from the 2005 season
The JARPNII offshore operations from 2005 to 2009 season were conducted in sub-areas 8 and 9
in the western North Pacific. For the offshore operation, sample size of 100 minke whales, 50 Bryde’s
whales and 100 sei whales were allocated in each season. A total of 17 sperm whales were taken from2005 to 2009 season.
Table 3 shows the TTD and IDR information in each season. Regression analysis revealed
significant decrease of the TTD (p<0.0001) and increase of the IDR (p<0.0001) for common minkewhales during research years (from 1994 to 2009 season). It was also revealed significant decrease of
the TTD (p=0.0005) and increase of the IDR (p<0.0001) for Bryde’s whales during research years(from 2000 to 2009 season). The IDR for sei whales also increased significantly (p=0.021), however,
the TTD for sei whale did not show significant decrease (p=0.352).

Table 3. TTD and IDR for minke, Bryde’s and sei whales from the 2005 to 2009 JARPNII. The datafor sperm whales was excluded because of insufficient number of data for analysis.

Season2005
2006
2007
2008
2009
2005
2006
2007
2008
2009
2005
2006
2007
2008
2009

Species

Minke whale(offshore )Bryde’s whale

Sei whale

Instant
death rate(IDR)

Time to death(TTD)

Total
number
MED
2:30
1:30
0:55
0:00
0:00
2:15
2:25
0:00
0:00
0:00
3:20
2:40
3:55
3:30
3:25

100
100
100
59
43
50
50
50
50
50
100
100
100
100
100

4MEAN
2:32
2:01
3:02
2:37
1:49
2:25
2:14
2:23
4:49
1:59
3:59
3:43
4:54
4:31
4:29

S.D.
3:02
2:36
6:11
4:06
2:09
2:56
2:13
3:11
13:17
3:35
4:21
4:52
5:24
7:45
7:4640.0 %44.0 %
50.0 %
52.5 %
53.5 %
42.0 %
40.0 %
54.0 %
60.0 %
68.0 %
38.0 %
42.0 %
34.0 %
43.0 %
47.0 %

References
Ishikawa H. 1999. Research activity on whale killing methods in the Japanese Whale research
Program in the Antarctic Sea and Northwestern Pacific Ocean (JARPA and JARPN).
Document IWC/51/WK16 presented to the Workshop on Whale Killing Methods, May. 1999
(unpublished). 8pp.
Ishikawa H and Shigemune H. 2005. Improvements in more humane killing methods of Antarcticminke whale Balaenoptera bonaerensis in the Japanese Whale Research Program underSpecial Permit in the Antarctic Sea (JARPA). Jpn. Zoo Wildl. Med. 10(1) ; 27-34.
Ishikawa H and Shigemune H. 2008. Comparative experiment of whaling grenades in the Japanese
Whale Research Program under Special Permit (JARPA and JARPN). Jpn. Zoo Wildl. Med.
13(1) : 21-28.

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