JAPAN: Progress Report on the Killing Method of Whales in the Second Phaseof Japanese 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 the Antarctic
Sea (JARPA and JARPAII) and since the 1994 season in the Northwestern Pacific Ocean (JARPN andJARPNII). Since these programs adopt lethal methods, whale killing methods have been examined andimproved with a special interest in reducing the time-to-death (TTD) and increasing the instantaneousdeath rate (IDR) of whales.
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.
Japan has been collecting catch records including TTD for all whales taken by sampling vessels(catcher boats). Necropsies (gross anatomical observation) of whale carcasses have been conducted bya veterinarian or an experienced biological researcher on the research base ship. The necropsy recordincludes the hit point and internal 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.
All data was accumulated and analyzed so as to improve killing method of whales. Gunners andcrews of sampling vessels are briefed at a pre-cruise meeting on the analysis of the past research forthe killing methods and are encouraged to achieve the shorter TTD and higher IDR. During theresearch cruise, the latest necropsy records obtained by a researcher on the research base ship is 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. 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 and medical data from a researcher on the research base ship.
This rapid-analysis and data-feedback system has been considered as the main reason for thesuccessful improvement of TTD and IDR in the Japanese whale research (Ishikawa, 1999).
Improvement of whaling devices also contributed to reduce TTD. Large caliber rifle with solidbullets as the secondary killing method was introduced since 1996. As handling of rifles was easierthan 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 aharpoon hits the whale body with little misfiring than Japanese old grenade. Comparative experimentswith Norwegian new grenade, Whalegrenade-99, showed both Japanese improved and Norwegiangrenades reduced TTD and increase IDR significantly compared to the Japanese old grenade (Ishikawa,2007).
This document reports major efforts and results on the whale killing method mainly from 2005 to2008 season in the Japanese whale research (JARPAII and JARPN II).

IMPROVEMENT OF WHALING DEVICES
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 5280ps main engine and variable pitch propeller.
They also have a 75mm 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.
1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 aheavy weight was left in the whale body frequently. It sometimes cut harpoon line and caused “struckand lost”. (Lower) Improved harpoon head produces fewer and smaller shrapnel than the traditional
one, which is expected to reduce possible struck and lost.

Whaling devices for larger whale species
With the second phase of JARPA and JARPAN, larger whales than minke whale were targeted forlethal 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.
Improvement of grenades for coastal whaling vessels
Since 2002, small type whaling catcher boats took part in the coastal operation in the JARPN IIresearch. Although these catcher boats were equipped 50mm whaling cannon and small sized grenades(7g penthrite), it was concluded that the small penthrite grenades were insufficient to kill minke
whales as quickly as 30g penthrite grenades that were used in the offshore operation. Improvement of
the grenade for small type whaling catcher boats was conducted from 2004 to 2006. Newly developedgrenades consist of 27g penthrite with refined fuse and short type steel head similar to the figure
deployed for large sized grenades (see “Design of Harpoon head”).

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. In the 2007 JARPNII, 25 minke whales
and 15 Bryde’s whales were taken by the three gunner trainees.

Table 1. Summary of primary and secondary killing devices for target whale species.

Fin whale

Sei whale

SpermWhaleBryde’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.

Ditto.

Ditto.

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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)

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.

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

0sec. fuse

Second cold
harpoon or large
caliber rifle (.375)

50mm explosive
harpoon is used forcoastal operation.

Results of the 2005/06, 2006/07 and 2007/08 JARPAIIThe 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 2006/07
season. Although 850 Antarctic minke whales and 10 fin whales were planned to be taken in eachseason (50 fin whales in 2007/08), it was not achieved because a fire accident on the research baseship (2006/07) and violent interruption by anti-whaling groups (2007/08). Ten and three fin whales
were taken in the 2005/06 and 2006/07 season respectively, whereas no fin whale was taken in the2007/08 season.
Table 2 shows the TTD and IDR information in the 2005/06, 2006/07 and 2007/08 seasons. The
data for fin whales was excluded because of insufficient number of data for analysis.
Table1. TTD and IDR in the 2005/06, 2006/07 and 2007/08 JARPAII.

SeasonSpecies

2005/06
2006/07
2007/08

Antarctic
Minke whale

Instant
death 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 %

551

0:00

1:57

2:33

51.0 %

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Results of the 2005, 2006 and 2007 JARPNIIThe 2005, 2006 and 2007 JARPNII were conducted in the western North Pacific. For offshore
operation, 100 minke whales, 50 Bryde’s whales, 100 sei whales were taken in each season. Five, sixand seven sperm whales were taken in the 2005, 2006 and 2007 season, respectively. Table 3 shows
the TTD and IDR information in the 2005, 2006 and 2007 seasons. The data for sperm whales wasexcluded because of insufficient number of data for analysis.

Table 2. TTD and IDR for minke Bryde’s and sei whales in the 2005, 2006 and 2007 JARPNII. Total
number of minke whales in the coastal operation was combined with two surveys (in Sanrikuand Kushiro region) in a year.

Season2005200620072005200620072005
2006
2007
2005
2006
2007

Species

Minke whale(offshore )Minke whale(coastal)
Bryde’s whale

Sei whale

Instantdeath rate
(IDR)

Time to death
(TTD)

Total
number
MED
2:30
1:30
0:55
5:20
3:10
1:45
2:15
2:25
0:00
3:20
2:40
3:55

100
100
100
120
95
106
50
50
50
100
100
100

MEAN
2:32
2:01
3:02
6:13
6:42
4:42
2:25
2:14
2:23
3:59
3:43
4:54

S.D.
3:02
2:36
6:11
7:16
14:23
6:52
2:56
2:13
3:11
4:21
4:52
5:24

40.0 %
44.0 %
50.0 %
32.5%
43.2%
47.2%
42.0 %
40.0 %
54.0 %38.0 %42.0 %
34.0 %

References
Hajime Ishikawa and Hirohisa Shigemune, 2005. Improvements in more humane killing methods ofAntarctic minke whale Balaenoptera bonaerensis in the Japanese Whale Research Program
under Special Permit in the Antarctic Sea (JARPA). Jpn. Zoo Wildl. Med. 10(1) ; 27-34.
Hajime Ishikawa and Hirohisa Shigemune. 2008. Comparative experiment of whaling grenades in theJapanese Whale Research Program under Special Permit (JARPA and JARPN). Jpn. ZooWildl. Med. 13(1) : 21-28.

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