TROUBLED WATERS - Whale and Dolphin Conservation Society

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A REVIEW OF THE WELFARE IMPLICATIONS OF MODERN WHALING ACTIVITIES
It is apparent from Figure 1, that, while there have been improvements in the percentage of animals
killed within ten seconds from 17 per cent in 1983, to 80 per cent in 2002, there remain one in five
(20 per cent) of whales which do not die rapidly (in less than ten seconds), and whose survival can be
as long as 40 minutes. From the tail of the lower survival curve in Figure 1, it is apparent that,
despite alterations to the design of the harpoon, and increased training and monitoring of whalers,
the decay line for whales taking more than ten minutes to die has effectively remained unaltered
between 1996 and the most recent recorded data in 2002. One can interpret this as meaning that,
for approximately 10 per cent of all whales killed (the intersection of ten minutes on the time x axis,
with approximately 10 per cent on the survival line, y axis) by the Norwegians, death takes at least
ten minutes. This figure has not significantly improved since 1996.
The interpretation of the three criteria used to determine time of death is likely to be critical.
Differences in the perception of ‘flipper movement’ (passive or active), or ‘sinking without
swimming’ can create differences in TTD data. Whales are capable of sinking without swimming
during normal activity (Ridgeway et al. 1984, Dierauf & Gulland 2001), and so sinking alone is not
likely to be a fully reliable indicator of non-viability.
In practice, the use of the existing IWC criteria in the field by observers of the Japanese and
Norwegian whaling operation has highlighted inconsistencies in their interpretation. For example, in
a recent description of his experiences as a veterinary observer in the Norwegian hunt, Bruce (2003)
states that the IWC criteria were used in an ‘inclusive’ fashion (relaxation of the jaw AND no Flipper
movement AND no active movement). In contrast to this Norwegian example, recent data provided
by Japan from the IWC Humane Killing Workshop in 2003 (Ishikawa 2003a) indicate that Japan
does not make the criteria ‘inclusive’ in general (but sometimes combine criteria such as motionless
AND slackened jaw, or motionless AND slackened pectoral fins) Table 1. For the largest part Japan
uses ‘motionless’, a criterion which is not one of the IWC criteria, for determining TTD in most
animals (Table 1, 514 out of 566 – 90 per cent).
The IWC holds periodic scientific workshops to examine whale killing methods and associated
welfare issues. It has been repeatedly noted at these workshops 4 that existing criteria are in need of
improvement and that more reliable indicators of the point of sensibility and death should be
produced. An International Scientific Workshop on Sentience and Potential Suffering in Hunted
Whales was hosted by the RSPCA in London in 2001 (RSPCA, 2003). The purpose was to review
current criteria for assessing insensibility in cetaceans and consider the welfare implications of these
criteria for whales. A group of scientists and veterinarians with expertise in welfare, physiology and
anatomy reviewed current data on times to death in whale hunts, and the current IWC criteria for
determining the point of death in cetaceans. The group concluded that these criteria were not
adequate to determine precisely the point of death, and it was agreed that it should be possible to
greatly improve current indicators of sensibility and death in whales.
If the scientific community is concerned that the existing IWC measures do not give confidence that
the animal is dead, are there better measures? A preliminary study (Butterworth 2003a, 2003b)
stemming from this workshop identified that the following measures would be likely to provide
reliable information on the sensibility of cetacea – “breathing rate when the animal is stimulated
around the blowhole, electrocardiogram and heart rate, presence (or absence) of rhythmic swimming
activity, and the temperature of the surface of the eye”.