5 years ago

TROUBLED WATERS - Whale and Dolphin Conservation Society

TROUBLED WATERS - Whale and Dolphin Conservation Society

It can be argued that

It can be argued that the figures for IDR and average TTD quoted by Japan and Norway do not hold up well to scientific scrutiny. There is, for example, much debate over the adequacy of criteria that are currently used by the IWC to determine the onset of permanent irreversible insensibility and death in cetaceans, and some scientists believe that the current criteria 15 are inadequate (Butterworth et al. 2003). Furthermore, since cetaceans are adapted for diving, and consequently have developed mechanisms for storing oxygen in their tissues (Anon 2003a), they may survive, and potentially experience pain over a period that is longer than the current IWC criteria indicate (see chapter 11). Size considerations It is considered that one of the main reasons for the poor IDR in whaling operations is the fact that current killing methods, which have been designed and tested on relatively small minke whales, are not adequately adapted to account for the different morphology and physiology of other species on which they are used. The most profound physical differences occur between the sperm whale (an Odontocete or toothed whale), which can weigh up to 57 tonnes (Silva and Downing 1995) and reach 18.3 metres (Reeves et al. 2002), and the baleen whales (Mysticetes). For example, the brain of the sperm whale is buried deep in the whale’s head, behind a substantial depth of bone and the fatty tissue of the spermaceti organ, thus making a direct strike to the brain in this species very difficult (see chapter 10). The sperm whale also has physiological adaptations that enable it to dive to a maximum depth of 2000 metres and remain submerged for up to 79 minutes (Stewart 2002). There are also significant differences between the baleen whale species currently killed for commercial purposes. For example, while the sei whale can weigh up to 50 tonnes (Silva and Downing 1995) and can reach a maximum length of 19.5 metres (Reeves et al. 2002), the minke whale (Balaenoptera acutorostrata) weighs up to only 10 tonnes (Silva and Downing 1995) and reaches a maximum length of only 10.7 metres (Reeves et al. 2002). Several physiological factors will determine the efficacy, on a bigger species, of a device that was designed to kill smaller animals. For example, the thickness of the species’ blubber (which comprises between 15 per cent and 50 per cent of the total mass of a great whale depending on the season and the species (Castellini 2000)) may significantly affect the penetration of the projectile (Anon 2003a), which must reach a sufficient depth to be lethal. In addition, operational factors relating directly to the technology used will also affect whaling efficiency. For example, the quantity of explosives used will be a significant factor, as evidenced by the greater charge used by Japan to kill sperm whales. In addition, the strength of the forerunner rope may be significant since, if it is not sufficiently strong to take the strain of a larger species, the number of whales struck and lost, or that have to be secured and killed by other means (Anon 2003a), may increase. Secondary killing methods Clearly, the need for a secondary killing method to be used will directly correlate to the efficiency of the primary killing method, including its specific suitability for the species taken. That is, if a grenade explodes at a sub-lethal level, fails to explode at all, or fails to secure the animal, a secondary killing method, or an alternative means of securing the fleeing or sinking animal, will be required. As data on secondary killing methods in commercial whaling operations are only provided for minke whales, this correlation (between frequency of use of secondary killing methods on larger species and the adequacy of the primary method) is most clearly illustrated in Aboriginal Subsistence Whaling (ASW) operations. (See page 45). COMMERCIAL AND ABORIGINAL SUBSISTENCE WHALING 41

42 A REVIEW OF THE WELFARE IMPLICATIONS OF MODERN WHALING ACTIVITIES The IWC has not established any formal criteria for determining when to apply a secondary killing method to a wounded whale, and the decision, including about which method to use, rests with the hunter. This means that, in situations where a whale is not lethally wounded by the primary killing method, it is possible that the hunter may wait some time to see if the whale dies before deciding to administer a secondary killing method. Cost considerations, and the risk of damaging more, or higher value, edible tissue, are likely to influence this decision, particularly when the secondary killing method is a second explosive harpoon. The most commonly only used secondary killing method is the rifle. It is of concern that, despite a ban imposed by the IWC on the use of the ‘cold’ (non-exploding) harpoon 16 , Japan permits the use of a cold harpoon as a secondary killing method on minke, Bryde’s, sei and sperm whales in its North Pacific whaling operation 17 . The JARPN permit authorises its use “in order to shorten the time to death of the whale which was struck by an explosive grenade harpoon”. The adequacy of the rifle as a killing method It is essential that the goal of a secondary killing method should be to immediately kill, or render insensible to pain, an already wounded and compromised whale. In order to achieve this, any secondary killing method will need at least equal or greater power and accuracy than the primary killing method. When rifles are used as a secondary killing method, the target should be the brain, since rifles targeted elsewhere are unlikely to produce a swift death. The small amount of data available on secondary killing methods, largely derived from ASW operations, indicates that rifles may often be inadequate to kill whales with a single shot (Stachowitsch and Brakes 2003). In addition to factors related to the morphology of the target whale, the efficiency (and, therefore, the appropriate choice) of a killing method will also be determined by operational factors relating to the gunner, vessel and specification of the weapon used. Some of these factors will be within the control of the gunner, including the power and accuracy of the weapon, the accuracy of the gunner and his ability to identify and aim at specific external landmarks. Others will be outside his control, such as the prevailing weather conditions (see chapter 8). A further consideration when choosing both primary and secondary killing methods (including vessel type) should be species-specific behaviours. These include the manner in which a species behaves in response to being struck, which may have significant practical repercussions. For example, if the behavioural response to the stimulus of a harpoon is to dive (in an attempt to move away from the stimulus), this will have implications for the choice, and administration, of any secondary killing method (Anon 2003a). ‘Struck and lost’ whales The failure to land whales that are struck and injured, but not landed, by a whaling operation has grave welfare implications. It is also a conservation problem, if struck but lost whales do not count towards the quota established 18 . The schedule has specific requirements for the reporting of these ‘struck and lost’ individuals 19 in commercial whaling operations. Information provided to the IWC on struck and lost whales commonly reports that either the harpoon pulled out, the forerunner rope broke, or that the harpoon struck but did not engage properly (Anon 2003b). It is possible that not all whales that are struck are reported, as in some cases it may be difficult to evaluate whether a whale has actually been struck, especially when the primary killing method is a rifle as in some Aboriginal Subsistence hunts.

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