TROUBLED WATERS - Whale and Dolphin Conservation Society

9 The potential stress effects of
whaling and the welfare implications
for hunted cetaceans
Barbara Maas, Chief Executive, Care for the Wild International, The Granary, Tickfold Farm,
Kingsfold, West Sussex, UK.
Whaling may impose physical and psychological stress even before any harpoon is fired. This may
apply as much to whales that are struck and eventually killed as to those that evade capture. The
IWC has, so far, restricted discussions on whale hunting to primary and secondary killing methods.
However, from first sighting to the time when a whale is killed, the elements of pursuit, such as
approach, duration, speed and distance covered may affect morbidity (defined as the incidence of
disease or the occurrence of pathophysiological or degenerative changes) and mortality even among
animals that successfully evade harpooning.
Whaling operations and the potential for exertional stress and fear
Whether whales experience stress as a result of being hunted depends on the level of exercise imposed
on the animals. Øen and Walløe (1995) argued that because the top speed of most Norwegian
whaling boats does not exceed 7-8 knots, this only permits a “slow stealthy approach when they try to
position the boat next to the predicted surfacing of the whale” and so does not constitute a chase. Yet,
according to the 1994 minke whaling summary report, “one [veterinary] inspector reported that a
vessel had chased a whale for at least 6-7 hours. He proposed that a maximum permitted duration should
be introduced for such chases.” (Government of Norway 1995). Minke whales normally swim at speeds
of four to five knots but can maintain 20 knots for short spurts. Therefore, it would appear that
Norwegian whaling boats can force minke whales to exceed their comfortable swimming speed and
the potential for chase depends on pursuit duration and speed as well as distance covered.
Japanese catcher vessels are faster than Norwegian boats and can both match and maintain a minke
whale’s maximum speed. Thus, Japanese whale hunts have a greater potential to cause forced
exertion. Eyewitnesses report that pursuit times of 30 minutes are not unusual in Japanese hunts,
although 45 and even 90-minute chases also occur. In order to place a shot, the catcher boat must
obtain a proximity range of 40-60 metres, and several hours may pass before this range is achieved
(Tanaka 1987). It is routinely reported in Japanese hunts that a targeted whale’s respiratory rate is
deliberately raised to shorten surfacing intervals, as this increases opportunities for harpooning.
In aboriginal hunts, such as the hunting of gray whales in the North Pacific by the native Chukotka,
it can take two to three hours to place the first of several harpoons (Zemsky et al. 1999). Zemsky et
al. describe the duration of Chukotka hunts - “after a long chase of a whale, whalers have to stop
whaling due to the impossibility to approach the animal at a near distance (sic)” (Zemsky et al. 1999).
This suggests a race in which whalers try to get close enough to set the harpoon. The application of
floats hamper a whale’s escape by slowing it down and impeding dives. Zemsky et al. (1999) list the
The potential stress effects of whaling and the welfare implications for hunted cetaceans
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