TROUBLED WATERS - Whale and Dolphin Conservation Society

More documents

Recommendations

Info

Thyroid function in cetaceans can also be affected by stressful conditions, but interpretation should take account of sex and age (St. Aubin et al. 1996). For examples see; a) beluga whales (Delphinapterus leucas): St. Aubin and Geraci 1988, 1992; b) captive white-sided dolphins (Lagenorhynchus obliquidens): Ridgeway and Patton 1971; c) bottlenose dolphins (Tursiops truncatus): Orlov et al. 1988; see also St. Aubin et al. 1996. As in most vertebrates, stress can alter immunocompetence in cetaceans (see Romano et al. 1992, 1993, 1994; St. Aubin et al. 1989, 1990; Medway et al. 1970; Townsend 1999; reviewed in Curry 1999). Suppression of natural killer cell activity is reported in beluga whales (De Guise et al. 1997), and capture stress can suppress leukocytes and blood iron levels (Geraci and Medway 1973, St. Aubin and Geraci 1989). Thomson & Geraci (1986) report high mortality associated with capture and confinement stress in various small cetaceans, including Phococoena phococoena (Dudock van Heel, 1962), Phocoenoides dalli (Ridgeway, 1966) and Delphinus delphis (Walker, 1975). Muscle damage and exertional myopathy in cetaceans Muscle damage was found in dolphins after capture experiments and is likely, therefore, to arise in other cetaceans. Muscle activity during pursuit and capture can affect blood enzymes – creatinine kinase (CK), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and blood urea nitrogen (BUN) and potassium levels in cetaceans. Colgrove (1978) diagnosed EM following the transportation of a bottlenose dolphin, with first signs appearing 22 hours post-transport. Young et al. (1997) found 11 blood and serum parameters linked to stress in net-caught wild and healthy captive bottlenose dolphins, which matched those for terrestrial animals suffering from EM. The authors conclude that dolphins are susceptible to EM. Thurnbull and Cowan (1998) speculate that the deaths of small cetaceans following capture for marine collections may be linked to EM. Dolphins may be particularly prone to stress-related cardiomyopathy or contraction band necrosis (CBN). CBN is characterized by lesions associated with hypercontracted myocardial cells, which in turn have been linked to elevated catecholamine concentrations (Reichenach and Benditt, quoted in Thurnbull and Cowan 1998). They can occur following traumatic circumstances ranging from psychological stress and drowning to exertional myopathy and are considered to contribute to their fatal outcome. Identical lesions occurred in a sample of stranded cetaceans of nine species. The authors attributed these lesions to physiological and psychological stress linked to stranding, disease and injury. Elevated CK levels in some dolphins killed during purse-seining are considered indicative of “muscular exertion or muscle damage” which may result in unobserved post-release mortality (Stuntz and Shay 1979 quoted in Curry 1999). More recent evidence for potential stress-related injury or unobserved mortality emerged for dolphins involved in purse seine fishing operations (NOAA 2002). Conclusions The degree of exercise imposed on whales during whaling may fall outside the species’ adaptive range. “Even species that have evolved for efficient running, either for predator avoidance or for predation, may develop exertional myopathy following intense or prolonged muscular activity associated with extreme stress during air or ground pursuit.” (Williams and Thorne 1996). Whalers depend on gaining a minimum distance between themselves and whales for successful harpooning. From what is known about the behavioural response of cetaceans to ships, this range is likely to fall below what would naturally be maintained by wild cetaceans in many cases. Pursuit as part of whaling may, therefore, be stressful The potential stress effects of whaling and the welfare implications for hunted cetaceans 73
74 A REVIEW OF THE WELFARE IMPLICATIONS OF MODERN WHALING ACTIVITIES and manifest in a series of lethal and sub-lethal pathologies. Some whales, which successfully evade being harpooned, or are missed, may still suffer fatal syndromes, such as exertional myopathy (EM). Thus, pursuit may increase anthropogenic mortality levels, and this has implications for the welfare of all hunted whales, including those that are pursued but escape the harpoon. Such effects may be exacerbated where gravid females or females accompanied by dependent offspring are targeted. Physiological assessments of stress, as part of currently practised lethal whale research, seem plagued by technical (manner and schedule of sampling, handling and storage etc, see Ishikawa, 1996; Øen and Walløe 1999) and biological problems, which can significantly distort results. A physiological stress assessment carried out during current lethal research is therefore fraught with difficulties. This includes problems with partitioning the physiological and biochemical effects of pursuit and killing, and the fact that the trauma of harpooning will mask any effects of pursuit. With regard to EM the fact that clinical signs may not manifest for hours, days, weeks or even months poses additional problems. Rather than focus on harpooning alone, the IWC might consider whale hunting to start from when a whale is first sighted to when it is killed. Factors such as pursuit duration and speed, distance covered as well as direction of approach and weather condition should be taken into account and recorded. Such information, particularly if combined with behavioural data from target and non-target animals, and easily monitored biological parameters, such as respiratory rate, would provide a practical basis for assessing the potential stress-related risks of whaling. References Bartsch, R.C., E.E. Meconnell, G.D. Imes, and JM. Schmidt. 1977. A review of exertional rhabdoyolysis in wild and domestic animals and man. Vet. Pathol. l4:314-324. Basson, P. A., and Hofmeyer, J. M. (1973). Mortalities associated with wildlife capture operations. In: The Capture and Care of Wild Animals (E. Young, ed.), pp. 151-153. Human and Rousseau Publishers, Cape Town, South Africa. Brambell, F.W.R. (1965) Report on the Technical Committee to enquire into the welfare of livestock kept under intensive husbandry conditions, HMSO, London. Broom, D. M. and Johnson, K. G. (1993) Stress and Animal Welfare, Chapman and Hall. Broom, D.W. (1985) stress, welfare and the state of equilibrium. In: Proc. 2nd Eur. Symp. Poult. Welfare. R.M. Wegner (ed.) World Poultry Science Association, Celle, pp72-81. Chalmers, G. A., and Barrett, M. W. (1982). Capture myopathy. In: Noninfectious diseases of wildlife (G. L. Hoff, and J. W. Davis, eds.). Iowa State University Press, Iowa, US. Colgrove, G. S. (1978). Suspected transportation-associated myopathy in a dolphin. J. Am. Vet. Med.Assoc. 173(9): 1121-1123. Cowan, D.F. and Walker, W.A. (1979) Disease factors in Stenella attenuata and Stenella longirostris taken in the eastern tropical Pacific yellowfin tuna purse-seine fishery. Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Administrative Report No. LJ-79-32C. Curry, B.E. (1999) Stress in Marine Mammals: The Potential Influence of Fishery-Induced Stress on Dolphins in the Eastern Tropical Pacific Ocean. NOAA Technical Memorandum NMFS, U.S. Dept. of Commerce, NOAA-TM-NMFS-SWFSC-260.
Page 1 and 2:
TROUBLED WATERS A REVIEW OF THE WEL
Page 3 and 4:
II A REVIEW OF THE WELFARE IMPLICAT
Page 5 and 6:
IV A REVIEW OF THE WELFARE IMPLICAT
Page 7 and 8:
2 A REVIEW REVIEW OF THE WELFARE IM
Page 9 and 10:
4 A REVIEW REVIEW OF THE WELFARE IM
Page 11 and 12:
6 A REVIEW OF THE WELFARE IMPLICATI
Page 13 and 14:
8 A REVIEW OF THE WELFARE IMPLICATI
Page 15 and 16:
10 A REVIEW OF THE WELFARE IMPLICAT
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28: 22 A REVIEW OF THE WELFARE IMPLICAT
Page 77: 72 A REVIEW OF THE WELFARE IMPLICAT
Page 105 and 106: 100 A REVIEW OF THE WELFARE IMPLICA
Page 129 and 130:
124 A REVIEW OF THE WELFARE IMPLICA
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Appendix II Colour plates ©Mark Vo
Page 147 and 148:
Page 149 and 150:
Figure 13. Processing minke whales
show all

TROUBLED WATERS - Whale and Dolphin Conservation Society

Create successful ePaper yourself

Delete template?

Save as template?