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The Animal Welfare Implications of Cetacean Deaths in Fisheries

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7. General conclusions<br />

Direct estimates <strong>of</strong> bycaught cetaceans from observer programmes and <strong>in</strong>direct<br />

data, such as the proportion <strong>of</strong> stranded <strong>in</strong>dividuals bear<strong>in</strong>g evidence <strong>of</strong> encounters<br />

with fisheries, <strong>in</strong>dicate that this is a significant conservation issue. <strong>The</strong> importance <strong>of</strong><br />

welfare aspects related to bycatch has only recently been recognised. A number <strong>of</strong><br />

welfare issues have been identified. <strong>The</strong>se <strong>in</strong>clude the <strong>in</strong>juries suffered, the length <strong>of</strong><br />

time to asphyxiation and the social implications <strong>of</strong> <strong>in</strong>dividuals dy<strong>in</strong>g. <strong>The</strong>se welfare<br />

issues are likely to be severe, <strong>in</strong>dicat<strong>in</strong>g that the welfare <strong>of</strong> bycaught cetaceans is<br />

<strong>of</strong>ten very poor. However, there is a lack <strong>of</strong> quantitative data on these areas and<br />

further research is needed on the duration <strong>of</strong> suffer<strong>in</strong>g, the severity <strong>of</strong> stressors and<br />

its impact <strong>in</strong> the short- and long-term. In particular, what are the implications for<br />

<strong>in</strong>dividuals that may survive fisheries encounters Such research will give a more<br />

comprehensive understand<strong>in</strong>g <strong>of</strong> how bycatch affects cetacean populations.<br />

8. Acknowledgements<br />

We are grateful to Philippa Brakes, Paul Jepson, Vassili Papastavrou, Ali Ross and<br />

Mark Simmonds for their comments on drafts <strong>of</strong> this report, Rob Deaville and Paul<br />

Jepson for provid<strong>in</strong>g the post-mortem data.<br />

9. References<br />

Acevedo-Gutierrez, A., Croll, D.A. & Tershy, B.R. (2002) High feed<strong>in</strong>g costs limit dive<br />

time <strong>in</strong> the largest whales. Journal <strong>of</strong> Experimental Biology, 205, 1747-1753.<br />

Akamatsu, T., Hatakeyama, Y. & Ishii, K (1991a) [Process <strong>of</strong> harbour porpoise’s<br />

entanglement <strong>in</strong> the gill net.] Technical Report <strong>of</strong> the National Research Institute <strong>of</strong><br />

<strong>Fisheries</strong> Eng<strong>in</strong>eer<strong>in</strong>g. Fish<strong>in</strong>g Gear Methods, 5, 25-36.<br />

Akamatsu, T., Hatakeyama, Y., Ishii, K., Soeda, H., Shimamura, T. & Kojima, T. (1991b)<br />

[Experiments on the recognizable part <strong>of</strong> the gill net and the process <strong>of</strong><br />

entanglement <strong>of</strong> bottlenose dolph<strong>in</strong>s Tursiops truncatus.] Nippon Suisan Gakkaishi,<br />

57, 591-597.<br />

Akamatsu, T., Wang, D., Nakamura, K. & Wang, K. (1998) Echolocation range <strong>of</strong><br />

captive and free-rang<strong>in</strong>g baiji (Lipotes vexillifer), f<strong>in</strong>less porpoise (Neophocaena<br />

phocaenoides), and bottlenose dolph<strong>in</strong> (Tursiops truncatus). Journal <strong>of</strong> the<br />

Acoustical Society <strong>of</strong> America, 104, 2511-2516.<br />

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