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I've read from several sources that humans kill 11,000 sharks per hour or 100 million per year, for example :

Is it true?

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    Just to do the calculation once, so we don't all have to: 100 million /365/24 = 11,415 per hour. Yes, the two figures are consistent. – Oddthinking Jul 23 '12 at 19:04
  • National Geographic have a quiz that puts it at 40 million sharks. – Oddthinking Jul 23 '12 at 19:08
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    I hunted for a while, and found all the references seem to lead to the same source: Watts, Susie. October 2000. Finned Alive. BBC Wildlife, 18: 35–39. Anyone got access to this magazine? – Oddthinking Jul 23 '12 at 19:21
  • So, how did they arrive at 40M from X million tons? ... and by sharks, do they mean all sharks? Even dogfish are sharks. – user7920 Jul 23 '12 at 20:08
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    @coleopterist Both statements contain wording that hurts their claims: the Humane Society specifies "great sharks" and the Sea Shepherd enumeration of causes doesn't specify by-catch. Dogfish by-catch is certainly a major contributor and, by quick research, seems necessary to make the overall claim true. – Larry OBrien Jul 23 '12 at 20:56
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This probably-non-peer-reviewed document by a fisheries scientist gives a lower estimate circa 2000 but I can't parse out if his ~55M estimate includes targeted fishing or "only" by-catch:

Considering an average weight of 15 kg per individual, the total number of skates, rays and sharks killed by fisheries would be close to 90 million fish per year, but this is probably overestimated as 15 kg for the average weight might be a bit low. However, if we consider only the sharks, then the figure is closer to 55 million or probably less (again, due to a conservative estimate of average weight per fish of 15 kg; many commercially important and common bycatch shark species easily attain average weights between 50 and 100 kg per fish). Sharks are only about ½ of the reported catch (i.e. 380,000 t), they represent most of the high-seas bycatch (lets say 390,000 t/y), but only a minor part of the likely 200,000 t/y or so of skates, rays and sharks taken and discarded (i.e. unreported) in coastal bottom trawl fisheries (i.e. 50,000 t/y). Thus, the total of 55 million sharks by dividing the total kill of 820,000 t of sharks by 15 kg per fish. These very rough figures try to consider all sources of shark catches, the reported ones, the unreported bycatches in high seas fisheries, and the unreported bycatches in coastal trawl fisheries.

[Emphasis added]

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    A lot of sharks are killed for their fins though, with the body dumped at sea. This will lead to a much higher ratio of sharks per ton. Since a lot of shark finning is illegal, I don't know if there are reliable figures? – Nick Jul 25 '12 at 10:33

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