Should we fish for sharks?

In some regions shark numbers have dropped more than 90 percent and a quarter of species are at risk of extinction - in large part due to over-fishing. Conventional conservation wisdom holds that it's impossible to fish sharks sustainably because they are long-lived and slow breeding. But Professor Colin Simpfendorfer argues that outright banning shark fishing is the wrong approach and that with careful management it is possible to maintain sustainable shark fisheries.