Can shark resources be harvested sustainably? A question revisited with a review, of shark fisheries

Sharks and other chondrichthyans are often described as long lived, slow gr owing and producing few offspring. These biological characteristics, togeth er with the common assumption that recruitment is directly related to stock , and pessimistic stock prognoses obtained from application of demographic analysis, have led to doubts that sharks can be harvested sustainably. Deve loped over the past 40 or so years from studies of only a few shark species , these doubts have been reinforced by declining catch rates in industrial, artisanal and recreational fisheries and in fishing programmes designed to reduce the risk of sharks attacking humans at bathing beaches. However, mo re recent studies and application of modelling techniques allowing for dens ity-dependent responses to the effects of stock reduction indicate that sha rk stocks can be harvested sustainably and, if carefully managed, can provi de very stable fisheries. It is now understood that some species (such as G aleorhinus galeus, Carcharhinus plumbeus, Carcharodon carcharias and severa l species of dogfish) have low productivity, whereas other species (such as Mustelus antarcticus, Rhizoprionodon terraenovae, Sphyrna tiburo and Prion ace glauca) have higher productivity. This paper reviews the use of shark p roducts, the effects of fishing on shark populations of the world, and rece nt developments in assessment of shark fishery stocks.