and crustaceans.The low productivity of deep-sea elasmobranchs,many ofwhich are poorly known taxonomically and whose population status is data-deficient,is a growing concern.Their inability to sustain fishing pressure has led experts to conclude that deep-sea elasmobranchs in general (not only larger species)are very vulnerable to overexploitation [64,72,73]. Several papers document the very low fishing mortality levels needed to over-exploit deep-sea sharks [9,74,75].Depth gives them no refuge;deep-sea fisheries have already reached the maximum depths attainable by elasmobranchs