All three species of Thresher Shark belong to the genus Alopias and include the Pelagic ( Alopias pelagicus ), Bigeye ( Alopias superciliosus ) and Common (Alopias vulpinus ) Thresher. All three species have biological characteristics that result in low productivity, Bigeye Thresher, in particular, is one of the less productive pelagic shark species, due to the very low fecundity and late maturity for females.