The Japanese roughshark (Oxynotus japonicus) is a rare species of shark in the family Oxynotidae, known only from a handful of specimens recovered from Suruga Bay and the off Japan. It is a benthic species that occurs at a depth of 150–350 m (490–1,150 ft). This shark is caught (and discarded) as bycatch by bottom trawlers throughout its entire limited range, and may be threatened given the declines in other bottom deep sea species in Suruga Bay. Reproduction is ovoviviparous, as in other dogfish sharks. Size at maturity is 59 cm (23 in) long for females and 54 cm (21 in) long for males.