A new analysis has found one in seven deepwater sharks and rays are threatened with extinction, with the biggest threat coming from overfishing.
James Cook University's Professor Colin Simpfendorfer was part of a team of international experts whose work was published today in the journal Science.
He said deepwater sharks and rays - species that spend most of their life at depths greater than 200m - are among the most sensitive marine vertebrates to overexploitation because of their long lifespans and low reproductive rates.
"Deepwater sharks and rays have biological characteristics similar to marine mammals which were formerly exploited for their oils and are now highly protected," said Professor Simpfendorfer.
Dr. Brittany Finucci, a fisheries scientist based at the National Institute of Water and Atmospheric Research in New Zealand said deepwater sharks and rays may be caught accidentally but are retained for their meat and liver oil.
"These are not new fisheries. However, the global expansion and diversification of deepwater shark and ray use and trade is a relatively new phenomenon," said Dr Finucci.
"Many deepwater sharks and rays can only withstand very small amounts of fishing pressure," said Dr. Nicholas Dulvy, Professor at Simon Fraser University.
"Some species may take 30 years or more to mature, and possibly up to 150 years in the case of the Greenland Shark. Some only produce 12 pups throughout their entire life. Because of their relatively large size and widespread distribution, deepwater sharks and rays play a vital ecological role, concentrating and dispersing nutrients throughout deep ocean habitats," said Professor Dulvy.
"Our results highlight that it is time to think about regulating the liver oil trade," said Dr. Rima Jabado, Deputy Chair of the IUCN Species Survival Commission (SSC) and Chair of the The International Union for Conservation of Nature SSC Shark Specialist Group.
"There has been enormous success in regulating the shark fin trade but trade and fishing regulations specific to deepwater sharks and rays are urgently needed.
"This could include national protections, regulations on deepwater fisheries, as well as listing species on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora.
"Deepwater sharks and rays have been out of sight, out of mind for too long. Now is the time to take action to prevent further endangerment," said Dr Jabado.
