Last month, scientists, conservationists, and the ecotourism industry alike were all disappointed when the National Marine Fisheries Service (NMFS) determined that the great hammerhead shark will not be listed under the Endangered Species Act (ESA). NMFS also decided against listing scalloped hammerhead sharks in the U.S. last year, a motion that was finalized this month. Despite notable evidence of the severe decline of both species in recent decades and their extreme vulnerability to being captured as bycatch, NMFS cited that there was not enough data on population trends in order for them to mandate a listing for either species.
Great hammerhead sharks are the largest of the hammerhead shark species, reaching nearly 20 feet in length, and they're also some of the longest-lived sharks. Because they give birth to few young and have very sensitive bodies, they are extremely vulnerable to human exploitation. In fact, the International Union for Conservation of Nature (IUCN) classified the great hammerhead shark as endangered in 2007. There are multiple populations of this species living around the world, including the northwest Atlantic population in U.S. waters-estimated to have declined by as much as 90 percent during the past century, mainly as bycatch in bottom longlines and other net fisheries.