A scientific mission to save sharks

A hammerhead shark less than a meter long swims frantically in a plastic container aboard a boat in the Sanquianga National Natural Park, off the Pacific coast of Colombia. she is a delicate female sphyrna crownthe smallest species of hammerhead shark in the world, and is named locally yellow horned—yellow hammerhead shark—by the color of its fins and the edges of its splendid curved head, which is full of sensors to perceive the movement of its prey.

Marine biologist Diego Cardeñosa of Florida International University, along with local fishermen, just captured the shark and implanted an acoustic marker before quickly returning it to the murky waters. A series of receivers will help follow their movements for a year and map the coordinates of their habitat, valuable information for their protection.

That hammerhead shark is far from the only shark species that keeps the Colombian biologist busy. Cardeñosa’s mission is to build scientific knowledge to support shark conservation, whether by locating the areas where the creatures live or identifying, with genetic testing, the species that are traded in the world’s main shark markets.

Sharks are threatened for several reasons. The demand for its fins to supply the mainly Asian market (see box) is a very lucrative business: between 2012 and 2019, it generated 1.5 billion dollars. This, added to their inclusion in bycatch (fish caught unintentionally in the fishing industry), as well as the growing market for shark meat, causes the deaths of millions each year. In 2019 alone, the total estimated deaths were at least 80 million sharks, 25 million of which were endangered species. In fact, in the Hong Kong market alone, a major shark fin trade site, two-thirds of the shark species sold there are at risk of extinction, according to a 2022 study led by Cardeñosa and molecular ecologist Demian Chapman, director of the shark and ray conservation program at Mote Marine Laboratory in Sarasota, Florida.

Sharks continue to face a difficult future despite decades of legislation designed to protect them. In 2000, the United States Congress passed the Shark Fining Prohibition Act and, in 2011, the Shark Conservation Act. These laws require that sharks brought ashore by fishermen have all their fins naturally attached and aim to end the practice of stripping the creatures of their fins and returning them, mutilated, to the water to die on the seafloor. . Ninety-four other countries have implemented similar regulations.

Perhaps the main political and diplomatic tool for shark conservation is in the hands of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), made up of 183 member countries plus the European Union. The treaty offers three degrees of protection, or appendices, to more than 40,000 species of animals and plants, imposing prohibitions and restrictions on their trade depending on their threatened status.

Sharks were listed on CITES Appendix II, which includes species that are not endangered but could become endangered if trade is not controlled, in February 2003, with the addition of two species: the basking shark (Cetorhinus maximus) and the whale shark (Rhincodon typus). After that, the list of protected species increased to 12 and then increased significantly in November 2023 with the inclusion of 60 more shark species in CITES Appendix II.

But do these tools really protect sharks? To search for answers, over the past decade researchers have worked to develop tests that can easily identify which shark species are being traded and determine whether protected species continue to be exploited. They have also focused on studying shark populations around the world in order to provide information for the establishment of protected areas that can help safeguard these animals.

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