The great hammerhead shark, Sphyrna mokarran or Tamataroa in Tahitian, has been a protected species in Polynesian waters since 2006, along with 20 other shark species that inhabit the area. According to a study published in Nature in 2020, French Polynesia is among the few places in the world where sharks populations are thriving thanks to a total ban on shark fishing. The great hammerhead shark population is "critically endangered" worldwide, meaning that the next step in the status would be "extinct in the wild", according to IUCN (International Union for Conservation of Nature). Yet, the species still faces major threats by targeted fisheries and by-catches, which accelerate its decline.
The S. mokarran is a highly migratory species, able to travel more than 3000 km in the Atlantic Ocean, but its movements in the Central Pacific Ocean remain a mystery. Its migrations could very likely lead it to unprotected waters where the fleets of foreign fisheriesawait. To date, discovery of key habitats, i.e. reproduction or breeding grounds in Polynesia, or even in the world has yielded nothing – meaning human activities could easily be affecting these key habitats without our knowledge. Consequently, the protection of the species in French Polynesia does not guarantee its conservation in the area. Understanding the ecology of the animal, its movements and its key habitats, can enable suggested management tools to be put forward to Polynesian public authorities in order to set up appropriate measures for the conservation of the great hammerhead shark in French Polynesia and more widely in the Central Pacific.