Sharks are functionally extinct from many reefs but hope remains

A landmark study published in Nature reveals sharks are absent on 20% of world’s coral reefs! The study was led by Aaron MacNeil and co-authors from the Global FinPrint project, including CORDIO’s Melita Samoilys, Kennedy Osuka and Clay Obota.

The study provides a benchmark for the status of reef sharks around the world, which can guide meaningful, long-term conservation plans for protection and recovery of reef sharks.

Reef sharks have become “functionally extinct” in some countries and are facing a widespread decline, which has remained undocumented on a global scale – despite the fact that coastal sharks comprise two thirds of species traded globally. The results were based on more than 15,000 hours of video from surveys of 371 reefs in 58 countries and territories around the world.

The loss of sharks is of concern in the western Indian Ocean region where sharks were found to be least abundant. In particular, with 0-1 sharks observed in Kenya and Tanzania, these populations are categorised as “functionally extinct”. Since sharks are important as top predators on coral reefs, tourism attractions and food resources, their decline has both ecological and socio-economic implications.

The single largest contributor of the loss in global reef sharks was overfishing using destructive fishing practices, such as longlines and gillnets. The study also revealed decline was strongly related to socio-economic conditions including:

  • – the size and proximity of the nearest market,
  • – poor governance, and
  • – the density of the human population.

Nonetheless, hope remains if key conservation measures are employed and policies put in place to engage key socio-economic aspects of tropical fisheries. These opportunities include:

  • – establishment of shark sanctuaries,
    – set up of closed areas,
    – catch limits, and
    – banning of gillnets and longlines.

Press release materials are available here. Watch more on the Global FinPrint project.