Publication Announcement: Widespread diversity deficits of coral reef sharks and rays

Reef sharks are at a much higher risk of extinction than previously thought

Protected areas and fisheries management key to survival

Overfishing is driving reef sharks toward extinction, according to new study published this week in Science.

The five main shark species that live on coral reefs — grey reef, blacktip reef, whitetip reef, nurse and Caribbean reef sharks — have declined globally by an average of 63 percent, according to the scientists of Global FinPrint, a five-year international study supported by the Paul G. Allen Family Foundation.

“These are some of the best estimates of population decline of widespread shark species because of the very large number of reefs and countries sampled,” according to Colin Simpfendorfer, lead author of the study and adjunct professor of Marine and Aquaculture Science at James Cook University in Australia. “This tells us the problem for sharks on coral reefs is far worse and more widespread than anyone thought.”

 Results from this latest research, which includes 22,000 hours of video footage from baited underwater video stations across 391 reefs in 67 nations and territories, indicates widespread overfishing is the main culprit driving reef sharks toward extinction.

Indonesia is the epicenter of global marine biodiversity, sitting in the heart of the coral triangle. Geographically, Indonesia should have the highest population and diversity of sharks and rays on the planet, but after decades of unsustainable fishing and overexploitation fish stocks have been depleted. This developing island nation has become the front lines for some of the world’s leading marine conservation issues.

“Since conducting the field work with Global FinPrint, Indonesia has shown a genuine shift in mindset and policy towards sustainability and environmental practices, and it is only the beginning,” said Lauren Sparks, Global FinPrint researcher in Indonesia and founder of Indo Ocean Project.  The Ministry of Marine Affairs and Fisheries has announced a nationwide ban on manta ray fishing in 2014, only a year after they were listed on CITES. And, recognizing the ecological and economic importance of Marine Protect Areas, the government of the Republic of Indonesia have committed to increasing their size and quality of their management with their support of the Sustainable Development Goal (SDG) 14: Life Below Water. At a national level, Indonesia has protected 23.1 million hectares (ha) within its border, just under the targeted 23.4 million ha by 2020. New targets have been set to protect 10% of Indonesian waters by 2030, a total of 32.5 million ha. (Kementrian Kelautan dan Perikanan, 2020).

“At Indo Ocean Project we support existing marine protected areas and assist in the establishment of new areas based on scientific truths.” explained Sparks, “We have continued to implement the use of BRUV surveys to identify key habitat zones for sharks, rays, and fisheries in Indonesia. Research like Global FinPrint’s is used locally to enact data-driven marine policy changes that have a global impact.”

Image by Adrienne Gituus from SoulWater Productions at Tanjung Luar fish market in Lombok, Indonesia

Sharks and rays are common in coral reef ecosystems, but as reefs are more heavily fished, they have become stripped of both shark and ray species or stripped of just shark species, leaving the ecosystem dominated by rays. The loss of sharks could have an impact on the overall health and function of the coral reef ecosystem.

“While overfishing and poor governance is associated with the absence of these species, they are still common in Marine Protected Areas (MPAs) and places where shark fishing was banned or highly regulated,” said Demian Chapman, lead scientist of Global FinPrint and director of the Sharks and Rays Conservation Program at Mote Marine Laboratory. “Reef sharks can be important for human livelihoods through dive tourism and if fished carefully. An investment in reef shark conservation can therefore be good for people, too”.

“Early results from this study were previously used to update the status of four of these species to more threatened categories on the International Union for the Conservation of Natures (IUCN) Red List. They were also presented during the most recent Conference of the Parties of the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES), helping world governments to make the groundbreaking decision to better regulate trade in these and more than 50 additional species of sharks.

“This means no trade should come from nations where the take of the species will threaten its survival,” Simpfendorfer said. “This study can be used to help identify those nations where such catches would be detrimental. We need to act now to stop widespread extinction of shark species in many parts of the world.”

 More than 150 researchers from more than 120 institutions across the world contributed to the research.

Special thanks to Adrienne Gittus from SoulWater Productions and Steve Woods for the use of their images in this article. All photos were shot in Indonesia.