World's Largest Reef Shark And Ray Survey Finds Sharks Absent From 20% Of Reefs

Marbled ray and wedgefish swim near bait bag at Ashmore Reef. Australian Institute of Marine Science / Global FinPrint

Rachael Funnell 22 Jul 2020, 23:06

Sharks, often painted as the villain of the piece, have been suffering from exploitation for decades but until now there haven’t been many wide-scale surveys into how years of mistreatment have affected these animals’ populations. Previous estimates worked on catch records from industrial fisheries, leaving large gaps in the record as coastal species were often excluded.

Groundbreaking research published in Nature has revealed that sharks are now virtually absent on many coral reefs across the globe. Video recordings from underwater cameras revealed that sharks were not seen on 20 percent of the 371 reefs they surveyed in 58 countries.

The researchers of the Global FinPrint study used 15,000 baited remote underwater video stations in an effort to estimate the conservation status of reef sharks across the globe. Fishing was found to have a profound impact on reef shark populations, and reef sharks were almost completely absent from reefs in several nations. These worst-affected areas were often associated with socio-economic complexities such as poor governance and overpopulation, which the researchers state could explain increased fishing of threatened species and less money invested into conservation efforts.

The study used baited underwater cameras to capture footage of shark species present on the reef.  Australian Institute of Marine Science / Global FinPrint

Interestingly, reef shark species in Australia appeared to be doing well as their populations remain nearly intact. Thriving species included the grey reef, whitetip reef, and blacktip reef sharks.

The researchers highlight that while much of the news is grave, there are still available solutions to employ that could turn things around for these amazing animals. Shark sanctuaries, closed areas, catch limits, and the removal of gillnets and longlines were all associated with areas where reef sharks were rife, demonstrating the efficacy of these protective measures. The study authors explain that this data should serve as a model to inform policies put in place to restore shark populations, working to improve the treatment of these animals both with the local fisheries but also gaining support from governments.

Adult tiger shark approaches bait bag at Ashmore Reef. Australian Institute of Marine Science / Global FinPrint

“Our survey not only reveals the plight of sharks on coral reefs, which is in many cases very worrying, it also reveals how control of shark fishing can make effective conservation gains,” said Dr Meekan, from the Australian Institute of Marine Science in Perth and principal investigator for the Global FinPrint project in the Indian Ocean region.

“Sharks are important for the ecology of coral reefs, particularly at a time when they are facing so many other threats from climate change. But few people realize that reef sharks are also an important part of the economies of many small island nations around the world because they are a key attraction for reef tourism.”

 

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