Findings

One of the starkest findings of Global FinPrint is that sharks were not detected on around 20 percent of surveyed reefs and reef shark populations are depleted in most nations around the world. Yet our global analyses also indicate that there remain several areas where sharks are still relatively common. These "reservoirs of hope" are places where sharks could spread out from to repopulate other areas if given the chance.

Some of these are inaccessible locations where fishing pressure is extremely low and could be the last reefs on the planet to still harbor pristine densities of sharks (for example, the Northern Great Barrier Reef). Other locations are places where people and sharks live alongside each other, but the humans have adopted conservation measures that are keeping shark populations relatively healthy.

A growing number of nations have decided to ban shark fishing. In some cases this is because the local people have a strong cultural connection with sharks, while in others it is because shark dive tourism is a much larger industry than shark fishing. These nations, some of which call themselves “Shark Sanctuaries,” had some of the highest numbers of sharks in our surveys.

From the Bahamas in the Western Atlantic, the Maldives in the Indian Ocean, and Palau, French Polynesia, New Caledonia and several others in the Central Pacific, our global analysis showed that Shark Sanctuaries are globally important areas for sharks.

Although national shark bans are a potentially effective approach in a few places, they are less likely to be adopted or effective if there is an established shark fishing industry; if sharks are often taken accidentally as bycatch, or if many shark fishers would lose their livelihood if a ban were implemented. Many people around the world rely on fishing, and there are very few alternative livelihoods that they can be employed in.

Regulation of shark fishing activities to ensure catches are sustainable could be the most realistic strategy in these nations. Our global analyses showed that nations could adopt catch limits or place restrictions on particularly effective shark fishing gear such as gillnets and longlines in order to enhance shark populations.

Closing certain areas to all forms of fishing is a common approach to marine ecosystem conservation. Several Global FinPrint studies have shown that these no-take Marine Protected Areas are a potentially effective tool for conserving some species of reef sharks. Reef sharks increased within 8 years of enforcement of a closed area (Ashmore Reef) in the Indian Ocean.

Members of our team combined BRUVS surveys with tracking data to show that no-take Marine Protected Areas need to be from 10 to 50 kilometers long to effectively protect the most common reef shark species. Our global analysis demonstrated that reefs within no-take Marine Protected Areas had more sharks than open areas, especially if these areas were very large.

Our global analyses identified several nations with high reef shark conservation potential, including Indonesia, Madagascar, Barbados and Fiji. These nations exhibited some degradation of reef shark populations and a lack of conservation measures. We estimated that a strong recovery of reef shark populations remains a possibility in these nations if they were to invest in shark fisheries management, large no-take Marine Protected Areas, or if they became Shark Sanctuaries. We are working with partners in many of these nations to engage with local governments and communities in order to explore these possibilities.