Unprecedented Study, Led By FIU Researchers, Shows Alarming Drop In Shark Populations
MIAMI (CBSMiami) -- For the first time in history, a group of scientists has spent four years gathering over 15,000 hours of video data to survey the health of the world's shark population, and the results are alarming. Thanks to overfishing and the brutal practice of finning, some regions of the world have no more sharks at all.
This unprecedented global study, led by FIU researchers, reveals sharks are functionally extinct from many reefs.
Functionally extinct meaning "too rare to fulfill their normal role in the ecosystem," according to the landmark study by Global FinPrint.
Researchers examined 371 reefs in 58 countries and found sharks were not observed on nearly 20 percent, indicating a widespread decline that has gone undocumented on this scale until now.
Essentially no sharks were detected on any of the reefs in the Dominican Republic, the French West Indies, Kenya, Vietnam, the Windward Dutch Antilles and Qatar. Among these, a total of only three sharks were observed during more than 800 survey hours, according to the study published today in Nature.
The research, backed by funding from the late Microsoft co-founder Paul Allen, did identify conservation measures that could lead to recovery of these iconic predators.
"While Global FinPrint results exposed a tragic loss of sharks from many of the world's reefs, it also shows us signs of hope," said Jody Allen, co-founder and chair of the Paul G. Allen Family Foundation. "The data collected from the first-ever worldwide survey of sharks on coral reefs can guide meaningful, long-term conservation plans for protecting the reef sharks that remain."
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Reef sharks are important food resources, tourism attractions, and top predators on coral reefs. Their loss is due in large part to overfishing of sharks, with the single largest contributor being destructive fishing practices, such as the use of longlines and gillnets.
"Although our study shows substantial negative human impacts on reef shark populations, it's clear the central problem exists in the intersection between high human population densities, destructive fishing practices, and poor governance," said Demian Chapman, Global FinPrint co-lead, associate professor in FIU's Department of Biological Sciences and researcher in the Institute of Environment.
"We found that robust shark populations can exist alongside people when those people have the will, the means, and a plan to take conservation action."
The study revealed several countries where shark conservation is working and the specific actions that can work. The best performing nations compared to the average of their region included Australia, the Bahamas, the Federated States of Micronesia, French Polynesia, the Maldives and the United States.
Shark conservation efforts in these nations include banning all shark fishing or limiting how many sharks can be caught.
"These nations are seeing more sharks in their waters because they have demonstrated good governance on this issue," said Aaron MacNeil, lead author of the Global FinPrint study and associate professor at Dalhousie University. "From restricting certain gear types and setting catch limits, to national-scale bans on catches and trade, we now have a clear picture of what can be done to limit catches of reef sharks throughout the tropics."
The FinPrint team is wrestling with the fact that conservation action on sharks alone can only go so far. Researchers are now looking at whether recovery of shark populations requires management of the wider ecosystem to ensure there are enough reef fish to feed these predators.
"Now that the survey is complete, we are also investigating how the loss of sharks can destabilize reef ecosystems," said Mike Heithaus, Global FinPrint co-lead and dean of the College of Arts, Sciences & Education at Florida International University. "At a time when corals are struggling to survive in a changing climate, losing reef sharks could have dire long-term consequences for entire reef systems."
