Ocean Shark and Ray Populations Have Declined by 70% in the Past 50 Years


Feb 2, 2021


Image Credit: Norbert Wu/Minden Pictures

A new large-scale global study has revealed a dramatic decline in shark populations over the last 50 years — mostly due to human activities.

Published in Nature last week, the study found that oceanic sharks and rays had declined by 71% between 1970 and 2018 — primarily due to shark-finning and fishing worldwide. “Such steep declines are shocking even to experts, especially when compared to land animal statistics,” says Sonja Fordham, President at Shark Advocates International, who was also involved the study, told the media.

While the study found declining numbers worldwide, they also noted that some regions, like the Indian Ocean countries, were worse off than the others. “The Indian Ocean is the worst ocean. There is almost no [fisheries] management at all… Policy-makers can no longer ignore the plight of sharks and rays. Countries should work toward new international shark and ray protections, but can start immediately by fulfilling the obligations already agreed internationally,” Nathan Pacoureau, ecologist focusing on global conservation priorities at Simon Fraser University in Canada, who led the study, said.

Moreover, the researchers explained as we are only beginning to realize the threats to these species from climate change, it is imperative that we urgently address the threat they face from fishing.

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Experts note that while the exact ramifications of removing top predators from ecosystems can be hard to predict — they will still be cascading, and jeopardize the integrity of the entire marine food web. “The implications of removing sharks is an unhealthy marine ecosystem… We just have to keep pushing for science-based fishing limits,” Cassandra Rigby, a research fellow at James Cook University in Australia, who has been researching on sharks for 20 years now and was involved in the study, told The Guardian.

Described as tenacious, sharks are believed to have survived several catastrophic mass extinctions. In fact, some sources suggest that the earliest sharks emerged around 450 million years ago, and the modern sharks — around 100 million years ago. “Sharks have got a very long evolutionary history and have seen so many other groups come and go. Dinosaurs have been and gone in the time [sharks] have existed,” Colin Simpfendorfer, professor of marine biology at James Cook University, who was also involved in the study, said. And yet, human activities are beginning to wipe them out.

However, Simpendorfer believes that it may not be too late to save the species from going completely extinct yet. But in order for that to happen, “sharks need to be off limits for fishing, as the data show that they are not recovering… [otherwise] we have to start imagining a future where there are oceans that don’t have sharks in them,” he warned.


Written By Devrupa Rakshit

Devrupa Rakshit is an Associate Editor at The Swaddle. She is a lawyer by education, a poet by accident, a painter by shaukh, and autistic by birth. You can find her on Instagram @devruparakshit.


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