Science

Grim Outlook For Sharks And Relatives: Extinction Is Knocking!

A new study in the journal Current Biology has published some stark news: one third of the world’s Chondrichthyan fishes – sharks, rays, and chimaeras – are threatened with extinction according to the International Union for Conservation of Nature (IUCN) Red List criteria. A group of experts have assessed over 1,000 species and have classified 90 as “Critically Endangered,” 121 as “Endangered,” and 180 as “Vulnerable.” Less than half of all species (44.1%) are of low conservation concern (“Least Concern”).

“On one hand, we’re pleased that chondrichthyan science contributions have doubled since our first global analysis of this kind, allowing us to assess the status of many more species with greater confidence,” said Dr. Nicholas Dulvy, Professor at Simon Fraser University. “On the other hand, our study reveals an increasingly grim reality, with these species now making up one of the most threatened vertebrate lineages, second only to the amphibians in the risks they face. The widespread depletion of these fishes, particularly sharks and rays, jeopardizes the health of entire ocean ecosystems and food security for many nations around the globe.”

Chondrichthyans make up the oldest, and largest, evolutionary radiation of vertebrates and are one of the taxonomic fish classes. While many just view these toothy animals as the “villain” of summer blockbuster films, they play an important part in our marine ecosystems (e.g. serving as a vital predator in our marine food web, transferring nutrients from the open ocean to coral reefs, etc.) and many coastal economies (bringing in millions of dollars via tourism each year). Not only does their extinction lead to ocean imbalance, but it “squanders opportunities for sustainable fishing, tourism, and food security over the long term.”

So, what exactly is killing off these top dogs of the sea? A far more terrifying killer: us. “Sharks, rays, and chimaeras are exceptionally susceptible to overfishing because they tend to grow slowly and produce few young, relative to other fish,” the team explains. “Overfishing has far outpaced effective resource management for these species.”

However, while sharks have long been the poster child for “extinction” in the chondrichthyan group due to their constant battle against shark fin soup and cartilage pills, it is actually rays that are the most threatened of the three chondrichthyan groups, with 41% of the 611 assessed species labelled as ‘threatened.’ “I spend a lot of time trying to get conservation attention for ‘flat sharks’ [rays and skates] and yet was a bit surprised at some of the news for [these animals],” said Sonja Fordham, president of Shark Advocates International, a project of The Ocean Foundation. “A key message from our first global assessment in 2014 was that rays were generally more threatened than sharks. […] I was taken aback to realize all five species of pelagic eagle ray are now threatened and that stingrays as a group are now in real trouble.” The team has found that the most threatened families include sawfishes, wedgefishes, giant guitarfishes, devil rays, pelagic eagle rays, and hammerhead sharks.

It was also determined that certain regions of our planet also pose bigger threats for these animals than others. “The tropics host incredible shark and ray diversity, but too many of these inherently vulnerable species have been heavily fished for more than a century by a wide range of fisheries that remain poorly managed, despite countless commitments to improve,” said Dr. Colin Simpfendorfer, Adjunct Professor at James Cook University. “As a result, we fear we will soon confirm that one or more of these species has been driven to extinction from overfishing, a deeply troubling first for marine fishes. We will work to make this study a turning point in efforts to prevent any more irreversible losses and secure long-term sustainability.”

“Conservation action is urgently needed to reverse declining trends and prevent further extinction, ecosystem damage, and food insecurity,” the team of experts advise. They suggest area closures to further restrict fishing, protecting important habitats, and implementing fisheries and wildlife treaty obligations as well as “concrete limits on fishing based on scientific advice and [a] precautionary approach […] to minimize mortality of imperiled species and ensure sustainable exploitation of others.” While this seems like something only policymakers, stakeholders and scientists can have a say in, Fordham adds that concerned citizens are the ‘key’ to reversing shark and ray declines. “People can most definitely affect how sharks are protected by letting policy makers know that they support conservation efforts. Often, the more specific the request, the better. These voices matter in terms of the positions that governments take and the priority with which safeguards are sought and implemented.” Fordham explains that in many countries, governments give the public opportunities to comment on regulations that affect sharks and rays – a simple letter of concern from a personal perspective (even one far for the coastline) can make a huge difference! “By voicing concern – through letters to lawmakers and news editors, as well as social media and art – everyone can help. Vocal, sustained support for shark and ray conservation from the public is not only truly meaningful; it’s essential for creating a brighter future for these extraordinary animals.”

Thankfully, the newest report does bring with it some good news – at least for skates. The New Zealand Smooth Skate (Dipturus innominatus) moved from “Near Threatened” to “Least Concern” based on population growth attributed to science-based quotas, and the previously “Endangered” Barndoor Skate (Dipturus laevis) and Smooth Skate (Malacoraja senta) are now classified as “Least Concern” and “Vulnerable,” respectively, due to fishing limits in Canadian and US Atlantic fisheries. “We have seen great progress over the last few decades in terms of growing public concern for sharks and rays, leading to beneficial government initiatives, including national fishing limits and significant actions under international treaties,” Fordham says. “So, even as shark and ray depletion is a complex global problem, there’s a pretty straight-forward path to substantial improvement. We already have many of the tools, frameworks, and commitments needed to save species.”

Fordham has hope that we can kick of new, significant improvements right away! “Now through mid-November, Atlantic fishing countries are considering scientific advice to ban the retention of seriously overfished, endangered North Atlantic shortfin mako sharks (through the International Commission for Conservation of Atlantic Tunas). If public pressure builds sufficiently to convince the EU and USA to stop blocking this urgent protection, it could turn the tide for one of the world’s most economically and ecologically valuable sharks – and set a good example for other species and regions.” Want to help? Visit Shark Advocates to see how your voice will make a difference… and how it can continue to speak out for the voiceless before it’s too late.


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