According to an eight-year scientific research, one-third of sharks and rays have been overfished and are on the verge of extinction.
“Sharks and rays are canaries in overfishing coal mines. If I tell you that three-quarters of tropical and subtropical coastal species are threatened, imagine the David Attenborough series with 75% of predators All disappeared. If the shark population is declining, then fishing will have serious problems,” said Nicholas Dulvy of Simon Fraser University in Canada, the lead author of the paper.
The health and food security of “the entire marine ecosystem” are at risk, said Dulvey, the former co-chair of the shark expert group. International Union for Conservation of Nature (World Conservation Union).
According to a paper published in the journal on September 6, the number of species of sharks, rays, and chimeras (collectively called cartilaginous fishes) more than doubled in less than ten years. Contemporary biology.
Rays are most threatened, 41% of the 611 species studied are at risk; 36% of 536 shark species are at risk; 9% of 52 chimeras.
Dulvy said: “Our research reveals an increasingly harsh reality. These species now constitute one of the most threatened vertebrate lineages, second only to amphibians in terms of risk.”
“The general depletion of these fishes, especially sharks and rays, endangers the health of the entire marine ecosystem and the food security of many countries around the world,” he said.
This evaluation is the second evaluation since 2014, and was conducted after a study in January found In the past 50 years, the number of sharks and rays has decreased by more than 70%, Species that used to be widely distributed, such as the hammerhead shark, are facing extinction.
Sharks, rays and chimeras are easily affected by overfishing because they grow slowly and rarely give birth.it has been estimated Every year 100 million sharks are killed by humans, overwhelming their slow reproductive capacity. The author states that industrial fishing is the “main threat” to cartilaginous fish, whether used alone or in combination with other fisheries.
The report stated that most sharks and rays were caught “unintentionally”, but they may be “unofficial targets” in many fisheries and are reserved for food and animal feed. The authors say that habitat loss and degradation, climate crisis and pollution have exacerbated overfishing.
Experts have found that this species is disproportionately threatened in tropical and subtropical waters, especially near countries such as Indonesia and India, because the demand for large coastal populations is very high, and most of the unregulated fisheries are usually caused by high Value products are driven by demand, such as fins.
According to the report, cartilaginous fish have experienced at least five mass extinctions in their 420 million-year history. However, at least three species are now critically endangered and may become extinct. The Java stingray has not been recorded since 1868, the Red Sea torpedo has not been recorded since 1898, and the shark that disappeared in the South China Sea has not appeared since 1934. Their disappearance will be the first time a marine species has been overfished in the world.
Colin Sinfindover, an adjunct professor at James Cook University in Queensland, Australia, said: “Tropical regions have an incredible diversity of sharks and rays, but for more than a century, many fisheries have been fishing for these inherent fragility. Species. Despite numerous promises to improve, it is still poorly managed.
“Therefore, we worry that we will soon confirm that one or more of these species have been extinct due to overfishing-this is a deeply disturbing issue for marine fish in the first place,” he said. “We will work hard to make this research a turning point in our efforts to prevent more irreversible losses and ensure long-term sustainability.”