The original story appeared in The Guardian. It is part of The Climate Desk collaboration.
According to an 8-year scientific research, a third of the shark and ray species were overfished to near extinction.
The canary in the coal mine that is overfishing is sharks and rays. Imagine a David Attenborough show with only 75 percent of the predators left if I told you three quarters of all tropical and subtropical coast species were at risk. Nicholas Dulvy of Canada’s Simon Fraser University, the lead author of this paper, said that if sharks are decreasing, then there is a problem with fishing.
The health of “entire ocean ecosystems” and food security is in jeopardy, said Dulvy, a former co-chair of the shark specialist group of the International Union for Conservation of Nature (IUCN).
According to a paper in Current Biology, September 6, the number of species that are facing “a global crisis of extinction” (sharks, rays and chimaeras), has increased more than twice in a decade.
The most endangered species of rays is the 611 shark species, which represent 41 percent; 36% of 536 species of sharks; and 9 per cent of 52 species of chimaera.
Dulvy stated that: “Our study has revealed an increasingly grim reality with these species now constituting one of the most endangered vertebrate linesages, second to the amphibians, in terms of the risks they face.”
He stated that the “widespread depletion” of fishes (especially sharks and rays) is a threat to the ocean ecosystems’ health and threatens food security in many countries around the world.
The assessment is the second to be carried out since 2014, and it comes after a study in January found shark and ray populations had crashed by more than 70 percent in the past 50 years, with previously widespread species such as hammerhead sharks facing extinction.
Overfishing is a problem for chimaeras and sharks. They grow slow and have few children. It has been estimated that 100 million sharks are killed by humans every year, overwhelming their slow reproductive capacity. According to the authors, industrial fishing is a major threat to chondrichthyans. It can be done alone or with other fisheries.
The majority of sharks and rays that are caught are “unintentionally,” however they could be an “official target” for many fisheries. They are kept as food or animal feed. The authors stated that overfishing is exacerbated by habitat loss, climate change, and pollution.
Experts found that the species is at risk in subtropical and tropical waters. This could be due to high demand from large populations of coastal people and unregulated fisheries.
According to the report, Chondrichthyans survived at most five mass extinctions over their history of 420 millions years. However, the report indicates that at least three species of Chondrichthyans are currently in danger and could be extinct. Since 1868, there has been no record of the Java stingaree, 1898 for the Red Sea torpedo Ray, or 1934 for the South China Sea’s Lost Shark. Overfishing would make this the first extinctive event in history for marine species.
Colin Simpfendorfer is an adjunct professor at James Cook University, Queensland, Australia. He said that “The tropics have incredible shark and Ray diversity but too many species inherently vulnerable have been heavily fished over a hundred years by a broad range of fisheries which remain poor managed, in spite of numerous commitments to improve.”
He said, “We fear that we will soon be able to confirm that at least one of these species was driven to extinction by overfishing–a highly troubling first for the marine fishes.” We will make this study an important turning point to avoid irreversible loss and ensure long-term sustainability.
Experts mainly from IUCN’s shark specialist group assessed 1,199 species. 391 species were placed in IUCN’s threatened categories: critically endangered (90 species), endangered (121 species) or vulnerable (181 species).
Devil Rays, sawfishes and giant guitarfishes are the most endangered. Over three quarters of all species are endangered in the subtropical and tropical coastlines, particularly in the western Pacific Ocean, northern Indian Ocean, and central Pacific Oceans. These oceans stretch from Pakistan to Japan.
The first global assessment in 2014 concluded that a quarter of chondrichthyan species were threatened. One third of chondrichthyan species are currently at risk of extinction. The authors also stated that the number of species with scarce data rose to almost two-fifths.
Sonja Fordham is coauthor of Shark Advocates International and President, an Ocean Foundation project. She said that while we were aware that sharks are in danger, there was more information, conservation measures, and yet twice as many species have been classified as endangered as they were in 2014. This is alarming, shocking even for experts.
She acknowledged that there were more conservation commitments and measures in place but she called on governments to take immediate action to reduce fishing.
Fordham stated that “time is running out” for shark and ray species.
Global Shark Trends Project was responsible for the completion of this study. It is a joint effort by IUCN shark specialists group Simon Fraser University and James Cook University as well as the Georgia Aquarium. Funded by Shark Conservation Fund.
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Publited Sat, 11 Sep 2021 at 12:13.38 +0000