Sunday, August 14, 2022

Shark, Ray Populations Have Declined By 71 Percent In The Past 50 years

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Overfishing has decimated the global shark and ray population, according to a study released this week in the journal Nature.

Scientists have found that since 1970, the global population of oceanic sharks and rays has declined by 71 percent due to an 18-fold uptick in fishing.

“This depletion has increased the global extinction risk to the point at which three-quarters of the species comprising this functionally important assemblage are threatened with extinction.”

The authors call for “strict prohibitions and precautionary science-based catch limits” to keep the shark and ray populations from collapsing and help them recover.

Figuring out how overfishing causes declines in and increasing extinction risks of individual species is hard for scientists to measure, specifically for apex predators like sharks. Scientists reached that 71 percent number by looking at two well-established indicators:

“the Living Planet Index (a measure of changes in abundance aggregated from 57 abundance time-series datasets for 18 oceanic shark and ray species)” and

“the Red List Index (a measure of change in extinction risk calculated for all 31 oceanic species of sharks and rays).”

Check out the article at nature.com.

John Liang
John Lianghttps://www.deeperblue.com/
John Liang is the News Editor at DeeperBlue.com. He first got the diving bug while in High School in Cairo, Egypt, where he earned his PADI Open Water Diver certification in the Red Sea off the Sinai Peninsula. Since then, John has dived in a volcanic lake in Guatemala, among white-tipped sharks off the Pacific Coast of Costa Rica, and other places including a pool in Las Vegas helping to break the world record for the largest underwater press conference.

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