A landmark study published in Science reveals that overfishing has caused shark and ray populations to plummet by over 50% since 1970, severely impacting ecological balance and elevating extinction risks.
The study, which developed the first aquatic Red List Index (RLI), shows a 19% increase in extinction risk for chondrichthyan fishes, including sharks, rays, and chimaeras, highlighting how bycatch and habitat degradation further threaten these vital species.
“The shark and ray RLI shows how declines began in rivers and nearshore waters before spreading across the oceans and into the deep sea,” said Professor Nicholas K. Dulvy of Simon Fraser University.
“The overfishing of large species like sawfishes and rhino rays was followed by declines in hammerheads, requiem sharks, and eventually deepwater species targeted for liver oil and meat.”
Widepsread disruption
Overfishing and bycatch have caused widespread disruptions to marine ecosystems. This new RLI provides a vital tool to monitor marine biodiversity and guide shark conservation efforts.
Dr Rima Jabado, deputy chair of the IUCN Species Survival Commission (SSC) and chair of the IUCN SSC Shark Specialist Group, said: “This new shark and ray RLI will help track progress toward ocean biodiversity and sustainability targets, identify the species and places most at risk and guide future conservation efforts”.
The study was completed as part of the Global Shark Trends Project (GSTP), a collaboration of the IUCN Species Survival Commission Shark Specialist Group, Simon Fraser University, James Cook University and the Georgia Aquarium established with support from the Shark Conservation Fund.
Read the full study
