The world’s oceans are facing a crisis as populations of chondrichthyan fish — a group that includes sharks, rays, and chimaeras — plummet at an alarming rate.
A recent study has revealed that overfishing, compounded by a range of environmental threats, is driving these species toward extinction at an unprecedented pace, with dire consequences for marine ecosystems.
Over Half of Populations Lost
Since 1970, chondrichthyan fish populations have declined by over 50%, according to researchers. This devastating drop has been accompanied by a 19% increase in the risk of extinction for these species. The potential loss of up to 22% of their ecological functions, which are critical for ocean health, has heightened the urgency for conservation efforts.
“These species are essential for maintaining balance in marine ecosystems,” said Dr. Nicholas Dulvy, co-chair of the Global Shark Trends Project. “The rapid decline in their numbers is not just a warning sign — it’s a crisis we need to address immediately.”
The Primary Culprits: Overfishing and Bycatch
Overfishing has been identified as the primary driver of this decline. Sharks and rays are frequently targeted for their fins, meat, and cartilage, while many more are caught incidentally as bycatch in commercial fishing operations. Habitat degradation, climate change, and pollution further exacerbate the problem.
“Bycatch is often overlooked, but it’s a major contributor to population declines,” said Dr. Sonja Fordham, a leading expert in shark conservation. “We need stronger policies to mitigate these losses.”
Ecosystem Collapse Looms
The sharp reduction in shark and ray populations disrupts marine food webs, impacting nutrient transfer to coral reefs and reducing the productivity of ocean ecosystems. These animals also play a key role in carbon storage, making their decline a contributing factor to global climate challenges.
“Healthy shark populations mean healthy oceans,” said Dr. Dulvy. “Their loss has cascading effects that extend beyond the marine environment to human livelihoods and climate stability.”
The findings stem from the Global Shark Trends Project, a collaboration involving 322 experts across 17 workshops worldwide. By developing the aquatic Red List Index (RLI), researchers were able to measure changes in extinction risk for these species over time, offering critical insights into their population trends.
“This index is a game-changer for marine conservation,” noted Dr. Fordham. “It provides a clear picture of the urgency required to protect these species.”
Glimmers of Hope and the Road Ahead
Despite the grim findings, some regions have made notable progress in conserving sharks and rays. Nations such as Australia, Canada, New Zealand, the United States, and parts of Europe and South Africa have implemented stronger fisheries governance and reduced fishing pressures. However, global cooperation remains essential.
To reverse these declines, experts emphasize the need for reduced fishing pressure, the elimination of harmful subsidies, and the strengthening of international conservation policies.
“We have the tools and knowledge to save these species,” said Dr. Dulvy. “But it will take a global effort to make meaningful change.”
Charting the Future
The RLI has the potential to guide future conservation efforts and monitor ocean biodiversity more effectively. However, challenges persist, particularly in protecting deepwater species, which remain vulnerable due to limited knowledge and insufficient regulations.
As the international community grapples with these challenges, one thing is clear: the time to act is now.
The survival of sharks and rays depends on immediate, coordinated efforts to address overfishing, protect critical habitats, and combat climate change. The health of the oceans — and the planet as a whole — hangs in the balance.