According to a recent research, shark and ray populations worldwide have decreased by about 50% since 1970. The main factor is overfishing, which has wiped out populations of chondrichthyan fishes, including chimaeras, rays, and sharks, over the last 50 years. The decline of global shark and ray populations is also driven by pollution, climate change, and habitat deterioration in addition to deliberate targeting and bycatch. The study emphasizes the urgent need for conservation measures to prevent these species from going extinct.

Overfishing and Expanding Threats

The decline of global shark and ray populations was first observed in rivers, estuaries, and nearshore coastal waters before extending into the seas and deep oceans. Populations of hammerheads, eagle rays, giant stingrays, angel sharks, and requiem sharks declined following the successive extinction of larger, functionally significant species such as sawfish and rhino rays. For the liver oil and meat trade, fishers eventually turned to deep-water sharks and skates, according to Simon Fraser University lead scientist Nicholas K. Dulvy.

“Over one-third of chondrichthyans now face the threat of extinction,” according to a statement from James Cook University. The issue is made worse by persistent undermanagement and underassessment of fisheries, especially in nations with less developed governments.

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Conservation and Hope for Recovery

Despite the alarming trend of global shark and ray population decline, the report offers hope. It emphasizes that the loss can be halted by removing harmful subsidies, improving fisheries governance, and reducing fishing pressure to sustainable levels. According to co-author Colin Simpfendorfer of James Cook University, “Progress has already created bright spots of hope for chondrichthyans, including in Australia, Canada, New Zealand, the United States, and parts of Europe and South Africa.”

To ensure sustainability and recovery, science-based catch limits and strategies to reduce incidental catch, such as spatial safeguards, are essential. The findings, titled Ecological Erosion and Expanding Extinction Risk of Sharks and Rays, were published in Science on December 6.

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