New research links youthfulness to greater vulnerability.
One of the younger shark species, oceanic whitetip shark (Carcharhinus longimanus), at Elphinstone Reef in Egypt in the Red Sea. (Credit: Thomas Ehrensperger / Wikimedia / CC BY-SA 3.0)
Sharks and rays are among the ocean’s most threatened vertebrates, but new research shows that younger evolutionary lineages are at especially high risk of extinction. The findings challenge assumptions that all sharks are equally resilient and point to deep biological differences shaping their survival prospects.
A global analysis led by researchers at the University of Zurich examined extinction risk across hundreds of shark and ray species, comparing life-history traits, evolutionary age and exposure to human pressures. The results reveal a clear pattern: species that evolved more recently are disappearing faster than their older relatives.
Built for speed, not survival
Younger shark and ray species tend to grow faster, mature earlier and produce more offspring than ancient lineages. While these traits may offer short-term advantages, they often come at the cost of lower resilience to sustained fishing pressure, habitat loss and environmental change. Rapid life cycles do not compensate when mortality rates are high and habitats are degraded.
In contrast, older evolutionary lineages—some dating back tens of millions of years—appear better buffered against extinction despite slower reproduction. Their long-term persistence suggests that evolutionary history matters when assessing risk, not just population size or fishing intensity.
Human pressure amplifies risk
The study shows that younger species are often concentrated in coastal and continental shelf regions, where fishing, bycatch, pollution and habitat destruction are most intense. Many also overlap with high-value fisheries, making them disproportionately exposed to exploitation.
This combination of biological vulnerability and geographic exposure creates what researchers describe as a double jeopardy: species least equipped to absorb losses are facing the strongest human pressures.
Implications
The findings suggest that conservation strategies should go beyond species counts and focus more closely on evolutionary diversity. Protecting older lineages preserves deep branches of the shark family tree, but safeguarding younger shark and ray species from vanishing before their ecological roles are fully understood is equally important to prevent rapid biodiversity loss.
