Scientists have warned that overfishing and environmental changes are weakening the biological foundations of global fisheries. A new analysis shows a long-term decline in fish growth over the past century.
Researchers from Australia’s James Cook University (JCU) analysed nearly 7,700 growth records covering 1,479 marine species from 1908 to 2021. According to a recent university statement, the study found that growth performance has been declining since around 1908. The sharpest falls appear among commercially valuable species, Xinhua reports from Sydney.
Lead researcher Helen Yan, who carried out the study as part of her PhD at JCU, said human-driven pressures are reshaping fish ecology and life histories on a large scale. The team assessed growth performance, a life-history trait that reflects the balance between growth rate and body size, over a 113-year period.
“Managed fisheries experienced an average 9% decline in growth performance over the last century,” Yan said. “This indicates that fish are growing to relatively smaller sizes and/or at slower rates.”
She said commercial size-based fishing practices, rather than temperature, are the main driver of the global decline. However, she added that climate change may intensify the effect.
Yan noted that intensive fishing is leaving a clear biological imprint on fish populations. The trend is most visible in temperate regions, where fishing pressure remains highest.
The scientists warned that smaller and slower-growing fish are disrupting food webs, reducing fishery yields and making recovery more difficult. They called for stricter catch limits, stronger size and habitat protections, and long-term monitoring to track these changes.
