Researchers warn that overfishing and environmental change are eroding the biological foundations of many fisheries. A new analysis reveals a global decline in fish growth over the last century.
Scientists from Australia’s James Cook University (JCU) analyzed nearly 7,700 growth records covering 1,479 marine species from 1908 to 2021.
The study found that growth performance has declined since around 1908, with the greatest reductions among commercially valuable species, according to a recent university statement.
Helen Yan, who led the study as part of her PhD program at JCU, said human-driven pressures are causing large-scale changes in the ecologies and life histories of fish.
Researchers measured growth performance—a life-history trait that reflects the trade-off between growth rate and body size—over 113 years.
“Managed fisheries experienced an average 9% decline in growth performance over the last century. This indicates fish are growing to smaller sizes and/or at slower rates,” Yan said.
The study found that commercial, size-based fishing practices—not temperature—are the primary drivers of the global decline, although climate change may amplify the effects.
Intensive fishing is leaving a clear biological imprint on fish populations, particularly in temperate regions where fishing pressure is highest, Yan noted.
Scientists warn that smaller, slower-growing fish disrupt food webs, reduce fishery yields, and complicate recovery efforts. They stress the need for stricter catch limits, size and habitat protections, and long-term monitoring to detect life-history changes.
