Researchers have warned that overfishing and environmental change are eroding the biological foundations of many fisheries, with a new analysis revealing a global decline in fish growth over the last century.

Researchers from Australia’s James Cook University analysed nearly 7,700 growth records covering 1,479 marine species from 1908 to 2021.

They found that growth performance declined from about 1908 onwards, with the greatest declines concentrated among commercially valuable species, according to a recent university statement.

Helen Yan, who led the study as part of her PhD programme at JCU, said human-driven pressures are causing large-scale changes to the ecologies and life histories of fishes.

Researchers measured growth performance, a life-history trait that captures the trade-off between growth rate and body size across 113 years.

“Managed fisheries experienced an average 9-per cent decline in growth performance over the last century. This indicates fish are growing to relatively smaller sizes and/or at slower rates,” said Ms Yan.

Commercial size-based fishing practices, not temperature, are the primary drivers of the global decline in growth, although climate change may amplify the effects, she added.

Intensive fishing is leaving a clear biological imprint on fish populations, Ms Yan said, noting that the trend is most evident in temperate regions where fishing pressure is highest.

Scientists warn that smaller, slower-growing fish alter food webs, reduce fishery yields and complicate recovery efforts, stressing the need for stricter catch limits, size and habitat protections, and longer-term monitoring to detect life-history changes.

(Xinhua/NAN)