Ten years of letting the Yangtze rest

The Yangtze fishing ban was always a gamble with a long payout. Announced in 2020 and enforced from January 2021, it ended all commercial fishing across the entire basin of the world’s busiest river for a planned ten years, an intervention of a scale that conservation biology rarely gets to run. The question, from the start, was whether the river could actually come back, and how fast. A paper in the 12 February issue of Science provides the first rigorous answer: within three years of the ban, the long decline that had been running for seven decades had stopped, and the measurable indicators of fish health were turning upward.

The study, led by researchers at the Institute of Hydrobiology of the Chinese Academy of Sciences, compares fish communities in the river’s mainstem before the ban (2018 to 2020) with the first three years after it (2021 to 2023). The contrast is across the board. Fish biomass, the body condition of individual fish, and species diversity all improved, and there are signs of initial recovery among threatened species, the slowest and most sensitive part of any fish community to come back. Large fish benefited especially, which is exactly what an end to fishing pressure should allow: the big individuals that decades of nets had removed are the ones with the highest reproductive value, and their return is the mechanism by which the whole community rebuilds.

The result matters as evidence for a larger debate about river restoration. Rivers are the most heavily managed ecosystems on Earth, and for most of the past century the management question has been how much extraction a river can tolerate, not whether it can recover. The Yangtze, with half a billion people in its basin and one of the fastest industrialising regions in history on its banks, is the hardest possible test case. If even this river, under this much pressure, can show measurable recovery in three years, the case for protected river corridors elsewhere becomes stronger, and the case for treating fisheries management as a reversible choice rather than a one-way door is considerably harder to dismiss.

The authors are careful about what the data do and do not show. Three years is early in a ten-year experiment, and the study measures the start of a trajectory, not its endpoint. Biomass and diversity are not the same as a fully restored food web; the return of large fish changes the dynamics among species in ways that will take years to play out, and some parts of the river and its tributaries may recover at very different rates than the mainstem. The paper also does not address the social side of the ban, the livelihoods that were displaced and compensated, which is a cost that no ecological ledger can balance on its own.

What the finding does establish is that the river’s biology responded to the intervention quickly enough to be visible in an ordinary scientific timescale. Conservation interventions on this scale usually fail, or take decades to show any signal, or get confounded by everything else happening in the basin. The Yangtze appears to be doing none of those things. Seven decades of decline halted in three years is not a recovered river, but it is the first clear sign that the river can be recovered, and that the gamble, at least on the biological side, is paying off.