Hope for the Yangtze: study shows how a fishing ban is reviving the river

The Yangtze River is Asia’s longest river at over 6,300 kilometers and the third-longest river in the world. For millennia it was among the world’s most species-rich freshwater ecosystems. It supplied people, animals, and entire cultures with water, food, and habitat—and formed the ecological backbone of large parts of China.

But by the rapid industrialization beginning in the 1950s at the latest, its decline had begun. Within just a few decades, China developed into the world’s second-largest economy—an economic success associated with considerable ecological costs. The Yangtze, the country’s main transportation artery and the livelihood of 30 to 40% of the Chinese population, increasingly became a symbol of nature being subordinated to economic interests. Today, about 12% of the world’s population lives in its catchment area.

For decades, unfiltered industrial and household wastewater, pesticides, heavy metals, and enormous amounts of nitrogen and phosphorus flowed into the river. At the same time, huge dams were built that interrupted fish migration routes, disrupted sediment transport, and changed flow, temperature, and oxygen levels. Plastic waste, microplastics, and persistent pollutants still accumulate to this day, especially in reservoirs. On top of that came rapidly growing shipping traffic: between 2005 and 2019, freight volume nearly tripled. Bank erosion, pollutant inputs, and constant underwater noise further stressed habitats.

The consequences of these decades of overexploitation were dramatic. Fish stocks collapsed, catches fell to a quarter of their historic maximum, and 135 species previously recorded disappeared from current surveys. Several endemic and culturally significant animals were eradicated—including the Chinese river dolphin and the Chinese paddlefish. The Yangtze sturgeon (Acipenser dabryanus) is now considered extinct in the wild. The Yangtze giant softshell turtle (Rafetus swinhoei), of which probably only two males still exist, is also on the verge of disappearing entirely.

2021: a law to save the Yangtze

To break the decades-long downward spiral of overfishing, pollution, and biodiversity loss, the Yangtze River Protection Law came into force in 2021. Its central element is a ten-year, river-wide fishing ban from 2021 to 2030.

Seasonal closed seasons had already existed since 2002, but they proved ineffective. The ecological decline continued unchecked. The Chinese government therefore opted for a radical step: for the first time, commercial fishing was completely banned throughout the entire Yangtze catchment.

Implementing this ban required enormous organizational and financial efforts. Around 111,000 fishing boats were taken out of operation, and more than 231,000 fishers in eleven provinces and major cities had to be relocated or retrained. The state invested more than US$2.74 billion for this.

However, the fishing ban is only one part of a comprehensive package of measures. The Yangtze River Protection Law also includes:

• strict controls on environmental pollution and severe penalties,
• the regulation of sand mining, bank development, industrial settlements, shipping, and aquaculture,
• the expansion of wastewater treatment,
• the reduction of agricultural nutrient inputs,
• as well as the promotion of research, protected areas, and restoration projects.

In the past ten years alone, more than US$300 billion has already flowed into conservation, management, and restoration measures in the Yangtze basin. Nevertheless, biodiversity loss long continued. The decisive question was therefore: can such a law actually work? That is exactly what a study published in the journal Science in 2026 has now investigated.

Data from 57 river sections—before and after the fishing ban

An international research team examined changes in fish communities in 57 sections of the Yangtze mainstem. The years 2018 to 2020 (before the comprehensive fishing ban) were compared with 2021 to 2023 after it came into force. The direct comparison shows a surprisingly clear recovery.

Thus, total fish biomass increased by a median of 209%—more than doubling within just a few years. This finding is particularly meaningful because biomass is considered a key indicator of an ecosystem’s productivity and stability. At the same time, biodiversity also increased: the number of recorded species rose by 13%. This is not a dramatic leap, but after seven decades of continuous decline, it marks a turning point.

In addition, individuals were distributed more evenly across different species. The so-called evenness value increased by 7%. This means that the system is no longer shaped by a few dominant species, and a more balanced—and therefore more stable—community is developing again.

Large-growing fish species that reach more than 20 centimeters in length as adults benefited particularly clearly. Their biomass increased by 232%. Smaller species, by contrast, recorded a slight decline of 18%. According to the study authors, this shift is a typical sign of the removal of intense fishing pressure: large, slow-growing species are the first to be depleted under heavy fishing pressure and can only recover once that pressure is removed. When fishing ends, they rapidly gain body mass and survival chances, and the ecological balance shifts again in favor of larger individuals.

In addition, the fish examined showed a better overall condition factor. On average, they were stronger and better nourished—an indication that not only stocks are recovering, but that environmental conditions in the river have improved as well.

A glimmer of hope for threatened Yangtze species

In addition to the general recovery of fish stocks, the study also documents initial positive developments in several highly endangered species. The researchers speak of “signs of an initial recovery” in migratory and threatened fish.

Particularly striking is the development of the tonguefish Cynoglossus gracilis. After the fishing ban came into force, its stocks increased and the fish migrated farther upstream again. This suggests that improved habitats and the disappearance of fishing gear are once again enabling it to reach traditional spawning grounds.

Several rare and threatened fish species also showed a positive trend despite still low population numbers. These include the Chinese sucker (Myxocyprinus asiaticus) and the cyprinid fish Ochetobius elongatus. These species remain rare, but their increasing presence in the surveys is considered an important signal that the ecosystem is becoming viable again. It is also interesting that not only species from targeted breeding and release programs are benefiting, but also those that so far have hardly been actively protected.

The researchers also recorded more individuals of the Yangtze sturgeon, which the IUCN classifies as extinct in the wild. However, this development does not indicate a self-sustaining wild population; it is primarily due to continued release programs and improved survival rates as a result of the fishing ban. Natural reproduction in the free-flowing river is still not considered assured.

The development of the only remaining freshwater mammal in the Yangtze is also impressive: the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis). Its population grew from 445 individuals in 2017 to 595 animals in 2022—a rise of around 33% within five years. This makes it one of the biggest winners of the fishing ban.

The researchers attribute this development to several factors. Thanks to the increase in fish biomass, the porpoises have more food available today. At the same time, the risk of dying as bycatch in nets or colliding with ships has decreased. The decline in shipping traffic and the associated underwater noise likely also contributed to relief. Taken together, both survival chances and living conditions have improved significantly.

Despite these encouraging findings, the researchers urge caution. In particular, migratory fish species such as the Yangtze sturgeon and the Chinese high-fin banded shark remain restricted in their reproduction and genetic diversity by large dams, because they still cannot reach their historic spawning grounds. For lasting recovery, additional measures such as fish passes, translocations, or new spawning habitats are necessary. The fishing ban has stopped the downward trend, but whether it will lead to long-term rescue is still open.

Why does the fishing ban work so quickly?

To understand why fish stocks recovered so markedly within a few years, the research team analyzed the relationships between conservation measures and biological changes using so-called structural equation models. These statistical methods allow multiple influencing factors to be considered simultaneously and quantify their respective contribution to the development of fish communities.

The result: the most important driver of the observed recovery is the complete removal of fishing pressure in the Yangtze river system. The fishing ban had the strongest direct effect on the increase in fish biomass and on the rise in species numbers.

During the study period, other environmental factors also improved: nitrate and phosphorus levels declined, shipping decreased, riverbanks were restored, and hydrological management—such as adjusted reservoir operations—was optimized. All these measures helped stabilize the system and improved living conditions for fish.

However, the models show: without the fishing ban, the rapid and clear recovery would hardly have been possible. Only the immediate cessation of direct biomass removal created the conditions under which stocks, body size, and species diversity could visibly improve within a few years.

What the law alone cannot solve

Despite the positive developments in the Yangtze basin, fundamental problems remain. Among the biggest are the large dams such as Gezhouba and the Three Gorges Dam, which continue to block migration routes for many fish species and limit exchange between subpopulations.

There are also pressures that the fishing ban can hardly influence: climate change is altering water levels and temperature regimes, microplastics are accumulating in sediments and organisms, and residues of pharmaceuticals and industrial chemicals continue to enter the river. These factors exert long-term effects on the ecosystem and can weaken recovery trends at any time.

The researchers therefore caution that although the successes so far are encouraging, they rest on a delicate balance. Without additional measures to improve river connectivity, further reduce pollutant inputs, and adapt to climate change, the current recovery remains fragile.

Could this work in other rivers as well?

The study’s authors emphasize that the experiences from the Yangtze could in principle also be relevant for other large river systems. They mention, among others, the Mekong and the Amazon, which also suffer from overfishing, habitat loss, and heavy environmental stress.

However, the model cannot simply be transferred. Decisive for success in the Yangtze was the interaction of several factors. In addition to the fishing ban, measures to improve water quality, restore habitats, and regulate industry and shipping were necessary. Equally important was social support for affected fishers, who were assisted through retraining and compensation.

Above all, the program required long-term political stability and consistent enforcement. Without reliable oversight, sufficient funding, and lasting political backing, comparable conservation measures in other regions would hardly be able to achieve the same effect.

A global signal

The Yangtze provides an impressive example that large-scale and politically courageous conservation laws can indeed have an impact. For more than seven decades, biodiversity in the river system declined almost continuously. Within a few years, this trend has now been halted for the first time.

The study reaches a clear conclusion: ambitious political decisions can slow biodiversity loss—even in one of the world’s most heavily burdened river systems. The Yangtze shows that even severely damaged ecosystems retain their capacity to recover if humans consistently give them space.

A ten-year, complete fishing ban may seem radical. It cannot bring back the Chinese river dolphin or the Chinese paddlefish. But in the Yangtze, within just three years this measure achieved what decades of half-hearted conservation efforts could not: fish biomass increased significantly, biodiversity is rising, large fish species are returning, and threatened species are showing the first signs of recovery.

Whether this development is lasting will become clear after 2030, when the ban is set to expire. But one thing is already certain today: for the first time in generations, there is well-founded hope again for Asia’s longest river.

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Source

• Xiong, F., Li, Z., Brosse, S., et al. (2026). Fishing ban halts seven decades of biodiversity decline in the Yangtze River. Science, 391(6786). https://doi.org/10.1126/science.adu5160