Brantas River Crisis: Pollution Threatens Fish and Livelihoods in East Java

The Brantas River, one of East Java’s longest and most vital waterways, is in a state of environmental collapse. Severe pollution from industrial waste, plastic debris, and unregulated riverside settlements has led to the extinction of at least half of its native fish species over the past decade, according to local researchers and activists. With 17 million people across 17 cities and regencies depending on the river for water, food, and livelihoods, the crisis has sparked urgent calls for government intervention.

On Monday, dozens of activists from the Nusantara Freshwater Fish Lovers Community (Kopipa) staged a poignant protest in Surabaya, floating replicas of the extinct Hampala barb fish down the Kalimas River, a tributary of the Brantas. Their message was clear: without immediate action, the river’s ecosystem—and the communities it sustains—faces irreversible damage.

“The Brantas River is a nationally strategic waterway, but it is now in a critical state,” Jofan Ahmad, coordinator of Kopipa, told local media. He pointed to inadequate government oversight of industrial waste and plastic pollution as key drivers of the river’s decline.

A Dying Ecosystem

Research by Ecological Observation and Wetland Conservation (Ecoton), a Surabaya-based environmental group, paints a grim picture. A study conducted last year found only seven species of local fish remaining in the downstream areas of the Brantas River, compared to 13 documented a decade ago. Among the species lost are the Schilbeid catfish, bronze featherback, and several types of cyprinid and ray-finned fish—once staples of the river’s biodiversity.

Kurnia Rahmawati, a fish and culture researcher at Ecoton, highlighted the broader implications of these losses. “Indonesia is the second-largest fish producer in the world after China, yet it also ranks among the highest for freshwater fish extinction, just behind the Philippines,” she said. “Freshwater fish are a critical source of protein for many communities. Their decline poses a direct threat to food security.”

Disturbingly, Ecoton’s research also uncovered a stark imbalance in the sex ratio of surviving fish, with females outnumbering males by more than two to one. This disparity, researchers suggest, may be linked to endocrine-disrupting chemicals found in industrial and domestic waste, which can cause intersex conditions in fish and slash reproductive rates by up to 76 percent. Microscopic images of fish stomachs from the Brantas, widely circulated by activists, reveal ingested plastic fibres and fragments—a visceral symbol of the river’s toxic burden.

Industrial Culprits and Human Costs

Stretching over 320 kilometres, the Brantas River winds through some of East Java’s most industrialised areas, supporting a population of millions. Yet, its proximity to industry has become its downfall. Ecoton has identified numerous potential pollution sources along the river, including 12 paper mills, 14 sugar factories, 4 flavouring plants, 20 recycling facilities, and 5 feed mills. Without stringent regulation, waste from these operations—laden with harmful chemicals—flows directly into the river, poisoning its waters.

The human toll is equally alarming. Fishermen, farmers, and riverside communities who rely on the Brantas for their daily needs now face dwindling fish stocks and contaminated water. “If this pollution continues unchecked, not only will more fish species disappear, but the livelihoods of thousands will be at risk,” warned Zulfikar, a member of Kopipa.

The crisis is not unique to the Brantas. A 2024 report from Indonesia’s Environment and Forestry Ministry revealed that 60 percent of the country’s rivers are severely polluted, with industrial and domestic waste, dam construction, land use changes, and invasive species all contributing to the degradation of aquatic ecosystems. For a nation where rivers are lifelines for millions, the scale of the problem is staggering.

Calls for Action

Faced with mounting evidence of environmental devastation, activists and researchers are pressing the East Java administration to act decisively. Ecoton and Kopipa have proposed a series of measures to curb pollution and restore the river’s health. These include installing CCTV cameras and water quality monitoring devices at every industrial waste outlet along the Brantas, with real-time data made publicly accessible to ensure transparency.

They also advocate for the creation of a dedicated task force to oversee liquid waste disposal in East Java, alongside a comprehensive river restoration programme aimed at rehabilitating fish habitats. Such initiatives, they argue, are essential not only for the river’s ecosystem but for the well-being of the millions who depend on it.

“The government must take immediate action,” Zulfikar urged. “Pollution in the Brantas River directly impacts food security and the health of local communities. We cannot afford to wait.”

The plight of the Brantas River reflects a broader environmental crisis gripping Indonesia. As industrialisation and urbanisation accelerate, the nation’s waterways are increasingly treated as dumping grounds for waste, with little regard for the downstream consequences. The introduction of non-native fish species, often for commercial purposes, has further strained local ecosystems by outcompeting native species for resources.

Moreover, large-scale infrastructure projects, such as dams, disrupt fish migration patterns and alter downstream environments, compounding the pressures on already vulnerable species. Land use changes—converting natural riverbanks into industrial or residential zones—have stripped away critical habitats, leaving fish and other wildlife with nowhere to go.

For communities in East Java, the stakes could not be higher. The Brantas River is more than a waterway; it is a source of life, culture, and sustenance. Its decline threatens not just biodiversity but the very fabric of local society, from fishermen who can no longer cast their nets to families who struggle to access clean water.

A River at a Crossroads

The crisis in the Brantas River is a stark reminder of the delicate balance between industrial progress and environmental preservation. While Indonesia’s economic ambitions have propelled it onto the global stage, the cost to its natural resources is becoming increasingly apparent. If left unaddressed, the pollution plaguing the Brantas could serve as a harbinger of wider ecological collapse across the archipelago.

There is, however, room for hope. Community-led initiatives, such as those by Kopipa, demonstrate a growing awareness of the need to protect Indonesia’s rivers. Coupled with rigorous scientific research from organisations like Ecoton, these efforts provide a roadmap for recovery—if only the political will can be mustered to follow it.

The East Java administration now faces a critical decision. Will it prioritise short-term industrial gains, or invest in the long-term health of its rivers and people? For the Brantas—and the millions who call its banks home—the answer cannot come soon enough.

As Kurnia Rahmawati of Ecoton put it, “This is not just about fish. It’s about our future. If we lose our rivers, we lose a part of who we are.” Her words echo a sentiment felt by many in East Java: the fight for the Brantas is a fight for survival.