Unlike Any Other The Halda River
In the hills and fertile valleys of southeastern Bangladesh flows a river unlike any other the Halda River. To the untrained eye, it may seem like just another South Asian waterway, winding through Chattogram and Khagrachhari districts.
But beneath its currents lies a living laboratory of biodiversity and culture, an economic lifeline for thousands of households, and a fragile ecosystem facing the same pressures that haunt rivers across the globe: pollution, over-exploitation, and the delicate struggle to balance conservation with development.
The Halda River is the world’s only tidal river where carp fishes like rui, katla, mrigal, and kalibaus engage in natural spawning and release fertilised eggs. For centuries, this phenomenon has sustained fishing communities, feeding aquaculture industries and embedding traditions into the cultural fabric of Bangladesh.
Alongside its fisheries heritage, the river is home to endangered Gangetic dolphins (Platanista gangetica), whose presence signals the ecological health of the waterway.
Yet the Halda River is also a site of tension. It is where modern pressures, tobacco cultivation, industrial encroachment, pollution, clash with centuries-old community practices. Its fate is a microcosm of global riverine challenges: the fight to conserve biodiversity while maintaining human livelihoods.
The Halda River: A Cradle of Life and Livelihood
Originating in Khagrachhari’s hill tracts, the Halda River snakes through valleys before merging with the Karnaphuli. For generations, it has been a cradle of aquatic wealth. Historical records reveal that in 1946, nearly 250,000 kilograms of fertilised carp eggs were collected from its waters, an unmatched bounty illustrating the river’s extraordinary natural productivity.
Though yields have declined in recent decades, the Halda River remains vital. Fisheries experts estimate it contributes approximately Tk 800 crore (USD 68 million) annually, factoring in fish production, hatcheries, aquaculture, and employment in surrounding areas.
Egg collection is not just an economic activity. It is a cultural ritual. During Baishakh and Jaishtha (April and May), local communities line the riverbanks, boats ready at night. They wait for mother carps to spawn under optimal rainfall, temperature, and current conditions. Fertilised eggs are nurtured in earthen wells or hatcheries until fry are ready for sale or farming. This cycle links rural livelihoods with Bangladesh’s national economy, showcasing a harmonious blend of tradition and modern aquaculture.
Positive Signs: Dolphins as Guardians of the Halda River
If carp are the Halda River’s economic lifeline, the dolphins are its ecological spirit. The river hosts Gangetic dolphins, a freshwater species once abundant across South Asia but now endangered due to damming, pollution, and human interference.
A 2018 survey by Chattogram University’s Halda River Research Laboratory (HRRL) recorded 167 dolphins. Two years later, numbers dropped to 127, only to rebound slightly to 147 in 2022. These fluctuations reflect both the fragility of the species and the resilience of the river when protected.
For locals, dolphins are more than wildlife; they are guardians of the river. Their presence indicates a healthy ecosystem, critical for sustaining fish populations and community livelihoods.
Globally, freshwater dolphins face dire threats. The extinction of the Yangtze dolphin and the decline of Amazon river dolphins underscore the urgent need to protect habitats like the Halda River. Bangladesh now occupies a critical role in freshwater conservation, providing lessons for river management worldwide.
Negative Impact: Pollution and Industrial Pressures
Despite its wealth, the Halda River has endured relentless human pressures. Decades of industrial activity, mechanised boats, unregulated dredging, and indiscriminate netting of brood fish have eroded water quality.
Recent progress has included shutting down factories such as Asian Paper Mills and the Hathazari 100-megawatt power plant, restricting mechanised boat movements, and seizing illegal nets. Yet the threat persists, more insidious than before. Tobacco cultivation upstream, particularly in Manikchhari and Ramgarh, introduces pesticides and chemical runoff during monsoons, contaminating the river and damaging carp spawning grounds.
Household and poultry waste further pollutes tributaries. Unlike industrial discharges, these diffuse sources are hard to regulate, gradually eroding water quality and endangering both fish and dolphin populations. Invasive species, such as banned sucker fish, compete with native fauna, complicating conservation efforts.
Community Action: A Beacon of Hope
The Halda River is not solely a story of decline. Community and government interventions have shown that recovery is possible. In 2016, a project promoted vegetable cultivation upstream as an alternative to tobacco. Backed by the Integrated Development Foundation (IDF) and financed by Palli Karma-Sohayak Foundation (PKSF), it reduced tobacco farming nearly to zero by 2020. Farmers received seeds, saplings, fertilizers, and loans, proving that sustainable alternatives are profitable.
Government officers continue awareness campaigns and regular dialogues with farmers, aiming to sustain these gains despite renewed pressure from tobacco companies. Parallel efforts by fisheries officers, including the seizure of over 90,000 meters of illegal nets in eight months, demonstrate the power of coordinated enforcement.
The government’s “Development and Management of Halda River Natural Fish Breeding Ground Project” supports hatcheries and training programs, reinforcing traditional practices with scientific oversight. In 2020, the river was declared a “Fisheries Heritage” over 23,800 acres, linking conservation with national identity and pride.
Positive Momentum: Revival of Natural Spawning
In May 2025, egg collectors harvested 14,000 kilograms of fertilised carp eggs, a remarkable increase from 1,680 kilograms the previous year. Heavy rainfall, runoff, and cleaner spawning grounds allowed mother carps to perform natural spawning in abundance.
Collectors celebrated the seasonal harvest, some continuing traditions over 50 years old. The coordinated monitoring by HRRL, Bangladesh Fisheries Research Institute, and river police ensured optimal results.
This rebound shows that targeted interventions can yield rapid results. It also offers a global example of how river ecosystems can recover when pollution is reduced and communities are engaged.”
Negative Consequences: Economic and Ecological Fragility
Despite these successes, the Halda River remains vulnerable. Pollution, upstream land-use changes, and invasive species threaten both fish productivity and dolphin survival. Every year of unchecked runoff or illegal fishing erodes the river’s value, jeopardising livelihoods and national aquaculture output.
The decline of fish or dolphin populations would reverberate beyond Bangladesh, affecting regional biodiversity and aquaculture economies across South and Southeast Asia. The river’s fragility underscores the urgent need for sustainable management.
Global Significance of the Halda River
Why should the world pay attention to a river in Bangladesh? The Halda River is ecologically and economically significant on a global scale.
Its unique natural carp spawning preserves genetic diversity crucial for global aquaculture. Its freshwater dolphins are among the last strongholds of a vulnerable species. Its flood-mitigation role supports climate resilience in deltaic regions. Cultural traditions surrounding egg collection represent an intangible heritage, linking human society to natural cycles.
The Halda River also exemplifies how governance, science, and community collaboration can restore a threatened ecosystem. International researchers and policymakers can draw lessons applicable to river conservation worldwide.
Opportunities: Eco-Tourism and Innovation
Eco-tourism around the Halda River’s spawning grounds and dolphin habitats could generate sustainable livelihoods while raising global awareness. Integrating traditional practices with modern hatchery technologies could reduce pressure on the river and improve productivity.
Developing climate adaptation strategies around the river would further highlight its role as a natural buffer against floods, supporting food security and economic resilience in Bangladesh’s delta. International collaborations, conservation funds, and technological expertise could strengthen monitoring and management.
Positive Lessons: Community and Policy Synergy
The Halda River shows that targeted interventions combining policy frameworks, scientific research, and local engagement, can reverse ecological decline. Its revival demonstrates the potential of participatory conservation, even in densely populated and resource-constrained settings.
“The Halda River is proof that community-driven conservation can work,” says MNUA Chowdhury. “It’s a model for other nations managing rivers under human pressure.”
A River Worth Saving: Local and Global Imperative
The Halda River is more than water flowing through Bangladesh; it is a living mosaic of biodiversity, culture, and economy. Its revival offers hope that rivers under pressure can recover when human activity is managed wisely.
Decline in the river would affect not only local livelihoods but also global aquaculture, freshwater biodiversity, and climate resilience. Conversely, its protection offers lessons for river conservation worldwide: the importance of community engagement, cultural respect, scientific monitoring, and policy enforcement.
For Bangladesh, the Halda River nurtures livelihoods, heritage, and ecosystems. For the global community, it is a rare ecological jewel. Saving it is a moral, environmental, and economic imperative, a chance to demonstrate that human development and nature conservation can coexist.