After decades of decline, the Ganga's fish diversity has made a significant comeback. A study by the ICAR-Central Inland Fisheries Research Institute (ICAR-CIFRI) reports 230 fish species thriving in the river, a 61 per cent increase since 2012 and the highest in 50 years.
“This is the result of a number of rejuvenation plans over the years, including the ongoing Namami Gange,” said CIFRI Director Basanta Kumar Das.
ICAR-CIFRI’s Fisheries Resource Assessment and Informatics Division head Srikanta Samanta said, “The Ganga rejuvenation plan, starting from the Ganga Project Directorate in the 1980s to the present National Mission for Clean Ganga, has significantly improved the ecology of the river.”
Scientific surveys conducted over more than two centuries provide a detailed understanding of the ecological changes in the Ganga. The first comprehensive assessment in 1822 recorded 271 fish species, indicating a highly diverse river ecosystem. But due to rapid industrialisation, untreated sewage, declining water quality, habitat loss and intensive fishing, the river saw a steady decline in fish diversity. By 1974, the number of recorded species had fallen to 207, and the decline continued into the late 20th century.
In 1991, studies showed only 172 species, with fish diversity reaching its lowest in the late 1990s. In 1998, the number dropped to 110 species, the lowest recorded.
The latest count of 230 species marks the strongest recovery in over half a century. Scientists attribute this improvement to long-term river rejuvenation initiatives, improved fisheries management and habitat restoration.
The study, covering 33 tributaries and six floodplain wetlands in the Ganga basin, found that Uttar Pradesh now supports the highest fish diversity along the river. Bijnor has 109 species, while Narora has 93.
In West Bengal, Farakka emerged as a key refuge, with 85 species recorded. Other stretches such as Berhampore, Frazerganj, Balagarh, and Tribeni showed moderate recovery. The lower reaches near the sea, including Diamond Harbour and Gadkhali, continued to report much lower diversity.
Officials said stock enhancement and river ranching programmes played a key role in reviving fish populations. ICAR-CIFRI carried out 167 ranching activities, releasing over 2.03 crore fingerlings of Indian major carps, Rohu, Catla and Mrigal, along with Mahseer, into the river system.
“The impact of ranching is clearly reflected in the increased landings of Indian Major Carps, with rises of 24.7 per cent at Prayagraj and 41 per cent at Varanasi compared to 1959,” officials said.
Progress has also been made in restoring Hilsa, a key migratory species. Since 2010, adult Hilsa released upstream of the Farakka barrage have been traced as far as Ballia in Uttar Pradesh, indicating a gradual extension of their migratory range.
The recovery of fish populations has been supported by improvements in water quality across river stretches. Scientists reported higher dissolved oxygen levels than in the 1980s, creating healthier conditions for aquatic life.
Monitoring data also show that levels of harmful metals and pesticides in the Ganga are now well below permissible limits. Although there is still pressure from dense human settlements along its banks, the river’s habitat has stabilised in many areas, aiding the recovery of fish populations.
Experts said this improved environment is not only helping fish populations recover but is also supporting the livelihoods of thousands of fishing communities who depend on the Ganga for food, income and cultural identity.
(With inputs from PTI)
1. How many fish species are currently found in the Ganga?
According to a recent study by the ICAR-Central Inland Fisheries Research Institute (ICAR-CIFRI), the Ganga River currently supports 230 fish species, reflecting a significant improvement in aquatic biodiversity.
2. How does this compare to earlier records?
This figure represents the highest fish diversity recorded in the Ganga in the last 50 years, marking a strong recovery after decades of ecological decline during the late 20th century.
3. What caused the decline in fish diversity earlier?
Fish diversity declined due to industrial pollution, untreated sewage discharge, habitat degradation, overfishing, and poor water quality, especially during periods of rapid urbanisation and industrial growth along the river.
4. What helped fish populations recover in recent years?
The recovery is linked to long-term river rejuvenation programmes, improved water quality, stock enhancement and river ranching initiatives, and better fisheries management practices implemented over the past decade.
5. Which regions along the Ganga show the highest fish diversity today?
The highest species diversity has been recorded in Uttar Pradesh, particularly in stretches near Bijnor and Narora, while parts of West Bengal such as Farakka have also emerged as important refuges.