KOLKATA, India (The Statesman/ANN) The Indian shad, commonly known as the hilsa (herring), is one of the most sought after species of fish on the Indian rice platter. But its habitats in the Gangetic plains are in decline because of over fishing.
Every year the monsoon’s first shower brings in schools of migratory “Indian shad (Tenualosa ilisha )” a species of fish commonly called hilsa (herring family) from the Bay of Bengal to the river Ganges for breeding. This amazing event sustains hilsa fishery in the river and has long been important to the economic and cultural heritage of the people of the Gangetic plains for whom the fish is a delicacy and “lucrative” item of Piscean export around the world.
The legacy of silvery hilsa — its peak and ebb — in India shares a common lineage with Bangladesh and Myanmar, where the species abounds in the mighty sweet water rivers looping through the lush verdant plains.
But after decades of migration barriers, over-fishing and pollution, this iconic fish’s habitat restricted now to the Bhagirathi-Hooghly river system below Farrakka barrage in the northern reach of Bengal, is witnessing an alarming decline.
The present scarcity of the exotic fish and its exorbitant price - ranging from 800-1200 rupees per kg in West Bengal - has raised serious concerns about the population of hilsa, its habitat management and conservation strategies.
An understanding of the gravity of the problems responsible for the decline of hilsa over the years is essential to visualise the tasks ahead for arresting the decline and ecologically restoring the silvery fish in the Ganges.
Fisherfolk and connoisseurs fondly remember the period prior to 1972 when hilsa provided a lucrative livelihood in the mid-stretch of the river, providing valuable protein, and generating employment for thousands of riparian fishermen in Uttar Pradesh, Bihar and West Bengal. The tragic decline of the hilsa started after the commissioning of Farakka Barrage in 1972.
The fragmentation of the river connectivity blocked the migration of mature hilsa from the sea to the river for breeding and the downstream migration of their progeny to the sea. As a result hilsa fishery upstream gradually collapsed. Assessment of the production trends of hilsa from 1961 to 2013 in the middle stretch of the Ganges by Central Inland Fisheries Research Institute (CIFRI) revealed a significant decline in the annual average production from 36 tons to 0.9 tons.
However, Hilsa fishery survived in the Bhagirathi-Hooghly river system below the barrage, sustained by the fish catch from the inland and marine coastal waters. During the pre-Farakka period (1957-1972) the average annual yield from the Bhagirati-Hooghly river system was 1472 tons. In the post Farakka period (1975-1999) the average annual yield increased to 6370 tonnes and recorded a significant increase to 76,100 tons in 2002.
But thereafter, the yield declined to 18,000 tons during 2013-14. The significant increase in the yield recorded from the 1990s was mainly due to the tremendous increase in mechanised and non-mechanised fishing crafts and drift gill nets for catching fish throughout the year in the lower estuarine- marine zone of the river.
The ‘total catchable potential’ (TCP) of hilsa as estimated by CIFRI for the Bhagirati-Hooghly river system is 3507 tons which has already been exceeded showing signs of over exploitation. But unfortunately the natural recruitment of young ones to enhance the hilsa population is seriously hampered by wanton killing of juvenile hilsa (khoka ilish). Recent findings by CIFRI reveal that during the period 1998-2012, the average catch of juvenile hilsa (2 to 20grams) from the system was a staggering 85 tons per year. Experts predict that saving even 1 per cent of these juveniles could enhance the hilsa production by 4,000 tons per year.
The government, the scientific community, fisherfolk and the public were aware of the aggravating problems of migration barrier, overexploitation and deteriorating water quality in the river leading to a decline in hilsa population. The two fish passes (fish locks) constructed in Bay No. 24 and 26 of the Farakka barrage for migration of hilsa were non-functional since their installation. A concerted effort was not undertaken to make the fish pass facility functional.
It would be pertinent at this point to draw a comparison of Gangetic hilsa fishery with the “American shad (Alosa sapidissima)” fishery in Chesapeake Bay, United States. Similar to the “Indian shad”, the “American shad” also migrates from the sea to freshwater rivers in the Chesapeake Bay for breeding. For 200 years it contributed luxuriant fishery in the Chesapeake Bay. But decades of a migration barrier, harvesting pressure and water quality deterioration led to the decline of production from 175 million pounds to 2 million pounds in 1970.
To restore the valuable fishery, an American Shad Fishery Management Plan was developed. At present shad restoration is underway in 15 river basins from Maine to Virginia. It is reported that between 2000 and 2014, more than 170 miles of spawning habitat has been created and American shad abundance in the Chesapeake Bay increased from 11 to 44 per cent of the goal set. Removal of migratory barriers has been a prime feature of the restoration programme.
The encouraging success achieved can serve as an example for initiating efforts in our country to install an effective fish pass in the Farrakka barrage and remove the only barrier for hilsa migration in the Ganga. A whole body of interdisciplinary experts spanning engineers, fishery scientists, hydrologists and ecologists can address the significant gaps in our understanding of appropriate fish pass facility and design a fish pass for the hilsa in Farakka dam akin to the fish elevators designed for shad migration in Chesapeake Bay.
The Ganga River Basin: Environment Management (GRB EMP) Plan being prepared by seven IITs of the country should consider incorporating this important aspect. Restoring the unhindered migratory run of hilsa to the spawning grounds in mid Ganges should be an important benchmark for eco-restoration of Ganges under the plan.
The second important issue is the problem of over-exploitation leading to depletion of the hilsa fishery in the the Bhagirati-Hooghly river system. Fisheries being a state subject, the control and management of hilsa in the river rests with the Government of West Bengal. In 2013, a specific notification to control overfishing and conserve hilsa was issued by the government.
The salient features of this are:
- Prohibition on catching hilsa using nono-filament gill net having mesh size below 90mm
- Prohibition on catching tender hilsa (khoka ilish or the fishlings) below 23 cm using any net of mesh size below 1 inch during February to April
- prohibition on transport, marketing, selling and processing hilsa having length 23cm
- Declaring five hilsa sanctuaries on Hooghly river from Farakka to Sagar covering a stretch of 250 km (fishing has been banned in the hilsa sanctuaries between June and August and October to December every year
- Prohibition of fishing within 5km of the Farakka barrage round the year
- Prohibition of bottom trawling in shallow continental shelf (12 nautical miles) for purpose of conservation of coastal biodiversity and habitat, necessary for survival and growth of hilsa.
In spite of these prohibitions, at present there is hardly any control over the exploitative system being practiced by fishermen. Fisherfolk complain that the six month ban on fishing in the declared hilsa sanctuaries is a proclamation of ban on livelihood practices of lakhs of them without providing any alternative livelihood. Surveillance especially in the marine zone is inadequate resulting in destructive fishing not only by the local fishermen but also by intruders from other countries.
The enforcement agencies’ vigilance at both landing sites and market places is constrained due to limited man power and lack of infrastructure. Creating awareness among consumers and various other stakeholders has become necessary to conserve the fish. The practice of holding hilsa festivals in West Bengal reflects the ignorance of people towards conservation of the valuable fish.
The third most important issue pertinent to the survival of hilsa fishery in the Bhagirathi-Hooghly river system is trans-national. At present 90 per cent of the global hilsa harvest comes from three countries - Bangladesh (50), India (20) and Myanmar (20). The shallow coastal waters of Bay of Bengal nurse the largest volume of hilsa. With the onset of monsoon the same stock of resident hilsa migrates inland for spawning in major regional rivers, Ganga in India, Padma, Jamuna and Megna in Bangladesh and Irrawaddy in Myanmar. Member countries share the view that the decline in hilsa production is due to a combination of the closure of the migratory routes, river siltation and overfishing. Therefore management and conservation of this mother stock of hilsa population in the bay is of utmost importance.
A welcome development has been that several research and development organizations like, ICAR-CIFRI in India and BFRI in Bangladesh at the national level, and IUCN, BOBP, BOBLME, IIED at the international level are collaborating to save the hilsa from extinction. Given the migratory nature of the fish it is encouraging to note that the research priority of most of the collaborative programmes is to assess the existing hilsa population in the Bay of Bengal and to develop innovative methods for conserving the species.
For conservation of hilsa fishery in the Ganga a realistic assessment of the hilsa population in the Bhagirathi-Hooghly system is imperative. Concerted efforts should be made to restore the fishery upstream by designing an effective fish pass facility in Farakka barrage.
United political will of the Central and state governments and involvement of stake holders is needed to effectively implement conservation measures for eco-restoration of hilsa fishery in Ganga.
(The writer retired as Head of the Fishery Resource & Environment Management Division, Central Inland Fisheries Research Institute, Barrackpore.)
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