One Of The Most Expensive River Fish In The World Is Declining Due To Climate Change

The Case Of Hilsa

A couple of years ago, a famous video by the Quint went viral; it humorously portrayed the inevitable fight between West Bengal and erstwhile East Bengal regarding whose Ilish maach (Hilsa fish) is the best? Meaning which side’s Ilish tastes better? ‘Ganga r Ilish ne Podda r Ilish’ (Ganga’s Ilish or River Padma’s Ilish?). As an Assamese who shares culinary similarities with neighbouring Bengalis, there are many emotions attached to the famous Ilish maach or the Hilsa fish.

Hilsa is the national fish in neighbouring Bangladesh, and is one of the costliest river fish in the world, with rates as high as Rs 900-1000 per kg! But it scares me to say that recent changes in climatic conditions along with a rise in anthropogenic activities have caused this fish to change its route. Before the Farakka barrage was commissioned in 1975, the Hilsa fish used to travel up to present-day Kanpur. The Farakka barrage was a necessity to keep the Kolkata port alive and relieve it from siltation as it is a major problem in almost all the rivers of Eastern India.

A recent report by the Times of India titled: ‘Hilsa changes route, migrates to Bangladesh waters’, dated 23 September 2019, stated a similar problem; the production has decreased to a quite an extent leading to economic losses. Often referred to as the King of fish, Hilsa is found to change its migration routes as a result of getting trapped in fishing nets and submerged sand bars.

An important fish of the Indo-Pacific region, the Hilsa is found in the Persian Gulf, Red Sea, Arabian Sea, Bay of Bengal, Vietnam Sea, and China Sea. The riverine habitat covers the Satil Arab, and the Tigris and Euphrates of Iran and Iraq, the Indus of Pakistan, the rivers of eastern and western India namely, the Ganga, Bhagirathi, Hooghly, Rupnarayan, Brahmaputra, Godavari, Narmada, Tapti, and other coastal rivers. It also covers the Irrawaddy of Myanmar, and the Padma, Jamuna, Meghna, Karnafully and other coastal rivers of Bangladesh. The major portion of Hilsa, (about 90%) is captured by Bangladesh, India and Myanmar. (Source: Decadal Studies of Hilsa and its Fishery in India -A Review)

But according to scientists, there has been an overall decline in the presence of the revered Hilsa in all of the major river transboundary river systems across India, Bangladesh, and Myanmar. The Hilsa is anadromous in nature, i.e., capable of withstanding a wide range of salinity, and migrating long distance from marine habitat to up-stream freshwater. Hilsa lives in the sea for most of its life but migrates to inland freshwater through rivers in Indian sub-continent for spawning.

An IUCN study, on the Hilsa fish, a few years ago, came up with an extensive document tracing the migration route of the fish, which was a joint study between India and Bangladesh. The study came up with the following reasons for the changing patterns in the route of the fish. They are:

1. River siltation has emerged as one of the major problems in Bangladesh. This phenomenon leads to a serious threat to river morphology, biodiversity, and depended on livelihoods as well.
2. High levels of sedimentation, (>200- 300 mg/l) can cause fish mortality.
3. It reduces sunlight penetration into the water, so it can cause changes in fish feeding behaviour.
4. Sediments silts can sink or suffocate fish eggs.
5. Sediments can carry toxic substances from agriculture and industry that can cause fish death.
6. Siltation reduces water transparency that is very crucial for fish spawning and migration as well.
7. Siltation and sedimentation narrow and shift river paths; that is also a reason for damaging fish habitats.
8. Overfishing in the estuarine mouth region created barriers, and also dispersed Hilsa on its way to breeding migration in the upper freshwater environment.
9. Under-sized fishing, through zero and small meshed gill/current nets, and unwanted hauling of the juveniles, are major human factors affecting the migration, spawning, and recruitment success of Hilsa.

The Way Forward

Who would have thought that climate change, mismanagement of river and coastal systems could bring about fighting conditions among people for the Ilish/Hilsa? And it is going to rise further if we don’t act soon. The decline in the production of the Hilsa on the Indian side has been a rising concern in the recent past. Few policy recommendations include, awareness generation and capacity building, ban on fishing during the spawning period, and also assisting and encouraging the locals to look for alternative livelihood options during this period, adhering to the regulations pertaining to the mesh size, having dedicated Hilsa fisheries and conserving them, etc.

Both India and Bangladesh should come together, along with the associated stakeholders, to decide upon the future of Ilish, to decide upon the economic conditions of millions of people who lives revolve around the fish and also for the sake of sustainability! 

Food (read Ilish) for thought?