Tenualosa ilisha, commonly known as Hilsa or Ilish, commercial and culturally significant fish species, is known for its remarkable anadromous migration – it travels from the sea to freshwater rivers to breed for reproduce their offspring. The migration of Hilsa is a crucial natural phenomenon that plays a pivotal role in their life cycle and is essential for the livelihoods of many coastal communities. These anadromous fish migrate thousands of kilometers, often crossing international borders, in search of suitable breeding grounds. The Hilsa migration is vital for both the fish’s life cycle and the livelihoods of coastal communities dependent on it. In the Ganges River, Hilsa fish typically begin their upstream migration from July, continuing through November. Conversely, downstream migration occurs from January to March. The peak of upstream migration coincides with the onset of the South-West monsoon, starting in July and extending through November.

Tenualosa ilisha

Farakka Barrage acts as a physical barrier to fish movement in River Ganga. As a result of these disruptions, Hilsa populations have faced declines in the upstream regions of the Farakka Barrage. The middle stretches of the Ganga River have experienced a severe depletion in the Hilsa fish population. Hilsa landings have seen a dramatic decline, ranging from 83.1% to 98.6%, in the middle stretch of the river (1995-2015), spanning from the Farakka Barrage to Prayagraj. Interestingly, downstream of the barrage, there has been an increase in Hilsa landings.