Monsoon Changes Threaten Bay of Bengal Fisheries: Hilsa and Marine Life at Risk

A new scientific study has sounded an alarming warning: Your favourite fish curry — especially those featuring hilsa — could soon become a rarity.

Published in Nature Geoscience, the research reveals that extreme weather events triggered by climate change are threatening the Bay of Bengal’s marine productivity, which supports millions across South Asia.

The Bay of Bengal’s Crucial Role

Despite covering less than 1% of the world’s ocean surface, the Bay of Bengal contributes nearly 8% of the global fishery production. It is a lifeline for over 150 million people who depend on it for protein and livelihood.

Key species like the hilsa fish, a culinary staple in India and Bangladesh, are particularly vulnerable.

What the Study Found

Led by researchers from Rutgers University, the University of Arizona, and international collaborators, the study reconstructed 22,000 years of monsoon and ocean history by analyzing fossilized shells of microscopic plankton called foraminifera.

Key findings include:

Both abnormally strong and weak monsoons block essential nutrient mixing in ocean waters.
Surface food availability declines by up to 50% during periods of intense rainfall or drought.
Extreme monsoon variability, amplified by global warming, risks permanent disruptions to marine ecosystems.

During the Heinrich Stadial 1 period (17,500–15,500 years ago), weak monsoons reduced wind-driven nutrient circulation, while during the early Holocene (10,500–9,500 years ago), strong monsoons created a freshwater “cap” that similarly starved plankton.

Why This Matters

"The ocean’s ability to support plankton growth is the foundation of the marine food web. Its decline would catastrophically reduce fish stocks," warned Yair Rosenthal, a climate scientist at Rutgers and study co-author.

Already, overfishing pressures — especially from artisanal fisheries that account for 80% of Bangladesh’s marine catch — are pushing fish stocks below sustainable levels.

The combination of climate stress and unsustainable fishing could devastate the Bay’s fisheries, hitting coastal communities hardest.

The Case of the Beloved Hilsa

The hilsa fish, celebrated in Bengali and Odia cuisine, is particularly vulnerable.
If marine productivity continues to crash during future extreme monsoon events, hilsa populations could collapse, driving up prices and making this beloved dish a rare luxury rather than a common meal.

Urgent Need for Action

According to Kaustubh Thirumalai, lead author of the study, both:

Stronger monsoons (more freshwater runoff) and
Weaker monsoons (less ocean mixing)
pose equal threats to the marine resource base.

The study stresses the urgent need to refine climate models and implement sustainable fisheries policies.

"These insights can inform strategies to protect coastal resources as climate impacts accelerate," said Rosenthal.

A Tipping Point for the Bay

The findings present a stark reality:

The Bay of Bengal’s role as a global food source hangs in the balance.
Immediate climate action and strict fishery management are critical to avert disaster.

Without intervention, millions could face food insecurity, economic displacement, and the loss of cultural heritage tied to iconic dishes like hilsa curry.

Conclusion

The Bay of Bengal’s future — and that of the communities it nourishes — demands swift, coordinated action.
Protecting this marine ecosystem is not just an environmental issue — it's a matter of food security, economic stability, and cultural preservation for millions.