He Fishes With Otters: But Bangladesh's Rising Saltwater Is Killing Them | Tides Of Time

Key Concepts

• King Tide: An exceptionally high tide occurring when the moon and sun’s gravitational forces align, often causing significant coastal flooding.
• Tidal Bore (Silver Dragon): A phenomenon where the leading edge of an incoming tide forms a wave that travels up a river against the direction of the current.
• Getbol: Korean term for vast, ecologically rich tidal mudflats.
• Microphytobenthos: Microscopic plants (algae/diatoms) living in the sediment of tidal flats, forming the base of the coastal food web.
• Salinization: The process of salt accumulation in soil and water, often exacerbated by rising sea levels and reduced freshwater flow.
• Land Reclamation: The process of creating new land from oceans or riverbeds, often through concrete development, which threatens tidal ecosystems.

1. The Sunderbans Delta: Adaptation and Survival

In the Sunderbans, the world’s largest mangrove forest, the king tides dictate the rhythm of life.

• Cooperative Fishing: Fisherman Shashura Bishwas utilizes a traditional, rare method of fishing with trained otters. The tides concentrate fish, but the increasing salinity—caused by freshwater being diverted for agriculture and rising sea levels—is disrupting this ecosystem.
• Human Displacement: In the village of Calabagi, rising tides and soil salinization have forced residents like Zafar Gazi to relocate inland. Researchers monitoring the area found that the soil is losing its freshwater integrity, with salt penetration threatening the viability of the land for future generations.

2. China’s Qiantang River: The "Silver Dragon"

The Qiantang River is famous for the "Silver Dragon," a legendary tidal bore.

• Ecological Role: The tidal bore acts as a massive natural mixer, carrying sediment and reoxygenating the river, which is vital for water quality.
• Human Interaction: Centuries of seawall construction have attempted to tame the river. However, massive land reclamation projects in the estuarine zone threaten to alter the river’s topography, potentially causing the tidal bore to disappear.
• The Surfer’s Perspective: Surfers like Anthony Kola and Jerome Cordoba treat the bore as a high-stakes challenge. Unlike ocean waves, a tidal bore is a "one-shot" event; if a surfer falls, the powerful river current poses a significant danger, pushing them toward concrete structures.

3. South Korea’s Getbol: The Legal Battle for Conservation

South Korea’s tidal flats (Getbol) are being contested between developers and environmentalists.

• Scientific Significance: With a tidal range of up to 9 meters, these flats serve as a "living laboratory" for studying microphytobenthos.
• Legal Precedent: A decade-long struggle culminated in a 2022 lawsuit by a civic coalition against the Ministry of Land, Infrastructure, and Transport to stop the Saemangeum airport development.
• Outcome: In September 2025, a Seoul court struck down the airport plan, marking a landmark victory for conservationists attempting to protect the remaining 30+ threatened tidal flats in the region.

4. Methodologies and Scientific Challenges

• Modeling Tidal Bores: Scientists struggle to accurately model tidal bores because they require precise, real-time data on river mouth conditions, bathymetry (underwater topography), and freshwater discharge. Because sediment transport constantly changes the riverbed, models are often inaccurate.
• Research Findings: The study of tidal bores is considered high-risk and high-cost, yet it is essential for understanding the physics of tsunamis, storm surges, and flood waves.
• Soil Analysis: Researchers in Bangladesh use salinity testing to track the "hanging homes" phenomenon, where rising sea levels create isolated islands, assessing how long the ground can structurally endure before becoming uninhabitable.

5. Notable Quotes

• On the Tidal Bore: "It’s like a monster. It’s like a tsunami... Whenever you fall from a river wave, behind is all the current pushing you." — Huang Xiong, drone pilot.
• On the Complexity of the River: "A tidal bore is a process that we still continue not to understand very well." — Unidentified Researcher.

Synthesis and Conclusion

The king tides serve as a global force that connects disparate regions through the shared challenges of climate change and human development. Whether it is the fishermen of the Sunderbans losing their livelihood to salt, the activists in South Korea fighting to preserve mudflats from concrete, or the engineers in China attempting to understand the physics of the Silver Dragon, the common theme is the struggle to coexist with a dynamic, rising ocean. The future of these coastal regions depends on a shift from "taming" the water to adapting to the inevitable rhythms of the moon and sun.