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Mai Po & Inner Deep Bay (Ramsar Site)

Wetlands where land meets sea | Northwest Hong Kong | Ramsar designated 1995 | ~1,500 hectares

Mai Po and Inner Deep Bay are where Hong Kong's wetlands meet the sea. At low tide, vast mudflats are exposed, stretching across the bay. Mangroves also line the shore. Traditional 'gei wai' shrimp ponds lie behind the mangroves, managed by local families for generations.

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This is not a charismatic coral reef, with colorful fish darting through clear water. But Mai Po is one of the most important coastal wetlands in East Asia. It's a crucial refueling station for tens of thousands of migratory waterbirds flying along the East Asian-Australasian Flyway.

Why it matters

Mai_Po_Marshes_view_2016.jpeg

By Wpcpey - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=53404790

Birds:

The site supports around 80,000 wintering waterbirds and 20,000–30,000 passage migrants each year, including the globally endangered Black-faced Spoonbill. The Ramsar Information Sheet notes that Mai Po has regularly held >20% of the global Black-faced Spoonbill population.

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Land-sea connection:

Freshwater from New Territories streams mixes with tidal seawater from Deep Bay. Nutrients and sediments flow from land to sea, linking upland habitats, wetlands, and coastal fisheries in one connected system.

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Blue carbon:

Mangroves and mudflats store carbon in their waterlogged soils. Protecting Mai Po means protecting a natural climate solution.

What you'll find there

  • Mudflats: Highly productive feeding grounds for shorebirds and invertebrates

  • Mangroves: Hong Kong's largest and best-developed mangrove stands

  • Gei wai shrimp ponds: Traditional, extensively managed ponds that provide supplementary feeding habitat for waterbirds

  • Freshwater marshes: Seasonal and permanent marshes supporting diverse plant and animal communities

Threats & management

Mai Po sits next to one of the world's largest cities. Urban development, pollution from the Pearl River Delta, and climate-driven sea-level rise all threaten the site. But Mai Po is also a conservation success story. Designated as a Ramsar Wetland of International Importance in 1995, it is protected under both Hong Kong law and international treaty. Management focuses on maintaining water levels, controlling invasive species, and balancing public access with bird conservation.

Why Mai Po belongs on Our Urban Sea

Mai Po broadens the story of marine conservation. It shows that protecting the coast is not only about what lies underwater — it is also about the wetlands that filter water, store carbon, and sustain life across the land-sea boundary. A marine map that stops at the shoreline misses half the story. Mai Po is where the story of Hong Kong's urban sea begins.

References

  • AFCD. (n.d.). Sha Chau and Lung Kwu Chau Marine Park. https://www.afcd.gov.hk/english/country/cou_vis/cou_vis_mar/cou_vis_mar_des/cou_vis_mar_des_sha.html

  • AFCD. (n.d.). North Lantau Marine Park https://www.afcd.gov.hk/english/country/cou_vis/cou_vis_mar/cou_vis_mar_des/cou_vis_mar_des_nl.html

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