At dawn on the tidal flats of the Red River estuary, the water shimmers silver as the tide recedes, revealing long stretches of mud reaching toward the distant mangrove forests. On the sea dike, residents start their day. Some households check the paddlewheels of their shrimp ponds, a group heads to the flats with baskets to rake for clams, and at a small riverside landing, a boat is ready to welcome visitors wanting to explore the mangroves. This rhythm of life tied to the sea and forest unfolds each day, forming the signature livelihood landscape of the Red River Delta Biosphere Reserve, where humans live alongside one of the most important tidal flat and mangrove ecosystems in northern Vietnam.

Amid shifting tides, erosion and accretion, and increasingly visible climate change, coastal communities have diversified their livelihoods: shrimp farming on the mudflats, seasonal harvesting of natural shellfish, tourist boat services combined with seafood cuisine, and check-in activities at still-pristine locations. But what distinguishes this coastal region is not only the diversity of livelihoods, but the way they are maintained through a close dependence on the health of the mangrove ecosystem.

The slow rhythm of life along the banks of the Red River, spanning the provinces of Ninh Binh and Hung Yen, seems to affirm that livelihood development can only be sustainable when the natural environment is protected. Conservation is meaningful only when local communities benefit from the ecological values they help preserve.

The sound of water trickling through the sluice gate, the wind pushing mats of algae along the shore, mornings at the small hut of Trinh Xuan Bay often begin like that. And in the buffer zone of Xuan Thuy National Park (the core zone of the biosphere reserve), the cautious footsteps of a man who has spent half his life understanding the lifeblood of the estuary still leave their mark. Nearly 60 years old, with more than 10 years managing 10 hectares of extensive shrimp ponds in Giao Minh commune, Mr. Bay still keeps the habit of reading the water color to gauge the “fullness or hunger” of the pond bottom, then slowly recounting stories of the past as if speaking to the shimmering tidal pond itself.

He vividly recalls the 1990s, when natural shrimp and fish were so plentiful that “one night could net 500 kilograms, more than we could ever eat.” The waters then carried silt and abundant resources from the Red River and the sea straight into every corner of the ponds. But now, the same waters have changed: saltier, more erratic, with less silt. The decline in natural food has reduced production. From earning up to VND 1 billion a year, he now makes only VND 300 to 400 million, even though his timing for releasing shrimp and raising crabs remains the same. Crabs are stocked in the tenth lunar month, black tiger shrimp in the second lunar month, and after each cycle he leaves the ponds idle for three months so the water can regenerate the ecosystem.

“The water rhythm decides everything,” he says, watching sunlight glaze a thin film over the pond. “Shrimp grow to the point where they are ready to leave the pond, and that is when you must harvest. Miss the water rhythm and you lose.”

A few bends away, Tran Van Huan, in his forties, is also living by that “breath”. Here, extensive aquaculture combined with forest stewardship is a profession where people treat water like a lifeline. Without industrial feed, shrimp grow only on algae, detritus, and plankton, all of which depend entirely on salinity, pH, and oxygen in each tide. “If the water goes bad, everything is gone,” Huan says, his eyes never leaving the water surface.

According to research by scientists from the Red River Delta Biosphere Reserve, if salinity exceeds 25 parts per thousand or pH moves outside 7.5 to 8.5, shrimp can suffer environmental shock and survival drops sharply. Therefore, each decision to open or close the sluice gate affects not only the farming season, but also the health of the adjacent mangrove forest.

Huan cannot forget the night before Typhoon Yagi, when he stayed awake until morning. “The river water rose like an underground storm, salty and murky. Every two hours I got up to check the gate. Too late and foul water would enter. Too fast and algae would wash away. Even one hour off and the entire season would be lost.” But for him, holding the water is never just about keeping shrimp. “Holding the water means holding the forest. If the forest dies, the birds leave. Without birds, the shrimp lose their natural plankton. The cycle is tight, held together by love for the land, not theory.”

Here, no textbook tells farmers when to open or close the gate. Their knowledge comes from footprints in the mud, from afternoons listening to birds signaling changes in the water flow, from sensing when the pond bottom is “hungry”, or when algae are just enough for another day of tide. Outsiders passing by would not understand why a single heron gliding across the sunset sky can make a water keeper look anxiously at the pond below.

From the stories of Mr. Bay and Huan, it is clear that the extensive aquaculture model in the Red River Delta Biosphere Reserve is an interwoven system: holding water keeps the forest, the forest keeps the birds, the birds sustain the natural nutrient cycle for shrimp. And as long as the rhythm of the tides is maintained, seemingly simple but fundamentally vital, people in this estuary can support their families while preserving the land they call home.

When the tide recedes, revealing vast moist mudflats, groups of people wade farther out, their footprints pressed gently into the soft mud. They bring bamboo rakes, simple nets, and worn plastic baskets. There is no engine noise, no smell of oil; only the soft suction sound of mud beneath their feet and small harvests gathered from nature bit by bit. In the Red River Delta Biosphere Reserve, natural fisheries remain steady, slow, clean, and harmless to the place that sustains them.

Nguyen Thi Muoi of Giao Hoa commune has spent more than 20 years “following the tide”. Each time the water retreats, she wades onto the flats with a small rake, searching for don, tiny bivalves that live deep in the saline mud and provide a decent income. “If there is plenty, I sell. If not, we eat it. As long as the water is clean and the forest remains, there will always be don tomorrow,” she says, her eyes fixed on the strip of mud she is raking.

Here, women like Muoi support entire families with simple tools, yet they are also the strictest guardians of sustainable harvesting, never using electric shocks, suction pumps, or destructive methods. Everything is written in community bylaws, the “soft law” co-developed by residents and the Red River Delta Biosphere Reserve Management Board so nature can regenerate after each harvest.

Vu Quoc Dat, Deputy Director of Xuan Thuy National Park, says about 1,000 workers from five buffer-zone communes enter the forest daily to gather natural products. Golden hours run from 5 a.m. until near noon, when the mudflats rise like fertile fields. To keep this livelihood from crossing the thin line between harvest and depletion, community patrol groups were formed, providing training and reminders, keeping rhythm for the entire community. “No one wants to exhaust the resource, because everyone knows that if the forest lives, we live,” Mr. Dat says.

Thirty years ago, this tidal area was proposed for a major sea reclamation project, with the idea of building three new coastal communes. But the plan fell apart due to unfavorable hydrology, high salinity intrusion, and insufficient disaster prevention infrastructure. What “failed” turned into an opportunity: livelihoods that do not destroy forests, livelihoods that depend on forests. Residents did not build concrete houses, only small huts to guard their ponds. From the tradition of “mangroves reclaiming land”, they shifted to a new direction: letting shrimp enter the forest, then letting shrimp protect the forest.

This gave rise to the ecological extensive farming model: stocking diverse species such as shrimp, crabs, and grouper, each finding its place in the natural food chain. No industrial feed, no heavy interventions. Algae, organic detritus, and plankton in the pond sustain each other, forming a closed nutrient loop. Each hectare yields VND 30 to 40 million, not much, but stable, enough to live, maintain ponds, and protect mangroves from being cleared.

Besides shrimp and fish, small livelihoods like collecting seaweed support hundreds of households. The natural seaweed growing along the flats provides Giao Minh and Giao Hoa residents an additional steady income: on idle days, just a few hours can yield 500 to 700 kilograms, earning about VND 200,000, not much, but important because it “does not harm anyone”, not even nature.

The entire ecosystem of the Red River Delta Biosphere Reserve, from pale-brown mudflats and comb-like mangrove branches to constantly shifting tidal flows, exists as a harmonious combination of harvesting, protection, and survival. Each year, migratory birds from northern Asia land in the mangroves like “sky rangers”, signaling that the land remains healthy, food-rich, and promising for people whose livelihoods depend on nature without harming it.

For years, one of the reserve’s most distinctive features has been the bird-watching tours, where visitors witness flocks flying from the far north, descending on the mudflats of Ba Lat estuary like returning to an old home. In winter, spoonbills, greenshanks, yellowlegs, gulls, plovers, and others spread into white, gray, and pale-brown patches over the mangroves like a living tapestry. This is also where rare species such as the black-faced spoonbill (Platalea minor), spoon-billed sandpiper (Eurynorhynchus pygmeus), and yellowlegs (Tringa flavipes) have been recorded, species that stop only in truly pristine environments.

Each bird season, tourists flock to Xuan Thuy National Park. On peak days, dozens of groups wait for boats to catch the best tidal window. They want to witness entire flocks bursting into flight, turning a part of the mangrove forest white for an instant, a moment easily missed.

Most of the boat operators are lifelong residents familiar with the tides. Among them, Dinh Van Nhat, 47, owner of Nhat Huong boat station, is a name every visitor remembers. He has worked in tourism for more than 10 years, starting with ferry rides to Bai Con, and in 2005 opened a small shop near Xuan Thuy National Park. At the same time, he welcomed early research teams studying conditions for establishing the park. Everything began simply: a wooden boat, a few pots of green tea, and the eyes of a man who knows every mudbank of the tidal zone.

Today, after several upgrades, Nhat runs a four-hour tour, about 30 kilometers across the reserve. The most praised feature is lunch on the boat: all ingredients come from the locality, freshly netted tiger shrimp, clam soup, sun-dried seaweed from the flats. He both steers and guides, introducing Con Lu, the mid-river sandbank, and the park’s history. Along the way, he reminds guests of simple but important rules: no breaking branches, no harming birds, no littering. “Going to see birds but harming them defeats the purpose,” he often jokes before anchoring for photos.

Besides international visitors, he also hosts students and university groups doing fieldwork. Some students conducting theses on birds are personally guided by him to feeding areas, where he teaches them to distinguish species. “So that when they work in conservation someday, they will know how to protect,” he says.

Alongside him, Le Tien Dung, a park officer, is deeply involved in bird-watching trips. Working at the park since its founding in 2003, from ranger to conservation specialist, he knows each species as old friends. He explains that migratory birds choose Xuan Thuy for two reasons: clean environment and abundant food. “The wetland fauna here is unique. Winter coincides with the period when farmers drain ponds after shrimp harvests, boosting food supply, which birds love,” he says while driving.

Passing clusters of mangrove and Avicennia trees, he suddenly brakes and turns off the engine. But even the faint movement of the car startles hundreds of birds into flight, whitening the sky. “They are very sensitive. One strange sound is enough,” he says softly, eyes following the flock circling back over the mid-river sandbank.

Not only park staff but buffer zone residents also help guard this “sky”. Mr. Trinh Xuan Bay, in addition to shrimp farming, guides bird-watching groups when needed. He and locals have formed 10 community patrol teams over more than a decade. Any unusual event, river debris, gunshots, tree cutting, is reported to the park immediately. “What belongs to everyone must be protected by everyone,” he says simply.

Thanks to this cooperation, each bird season brings a new vibrant rhythm to Xuan Thuy. Boat trips through the mangroves carry not only tourists but also the spirit of the region’s livelihood and conservation philosophy.

In recent years, a new vitality has flowed through the Red River Delta Biosphere Reserve, not only through clam rakes and shrimp ponds, but also through boats taking people into the wild for check-in experiences. Amid water channels, mudflats, and mangroves, each sunrise or sunset offers a moment for people to pause from urban life, breathe the salty sea breeze, smell the silt of the forest mud, and listen to birds and gentle waves.

These experiences are not vibrant or luxurious but simple, peaceful, and familiarly rustic. Visitors can wander the sandbanks, slip through mangrove clusters, stand on the sea dike facing the open ocean, and take photos against broad horizons, rippling waves, and green forests. In the afternoon, they can watch the sunset reflected on the reddish silted waters, a scene lost in many places due to rapid development. This raw beauty, with mangroves, mudflats, river mouths, silt, and tides, is a rare “specialty”.

Through layers of livelihood, people around the Red River Delta Biosphere Reserve have gradually built a harmonious way of living, where nature is a partner rather than a victim. Each shrimp pond, each clam rake, each boat tour, and each check-in photo carries responsibility for the environment. By protecting forests, water, and the lifeblood of the tidal landscapes, they preserve opportunities for future generations to live, make a living, and witness the beauty of estuarine nature.