On a mid-June morning, around 9h, strong Lao winds whipped up large waves across the sea off Phu Trach commune. After more than three hours spent diving for seaweed, Le Van Nam, 48, swiftly started his boat's engine, heading for shore. "With a full load of seaweed, the boat could easily capsize in these big waves," he explained.

At the An Hau boat harbor in Nam Lanh village, Phu Trach commune, Le Xuan Hieu, 53, started his workday at dawn. He fired up his basket boat's engine, grabbed his diving goggles, and set off for the waters near Yen Island - Vung Chua. This area is known for its submerged rock formations, densely covered with sargassum. The most opportune time for harvesting is during low tide, when the water is shallow and the waves are calm.

After navigating the waves for over 20 minutes, he anchored his boat approximately 500 m from shore. Below the surface, in waters over one meter deep, lay rocky outcrops teeming with sargassum. Donning his old diving goggles, he plunged into the sea, beginning hours of repeated dives among the reefs to collect the seaweed.

Sargassum, a brown seaweed, clings tightly to rocks on the seabed. To harvest it, divers submerge their heads, legs pointing upwards, using both hands to locate and detach each clump from its base. After nearly a minute underwater, Hieu surfaces with sargassum bundles, some several meters long. The seaweed is then collected around the basket boat and pulled aboard. This process repeats constantly: a deep breath, a dive to the seabed, cutting the seaweed, and bringing it to the surface. Sargassum (Sargassum), a type of seaweed from the Sargassaceae family, thrives in tropical seas. Along the Quang Binh coast, it grows densely on submerged reefs and is harvested seasonally by local fishermen.

Once anchored, the fisherman repeatedly dives to the seabed, harvesting seaweed. Each time he collects a substantial amount, he swims back to the boat's side and hauls the seaweed into the hull.

Divers explain that sargassum firmly attaches to underwater rocks and can reach several meters in length. During harvesting, fishermen carefully remove only the stems and leaves, ensuring the roots remain intact for regrowth in subsequent seasons.

Sargassum flourishes from April to June (lunar calendar). However, during the stormy season, waves often damage and decompose large seaweed beds. After periods of turbulent seas, seaweed frequently washes ashore along Phu Trach commune's coastline. Yet, most of this is fragmented and lacks commercial value. Only whole plants, with long stems and thick leaves, harvested directly from the seabed by divers, command a market price and provide income for the fishermen.

Once the sargassum bed around his boat was depleted, Hieu weighed anchor and moved to another reef to continue. Under the intensifying sun, the 53-year-old maximized his time while the sea was still calm. "The waves grow larger towards noon, making diving impossible, so I have to make the most of the calmer, less windy conditions now," he stated.

On shore, wives await to assist. As the boats dock, they swiftly transfer batches of seaweed from the vessels onto carts, bringing them to a processing area for initial preparation and drying. The seaweed, piled high on carts, is then moved to the sandy beach and spread in long layers to dry.

Under the scorching sun, nearing 40 degrees C, the hot sand burns. Locals, wearing conical hats and with faces covered, diligently dry the seaweed. Clumps of seaweed are carefully separated and spread in thin layers on the sand to ensure even drying and preserve quality.

Residents spread sargassum across Phu Trach commune's beach for sun-drying. By approximately 14h, when the seaweed darkens and becomes crispy, they shake off any sand and bag it. It is then sold to traders for about 7.000 dong per kg.

"My husband and I collect approximately 2 quintals of dried seaweed daily, earning nearly 1,4 million dong," stated Lan, Nam's wife.

A local trader indicated that after purchase, the sargassum is exported to China. However, the exact end-use remains unclear to the buyers. Various sources suggest sargassum serves as a raw material in medicine, food products, and several industrial applications.

Dac Thanh