The seaweed harvesting season typically runs from May to July, when fishermen head offshore to collect the algae before it naturally withers.
Le Van Minh, a 68-year-old fisherman in Tam Hai, said harvesters usually travel about one kilometre from shore and dive to depths of 3-5 metres to cut the seaweed.
Once cut, the seaweed floats to the surface and is collected before being brought ashore for drying.
Minh said he and his wife dry between 100 kilogrammes and 200 kilogrammes of seaweed a day. With dried seaweed selling for about VND 5,000 per kilogramme, the couple can earn between VND 500,000 and VND 1 million a day during the season.
"We harvest while protecting the resource. We do not collect immature seaweed or harvest out of season so it can regenerate for future years," he said.
Another fisherman, 70-year-old Pham Van Giao, said a typical harvesting trip lasts between four and six hours and can generate daily earnings of VND 700,000 to VND 1 million.
Despite the income, he said the work carries risks, including hearing problems caused by water pressure and the possibility of basket boats capsizing in rough seas.
The seaweed trade also creates seasonal jobs for local women, who help dry and clean the harvest before it is sold.
Tran Thi Huong, 59, said she earns about VND 130,000 for processing each 100 kilogrammes of seaweed.
Local trader Le Thi Lien said she purchases between 1.5 and 3 tonnes of dried seaweed daily for domestic distribution and export markets.
Ho Tung Chinh, chairman of the Tam Hai Farmers' Association, said residents are encouraged to harvest seaweed sustainably by waiting until after May 15 and cutting the plants above the base to allow regeneration.
