The diversity and traditional knowledge of seaweed in Thai An village, Nui Chua national park, Vietnam

Abstract

Thai An village is characterized by high seaweed diversity; however, local knowledge regarding its utilization remains limited despite long-term interactions. Seaweed samples collected within 1 meter of a transect line were presented to 33 informants, including traders, gatherers, and consumers, through semi-structured interviews in an ethnobotanical study. A total of 71 species were identified, comprising 28 red, 27 brown, and 16 green seaweed species, with species composition varying across five surveys. The highest diversity was recorded in March 2024 (39 species), whereas the lowest was observed in August 2023 (9 species). Sixteen seaweed species were reported to have traditional uses across seven categories: food, beverages, medicine, fertilizers, animal feed, economic activities, and ornamental purposes. Food was the most frequently cited use (10 species), followed by beverages (8 species). Preparation methods varied, particularly in the production of sweet jellies, which were mainly based on the species used. No significant differences were found in seaweed utilization based on gender, education level, occupation, or involvement in seaweed-related activities. Use Values ranged from 0.03 to 2.15, with Gelidiella acerosa, Hydropuntia eucheumoides, Sargassum spp., Porphyra sp., Betaphycus gelatinus, and Gracilaria salicornia exhibiting the highest values. Fidelity Level values ranged from 2.3 to 100.0, with the “food” and “beverage” categories receiving the highest scores. This study provides valuable insights into traditional knowledge associated with seaweed resources, contributing to the conservation of indigenous practices and fostering opportunities for local economic development, seaweed aquaculture, food security, and climate change mitigation.​