Fish Diversity, Ecological Functional Guilds and IUCN Conservation Status in the Lower Mekong River, Northeastern Thailand

Abstract

This study aimed to quantify spatial and seasonal variation in fish diversity, classify fish into ecological functional guilds, and assess conservation status using the IUCN Red List in the Mekong River across three provinces in northeastern Thailand: Loei, Nakhon Phanom, and Ubon Ratchathani. Fish sampling was conducted during three seasonal periods. A total of 84 fish species belonging to 61 genera and 21 families were recorded. The highest diversity was the family Cyprinidae, with 45 species, followed by the families Bagridae and Siluridae, each represented by six species. The assessment of species diversity and evenness indicated that the fish community exhibited a moderate level of diversity with a relatively even distribution of species. Classification of fish based on ecological functional guilds showed that most species belonged to group G3, which inhabits and spawns in the main river channel, accounting for 29 species. The conservation status assessment based on the International Union for Conservation of Nature (IUCN) Red List revealed that most species were categorized as Least Concern (LC), with 65 species, followed by Vulnerable (VU), with six species. One species was classified as Endangered (EN), namely Probarbus jullieni. The findings of this study provide important baseline information for fisheries management and biodiversity conservation in the Mekong River ecosystem of Thailand.