Biodiversity of Epibenthic Invertebrates in the Subtidal Mekong Estuaries, Southern Vietnam with Remarks on Decapod Assemblages

Epibenthic invertebrates in three estuaries of the Mekong River, namely Co Chien, Ba Lai, and Cua Dai, were sampled for ecological analysis in November 2022. The objectives of this research were to provide the first baseline survey of epibenthic communities in the Mekong estuaries and to describe more precisely the relationships between epibenthic characteristics and environmental parameters. In total, seven major taxa, including Bivalvia, Decapoda, Gastropoda, Isopoda, Molpadida, Stomatopoda, and Xiphosura were recorded in this estuarine system. The abundances of the epibenthic invertebrates range from 48 to 176 inds/1000 m². Decapos always occupy the highest numbers with a percentage ranging from 86‒95%. There are 24 decapod species were recorded in this study with the following as dominant families Palaemonidae, Penaeidae, and Paguridae. Our findings highlight that the diversity of epibenthic communities, particularly for decapods, is notably high; however, the epibenthic density is considerably low. Epibenthic density and diversity were significantly correlated with salinity, TDS, depth, and pH but also other factors may play a role. The assessment of epibenthic assemblage diversity and its correlation with environmental factors holds significant importance in the formulation of conservation strategies.