SPECIES DIVERSITY OF ZOOPLANKTON IN THE COASTAL MUDFLATS OF AN GIANG PROVINCE, VIETNAM

Abstract

This study aimed to investigate the species composition and diversity of zooplankton communities in the coastal mudflat areas of An Giang province, Vietnam, by analyzing their distribution across representative coastal habitats. Sampling was conducted during the dry season in three typical habitats, including estuarine, intertidal, and subtidal zones. Samples were collected using a Juday plankton net (25 µm mesh size), preserved in 5% formalin, and examined under a light microscope for taxonomic identification and morphological characterization. A total of 12 zooplankton species were recorded, belonging to two main groups: Rotifera and Copepoda (phylum Arthropoda). Rotifers dominated the community with 9 species (75%), whereas copepods accounted for 3 species (25%). Common taxa included Brachionus sp., Keratella sp., Apocyclops sp., Paracalanus crassirostris, and Pseudodiaptomus incisus. Species composition varied among habitats, with higher richness observed in estuarine and intertidal zones compared to subtidal areas. Rotifers were widely distributed and consistently present across all habitats, while copepods tended to concentrate in deeper and more saline waters. The Shannon-Wiener diversity index (H′) ranged from 1.08 to 1.24, with the highest value recorded in the estuarine habitat (H′ = 1.24), followed by the intertidal zone (H′ = 1.20) and the lowest in the subtidal zone (H′ = 1.08). These findings provide baseline scientific data on zooplankton community structure in coastal mudflat ecosystems, supporting ecological monitoring, water quality assessment, and the sustainable use of indigenous plankton resources in aquaculture.