Abstract

• The present study investigated the occurrence and abundance of zooplankton in Inya Lake, Kamayut Township, Yangon, from June 2023 to May 2024. The zooplanktons were collected monthly from the five study sites in Inya Lake; Site I (Approximately 90 m from the Restaurants), Site II (Approximately 240 m from Kan Thar Yar hospital), Site III (Approximately 500 m from Sailing and Rowing Club), Site IV (Approximately 120 m from U.S Embassy) and Site V (Approximately 240 m from Mya Kyune Thar Golf club). They were immediately preserved in 5% formalin after collection and identified based on their morphology and morphometric measurements. The results revealed that a total of 37 species of zooplankton comprising 24 species of rotifers belonging to 8 families and 10 genera, Cladocerans 8 species belonging to 4 families and 6 genera and Copepods 5 species, 4 families and 4 genera were recorded. The collected rotifers were identified and categorized into three sizes: large, small, and super small, based on their body length. The most abundant rotifer species were of small size. Among them, Brachionus calyciflorus was the most abundantly occurring species in the freshwater environment. The findings confirm that Inya Lake supports a diverse zooplankton community whose seasonal peaks (wet and cold seasons) and species composition are characteristic of productive freshwater bodies.