Species composition and abundance of rotifers distributed in different water bodies along Hau river

Abstract

This study was conducted to assess the status the species composition and distribution of rotifers and their relationships with environmental factors along the Hau River at An Giang, Can Tho, Hau Giang and Soc Trang province to serve as database for further studies on rotifers. The study was conducted in the period of January to August 2018 with 2 sampling periods. Samplings were caried out in March (dry season) and June transitional period) at 10 sites on the Hau river. Samples taken consisted of zooplankton, water parameters including temperature, pH, salinity, transparency, velocity, dissolved oxygen (DO), total suspended solid (TSS), total dissolved solid (TDS), organic matter (BOD, COD), inorganic matter (NO3−, PO4 3−) and chlorophyll-a. These samples were collected through a cross section of the river. Positions of the sampling sites were recorded by a GPS device. The results showed that 52 species of rotifers were recorded in Hau river. The number of rotifer species was slightly higher in June compared to that in March with 42 and 39 species, respectively. Highest rotifer species number was recorded at midstream, followed by upstream and downstream. Mean density (±SD) of rotifer was 2,775.43 ± 2994.42 ind/m3. In the dry season the density was higher than in the transitional period. Highest density was recorded at the midstream with 3,094.28 ± 1562.24 ind/m3, followed by the downstream, 2,774.22 ± 5077.08 ind/m3 and lowest in the upstream with 2,351.50±1306.40 ind/m3.