Preliminary Study On Rotifer Community Structure In The Guangzhou Segment Of River Pearl

The community structure of planktonic rotifers and the main environmental parameters were studied at the four sites (Zhongda port,Huangpu harbour,Beiting and Suishi) of the Guangzhou segment of River Pearl from April 2004 to April 2006. Main results are presented in the followings.1 71 species of rotifer belonging to 20 genera and 13 families were identified during the survey period. Filinia novaezealandiae,Lecane elegans and Lecane undulata were confirmed to be new records in China. The dominant species were Liliferotrocha subtilis, Anuraeopsis fissa, Brachionus angularis, Brachionus caudatus , Filinia novaezealandiae and Trichocerca pusilla.2 The highest rotifer density (5975 ind./L) was recorded at Zhongda Port in the beginning of December 2004. Mean rotifer densities ranged from 800 ind./L at Suishi to 1603 ind./L at Beiting.3 High rotifer densities appeared in the beginning of summer and the end of autumn, while low rotifer densities in the rainy season (flood period) and the late dry season, suggesting that the river discharge had important effect on the density fluctuation of rotifers.4 The difference in sampling methods affects the estimate of zooplankton species and standing crop, which in turn leads to variable outcome of zooplankton community structure.