Population dynamics of Rotifera in Ismailia Canal, Egypt

Abstract

Ismailia Canal is one of the most important tributaries of the River Nile in Egypt. The population dynamics of rotifers in three zones of Ismailia Canal were studied in spring and autumn 2011, in relation to some physical and chemical characteristics of water. A total of 40 rotifers’ species were identified, the dominant were Keratella cochlearis, Collotheca pelagica and Polyarthra vulgaris. Keratella cochlearis dominated in all the sampling sites and contributed 57.1% and 25.4 % of the total rotifers in spring and autumn. Brachionus was the most taxon-rich genus being represented by eight species. In autumn, rotifers population density and species richness were positively correlated with water temperature and transparency and a negative relation detected with electric conductivity in both seasons. But, in spring no clear relation was observed in response to the water physical and chemical characteristics and rotifers population dynamics which may be its occurrence in this season depend on algal abundance. The dominant rotifer species in Ismailia Canal and its two branches Suez and Port Said are eutrophic indicator species. Thus, the community composition of the rotifers indicate that, Ismailia Canal and its two branches are highly eutrophic and shows signs of partial pollution.