Benthic invertebrate fauna in Ashtoum El Gamil protected area (Lake Manzalah), Egypt.

Macrobenthic and meiobenthic invertebrates samples were collected seasonally during 2010 from five stations in Ashtoum El Gamil protected area which located in the north western part of Lake Manzalah. Macrobenthic community was found including fifteen species belonging to three groups. Of these, 11 Mollusca, 2 Arthropoda and 2 Annelida. Some of them have a freshwater origin and others have marine origin. Mollusca has been ranked the first position, constituting about 68.5 % of the total population density (P. D.) of macrobenthic invertebrates, followed by Arthropoda and Annelida, constituting 28.7 % and 2.8 % respectively. The highest average standing crop was recorded in station 3. Macrobenthic fauna average value reached its maximum in winter in the whole area, while summer was the least productive season. Meiofauna community consisted of 3 main groups. Ostracoda was the first one, constituting 70.71 % of the total population of meiofauna followed by Foraminifera (27 %) and Nematoda (1.5 %). Meiofauna flourished during summer and spring in the area, while it reached its minimum levels during autumn and winter. Salinity and nature of the sediment were important factors affecting distribution and abundance of benthic invertebrates.