SPATIAL AND TEMPORAL DISTIRIBUTION OF BENTHIC OLIGOGHAETA IN EUPHRATES RIVER, MIDILLOF IRAQ

The present study discusses spatial and temporal distribution of aquatic oligochaetes community as sorted from macrobenthic fauna collected during River Euphrates in Iraq. Extending from Al-Musayab district ( S1), Saddat Al-Hindiah district (S2) to Al-Hindiah district ( S3) . Twelve species of oligochaetes ( 9 genera ; 3 families) were determined during study period . Highest individual number were recorded in S3 ( 9954.56 ind../m2) during Jan. 2014 and the lowest number were recorded in S3 ( 222.2 ind./m2 ) during Oct.2013. The highest average monthly dencity was recorded during Dec. 2013 and Jan 2014, while the highest site average density was recorded in S3. Tubificid worms made up the majority component of aquatic oligocheata in investigated area of the river specially Limnodrilus spp. which include four species Limnodrilus hoffmeisteri (Claparede1862), L. claparedeians (Ratzal 1869), L. profundicola (Verrill,1871 ) L. udekemianus (Claparede1862). Stylaria lacustris was the most abundant Naidid worms. This study recorded two species as new records on Euphrates river {Spirosperma ferox (Eisen,1879), Pristina jenkinae (Stephenson ,1931) } and one species as new record on Iraqi fauna{ Bothrioneurun pyrrhum (Marcur,1842)} .