The Role ofAlien Polychaetes along theAlexandria Coast, Egypt

The alien polychaetes are widely distributed in the whole Mediterranean Sea as well as in the Egyptian waters. The objective of this study is to highlight the distribution and abundance of the alien polychaetes along the Alexandria coast, their contribution to the total polychaete community and the changes they caused in the community structure. Through monthly sampling polychaetes were collected at four sites of different ecological characteristics During June 2005 - May 2006 from hard substrates at 0.5-1m depth and from soft bottom of the intertidal zone. Ten alien species were recorded from the study area, five of them (Linopherus canariensis Langerhans, 1881, Loimia medusa Savigny in Lamarck 1818, Syllis schulzi Hartmann- Schroder 1960, Phyllodoce longifrons Ben-Eliahu 1972 and Leodice antennata Savigny in Lamarck, 1818) were found for the first time in the Egyptian waters. Six species were widely distributed in the study area demonstrating considerable different count on both the spatial and temporal scales, with total count fluctuating between 10 - 18810 ind/m 2 (individual/m 2 ), constituting 14.3% - 45.5% of the total polychaetes and peaks occurring in different times at the sampling sites. Syllis schulzi and Pseudoneries anomala were the major components, accounting for 53.4 and 41.5% of the alien polychaetes, and of pronouncedly less contribution was Linopherus canariensis (3.8%), in addition to occasional active contribution of Hydroides elegans and Loimia medusa, which displayed at times up to 22% and 19% respectively at some sampling sites.