the role ofalien polychaetes along thealexandria coast, egypt

the alien polychaetes are widely distributed in the whole mediterranean sea as well as in theegyptian waters. the objective of this study is to highlight the distribution and abundance of the alienpolychaetes along the alexandria coast, their contribution to the total polychaete community and the changesthey caused in the community structure. through monthly sampling polychaetes were collected at four sitesof different ecological characteristics during june 2005 - may 2006 from hard substrates at 0.5-1m depth andfrom 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-schröder 1960, phyllodoce longifrons ben-eliahu 1972 and leodice antennata savigny in lamarck, 1818)werefound for the first time in the egyptian waters. six species were widely distributed in the study area demonstratingconsiderable different count on both the spatial and temporal scales, with total count fluctuating between 10- 18810 ind/m2 (individual/m2), constituting 14.3% - 45.5% of the total polychaetes and peaks occurring indifferent 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 linopheruscanariensis (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.